Standard Test Procedure RHD.bd

Government of the People’s Republic of BangladeshMinistry of Communications

Roads and Highways Department

STANDARD TEST PROCEDURES

MAY 2001

INSERT THE NEW

FOREWARD

SIGNED BY

FAZLUL HAQUE

STANDARD TEST PROCEDURES (STP)

Introduction

To enable roads and bridges to be built in accordance with the Roads and HighwaysDepartment’s Technical Specifications (Volume 3 of 4 of the Standard Tender Documents), it isnecessary for quality control tests to be carried out at both construction sites and regional testingcentres.

The results of these tests are intended to assist the Engineer in deciding whether or not aparticular item of work is satisfactory and to provide a permanent record to show the work hasbeen carried out in accordance with the Contract Specification.

To be of use to the field engineer the results of many of the tests detailed must be submitted assoon as possible after completion of the particular item of work, as any work which does notconform with the Contract Specification may be rejected by the Engineer.

The Standard Test Procedures detailed in this document are mandatory for the quality control ofroads constructed by the Roads and Highways Department. The RHD Technical Specificationswhen including a test make reference to this document and the tests are referred to by theirsection number and title, for example, STP 4.3 – Standard Compaction of Soil.

Standard Laboratory Test forms have been produced for the tests detailed in this document.Sample calculations are shown using these forms in the relevant sections of the document andcopies of the blank forms are available for downloading from the Roads and HighwaysDepartment’s Internet Web Site at www.rhdbangladesh.org under the section covering StandardTest Procedures. Alternatively a computer ‘ floppy disc’ containing copies of the forms can bepurchased from the Procurement Circle at RHD Sarak Bhaban, Ramna, Dhaka.

This manual covers all tests which are needed to be carried out at site or regional laboratories;however, other more specialist or complex tests may be required and these can be carried out atthe Bangladesh Road Research Laboratory and in this respect, or other matters concerningthese Standard Test Procedures, queries should be referred in the first instance to the Director,Bangladesh Road Research Laboratory, Paikpara, Mirpur, Dhaka.

I

Roads and Highways DepartmentBangladesh Road Research Laboratory

Table of Contents

CHAPTER 1 : DEFINITIONS, SYMBOLS AND UNITS

1.1 Scope...............................................................................................................1.11.2 Terminology......................................................................................................1.11.3 Definitions ........................................................................................................1.11.4 Greek Alphabet.................................................................................................1.51.5 Symbols and Units............................................................................................1.6

1.6 Conversion Factors and Useful Data .................................................................1.6

CHAPTER 2 : SAMPLING

2.1. General ............................................................................................................2.12.2 Sampling of Soils..............................................................................................2.12.3 Sampling of Bricks............................................................................................2.6

2.4 Sampling of Aggregates....................................................................................2.92.5 Sampling of Cement .......................................................................................2.122.6 Sampling of Concrete .....................................................................................2.132.7 Sampling of Bitumen.......................................................................................2.162.8 Sampling of Bituminous Materials ...................................................................2.17

2.9 Preparing and Transporting Samples..............................................................2.172.10 Sample Reception ..........................................................................................2.192.11 Sample Drying................................................................................................2.19

CHAPTER 3 : CLASSIFICATION TESTS

3.1 Determination of Moisture Content....................................................................3.13.2 Determination of Atterberg Limits ....................................................................3.113.3 Particle Size Distribution .................................................................................3.223.4 Determination of Organic Content...................................................................3.32

3.5 Standard Description and Classifications ........................................................3.34

CHAPTER 4 : DRY DENSITY - MOISTURE CONTENT RELATIONSHIPS

4.1 General Requirements ......................................................................................4.1

4.2 Sample Preparation..........................................................................................4.24.3 Standard Compaction using 2.5 kg Rammer .....................................................4.84.4 Heavy Compaction using 4.5 kg Rammer........................................................4.194.5 Vibrating Hammer Method ..............................................................................4.19

II

CHAPTER 5 : STRENGTH TESTS: CALIFORNIA BEARING RATIO AND DYNAMIC CONE PENETROMETER TEST

5.1 California Bearing Ratio (CBR) Test..................................................................5.1

5.2 Dynamic Cone Penetrometer (DCP) Test........................................................5.21

CHAPTER 6 : DETERMINATION OF IN-SITU DENSITY

6.1 Introduction.......................................................................................................6.16.2 Sand Replacement Method...............................................................................6.16.3 Core Cutter Method ........................................................................................6.10

CHAPTER 7 : TESTS FOR AGGREGATES AND BRICKS

7.1 Determination of Clay and Silt Contents in Natural Aggregates .........................7.17.2 Particle Size Distribution of Aggregates.............................................................7.57.3 Shape Tests for Aggregates .............................................................................7.97.4 Fine Aggregate : Density and Absorption Tests ...............................................7.15

7.5 Coarse Aggregate : Density and Absorption Tests ..........................................7.217.6 Aggregate Impact Value .................................................................................7.267.7 Aggregate Crushing Value and 10% Fines Value ............................................7.327.8 Tests for Bricks...............................................................................................7.39

CHAPTER 8 : TESTS OF CEMENT

8.1 Fineness of Cement..........................................................................................8.18.2 Setting Time of Cement ....................................................................................8.28.3 Compressive Strength of Cement .....................................................................8.5

CHAPTER 9 : TESTS ON CONCRETE

9.1 Slump Test .......................................................................................................9.1

9.2 Crushing Strength of Concrete ..........................................................................9.5

CHAPTER 10 : TEST FOR BITUMEN AND BITUMINOUS MATERIALS

10.1 Bitumen Penetration Test ...............................................................................10.110.2 Bitumen Softening Test ..................................................................................10.610.3 Specific Gravity Test of Bitumen ..................................................................10.1210.4 Bitumen Extraction Tests .............................................................................10.16

10.5 Flash Point and Fire Point Tests of Bitumen .................................................10.3310.6 Viscosity Test of Bitumen .............................................................................10.4110.7 Distillation of Cut-Back Asphaltic (Bituminous) Products ...............................10.5110.8 Float Test of Bitumen ...................................................................................10.57

III

CHAPTER 10 : TEST FOR BITUMEN AND BITUMINOUS MATERIALS

10.9 Marshall Stability and Flow ..........................................................................10.6010.10 Bulk Specific Gravity of Compacted Bituminous Mixtures Test .....................10.7610.11 Maximum Theoretical Specific Gravity of Paving ..........................................10.8110.12 Spray Rate of Bitumen .................................................................................10.86

CHAPTER 11 : STEEL REINFORCEMENT TESTS

11.1 General Requirements ...................................................................................11.1

11.2 Tension Test of Steel Reinforcing Bar ............................................................11.811.3 Bend Test of Reinforcing Bar .......................................................................11.14

CHAPTER 1 Standard Test ProceduresDefinitions, Symbols and Units

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CHAPTER 1

DEFINITIONS, SYMBOLS AND UNITS

1.1 Scope

This standard sets out the basic terminology, definitions, symbols and units used in the variousparts of the manual, and refers specifically to soils, although some terms may also be applicablewhen testing other materials.

Only the terms commonly in use and most likely to be met in the more routine tests on soils havebeen included.

Conversion factors and other useful data are also included.

1.2 Terminology

The following terminology applies to the soil testing standards.

1.2.1 Soil. An assemblage or mixture of separate particles, usually of mineral compositionbut sometimes of organic origin, which can be separated by gentle mechanical meansand which includes variable amounts of water and air (and sometimes other gases). Asoil commonly consists of a naturally occurring deposit, but the term is also applied tomade ground consisting of replaced natural soil or man-made materials exhibitingsimilar behaviour, e.g. crushed brick, crushed rock, pulverised fuel ash or crushedblast-furnace slag.

1.2.2 Cohesive soil. Soil which because of its fine-grained content will form a mass whichsticks together at suitable moisture contents.

1.2.3 Cohesionless soil. Granular soil consisting of particles which can be identifiedindividually by the naked eye or by using a magnifying glass, e.g. gravel, sand.

1.3 Definitions

1.3.1 Sample. A portion of soil taken as being representative of a particular deposit orstratum.

1.3.2 Specimen. A portion of a sample on which a test is carried out.

1.3.3 Sampling. The selection of a representative portion of a material.

1.3.4 Quartering. Reducing the size of a large sample of material to the quantity required fortest by dividing a circular heap, by diameters at right angles, into four more or lessequal portions, removing two diagonally opposite quarters, and thoroughly mixing thetwo remaining quarters together so as to obtain a truly representative half of the originalmass. The process is repeated until a sample of the required size is obtained.

1.3.5 Riffling. The reduction in quantity of a large sample of material by dividing the massinto two approximately equal portions by passing the sample through an appropriatelysized sample divider (“riffle box”). The process is repeated until a sample of therequired size is obtained. When dividing some coarse-grained materials a combinationof quartering and riffling methods may be necessary on different sized fractions of thesample.


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1.3.6 Dry soil. Soil that has been dried to constant mass at a temperature of 1050C to1100C. Other drying temperatures. e.g. 600C, may be specified for particular tests.

1.3.7 Moisture content (w). The mass of water which can be removed from the soil, usuallyby heating at 1050C, expressed as a percentage of the dry mass. The term watercontent is also widely used.

1.3.8 Liquid limit (LL). The moisture content at which a soil passes from the liquid to theplastic state, as determined by the liquid limit test.

1.3.9 Plastic limit (PL). The moisture content at which a soil on losing water passes fromplastic state to semi-brittle solid state and becomes too dry to be in a plastic conditionas determined by the plastic limit.

1.3.10 Plasticity index (PI). The numerical difference between the liquid limit and the plasticlimit of a soil :

PI = LL – PL

1.3.11 Non-plastic. A soil with a plasticity index of zero or one on which the plastic limitcannot be determined.

1.3.12 Liquidity index (IL). The ratio of the difference between moisture content and plasticlimit of a soil, to the plasticity index :

IL = w - PL

PI

1.3.13 Shrinkage limit (ws). The moisture content at which a soil on being dried ceases toshrink.

1.3.14 Linear shrinkage (LS). The change in length of a bar sample of soil when dried fromabout its liquid limit, expressed as a percentage of the initial length.

1.3.15 Bulk density (ρ). The mass of material (including solid particles and any containedwater) per unit volume including voids.

1.3.16 Dry density (ρd). The mass of the dry soil contained in unit volume of undried material :

ρρ

d = 100

100 + w

1.3.17 Particle density (ρs). The average mass per unit volume of the solid particles in asample of soil where the volume includes any sealed voids contained within the solidparticles.

1.3.18 Particle size distribution. The percentages of the various grain sizes present in a soilas determined by sieving and sedimentation.

1.3.19 Test sieve. A sieve complying with a recognised Standard.

1.3.20 Cobble fraction. Solid particles of sizes between 200 mm and 60 mm.


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1.3.21 Gravel fraction. The fraction of a soil composed of particles between the sizes of 60mm and 2 mm. The gravel fraction is subdivided as follows :

Coarse gravel 60 mm to 20 mmMedium gravel 20 mm to 6 mmFine gravel 6 mm to 2 mm

1.3.22 Sand fraction. The fraction of a soil composed of particles between the sizes of2.0 mm and 0.06 mm. The sand fraction is subdivided as follows :

Coarse sand 2.0 mm to 0.6 mmMedium sand 0.6 mm to 0.2 mmFine sand 0.2 mm to 0.06 mm

1.3.23 Silt fraction. The fraction of a soil composed of particles between the sizes of 0.06 mmand 0.002 mm. The silt fraction is subdivided as follows :

Coarse silt 0.06 mm to 0.02 mmMedium silt 0.02 mm to 0.006 mmFine silt 0.006 mm to 0.002 mm

1.3.24 Clay fraction. The fraction of a soil composed of particles smaller in size than0.002 mm.

1.3.25 Fines fraction. The fraction of a soil composed of particles passing a 63 µm test sieve.Note that this includes all material of silt and clay sizes, and a little fine sand. For mostpractical purposes, the limiting sieve size can be taken to be 75 µm.

1.3.26 Voids. The spaces between solid particles of soil.

1.3.27 Voids ratio (e). The ratio between the volume of voids (air and water) and the volumeof solid particles in a mass of soil:

e = - 1 (see 1.3.16 and 1.3.17)s

d

ρρ

1.3.28 Porosity (n). The volume of voids (air and water) expressed as a percentage of thetotal volume of a mass of soil.

n e

l =

+ e x 100 (%)

1.3.29 Saturation. The condition in which all the voids in a soil are completely filled withwater.

1.3.30 Degree of saturation (Sr). The volume of water contained in the void spaces betweensoil particles, expressed as a percentage of the total voids:

S = w

(%) (see 1.3.7; 1.3.17; 1.3.27)rsρ

e

1.3.31 Compaction. The process of packing soil particles more closely together by rolling orother mechanical means, thus increasing the dry density of the soil.

1.3.32 Optimum moisture content. The moisture content at which a specified amount ofcompaction will produce the maximum dry density.


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1.3.33 Maximum compacted dry density. The dry density obtained using a specified amountof compaction at the optimum moisture content.

1.3.34 Relative compaction. The percentage ratio of the dry density of the soil to themaximum compacted dry density of a soil when a specified amount of compaction isused.

1.3.35 Dry density / moisture content relationship. The relationship between dry densityand moisture content of a soil when a specified amount of compaction is used.

1.3.36 Percentage air voids (Va). The volume of air voids in the soil expressed as apercentage of the total volume of the soil :

V = 1 - + w

100 100 (%)a

d

w

w

s

ρρ

ρρ

(see 1.3.7; 1.3.16; 1.3.17; 1.3.37)

1.3.37 Air voids line. A line on a graph showing the dry density / moisture contentrelationship for soil containing a constant percentage of air voids. The line can becalculated from the equation :

ρ ρ

ρ

d = 1 -

V100

1 +

w100

w

a

s

where, ρd is the dry density of the soil (Mg/m3);ρw is the density of water (Mg/m3);Va is the volume of air voids in the soil, expressed as a percentage of the total

volume of the soil;ρs is the particle density (Mg/m3);w is the moisture content, expressed as a percentage of the mass of dry soil.

1.3.38 Saturation line (zero air voids line). A line on a graph showing the dry density /moisture content relationship for soil containing no air voids. It is obtained by putting Va= 0 in the equation given in definition 1.3.37.

1.3.39 Limiting densities. The dry densities corresponding to the extreme states of packing(loosest and densest) at which the particles of a granular soil can be placed.

1.3.40 Maximum density (ρdmax). The maximum dry density at the densest practicable stateof packing of particles of a granular soil.

1.3.41 Minimum density (ρdmin). The minimum dry density at the loosest state of packing ofdry particles which can be sustained in a granular soil.

1.3.42 Maximum (minimum) porosity or voids ratio. The porosity or voids ratiocorresponding to the minimum (maximum) dry density as defined above.

1.3.43 California bearing ratio (CBR). The ratio (expressed as a percentage) of the forcerequired to cause a circular piston of 1935 mm2 cross-sectional area to penetrate thesoil from the surface at a constant rate of 1 mm/min, to the force required for similarpenetration into a standard sample of crushed rock. The ratio is determined atpenetrations of 2.5 mm and 5.0 mm, and the higher value is used.


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1.3.44 Penetration resistance. The force required to maintain a constant rate of penetrationof a probe, e.g. a CBR piston, into the soil.

1.3.45 Consolidation. The process whereby soil particles are packed more closely togetherover a period of time by application of continued pressure. It is accompanied bydrainage of water from the voids between solid particles.

1.3.46 Pore water pressure (uw). The pressure of the water in the voids between solidparticles.

1.3.47 Excess pore pressure. The increase in pore water pressure due to the application ofan external pressure or stress.

1.3.48 Swelling. The process opposite to consolidation, i.e. expansion of a soil on reductionof pressure due to water being drawn into the voids between particles.

1.3.49 Swelling pressure. The pressure required to maintain constant volume, i.e. to preventswelling, when a soil has access to water.

1.3.50 Permeability. The ability of a material to allow the passage of a fluid. (Also known ashydraulic conductivity.)

1.3.51 Piping. Movement of soil particles carried by water eroding channels through the soil,leading to sudden collapse of soil.

1.3.52 Erosion. Removal of soil particles by the movement of water.

1.3.53 Dispersive (erodible) clays. Clays from which individual colloidal particles readily gointo suspension in particularly still water.

1.3.54 Shear strength. The maximum shear resistance which a soil can offer under definedconditions of effective stress and drainage.

1.4 Greek Alphabet

A number of the symbols traditionally used in soils testing are taken from the Greek alphabet.This is reproduced below for reference purposes:

Capital Small Name Capital Small NameA α alpha N ν nuB β beta Ξ ξ xiΓ γ gamma O ο omicron∆ δ delta Π π piΕ ε epsilon P ρ rhoZ ζ zeta Σ σ sigmaH η eta T τ tauΘ θ theta Y υ upsilonI ι iota Φ φ phiK κ kappa X χ chiΛ λ lambda ψ ψ psiM µ mu Ω ω omega


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1.5 Symbols and Units

The following symbols are used in the standards in the manual. The symbols generally conformto international usage. The units are those generally used. An asterisk indicates that no unit isused.

Term Symbol UnitMoisture content w %Liquid limit LL %Plastic limit PL %Shrinkage limit ws %Plasticity index PI %Liquidity index IL *Bulk density ρ Kg/m3

Dry density ρd Kg/m3

Particle density ρs Kg/m3

Density of water ρw Kg/m3

Voids ratio e *Porosity n %Degree of saturation Sr %Percentage air voids Va %Maximum dry density ρdmax. Kg/m3

Minimum dry density ρdmin. Kg/m3

Maximum voids ratio emax. *Minimum voids ratio emin. *California bearing ratio CBR %Mean particle diameter D mm or µmPercentage by mass finer than D K %Elapsed time t minutes or secondUnconfined compressive strength qu kPa

1.6 Conversion Factors and Useful Data

1.6.1 General. The modern form of the metric system is known as the SI system.

SI is the accepted abbreviation for Systeme International d’Unites (International Systemof Units), the system finally agreed at an international conference in 1960.

1.6.2 Conversion factors. Conversion factors for SI and imperial units are given in Table 1.6.1.


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Table 1.6.1 CONVERSION FACTORS, IMPERIAL AND SI UNITS.

Imperial to SI SI to ImperialLength 1.609

0.304825.4

kmm

mm

: mile: foot (ft): inch (in)

0.62153.281

0.03937Area 0.4045

0.09590645.2

hectare (ha)m2

mm2

: acre: square foot: square inch

2.47110.76

0.001550Volume 0.764

0.028324.5463.78528.3216.39

16387

m3

m3

litrelitrelitre

mlmm3

: cubic yard: cubic foot: gallon (UK): gallon (USA): cubic foot: cubic inch: cubic inch

1.308935.34

0.22000.2642

0.035310.06102

Mass 1.0160.4536453.628.35

Mg (tonne)kggg

: ton: pound (lb): pound: ounce (oz)

0.98422.205

0.03527Density 0.01602 Mg/m3 (g/cm3) : pound per cubic foot 62.43Force 9.964

4.448kNN

: ton force: pound force

0.10040.2248

Pressure 0.047886.89547.88

kN/m2 (kPa)kN/m2

N/m2 (Pa)

: lb f/sq ft: lb f/sq in: lb f/sq ft

20.890.1450

0.02089NOTE

1 litre (L) = 1,000 cm3

= 1,000 mL

1 kN = 1,000 N

1MN/m2 = 1 N/mm2

1 tonne = 1,000 kilograms(kg)1 kg = 1,000 grams (g)1 kgf = 9.81 N1 tonne f = 9.81 kN

1 Megagram (Mg)/m3 = 1,000 kg/m3

1 Megagram/m3 = 1 g/cc

Examples

To convert imperial to SI, e.g. to convert feet to metres, multiply number of feet by 0.3048.

To convert SI to imperial, e.g. to convert metres to feet, multiply number of metres by 3.281.

1.6.3 Useful data and information

1.6.3.1 Standard gravity. The international standard acceleration due to the earth’s gravity isaccepted as;

g = 9.80665 m/s2

although it varies slightly from place to place. For practical purposes g = 9.81 m/s2, theconventional reference value used as a common basis for measurements made on theEarth.

1.6.3.2 Mass. The kilogram (kg) is equal to the mass of the international platinum prototypekept by Bureau International des Poids et Measures (BIPM) at Sevres. It is the onlybasic quantity to be a multiple unit :

1 kg = 1,000 g (grams)


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There is no SI unit of ‘weight’. When ‘weight’ is used to mean the force due to gravityacting on a mass, the mass (kg) must be multiplied by g(9.81 m/s2) to give the force inNewton’s (N).

1.6.3.3 Density. The megagram per cubic metre (Mg/m3) is the density unit adopted for soilmechanics. It is 1000 times larger than the kilogram per cubic metre, the basic SI unit,and is equal to one gram per cubic centimetre :

1 Mg/m3 = 1 g/cm3

= 1,000 kg/m3

The density of soil particles (particle density) is expressed in Mg/m3, which isnumerically equal to the specific gravity (now obsolete). Using Mg/m3, the density ofwater is unity.

1.6.3.4 Force. The Newton (N) is that force which, applied to a mass of 1 kilogram, gives it anacceleration of 1 metre per second per second.

1 N = 1 kg m/s2

The kilonewton (kN) is the force unit most used in soil mechanics:

1 kN = 1,000 N= approximately 0.1 tonne f or 0.1 ton f

1.6.3.5 Pressure and stress. The Pascal (Pa) is the pressure produced by a force of 1Newton applied, uniformly distributed, over an area of 1 square metre.

The Pascal has been introduced as the pressure and stress unit, and is exactly equalto the Newton per square metre:

1 Pa = 1 N/m2

In dealing with soils the usual unit of pressure is kilonewton per square metre (kN/ m2),or kilopascal:

1 kN/m2 = 1 k Pa = 1,000 N/m2

The bar is not an SI unit but is sometimes encountered in fluid pressure:

1 bar = 100 kN/m2 = 100 k Pa = 1000 mb (millibars)


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1.6.3.6 Comparison of BS and ASTM sieve sizes

Sieves to ASTM D422BS sieve aperture sizeNearest designation Aperture size

75 mm635037.528-2014106.353.35-21.18-600 µm425300-212150-7563

3 inch21/2 inch2 inch11/2 inch-1 inch¾ inch-3/8 inch-No. 4No. 6No. 8No. 10No. 16No. 20No. 30No. 40No. 50No. 60No. 70No. 100No. 140No. 200No. 230

75 mm63.550.838.1

25.419.05

9.52

4.753.352.362.001.18850 µm6004253002502121501067563

CHAPTER 2 Standard Test ProceduresSampling

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CHAPTER 2

SAMPLING

2.1 General

This standard deals with the sampling of soils, bricks, aggregates, cement, concrete, bitumenand bituminous materials. A sample is a small quantity of material which represents in every way,a much larger quantity of material. In taking a sample we are not usually attempting to select thebest or worst examples of the materials used but the typical material as used in the works.Sampling should therefore be done on a completely random basis and personal preferencesshould not be allowed to interfere with the selection.

2.2 Sampling of Soils

Samples are of one of two main types: disturbed or undisturbed.

2.2.1 Disturbed samples. Usually taken with a pick and shovel, scoop or other appropriatehand tool, care should be taken to prevent coarse material from rolling off the sides ofthe tool, which will leave behind too fine a sample.

Disturbed samples can be taken in test pits, trenches or similar excavations, augerholes and boreholes. Disturbed samples can also be taken from stockpiles of materialand from material laid during road construction. Small disturbed samples can also beavailable as the result of carrying out other work, e.g. samples from the StandardPenetration Test (SPT) shoe, and samples from the cutting shoe of undisturbed sampletubes.

2.2.1.1 Techniques. The sampling technique employed will be influenced by factors such asthe type and quantity of material being sampled, the equipment available, physicalconstraints of the sampling location, the intended use of the material being sampled.

2.2.1.1.1 Test pits. Based upon the changes in moisture condition, colour consistency, soil type,structure etc., the sides of the test pit are inspected to their full depth and anyobservable change is recorded with depth. Any vegetation growing around the upperedge of the test pit should be removed. Now every distinguishable gravel, soil or sandlayer should separately sampled by holding a spade or canvas sheet at the lower levelof the layer against the side of the pit and by cutting a sheer groove to the full depth ofthe layer with a pick or spade. If the test pit had been dug sometimes before, thenweathered material should be removed from the surface before sampling. The materialobtained in this way should be placed in sample bags. The canvas sheet may also bespread out on the floor of the test pit if this is more convenient. Once all the layers havebeen sampled, all of the material from a particular layer must be combined on either aclean, hard, even surface or on a canvas sheet and properly mixed with a spade. Thematerial sampled should not be contaminated with other material.

Samples should preferably be sealed in airtight tins and should fill the tin completely.Duplicate or even triplicate samples should be taken. If the bulk sample is too large,quarter or riffle out into sample bags a representative sample of the layer as explainedearlier. The sample bags must be clearly and indelibly marked, so that the samples canbe identified in the laboratory. All test pits should be properly fenced to safeguardvillagers and animals.


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Caution: It is recommended that in any case no excavation deeper than 1.5m should bemade unless:

a) It is properly propped and bracedb) The gradient of the sides is at least equal to the natural angle of repose of the soil.c) It is in firm rock.

2.2.1.1.2 Stockpiles. When sampling from a stockpile the material on the top and sides of thepile must not be used as this is generally coarser than the interior of the stockpile. Thecorrect procedure is to dig small holes in the stockpile (Figure 2.2.1) and sample thematerial from the base of these holes. At least ten holes must be made at differentplaces on the stockpile and the materials obtained should be thoroughly mixedtogether. However, stockpiles are often scraped together in natural material withbulldozers, in which case it is better to wait until the stockpile has been completedbefore taking samples. Samples will be carried out using hand tools. Sampling can alsobe done using a mechanical loader-digger (in large stockpiles). Samples may becollected by using two shovels perpendicularly, one to prevent material falling on to thesamples and one to clean off and take the sample (Figure 2.2.2). Samples may also becollected by digging a groove from the top to the bottom of the stockpile (Figure 2.2.3).

Table 2.2.1Type of Test Soil Group*

Fine-grained

Medium-grained

Coarse-grained

Moisture contentAtterberg limitsParticle size distribution (sieving)Particle size distribution (sedimentation)Particle densityMDD testCalifornia bearing ratiopH value

50 g1 kg150 g250 g1.5 kg80 kg6 kg150 g

350 g1.5 kg2.5 kg100 g**2 kg80 kg6 kg600 g

4 kg2.5 kg17 kg100 g**4 kg80 kg12 kg3.5 kg

Mass of sample required for each test on disturbed samples is given in Table 2.2.1.These masses include some allowance for drying, wastage and rejection of stoneswhere required. Multiply these masses by the number of tests required. Whereappropriate, these masses assume that soils are susceptible to crushing.

** Sufficient to give the stated mass of fine-grained material.* Soil group

i) Fine-grained soils: Soils containing not more than 10% retained on a 2 mm testsieve.

ii) Medium-grained soils: Soils containing more than 10% retained on a 2 mm testsieve but not more than 10% retained on a 20 mm test sieve.

iii) Coarse-grained soils: Soils containing more than 10% retained on a 20 mm testsieve but not more than 10% retained on a 37.5 mm test sieve.

A soil shall be regarded as belonging to the finest-grained group as appropriate underthe above definitions.

2.2.1.1.3 Road pavement layers. When sampling from a partly constructed road pavement, forexample in crushed brick consolidation work, several small areas should be marked outand all the material must be collected from the excavated holes or trenches of eacharea. Care must be taken to ensure all the fine material is collected by using small toolslike brushes. Undisturbed samples are not generally taken in roadwork layers. Core-cutters used primarily in fine grained soils for in-situ density determination can alsoprovide an undisturbed sample.


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2.2.2 Undisturbed samples. It is extremely difficult to obtain a truly “undisturbed” sample.Samples generally described as undisturbed can be taken in the form of excavatedblocks, from which test specimens are later prepared, or in metal tubes fitted withsharpened cutting shoes. Sample tubes of this type are driven or jacked into the groundusing a variety of methods and the sample are more frequently taken in boreholesusing machine-operated equipment, but can also be obtained in test pits using hand-operated equipment.

2.2.2.1 Techniques

2.2.2.1.1 Block samples. Cohesive material in test pits or other locations can be sampled inblocks by carefully cutting away surrounding material and then undercutting the blockto remove it.

2.2.2.1.2 Samples in moulds and tubes. Metal tubes for taking undisturbed samples arecommonly 75 mm or 100 mm φ and 450 mm long (known as U3 or U4 tubes) or 38 mmφ and 230 mm long. The latter are convenient for use in test pits, when they can bedriven by using a hammer or preferably by a driving dolly. On ejection and trimming,the samples are suitable sizes for triaxial testing. The larger sample tubes are fittedwith detachable cutting shoes and are generally driven using mechanised equipment orhand-operated hammering device. Considerable care is required to maintain theverticality of the tube when driving it. Samples in tubes or block sample should becarefully waxed after removing just enough of the top of the sample with a palette knifeto form a flat surface.

2.2.3 Labeling sample. The sample must be comprehensively labeled. The label shouldinclude information from the following list, as appropriate;

a) Name of the projectb) Name of the samplerc) Date and time of samplingd) Location within project: chainage; offset; carriageway; construction area, etc.e) Depth of sample below reference datum, e.g. finished road levelf) Sample numberg) Description of the layerh) Description of the materiali) Test pit; borehole; auger hole numberj) Type of samplek) Sampling methodl) Supplier’s namem) Source of materialn) Number and type of container(s), and the number(s) with which the containers are

markedo) How samples are being sentp) Registration number of sampled truckq) Additional information, e.g. how the material was processed before sampling.

Metal tubes should be labeled on the side of the tube and not on the end cap. The endof the metal tube marking the top of the stratum should be so marked (i.e. with a T).The present system uses pre-printed ‘Sample Record Cards’, shown as Form 2.2.1.


MAY 2001 Page 2.5


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2.3 Sampling of Bricks

2.3.1 Scope. The scope of this standard is to provide methods of sampling bricks withoutbias and to give guidance as to the frequency and size of samples required for testing.The physical form of the consignment of bricks will normally dictate the choice andmethod of sampling.

No special equipment is required for sampling bricks.

2.3.2 Sampling methods. The sample may be drawn either by a) random sampling; or b)stratified sampling.

1. Sampling in motion

Whenever practicable a sample shall be taken whilst the bricks are being moved forexample during loading or unloading. The lot shall be divided into a number ofconvenient portions (not less than ten) such that when equal number of bricks aredrawn from each of these portions the number of bricks required for the inspection andtesting is provided.

2. Stacked materials

The number of bricks required for the tests should be sampled from a consignment ofnot more than 15,000 units for machine-made bricks and 5,000 units for hand-madebricks. The number of bricks required for all the various tests is detailed in Table 2.2.The bricks should be sampled at random so that each brick in the stack or stacks hasan equal chance of being chosen, including those bricks within the stacks. This mayrequire the dismantling of part of the stack in order to reach the bricks inside. This willbe difficult unless the stacks are small. If possible, an equal sub-sample of not morethan 4 bricks should be taken from at least 6 real or imaginary similarly-sized sectionsof the consignment.

3. Brick soling

Bricks laid as whole bricks such as in herring bone paving or in shoulder work shouldbe sampled from an area of one square metre marked on the road. All whole brickswithin the marked area should be returned to the laboratory as one sample. Severalsuch areas may require to be marked out in order to collect the number of bricksrequired for the various tests.

4. Crushed brick

Crushed brick laid as a road pavement layer should be sampled in accordance with2.2.1.1.3. It is most important that all fine material is removed from the test hole.

2.3.3 Treatment of samples. When the sample is to provide bricks for more than one teststhe total number shall be collected together and then divided by taking bricks at randomfrom within the total sample to form each successive sub-sample. Crushed bricks maybe riffled or quartered if necessary before transportation, provided that therequirements for minimum test sample weights are met.

2.3.4 Number of bricks required

Table 2.3.1 gives a guide as to the number of brick required against the specified test.


MAY 2001 Page 2.7

Table 2.3.1 Number of bricks required for testing

Purpose Number of bricks required for sample

Dimensional checksSoluble salt contentCompressive strengthWater absorption

24101210

2.3.5 Sample identification. The following information should be clearly indicated on thesampling certificate by the sampling personnel.

a) Sampling agentb) Contract name / work namec) Client named) Where the bricks will be usede) Supplier of bricksf) Date of manufactureg) Type of brickh) Size of consignmenti) Type of test required.

A sampling certificate is shown as Form 2.3.1.


MAY 2001 Page 2.8

Form 2.3.1


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2.4 Sampling of Aggregates

2.4.1 Definitions

a) Batch. A definite quantity of some commodity manufactured or produced underconditions which are presumed uniform.

b) Sampling increment. A quantity of material taken at one time from a larger body ofmaterial. When sampling aggregates, the material taken by single operation of ascoop should be treated as a sampling increment.

c) Bulk sample. An aggregation of the sampling increments.d) Laboratory sample. A sample intended for laboratory inspection or testing.e) Test portion. The material used as a whole in testing or inspection.

2.4.2 Equipment

a) A small scoop, to hold a volume of at least 1 L (about 1.5 kg). This scoop is usedfor sampling aggregates of nominal sizes less than 5mm.

b) A large scoop, to hold a volume of at least 2 L (about 3 kg.). This scoop is used forsampling any grading of aggregate but is required particularly for aggregates ofnominal sizes greater than 5mm.

c) Containers, clean and non-absorbent for collecting the increments of a sample.d) Containers, clean and impervious for collecting samples for sending to the

laboratory. They should be durable and at least 100 micron thick.e) A sample divider, appropriate to the maximum size to be handled. A riffle box is

suitable or a flat shovel and a flat metal tray for use in quartering.

2.4.3 Procedure for sampling coarse, fine and all-in aggregate

a) Only an experienced person should be allowed to sample.b) Obtain a bulk sample by collecting, in the clean containers, sufficient number of

increments to provide the required quantity of aggregate for all the tests to bemade. However, the number of increments should be not less than those given inTable 2.4.1.

Table 2.4.1 Minimum number of sampling increments

Nominal size ofaggregate

Nominal size ofsamplingincrements

Nominal size ofsamplingincrements

Approximate minimummass for normal densityaggregate kg.

Large scoop Small scoop28 mm and larger 20 - 505 mm to 28 mm 10 - 255 mm and smaller 10 half scoops 10 10

c) Take increment from different parts of the batch in such a way as to represent theaverage quality.

d) When sampling from heaps of aggregates, take the required number of incrementsfrom positions evenly distributed over the whole surface of the heap.

e) When sampling from ground level, care should be taken to avoid contamination ofthe material.

f) When sampling form material in motion, calculate the sampling times to give therequired number of sampling increments, ensuring that they are randomlydistributed throughout the batch of aggregate.

g) When sampling from a falling stream of aggregate, take increments from the wholewidth of the stream.

h) When sampling from a conveyor belt, stop the conveyor at appropriate times andtake all the material from a fixed length of the conveyor.


MAY 2001 Page 2.10

i) Combine all the increments and either dispatch the bulk sample or reduce it andthen dispatch the smaller sample for testing.

j) Never sample manually form a moving conveyor.

2.4.4 Reduction of sample. It is sometimes necessary to reduce the mass of bulk sample atsite substantially. This shall be done in such a way to preserve at each stage arepresentative part of the bulk sample. The reduction of sample should be done inaccordance with 2.9.1.1.

2.4.5 Dispatching of samples. The samples should be transferred completely to containerswhich shall then be sealed for dispatch. Individual packages should preferably notexceed 30 kg.

a) Information accompanying the samples.

Each sample should contain a card, suitably protected from damage by moistureand abrasion, giving details of the dispatcher and the description of the material.

b) Sampling certificate

Each sample, or group of samples from a single source, shall be accompanied by acertificate, from the person responsible for taking the sample. The certificate shallinclude as much as is appropriate of the following information.

i.) Name of testing agentii.) Client nameiii.) Contractor’s nameiv.) Contract namev.) Name and location of sourcevi.) Date and time of samplingvii.) Method of samplingviii.) Identification numberix.) Description of samplex.) Tests requiredxi.) Any other information that may be useful to the testerxii.) Name and signature of sampler



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2.5 Sampling of Cement

2.5.1 Introduction. In a general sense of the word, cement can be described as a materialwith adhesive and cohesive properties which make it capable of bonding mineralfragment into a compact whole mass. The main components of cement are compoundsof lime. One of the properties of cements is to be able to set under water by virtue of achemical reaction with the water. In civil engineering cement is normally confined tocalcareous, hydraulic cement. The variability of the proportions of the individual mineralcontent in the cement renders it to different behaviours in both chemical and physical.

Table 2.5.1 lists a number of cements and their designation.

Table 2.5.1 Main types of Portland cement

General description ASTM descriptionOrdinary PortlandRapid-hardening PortlandExtra rapid-hardening PortlandLow heat PortlandModified cementSulphate-resisting cementWhite PortlandSlag cement

Type IType III

Type IVType IIType V

Type S

2.5.2 Scope. This test provides methods for sampling hydraulic cements for testing. Theimportance of sampling has already been underlined in the introduction.

2.5.3 Equipment. No special equipment is required for sampling cements other than thefollowing:

a) Square mouthed shovel; size 2 in accordance with BS 3388.b) Suitable flexible container capable of collecting cement from the nozzle of a pump.c) Other suitable sealable containers.

Note. Containers to be used for sampling cement should be watertight and waterresistant in order to prevent water ingressing into the sample.

2.5.4 Methods

2.5.4.1 Sampling from concrete batch plant

2.5.4.1a Bulk cement

a.1 The flexible container is fitted around the discharge nozzle of the silo and cementis allowed to flow into it.

a.2 The flexible container is fitted around the discharge nozzle of the cement haulagetruck and cement is allowed to flow into it before discharge into the silo.

2.5.4.1b Bagged cement

Using the random numbers method of sampling decide on the size of a lot and take atrandom one bag of cement to represent that lot.

2.5.5 Rate of sampling. The rate of sampling is governed by the particular tests required bythe specification. Normally the manufacturer delivers cement in batches. One sample isnormally taken from each batch.


MAY 2001 Page 2.13

2.5.6 Test type requirement. For pre-construction approval of cement all tests such aschemical composition, physical properties of: fineness, setting times and compressivestrengths are normally required. Upon approval of the cement type, the supplier andmanufacturer, cement is procured. The tests required to be carried out to confirmcontinuous quality during construction are limited due to the length of the tests,however, samples from each batch, for each type of cement, from each supplier fromeach delivery are taken for routine testing:

a) compressive strengthb) initial and final setting timesc) fineness modulus

Other physical tests and chemical tests are normally required once per month fromeach manufacturer, for each type of cement.

2.5.7 Sampling certificates. A sampling certificate should be issued every time samples ofcement are delivered or collected for sampling. The certificate should include at leastthe following information:

a) Name of testing agencyb) Clientc) Manufacturerd) Cliente) Cement typef) Location of sampleg) Sample unique identification numberh) Name and signature of sampleri) Purpose of sampling (test types to be performed)j) Date of samplingk) Any other relevant information

2.6 Sampling of Concrete

2.6.1 Scope. The purpose of this test is to provide methods which could be used on site forobtaining from a batch of fresh concrete, representative samples of the quantityrequired for carrying out the required tests and for making test specimens.

2.6.2 Definitions

a) Batch. The quantity of concrete mixed in one cycle of operations of a batch mixer,or the quantity of concrete conveyed ready-mixed in a vehicle, or the quantity ofconcrete discharged during 1 min. From a continuous mixer.

b) Sample. The quantity of concrete, consisting of a number of standard scoopfuls,taken from a batch of concrete.

c) Standard scoopful. The quantity of concrete taken by a single operation of thescoop, approximately 5 kg mass of normal weight concrete.

2.6.3 Apparatus

a) Scoop, made from minimum 0.8 mm thick non-corrodible metals suitable for takingstandard scoopfuls of concrete.

b) Container for receiving concrete from a scoop, made of plastic or metal, of 9Lminimum capacity.

c) Sampling tray, minimum dimensions 900 mm x 900 mm x 50 mm deep, of rigidconstruction made from a non-absorbent material not readily attacked by cementpaste.

d) Square mouthed shovel; size 2 in accordance with BS 3388.


MAY 2001 Page 2.14

2.6.4 Sampling procedure. Estimate the number of scoopfuls required for the test(s) byreference to Table 2.6.1.

Note. If a shovel is used or other defined apparatus, correlate between the quantity ofthe scoop and the quantity of the shovel.

Note. When sampling from a batch mixer or ready-mixed concrete truck disregard thevery first part and the very last part of the discharge. Preferably sample from the middlethird of the batch.

Note. If the batch to be sampled has been deposited in a heap or heaps of concrete,the parts should whenever possible be distributed through the depth of the concrete aswell as over the exposed surface.

Table 2.6.1 Quantities of concrete requiredTest specimen number of standard scoopfulsSlumpCompacting factorVebe timeFlow indexAir contentDensity2 cubes 100mm x 100mm2 cubes 150mm x 150mm2 beams 100mm x 100 mm x 500mm2 beams 150mm x 150 mm x 750mm2 cylinders 150mm x 300mm

464446446

186

2.6.5 Obtaining a sample. Ensure that the equipment is clean. Using the scoop obtain ascoopful of concrete from the central portion of each part of the batch and place it in thecontainer or containers. When sampling from a falling stream pass the scoop throughthe whole width and thickness of the stream in a single operation. Take the container(s)to the area where the sample is to be prepared for testing or moulding.

Sampling from a heap of concrete. Ensure that the shovel is driven into the heap andthat concrete is taken to represent the whole mass of the heap by taking a sub-samplefrom different areas of the heap well spaced over its entire surface area. Combine allsub-samples, agitate and mix well and prepare the sample for testing or moulding.

2.6.6 Protection of samples. At all stages of sampling, transport and handling, the freshconcrete shall be protected against gaining or loosing water and against excessivetemperatures.

2.6.7 Certificate of sampling. Each sample shall be accompanied by a certificate ofsampling from the person responsible for taking the sample and the certificate shallinclude at least the following information:

a) Testing agencyb) Clientc) Contract named) Location within the structure of concretee) Sample identification numberf) Delivery batch note number or any other means of identifying the batchg) Concrete temperature


MAY 2001 Page 2.15

h) Ambient temperature and weather conditionsi) Name of samplerj) Signature of sampler



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2.7 Sampling of Bitumen

Bitumen is normally contained either in metal drums or heated bulk tanks and differentmethods should be used for sampling each type.

2.7.1 From metal drums the sample must be taken by cutting holes in the side of the drumand removing a sample of bitumen from these holes. Samples should not be takenfrom the top and bottom of the drum as this may be contaminated during storage andtransport.

2.7.2 From a heated bulk tank it is necessary to obtain a sample from the full depth of thetank. This is best done from the top access opening using a purpose-made tube with aclosing plug at the bottom, as shown in Figure 2.7.1. The tube is pushed into the fulldepth of the bitumen, the flap closed and the tube withdrawn. The sample obtainedfrom the tube must be fully mixed before removing a portion for test.

Figure 2.7.1 Bitumen Sampling Tube

Handle

Cone


MAY 2001 Page 2.17

2.8 Sampling of Bituminous Materials

Pre-mixed bituminous materials may be sampled at the asphalt plant or at the sitewhere the material is being laid.

2.8.1 When sampling at the asphalt plant, the whole batch should be discharged into a lorryand then a sample taken from the material in the lorry. This is done in a similar way tosampling from a stockpile with fractions of the sample being taken from at least fivedifferent points of the material.

2.8.2 Sampling at the laying site may either be from the paving machine or the laid material.

a) When sampling from a paving machine, material should never be taken from thefront hopper as segregation often takes place here. Samples should always betaken from the rear screws, a scoop being used to collect material from the ends ofthe screw. Samples must only be taken when the screws are fully loaded andsamples should be taken from both ends.

b) When sampling the as laid material, an area to be sampled is marked out and allthe material within that area, to the full layer thickness should be removed.Generally it is better to obtain a sample from a number of smaller areas than onebig area. On completion of sampling, care must be taken to ensure the areas arerepaired to the standard of the original material.

Samples of bituminous materials are best transported in a closed tin or small drum.The details of the sample should be recorded, including sample number, date,origin of material, type of material, time of mixing, time of laying, chainage of laidmaterial and weather conditions. It is also necessary to record the temperatureafter mixing, the temperature at the time of laying and the temperature at the timeof rolling.

2.9 Preparing and Transporting Samples

2.9.1 Sample preparation

Many samples will require some preparation before being sent to the laboratory fortesting, particularly if their large sizes makes them difficult to handle or because theyrequire special protection.

2.9.1.1 Sample reduction. If the sample is delivered larger than required for a particulartesting programme, it must be divided to obtain a sample of the required size. In orderto ensure the test sample represents the original material, it is necessary to divide theoriginal sample either by quartering or by using a sample divider (Riffle box).

2.9.1.1.1 Quartering. In this method the original sample is placed on a hard clean surface(preferably concrete) and made into a neat circular pile. Using a shovel, this pile is thenseparated into quarters by making two lines at right angles through the centre of thepile. Two opposite quardrants should then be put aside and the remaining twoquadrants should be mixed together to give a smaller sample. If the divided sample isstill too large, the procedure should be repeated. Figure 2.9.1 shows the procedurediagrammatically.

2.9.1.1.2 Sample divider. A sample divider, or riffle box, is a purpose-made tool for splittingsamples and a riffle box is shown in Figure 2.9.2. The box consists of a number of slotsor chutes, alternate ones leading to two separate containers. The total sample is placedinto the top hopper and passes down the chutes, half of the sample being collected ineach container. The width of the chutes shall be appropriate to the maximum particle


MAY 2001 Page 2.18


MAY 2001 Page 2.19

size of the sample and in general should not be smaller than 1.5 times the maximumparticle size of the sample

If the sample is still too large, one of the containers may be put aside and the materialfrom the other container is passed through the sample divider again.

2.9.2 Sample transportation

All samples should be carefully packed and labeled before transporting them to thelaboratory. Sample bags must be strong enough to withstand rough handling and be ofa type which prevents loss of fines or moisture from the sample, e.g. thick polythenebags inside jute bags. The use of steel drums for large bulk samples could also beconsidered. Water samples in glass or plastic containers will require particular care inhandling.

Undisturbed samples should be placed in wooden boxes and packed in sawdust orsimilar material to provide added protection. Collision between tubes in transit caneasily damage sensitive samples.

2.10 Sample Reception

2.10.1 Registration. Full details of the sample, as written on the label is checked andamended and weighed and must be entered in the laboratory register. A uniquenumber is allocated to the sample and this number is used subsequently on all testsheets for the sample. A copy of the formalised testing programme should accompanythe sample through the various stages of testing.

2.10.2 Initial treatment

a) Natural moisture content samples should be taken first, as quickly as possible.b) Air drying should be done by leaving the soil spread out in trays or on a hard, clean

floor in the laboratory for 2-3 days.c) Oven drying must be done at the correct temperature (110±50C).d) No attempt should be made to quarter down or riffle material which is in lumps or is

larger than the size of the riffle-box chutes.

2.10.3 Storage. Storage of all samples should be in an orderly and systematic manner so thatthey can be subsequently located easily. The storage facility itself should be a securearea, free from the risk of contamination or other harmful influences.

Undisturbed samples may be damaged by vibration or corrosion of tubes and shouldbe stored with especial care. Tubes containing wet sandy or silty soils should be storedupright (suitably protected against being knocked over), to prevent possible slumpingand segregation of water. The end caps of tube samples which are to be stored for longperiods should be sealed with wax, in addition to the wax seal next to the sample itself.

Samples which have been tested should not be disposed of without the authority of thelaboratory section head.

2.11 Sample Drying

Many tests require the material to be drier at the start of the test than the sample asobtained from the field. Some means of drying the sample must, therefore, be utilised.

In the case of liquid and plastic limit tests, it is essential that the material is air driedand, as a general rule, it is preferable to dry samples in the air as opposed to drying in


MAY 2001 Page 2.20

an oven or by other artificial means. The frequent need to dry samples quickly is moreoften a sign of bad planning than of an efficient laboratory.

2.11.1 Air drying. This is essential for liquid and plastic limit tests and is the preferredprocedure for all other tests.

The sample should be spread out in a thin layer on a hard clean floor or on a suitablemetal sheet. Ordinary corrugated galvanised roofing sheets are perfectly satisfactoryfor this purpose. The material should be exposed to the sunlight and should be in alayer not more than 20 mm thick. Cohesive materials such as clays, require breakingby hand or with a rubber mallet into small pieces, to allow drying to take place withouttoo much delay. The soil should periodically be turned over and a careful check shouldbe made to ensure the material is removed to a sheltered place if it starts to rain.

In the case of soft stone or gravels, care should be taken to ensure only lumps ofcohesive fines are broken up and that the actual stone particles are not destroyed.

In the case of fine-grained materials, it is generally beneficial to the later stages oftesting to pass the dried particles through a No. 4 sieve.

Air drying should not normally take longer than 2 to 3 days if carried out correctly.

2.11.2 Oven drying. Oven drying should only be employed where air drying is not possible.Oven drying will not normally have any detrimental effect on the results for soundgranular materials such as sand and gravel, but may change the structure of clay soilsand thus lead to incorrect test results. Oven drying must never be used in the case ofliquid and plastic limit tests.

In oven drying the temperature should not exceed 1100C and the material should bedried as quickly as possible by spreading in thin layers on metal trays. Periodically, thematerial should be allowed to cool before testing is commenced.

2.11.3 Sand-bath drying. In certain cases an oven may not be available but the sample mustbe dried quickly; sand bath drying may then be utilised.

The sand-bath consists simply of a strong metal tray or dish which is filled with cleancoarse sand. The sand bath is placed on some form of heater such as a kerosenestove, a gas ring or an electric ring. The sample to be dried is placed in a heatproofdish which is embedded in the surface of the sand. A low heat should be applied sothat the sand becomes heated without causing damage to the bath. The sample shouldbe stirred and turned frequently to ensure the material at the base does not become toohot. The material should be allowed to cool before testing is commenced.

Chapter 3 Standard Test ProceduresClassification Tests

MAY 2001 Page 3.1

CHAPTER 3

CLASSIFICATION TESTS

3.1 Determination of Moisture Content

3.1.1 General requirements

3.1.1.1 Scope. Water is present in most naturally occurring soils and has a profound effect insoil behaviour. A knowledge of the moisture content is used as a guide to theclassification. It is also used as a subsidiary to almost all other field and laboratory testsof soil. The oven-drying method is the definitive method of measuring the moisturecontents of soils. The sand-bath method is used, where oven drying is not possible,mainly on site.

3.1.1.2 Definition. The moisture content of a soil sample is defined as the mass of water in thesample expressed as a percentage of the dry mass, usually heating at 1050C, i.e.

moisture content, w = W

D

MM

x 100 (%)

where, WM = mass of water

DM = dry mass of sample

3.1.1.3 Sample requirements

3.1.1.3.1 Sample mass. The mass required for the test depends on the grading of the soil, asfollows;

a) Fine-grained soils*, not less than 30 gramsb) Medium-grained soils*, not less than 300 gramsc) Coarse-grained soils*, not less than 3 kg

*Soils groupi) Fine-grained soils: Soils containing not more than 10% retained on a 2 mm test

sieve.ii) Medium-grained soils: Soils containing more than 10% retained on a 2 mm test

sieve but not more than 10% retained on a 20 mm test sieve.iii) Coarse-grained soils: Soils containing more than 10% retained on a 20 mm test

sieve but not more than 10% retained on a 37.5 mm test sieve.

3.1.1.4 Accuracy of weighing. The accuracy of weighing required for test samples is asfollows;

a) Fine-grained soils: within 0.01 g.b) Medium-grained soils: within 0.1 g.c) Coarse-grained soils: within 1g.

3.1.1.5 Safety aspects

a) Heat-resistant gloves and / or suitable tongs should be used to avoid personalinjury and possible damage to samples.


MAY 2001 Page 3.2

b) If glass weighing bottles are used they should be placed on a high shelf away fromheating elements.

c) A heat-insulated pad should always be used to place hot glassware of anydescription.

3.1.2 Oven-drying method (standard method)

3.1.2.1 Apparatus

1) Thermostatically controlled drying oven capable of operating to 105±50C.2) Glass weighing bottles or suitable metal containers (corrosion-resistant tins or

trays).3) Balance (to the required sensitivity).4) Dessicator containing anhydrous silica gel.5) Scoop, other small tools as appropriate.

Optional: Test sieves - 2 mm, 20 mm, 37.5 mm (to check classification of sample,in order to confirm required sample size).

3.1.2.2 Test procedure

a) One clean container with the lid (if fitted) is taken and the mass in grams isrecorded (m1) together with container number.

Note: The container plus lid or bottle plus stopper should have the samenumber and be used together.

b) The sample of wet soil is crumbled and placed in the container. The container withthe lid on is weighed in grams (m2).

c) The lid is removed and both lid and container are placed in the oven. The sample isthen dried in a thermostatically controlled drying oven which is maintained at atemperature of 105±50C. A period of 16 to 24 hours is usually sufficient, but thisvaries with soil type. It will also vary if the oven contains a large number of samplesor very wet samples. The soil is considered dry when the differences in successiveweighings of the cooled soil at 4 hour intervals do not exceed 0.1% of the originalmass.

Note. 1) For peats and soils containing organic matter a drying temperature of600C is to be preferred to prevent oxidation of organic matter.2) For soils containing gypsum a maximum drying temperature of 800C ispreferred. The presence of gypsum can be confirmed by heating a smallquantity of soil on a metal plate. Grains of gypsum will turn white within a fewminutes, but most other mineral grains will remain unaltered.

d) The container is removed from the oven. For medium and coarse-grained soils, thelid should be replaced (if fitted) and the sample allowed to cool. For fine-grainedsoils, the container and lid, or bottle and stopper if used, should preferably beplaced in a dessicator and allowed to cool. After cooling, the lids or stoppers shouldbe replaced and the container plus dry soil weighed in grams (m3).

3.1.2.3 Calculation and expression of results

Moisture content, w =mass of moisturemass of dry soil

x 100%

= mass of container + wet soil) - (mass of container + dry soil)

(mass of container + dry soil) - (mass of container) x

(100%


MAY 2001 Page 3.3

i.e. wm mm m

=−−

2 3

3 1100% x

For values up to 10% the moisture content should be expressed to two significantfigures, e.g. 1.9%, 4.3%, 9.8%. For moisture contents above 10% express the result tothe nearest whole number, e.g. 11%, 27%.

Note. If the moisture content is to be related to the Atterberg limits, e.g. for determiningthe liquidity index, and the soil contains material retained on a 425 µm sieve, themeasured moisture content, w (in %), can be corrected to give the equivalentmoisture content, wa (in %), of the fraction passing the 425 µm sieve, using theequation :

w wpa

a=

100

where, pa is the percentage by dry mass of the portion of the soil sample passing the425 µm test sieve.

If the particles retained on the 425 µm sieve are porous and absorb water, the amountof absorption should be determined and the value of water calculated from theequation.

ww

pw

ppa

ar

a

a= −

−

100 100

where; wr, is the moisture content of the fraction retained on the 425 µm test sieve.

3.1.2.4 Report. The test report shall contain the following information:

a) the method of test used;b) the moisture content;c) the temperature at which the soil was dried, if less than 1050C;d) the comparison with Atterberg limits, if required (see Note to 3.1.2.3);e) full details of the sample origin.

The operator should sign and date test sheet. An example of the calculations made isshown in Form 3.1.1.

3.1.3 Sand-bath (subsidiary method)

3.1.3.1 Apparatus

i) Strong metal heatproof tray or dish containing clean sand to a depth of at least25mm (sand-bath).

ii) Moisture content containers for fine soils (excluding glass containers), as used foroven drying. For coarser soils heat-resistant trays 200-250 mm square and50-70 mm deep, the size depending on the quantity of soil required for test.

iii) Heating equipment, such as a bottled gas burner or paraffin pressure stove, orelectric hot plate if mains electricity is available.

iv) Scoop, spatula, appropriate small tools.


MAY 2001 Page 3.4

Form 3.1.1


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a) A clean dry container with the lid (if fitted) is weighed, in grams (m1). The number ofthe container is recorded.

b) The sample of wet soil is crumbled, placed in the container and weighed in grams(m2).

c) The sand-bath is placed on some form of heater such as a kerosene stove, a gasburner or an electric heater. The sample in its container is embedded in the surfaceof the sand in the sand-bath. Care should be taken to ensure that the container isnot heated too much. The sample should be stirred and turned frequently so thatthe sample does not burn. Small pieces of white paper will act as an indicator andturn brown if over-heated. To check that the sample is completely dry it should beweighed and returned to the sand-bath for another 15 minutes. If the loss in massafter heating for a further period of 15 min does not exceed the following, thesample may be considered to be dry :

Fine-grained soils 0.1gMedium-grained soils 0.5gCoarse-grained soils 5g

d) After drying, the sample is removed from the sand-bath, the container lid (if fitted) isfirmly secured in place and the sample is allowed to cool. When cool, the containerand the dry soil is weighed in grams (m3).

Note. Do not place hot trays onto the unprotected pan of a balance.

e) Normally, more than one determination of moisture content is made and theaverage value is taken.

3.1.3.3 Calculation and expression of results. Calculation and expression of results areidentical to those for oven-drying method.

3.1.3.4 Report. Report is also identical to that for oven-drying method.

3.1.4 Speedy Moisture Test

3.1.4.1 General

3.1.4.1.1 Introduction. A rapid test method for determination of moisture in soils is by the use ofa calcium carbide gas pressure moisture tester - commonly called the Speedy moisturetester. Soil samples are used in 6, 26 and 200 gram sizes.

3.1.4.1.2 Apparatus. The basic apparatus includes the moisture tester, a scale for weighing thesample, a cleaning brush, a scoop for measuring the calcium carbide reagent and asturdy carrying case. For the 26 gm sample test, steel balls are used to break downcohesive materials.

Calcium carbide reagent is available in cans. This may be a finely pulverized materialand should be of a grade capable of producing at least 2.25 cu.ft. of acetylene gas perpound of calcium carbide.

In performing the test, in the 26 gram sample unit, three scoops of reagent(approximately 24 grams) and two balls are placed in the large chamber of the tester.

When using the 6 gram sample tester, place on level scoopful (approximately 8 grams)of calcium carbide in the larger chamber of the tester. Steel balls are not used with the6 gm sample tester.


MAY 2001 Page 3.6

Speed moisture tester is shown in Figure 3.1.1.

3.1.4.1.3 Preparation of the material. The speedy moisture test gives consistently accurateresults in approximately 3 minutes. The material should be prepared for test as follows:

a) Sands and fine powders : No preparation necessary.b) Clays, soils and other coarse materials: Use steel ball speedy moisture test.c) Aggregates: No preparation necessary.

3.1.4.1.4 Pre-caution. Five rules should be noted before testing. Make sure that:

a) The body or cap, whichever is being used for the material, is perfectly clean andcontains no active absorbent from a previous test.

b) The material is truly representative of the bulk and carefully weighed.c) The material and the absorbent are kept separate until the cap is tightly secured to

the body.d) The material has been thoroughly prepared – ground or pulverized or mixed with

sand (if necessary) so that the absorbent can act freely on the material.e) Make sure that the steel ball pulverizes are used when testing clays, soils etc.

3.1.4.2 Procedure

a) Weight the desired 6, 26, or 200 gram test sample on the scale.b) Place the soil sample in the cap of the tester. Then, with the pressure vessel in

approximately horizontal position, insert the cap in the pressure vessel and seal theunit by tightening the clamp, taking care that no calcium carbide comes in contactwith the soil sample until a seal is achieved.

c) Raise the moisture tester to a vertical position so that the soil in the cap falls intothe pressure vessel.

d) Then shake the tester vigorously so that all the lumps will be broken up, permittingthe calcium carbide to react with all the available free moisture. When steel ballsare used in the tester, the instrument should be shaken with a rotating motion. Thiswill prevent damage to the instrument and eliminate the possibility of soil particlesbecoming embedded in the orifice leading to the pressure diaphragm.

e) Continue shaking for approximately one minute for granular soils and up to threeminutes for other soils, to allow for complete reaction between the calcium carbidereagent and free moisture. Time should be permitted to allow dissipation of the heatgenerated by the chemical reaction.

f) When the dial indicator stops moving, read the dial while holding the instrument in ahorizontal position at eye level.

g) Record the sample weight and the dial reading.h) With the cap of the instrument pointed away from the operator, slowly release the

gas pressure. Empty the pressure vessel and examine the material for lumps. If thesample is not completely pulverized, the test should be repeated using a newsample.

i) The dial reading is the percent of moisture by wet weight and must be converted todry weight percent.


MAY 2001 Page 3.7

Figure 3.1.1 a) Speedy moisture tester

Small weight

Small brush

Measuring scoop

Large wirehandledbrush

Bushing to hold

Adapter nut and filter

Rubber gauge gasket

Gauges

Standardtesterbody

Stirrupsidescrew

Nylonwasher

Rubber cap gasket

Cap

Stirrup

Helicol

Clampingscrew


MAY 2001 Page 3.8

Figure 3.1.1 b) Speedy moisture tester

Knife-edge(square shape)

Platform base

Agates

Knife edge(pear shape)

Scale link

Scale cradle

Scale pan


MAY 2001 Page 3.9

3.1.4.3 Expression of results and report

Moisture content should be expressed to two significant figures, e.g. 1.9%, 4.3%. Wetweight / dry weight conversion Chart (when steel ball pulverizes are not used) ispresented in Table 3.1.1 and the conversion chart (when using steel ball pulverizes) isshown in Figure 3.1.2. The test report shall contain the following information:

a) Method of test used,b) The moisture contentc) Full details of the sample origin.

Table 3.1.1

Wet Weight / Dry Weight Conversion ChartNot Applicable When Steel Ball Pulverizes Used – See Figure 3.1.2

With Calibration Curves on Reverse Side

SPEEDY READING SPEEDY READING SPEEDY READINGWet Weight Dry Weight Wet Weight Dry Weight Wet Weight Dry Weight

1.0%2.0%3.0%4.0%5.0%6.0%7.0%8.0%9.0%

10.0%10.5%11.0%11.5%12.0%12.5%13.0%13.5%14.0%14.5%15.0%15.5%16.0%16.5%17.0%17.5%18.0%18.5%19.0%19.5%20.0%

1.0%2.1%3.2%4.3%5.4%6.5%7.6%8.7%9.8%

11.0%11.7%12.3%13.0%13.6%14.2%14.9%15.6%16.3%16.9%17.6%18.3%19.0%19.7%20.4%21.2%21.9%22.7%23.4%24.2%25.0%

20.5%21.0%21.5%22.0%22.5%23.0%23.5%24.0%24.5%25.0%25.5%26.0%26.5%27.0%27.5%28.0%28.5%29.0%29.5%30.0%30.5%31.0%31.5%32.0%32.5%33.0%33.5%34.0%34.5%35.0%

25.8%26.5%27.4%28.2%29.0%29.8%30.7%31.5%32.4%33.3%34.2%35.3%36.0%36.9%37.9%38.8%39.8%40.8%41.8%42.8%43.9%44.9%45.9%47.0%48.1%49.2%50.3%51.5%52.6%53.8%

35.5%36.0%36.5%37.0%37.5%38.0%38.5%39.0%39.5%40.0%40.5%41.0%41.5%42.0%42.5%43.0%43.5%44.0%44.5%45.0%45.5%46.0%46.5%47.0%47.5%48.0%48.5%49.0%49.5%50.0%

55.0%56.2%57.4%58.7%60.0%61.2%62.6%63.9%65.2%66.6%68.0%69.4%70.9%72.4%73.8%75.4%76.9%78.5%80.1%81.8%83.4%85.1%86.9%88.6%90.6%92.3%94.1%96.0%98.0%

100.0%


MAY 2001 Page 3.10


MAY 2001 Page 3.11

3.2 Determination of Atterberg Limits

3.2.1 Scope. As the moisture content of a soil decreases the soil passes from the liquid stateto the plastic state to the solid state. The range of moisture contents over which the soilis plastic is used as a measure of the plasticity index. The points at which a soilchanges from one state to another are arbitrarily defined by simple tests called theliquid limit test and plastic limit test. These tests are known as the Atterberg limits. TheAtterberg limits are empirical tests which are used to indicate the plasticity of finegrained soil by the differentiation between highly plastic, moderately plastic and non-plastic soils. The tests enable classification and identification of the soil to be carriedout and give a rough guide to the engineering properties.

3.2.2 Sample preparation. It is preferable not to dry the soil before preparation for the test.Two preferred methods of preparation are described, depending on whether the soilcontains a significant proportion of particles larger than the 425 µm sieve.

3.2.2.1 Method for fine soils. If the soils contains few or no particles retained on a 425 µmsieve, take a representative sample weighing about 500 g, chop it up and mixthoroughly for at least 10 minutes with distilled water to form a thick homogeneouspaste. Seal in an airtight container (e.g. a corrosion-resistant tin or a polythene bag) for24 hours before testing. Mixing should be carried out on a glass plate with two paletteknives. The required 24 hour maturing period may be shortened for soils with low claycontents.

If only a few particles larger than 425 µm are present, these can be removed by fingersor with tweezers during mixing. If coarse particles are present determine their massand the mass of the sample used. These weighings enable the approximate proportionof coarse material to be reported if required.

3.2.2.2 Wet preparation method. This is the preferred method for soil containing coarseparticles, and should be used for all such soils that are sensitive to the effects of drying.

Procedure

1. Take a representative specimen that will give at least 350 g passing a 425 µmsieve, and weigh it (m grams). This quantity should be sufficient for a liquid limitand a plastic limit test. Weighings should be carried out to an accuracy of within0.01 g.

2. Take another representative sample for determination of moisture content (w %).Calculate and record the mass of dry soil in the test sample (mD) from the equation:

m = 100m

100 + wD

3. Cut up the weighed sample in a beaker and just cover with distilled water. Stir toform a slurry. Do not use a dispersant.

4. Pour the slurry through a 2 mm sieve nested on a 425 µm sieve. Use the minimumamount of distilled water to wash clean the particles retained on both sieves.Continue until the water passing the 425 µm sieve is virtually clear. Collect all thewashings.

5. Dry (at 1050C to 1100C) and weigh the retained material (mR grams) to an accuracyof within 0.01 g.

6. Allow the collected wash water to stand undisturbed, and pour or siphon off anyclear water. A settling time of several hours may be required. It is important no tolose any soil particles during the siphoning procedure (see Note).


MAY 2001 Page 3.12

7. Allow the suspension to partially dry in warm air, or in an oven at not more than500C, or by filtration under vacuum or pressure, until it forms a stiff paste. Butprevent local drying at the surface or edges, by repeated stirring.

Note 1. A suitable consistency for the paste corresponds to not less than 50 blows ofthe Casagrande apparatus.

Note 2. When using this method, care should be taken with samples containingsoluble salts. These samples should be allowed to dry by evaporation only,and not by siphoning or pouring off excess water.

3.2.2.3 Dry preparation method. If the use of a dry preparation method is unavoidable thenthe procedure should be followed as shown schematically in Figure 3.2.1.

3.2.3 Liquid limit test (Casagrande method)

1. Apparatus

a) Equipment for the determination of moisture content (weighing to 0.01 g).b) Soil mixing equipment (glass plate, spatulas, distilled water).c) Timer clock.d) Casagrande liquid limit device (Figure 3.2.2).e) Grooving tool and height gauge (Figure 3.2.3).

2. Calibration of apparatus

The height of the underneath of the cup when fully lifted should be such that the10 mm gauge will just pass between it and the base. Some grooving toolsincorporate a block of the correct thickness. The locking nuts must be adjusted tomaintain the correct height of drop.

The device should be checked to make sure that the cup falls freely, that there isno side play in the cup, that the screws are tight, that the cup and base are notworn and that the blow counter works correctly and is set to zero. Details of theliquid limit device and how the cup fall is set are shown in Figure 3.2.4.

The dimensions of the grooving tool are important and a reference (unused) toolshould be available to check the tool being used against. When the tip of the toolbeing used becomes worn to a width of 3 mm it should be re-ground to thecorrect dimensions.

3. Test Procedure

a) Mix about 300 g of the prepared soil (after 24 hours maturing) with a littledistilled water if necessary, using two spatulas, for at least 10 minutes. At thispoint the first blow count should be about 50 blows. If a plastic limit test isrequired it is convenient to set aside a portion of soil for this purpose.

b) With the cup resting on the base, press soil into the cup being careful to avoidtrapping air. Form a smooth level surface parallel to the base giving amaximum thickness of 10 mm (see Figure 3.2.5).

c) Beginning at the hinge, and with the chamfered edge of the tool facing thedirection of movement, make a smooth groove with a firm stroke of thegrooving tool, dividing the sample into two equal parts. The tip of the groovingtool should lightly scrape the inside of the bowl, but do not press hard.

When using the tool, apply a circular motion so that it is always normal to the surface ofthe cup (see Figure 3.2.5).


MAY 2001 Page 3.13


MAY 2001 Page 3.14


MAY 2001 Page 3.15

Figure 3.2.4 a) The parts of the Casagrande device.b) The fully raised cup set to the specified height.

d) Rotate the handle at a speed of two turns per second – check with a secondstimer.

Stop turning when the bottom of the groove closes along a continuous lengthof 13 mm (use the back of the grooving tool as a gauge). Record the numberof blows.

e) Add a little more soil from the mixture on the glass plate to the cup and mix inthe cup. Repeat stages (b) to (d) stated above until two consecutive runs givethe same number of blows for closer. Record the number of blows.

f) Remove a portion of about 10 g of the soil adjacent to the closed gap with aclean spatula, transfer to a weighed container and fit the lid immediately.Record the container number and determine the moisture content.

g) Repeat steps (b) to (f) stated above after adding increments of distilled water,mixing the water well in. At least two determinations should give more than 25blows, and two less than 25, in the range of about 10 to 50 blows. Do notadd dry soil to the soil paste. Protect the soil on the glass plate from dryingout at all times. Each time the soil is removed from the cup for the addition ofwater, wash and dry the cup and grooving tool.

thickness10 mm

level surface

Figure 3.2.5 a) Soil placed in Casagrande bow b) Use of the grooving tool

12

3position ofgrooving tool

when cutting

b)

base

a)

cup

pivot

locking screwlocknut

adjusting screwcam follower

handle

directionor rotation

10 mm


MAY 2001 Page 3.16

4. Calculation and Expression of Results

After determining the moisture contents plot each moisture content against thenumber of blows on the printed test sheet. A line of best fit is drawn through theplotted points. This is called the ‘flow curve’. The liquid limit is defined as thepercentage moisture content that corresponds to 25 blows as determined fromwhere the ordinate at 25 blows intersects the flow curve. Record this value ofmoisture content to the nearest 0.1%. An example is given on the attached testsheet (see Form 3.2.1)

5. Report

The full report will include the sample details, method of preparation of thesample and the percentage passing the 425 µm sieve. The operator should signand date the test form.

3.2.4 Plastic limit test

1. Apparatus

a) Equipment for the determination of moisture content (weighing to 0.01 g).b) Soil mixing equipment (glass plate, spatulas, distilled water).c) Smooth glass plate free from scratches, for rolling threads on.d) A length of rod, 3 mm in diameter and about 100 mm long.

2. Test Procedure

a) Prepare and mature the test sample using wet or dry preparation method ortake the sample previously set aside from the liquid limit test.

b) Take about 20 g of the soil and allow it to lose moisture until it is plasticenough to be shaped into a ball without sticking to the fingers. Mould into aball between the fingers and roll between the palms of the hands until slightcracks appear on the surface. Moulding and kneading is necessarythroughout the test to preserve a uniform distribution of moisture and toprevent excessive drying of the surface only.

c) Divide the sample into two roughly equal portions and carry out a separatetest on each portion.

d) Divide the first portion into four pieces. Mould one piece into a cylinder about6 mm diameter between the first finger and thumb.

e) Roll the cylinder under the fingers of one hand on a smooth glass surface,applying enough pressure to reduce the diameter to about 3 mm in about 5 to10 complete forward and backward movements. Maintain a uniform pressure.Do not reduce pressure as the 3 mm diameter is approached. Use a metalrod of 3 mm diameter to judge the thread diameter.

f) Pick up the soil thread, mould further and repeat the above. Repeat until thethread shears both longitudinally and transversely at a diameter of 3mm.Crumbling may consist of one of the forms shown in Figure 3.2.6 dependingon the nature of the soil.

g) Crumbling can usually be felt by the fingers. The crumbling condition must beachieved, even if greater than 3 mm diameter. If smooth threads of 3 mmdiameter (like noodles) are formed, the soil is not dry enough, as illustrated inFigure 3.2.5. The first crumbling point is the plastic limit, do not attempt tocontinue reforming and rolling beyond this point.


MAY 2001 Page 3.17

i) Shearing and cracking bothlongitudinally and transversely.

ii) Falling apart in small pieces.iii) Forming an outside tubular layer

which splits at both ends.iv) Breaking into barrel-shaped

pieces. Heavy clay requiresconsiderable pressure to reducethe diameter to 3 mm.

v) No crumbling – soil too wet (likenoodles).

Figure 3.2.6 Some forms of crumbling in the plastic limit test

h) Gather the crumbled soil quickly, place in a small weighed container, and fitthe lid immediately. Repeat the above process on second, third and fourthpieces of soil and place all fragments in the same container. Weigh it as soonas possible.

i) Carry out the same operations on four pieces from the second portion,placing the fragments in a second container, and weigh.

3. Calculation and Expression of Results

Dry the specimens at 1050C – 1100C, weigh and calculate the moisture contentsto the nearest 0.1%. If the two values differ by more than 0.5% moisture contentrepeat the whole test on another portion of soil. Otherwise, the average of the twovalues is the plastic limit. If it is not possible to determine the plastic limit this factshould be reported.

4. Report

The plastic limit is reported to the nearest whole number. The test sheet must becompleted in full to give sample details, method of preparation and thepercentage of material passing the 425 µm sieve. The test sheet should besigned and dated by the test operator. An example of a completed test sheet isattached (Form 3.2.1).

3mm


MAY 2001 Page 3.18


MAY 2001 Page 3.19

3.2.5 Determination of the plasticity index

1. Procedure

The Procedure is a simple calculation and requires the determination of the liquidand plastic limits for the soil. The Casagrande method is to be used to determinethe liquid limit.

The plasticity index of a soil is the numerical difference between the liquidlimit and the plastic limit: PI = LL – PL

2. Report

The plasticity index is reported to the nearest whole number. If both the liquid andplastic limits cannot be determined the soil is described as non-plastic (NP). Twospecial cases may be found. If it is possible to determine the liquid limit but notthe plastic limit, the soil is reported as non-plastic. If the plastic limit is found to beequal to or greater than the liquid limit (as with some highly micaceous soils), thesample is also reported as non-plastic.

3.2.6 Determination of linear shrinkage

1. Apparatus

a) A drying oven capable of operating at 600C – 650C and 1050C – 1100C.b) Soil mixing equipment (glass plate, spatulas, distilled water).c) Vernier calipers measuring up to 150 mm and reading to 0.1 mm.

Alternatively, a steel rule graduated to 0.5 mm.d) Silicone grease or petroleum jelly.e) Evaporating dish (approx. 150 mm ∅).f) Moulds made of brass or other non-corrodible material. They shall be semi-

circular in cross section with an internal radius of 12.5 ± 0.5 mm and 140 mmlong, with square end pieces attached as supports which also serve toconfine the soil (see Figure 3.2.7).

Figure 3.2.7 Mould for linear shrinkage test

2. Test Procedure

a) Preparation of apparatus. Clean the mould thoroughly and apply a thin film ofsilicone grease or petroleum jelly to its inner faces to prevent the soiladhering to the mould.

140±1.0

40

3

R=12.5±0.5

20

6All dimensions are in millimetres.


MAY 2001 Page 3.20

b) Prepare and mature the test sample using wet or dry preparation method.Place a sample of about 150 g on the flat glass plate or in the evaporatingdish.

c) Add distilled water if necessary and mix thoroughly using the palette knivesuntil the mass becomes a smooth homogeneous paste with a moisturecontent at about the liquid limit of the soil.

Note. The required consistency will require about 25 bumps of theCasagrande apparatus. This moisture content is not critical to within afew percent.

d) Place the soil / water mixture in the mould such that it is slightly proud ofsides of the mould. Gently jar the mould to any air pockets in the mixture.

e) Level the soil along the top of the mould with the palette knife and remove allsoil adhering to the rim of the mould by wiping with a damp cloth.

f) Place the mould where the soil / water can air-dry slowly in a position freefrom draughts until the soil has shrunk away from the walls of the mould.Then complete the drying, first at a temperature not exceeding 650C untilshrinkage has largely ceased, and then at 1050C to 1100C to complete thedrying.

g) Cool the mould and soil and measure the mean length of the soil bar. If thespecimen has become curved during drying, remove it carefully from themould and measure the lengths of the top and bottom surfaces. The mean ofthese two lengths shall be taken as the length of the oven dry specimen.

Note. Should a specimen crack badly, or break, such that measurement isdifficult, the test should be repeated at a slower drying rate.

3. Calculation and expression of results

Calculate the linear shrinkage of the soil as a percentage of the original length ofthe specimen, LO (in mm), from the equation:

Percentage of linear shrinkage = 1 - LL

100D

O

Where, LD is the length of the oven-dry specimen (in mm).

4. Report

The linear shrinkage is reported to the nearest whole percentage. The test sheet(see Form 3.2.2) must be completed in full to give sample details, method ofpreparation and the percentage of material passing the 425 µm sieve. The testsheet should be signed and dated by the test operator. An example of thecalculation is shown in Form 3.2.2.


MAY 2001 Page 3.21

Form 3.2.2


MAY 2001 Page 3.22

3.3 Particle Size Distribution

3.3.1 Introduction. The determination of the particle size distribution of soil is an importantpart of classification. The particle size distribution of a granular material such as roadbase or a concrete aggregate, is an essential guide to the stability of the material foruse in the works, as the engineering properties of the material are strongly dependentupon the grading.

In the case of fine grained cohesive soils which contain only a small percentage ofsand and silt, it is not generally necessary to carry out a particle size distribution, as theAtterberg limits will provide sufficient guide to the properties of the soil. Particle sizedistribution can be done by dry sieving or wet sieving. Wet sieving may be used on anymaterial and is more accurate than dry sieving but takes slightly longer to perform.


3.3.2.1 Sample mass. Mass of soil sample required for sieving is shown in the Table 3.3.1.

Table 3.3.1 Mass of soil sample for sieving

Maximum size of materialpresent insubstantialproportion (morethan 10%)

Minimum mass of sampleto be taken forsieving

Test sieve aperturemm635037.5282014106.353.352 or smaller

kg5035156210.50.20.20.150.1

3.3.2.2 Accuracy of weighing. The accuracy of weighing required depends on the size of thesample or sub-sample and the following values should be used.

Minimum accuracy of weighingFine grained soils 0.1 gmsMedium grained soils 1 gmsCoarse grained soils 10 gms

3.3.2.3 System of sieve sizes. Different systems of sieves are used at present time. Anyoneof these sieve systems may be used in the test, provided all sieves in one set are of thesame system. Slight differences in aperture (mesh) sizes can easily be accounted forwhen the results are plotted on a logarithmic grading chart. Sieves designation andtheir sizes are shown in the Table 3.3.2.


MAY 2001 Page 3.23

Table 3.3.2 Sieves designation and their sizes

Sieves to ASTM D422BS sieve aperture sizeNearest designation Aperture size

75 mm635037.528-2014106.353.35-21.18-600 µm425300-212150-7563

3 inch21/2 inch2 inch11/2 inch-1 inch3/4 inch-3/8 inch-No. 4No. 6No. 8No. 10No. 16No. 20No. 30No. 40No. 50No. 60No. 70No. 100No. 140No. 200No. 230

75 mm63.550.838.1

25.419.05

9.52

4.753.352.362.001.18850 µm6004253002502121501067563

* Sieves marked with * have been proposed as an International (ISO) Standard. It isrecommended to include, if possible, these sieves in all sieve analysis data or reports.

3.3.2.4 Care and use of sieves

a) If too much material is placed on a sieve at any one time, some of the fine materialwill not reach the mesh and will be retained on the sieve, thus giving errors. It istherefore important to ensure the sieves are never overloaded. Table 3.3.3 givesthe maximum mass of material to be retained on each sieve at the completion ofsieving.


MAY 2001 Page 3.24

Table 3.3.3 Maximum mass of material to be retained on each sieve at the Completion of sieving

Test sieveAperture size

Maximum mass on sieve of diameter

450 mm 300 mm 200 mmmm5037.5282014106.353.3521.18µm60042530021215075

(2 in)(11/2 in)

(3/4 in)

(3/8 in)(1/4 in)

(4)(6)

(10)(16)

(30)(40)(50)(70)

(100)(200)

kg10864321.51.0---

------

kg4.53.52.52.01.51.00.750.5---

------

g---1000*-500*350*-300200100

757550504030

Note 1. Numbers in brackets indicate equivalent ASTM sieve sizes or numbers.Note 2. *It may be more appropriate to use a larger diameter sieve for material of

this size, depending on the size of the fraction in the sample.

1 mm = 1000 microns (1000 µm)

b) The fine sieves must not be overloaded, because this not only leads to inaccuracybut also reduces the life of the sieve.

c) It is very difficult to prevent overloading, when using mechanical sieve shakers andmechanical sieve shakers are not recommended except for coarse grainedmaterials.

d) Particles larger than 20 mm may be placed through the sieve by hand, but must notbe forced through. All smaller sizes must be shaken through the sieves.

e) The sieves must be kept clean by brushing with a brass or camel hair brush andwashing through all sieving. Fine sieves should be inspected for holes in the meshbefore use. Care in the use of sieves and prevention of overloading will lead tolonger lives.

3.3.3 Wet sieving method

3.3.3.1 Scope. When a perceptible amount of clay or silt or if fine particles are foundconnected with the larger particles, then wet sieving must always be used.

3.3.3.2 Apparatus.

(1) A typical range of aperture or mesh sizes would be : 75 mm, 63 mm, 50 mm,37.5 mm, 28 mm, 20 mm, 14 mm, 10 mm, 6.3 mm, 5 mm, 3.35 mm, 2 mm, 1.18mm, 600 ± = µm, 425 µm, 300 µm, 212 µm, 150 µm, 75 µm. Lids and receivesof appropriate size are required.


MAY 2001 Page 3.25

Notes a) The aperture sizes to be used will vary from sample to sample. Onlythe necessary aperture sizes should be used, except that, forconvenience or to prevent overloading, additional sieves may be usedso that the requirements of Table 3.3.3 are complied with.

b) The defining size separating fine sand and silt grades is 60 µm. Theaperture size normally found closest to this is 63 µm. However, inpractice the 75 µm sieve is more commonly used because it is morerobust and less time-consuming to use. This standard suggests thecontinued use of the 75 µm sieve as the washing sieve. Somemanufacturers’ offer a special ‘washing’ sieve which is of 200 mmdiameter and 200 mm deep with a 75 µm mesh.

c) It can be useful to have two sets of sieves, one for the wet sievingand one for the dry sieving processes.

(2) A balance readable to 1.0 g.(3) A balance readable to 0.1 g.(4) Sample divider(s) of appropriate slot width (riffle boxes).(5) Thermostatically controlled drying oven capable of maintaining 105±50C.(6) An evaporating dish about 150 mm diameter.(7) A corrosion-resistant tray, a convenient size being about 300 mm square and 40

mm deep.(8) Two or more large corrosion-resistant metal or plastics watertight trays with sides

about 80 mm deep, or a bucket of about 12 L capacity.(9) A scoop.(10) Sieve brushes, and a wire brush or similar brush.(11) Sodium hexametaphosphate (dispersing agent).(12) A quantity of rubber tubing about 6 mm bore.(13) A sprayer such as a small watering can use.(14) Appropriate number of enamel or porcelain dishes.(15) A mechanical sieve shaker (optional).


(1) The representative riffled sample is oven-dried at 105±50C to give a minimummass complying with Table 3.3.3. If separation of the silt and clay fractions is tobe carried out, or if the particle size distribution is to be extended below 75 µm, asecond riffled sample shall be obtained for a fine analysis.

(2) Weigh the cooled oven-dried sample to 0.1% of its total mass (m1).(3) Sieve the sample through all required sieve sizes of 20 mm size and larger. The

mass retained is recorded on the test sheet in each case. Any fine particlesadhering to the retained material should be removed with a stiff brush duringsieving. The brushing should be done carefully to avoid losing material. Takecare with soft materials to ensure that the brushing does not remove parts of thelarge particles.

Note. If adhering fine material cannot be removed easily by brushing, thefollowing procedure may be followed.

a) Remove the fine material from the coarse particles by washing.b) Dry and weigh the coarse particles to 0.1% of their mass.c) Dry the washings, add them to the material passing the 20 mm test sieve,

and mix thoroughly.

(4) The mass passing the 20 mm sieve is determined to 0.1% of its total mass (m2)and the sample is then divided (riffled) so that about 2 kg of material remains.The mass of this sub-sample is then determined to 0.1% of its total mass (m3).


MAY 2001 Page 3.26

(5) The sample shall then be placed in a large tray, enamel or porcelain bowl or inthe bucket, and covered with water. If the soil is cohesive add sodiumhexametaphosphate first at the rate of 2 grams per litre of water and stir untildissolved. Sodium hexametaphosphate is a dispersing agent and helps toprevent fine particles sticking together.

(6) The sample should be soaked for a minimum of 1 hour and frequent stirringshould be given during this time.

(7) The sample is then washed through the 75 µm (No. 200) sieve with a 2 mmmesh sieve placed on top of it to protect it. Washing is most easily done by thedecantation method. In this method, water is slowly added to the bowl or trayand the contents are vigorously stirred. Allow the contents to settle for a fewseconds before pouring. The excess water is decanted carefully over the side ofthe bowl through the 2 mm sieve and into the 75 µm sieve, making sure all thewater passes through the 75 µm sieve before running to waste. This process iscontinued until the water leaving the bowl is perfectly clear and all clay and siltparticles have been washed through the sieve. Make sure that the fine sievedoes not become overloaded, either by retained soil or by water.

Note. During this process DO NOT rub the material on the 75 µm sieve withyour fingers or otherwise. This is likely to damage the sieve and giveerrors in the test results.

(8) On completion of washing place the washed sample in a tray or evaporating dishand place in the oven to be dried at 105±50C.

(9) After drying and cooling, weigh the sample to 0.1% of its total mass beforecommencing sieving (m4).

(10) Fit the largest size test sieve appropriate to the maximum size of materialpresent to the receiver and place the sample on the sieve. Fit the lid to the sieve.

Note. If the sieve and receiver assembly is not too heavy to handle, severalsieves, in order of size, may be fitted together and used at the sametime.

(11) Agitate the test sieve so that the sample rolls about in an irregular motion overthe sieve. Particles may be placed by hand to see if they will fall through butthey must not be pushed through. Make sure that only individual particles areretained. Weigh the amount retained on the test sieve to 0.1% of its total mass.Keep each fraction separate so that check weighings may be carried out at alater date if required.

(12) Transfer the material retained in the receiver to a tray and fit the receiver to thenext largest sized sieve. Place the contents of the tray on the sieve and repeatthe operation in (11). Be careful not to lose fine material by using a brush toclean the sieve mesh and the receiver. Use of the lid helps to reduce loss offines.

(13) Sieving is then continued through progressively smaller sizes until the samplehas been passed through the 6.3 mm sieve. The mass of soil passing the 6.3mm sieve is determined to 0.1% of its total mass (m5). If the mass of materialpassing the 6.3 mm sieve is too big (i.e. substantially more than 150 grams),the actual mass passing should be recorded and the sample divided again byriffling to give a reduced sample of about 100 to 150 grams. The mass of thesub-sample is then determined to 0.1% of its total mass (m6).

Sieving is now continued through the remaining sieve sizes. The mass retainedon each sieve is recorded to 0.1% of its total mass. The mass passing the 75µm sieve should be determined (ME). This mass will be very small if washinghas been carried out thoroughly. If any of the sieves are in danger of becomingoverloaded the sample should be sieved a little at a time and the material


MAY 2001 Page 3.27

retained each time placed in a clean porcelain or enamel dish ready forweighing.

Note 1. If a mechanical sieve shaker is available this may be used to performthe sieving operation provided that all the sieves are the samediameter and that they are not overloaded during the process. Aminimum shaking time of 10 minutes is required.

2. Sample dividing is carried out to prevent having to sieve largeamounts of material through the fine sieve sizes with the consequentrisk of overloading. If only one or two fine sieves are to be used it maybe quicker not to divide the sample and to sieve the total samplethrough these sieves a little at a time. If 20 mm or 6.3 mm sieves arenot being used, dividing may be carried out for convenience at thesieve closest to 20 mm and 6.3 mm.


(1) Summation Check. The first stage in the calculation is to check that all theweights retained add up to those of the original sample or sub-samples makingdue allowance for the weights passing the smallest sieve and any sieve wherethe sample has been divided. If these weights are not close to the correct total(i.e. within 1%) it is then possible to re-weigh the containers and to locate anyerrors before the sample is discarded. If this check is left until a later date it willbe necessary to repeat the complete test if any error is found.

(2) Calculation of correction factors

a) It is necessary to calculate the correction or riffle factor for the first sieve sizewhere the sample has been divided:

Correction factor, f = Original mass passing sieve size

Mass of sub -sample after dividing1

= mm

2

3

b) The correction factor is then applied to each sieve smaller than the one wherethe sample was divided until the sample is again sub-divided. Where asecond sub-division takes place the new correction factor is given by :

New correction factor, f = f x Original mass passing sieve size

Mass of sub - sample after dividing2 1

= mm

x mm

2

3

5

6

c) The adjusted mass retained MAR is then obtained for each sieve size bymultiplying the actual mass retained MR by the respective correction factor.

Adjusted mass retained MAR = f x MR

d) The percentage retained is obtained by dividing the adjusted weight retainedby the total sample weight and expressing the result as a percentage:


MAY 2001 Page 3.28

% Retained = ARm

x 100%M

1

e) The cumulative percentage passing is then obtained by deducting thepercentage retained on the largest sieve size from 100% and then deductingthe percentage retained for each smaller size from the previous cumulativepercentage.

f) The percentages retained on each sieve and cumulative percentages passingeach sieve should be calculated to the nearest 0.1%. The values can beexpressed in tabular form and / or in graphical form.

An example of a sieve test calculation is shown in Form 3.3.1, and the resultsare shown plotted on a semi-logarithmic chart in Form 3.3.3.

3.3.3.5 Report. The report should include the tabulated results of the test calculated ascumulative percentages passing to the nearest whole number. The results should beplotted on a semi-logarithmically form (see Form 3.3.3). The method of test should bereported and the operator should sign and date the test sheet.

3.3.4 Dry sieving method

3.3.4.1 Scope. This method covers the quantitative determination of the particle sizedistribution of a soil down to the fine sand size. It should only be used with clean, freerunning or washed sands and gravels.

3.3.4.2 Apparatus. The apparatus used in the wet sieving method are also used in the drysieving method.


(1) Oven dry the riffled sample at 105±50C to give a specified minimum mass and thencool and weigh to 0.1% of its total mass (m1).

(2) Sieve the sample through all required sieve sizes of 20 mm size and larger. Themass retained is recorded on the test sheet in each case.

(3) The mass passing the 20 mm sieve is determined to 0.1% of its total mass (m2)and the sample is then divided so that about 2 kg of material remains. The mass ofthis sub-sample is then determined to 0.1% of its total mass (m3).

(4) Then sieve the dried and weighed sample through the largest sieve size requiredand the mass of the sample retained is recorded on the data sheet. Use of the lidwill help to reduce loss of fines.

(5) Sieving is then continued through progressively smaller sizes until the sample hasbeen passed through the 6.3 mm sieve (m4). If the weight of the material passingthe 6.3 mm sieve is too big (more than 150 gms). The actual mass passing shouldbe recorded and the sample is divided to give a reduced sample of about 100 to150 gms. The mass of the sub-sample is then determined to 0.1% of its total mass(m5).

(6) Sieving is now continued through the remaining sieve sizes. The mass retained oneach sieve is recorded to 0.1% of its total mass. The mass passing the 75 µm sieveshould be determined (ME). If any of the sieves are in danger of becomingoverloaded the sample should be sieved a little at a time and the material retainedeach time is placed in a clean porcelain or enamel dish ready for weighing. If amechanical sieve shaker is used, a minimum shaking time of 10 minutes isrequired.

3.3.4.4 Calculation and expression of results. The procedure is the same as of wet sievingmethod (section 3.3.3.4).An example of a sieve test calculation is shown in Form 3.3.2.


MAY 2001 Page 3.29

Form 3.3.1


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Form 3.3.2


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Form 3.3.3


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3.4 Determination of Organic Content

3.4.1 Scope. The “Loss on Ignition”: method for the determination of organic content is mostapplicable to those materials identified as peats, organic mucks, and soils containingrelatively undecayed or undecomposed vegetative matter or fresh plant materials suchas wood, roots, grass or carbonaceous materials such as lignite, coal, etc. This methoddetermines the quantitative oxidation of organic matter in these materials and gives avalid estimate of organic content.

3.4.2 Apparatus

3.4.2.1 Oven-Drying oven capable of maintaining temperatures of 110±5 C (230±9 F). Gravity,instead of blower convection may be necessary when drying lightweight material.

3.4.2.2 Balance-(to required sensitivity)3.4.2.3 Muffle Furnace-The furnace shall be capable of maintaining a continuous temperature

of 445±10 C (833±18 F) and have a combustion chamber capable of accommodatingthe designated container and sample. Pyrometer recorder shall indicate temperaturewhile in use.

3.4.2.4 Crucibles or Evaporating Dishes-High silica, alundum, porcelain or nickel crucibles of30 to 50 ml capacity or Coors porcelain evaporating dishes approximately 100 mm topdiameter.

3.4.2.5 Desiccator-A desiccator of sufficient size containing an effective dessicant.3.4.2.6 Containers-Suitable rustproof metal, porcelain, glass or plastic coated containers.3.4.2.7 Miscellaneous Supplies-Asbestos gloves, tongs, spatulas, etc.


3.4.3.1 A representative sample weighing at least 100 grams shall be taken from thethoroughly mixed portion of the material passing the 2.00 mm (No. 10) sieve.

3.4.3.2 Place the sample in a container and dry in the oven at 110±5 C (230±9 F) to constantweight. Remove the sample from the oven, place in the desiccator and allow to cool.

Note 1. This sample can be allowed to remain in the oven until ready to proceed withthe remainder of the test.

3.4.4 Ignition procedure

3.4.4.1 Select a sample weighing approximately 10 to 40 grams, place into tared crucibles orporcelain evaporating dishes and weigh to the nearest 0.01 gram.

Note 2. Sample weights for lightweight materials such as peat may be less than 10grams but should be of sufficient amount to fill the crucible to at least ¾depth. A cover may initially be required over the crucible during initial phaseof ignition to decrease possibility sample being “blow out” from the container.

3.4.4.2 Place the crucible or dish containing the sample into the muffle furnace for six hours ata temperature of 445±10 C. Remove the sample from the furnace, place into thedesiccator and allow to cool.

3.4.4.3 Remove the cooled sample from the desiccator and weigh to the nearest 0.01 gram.


MAY 2001 Page 3.33

3.4.5 Calculation

3.4.5.1 The organic content shall be expressed as a percentage of the mass of the oven driedsoil and shall be calculated as follows:

Percent Organic Matter = A - BA - C

x 100

where:A = Weight of crucible or evaporating dish and oven dried soil, before ignitionB = Weight of crucible or evaporating dish and dried soil, after ignition.C = Weight of crucible or evaporating dish, to the nearest 0.01 gram.

3.4.5.2 Calculate the percentage of organic content to the nearest 0.1 percent.


MAY 2001 Page 3.34

3.5 Standard Description and Classifications

3.5.1 Scope. The description of soils is an important stage in the process of sampling andtesting of soils for civil engineering purposes.

In order to be readily understood, the descriptions should be carried out in a standardand methodical manner. The terms “soil description” and “soil classification” aresometimes confused. Although interconnected, the use of the two terms can beseparated and definitions are given in 3.5.2 below. Given individually, both adescription and a classification may be useful. When used together, a greaterunderstanding of the likely engineering characteristics of the soil can be obtained.

3.5.2 Definitions

3.5.2.1 Soil description. A full description gives detailed information on the grading, plasticity,colour, moisture and particle characteristics of a soil, as well as on the fabric andstrength condition in which it occurs in a sample, borehole or exposure.

3.5.2.2 Soil classification. A classification places a soil in a limited number of groups on thebasis of grading and plasticity of a disturbed sample. These characteristics areindependent of the particular condition in which a soil occurs, and disregard theinfluence of the structure, including fabric, of the soil mass.

3.5.3 Soil groups and field identification methods

3.5.3.1 Coarse soils (over 65% sand and gravel sizes)

(1) Sands and gravels are coarse soils. Cobbles and boulders are very coarse soils.(2) Coarse soils are visible to the naked eye. A small hand-lens may be useful for

the examination of finer sands or the surface of larger particles.(3) If required, a set of sieves may be used to determine approximate proportions

(as judged by eye) of gravel sizes, e.g. 60 mm 20 mm, 6 mm and 2 mm.(4) Sands, particularly those mixed with clay or silt fines, may usefully be examined

mixed with a little water in the palm of the hand or in a small enamel bowl.(5) Observations on the ease of excavation will be helpful. Whether the soil can be

easily excavated with a spade, or requires a pickaxe or hoe for excavation willdetermine the consistency aspect of its description. If may also be useful to haveavailable a wooden peg approximately 50 mm square with one sharpened end.The ease with which this can be hammered into the ground is an indication of thedensity of the soil.

3.5.3.2 Fine soils (over 35% silt and clay sizes)

(1) Fine soils require to be examined by hand to obtain an adequate description,preferably with the aid of a plastic was bottle containing water. This should readilyaid the distinction of the soil between a clay and a silt.

(2) Silts can be detected by carrying out a test for dilatancy. A small sample of soil ismixed with water so that it is soft but not sticky, and held in the palm of the hand.The edge of the hand is jarred gently with the other hand and the sampleobserved. The appearance of a shiny film of water on the surface indicatesdilatancy. Squeeze the soil by pressing with the fingers, and the surface will godull again as the sample stiffens and finally crumbles. These reactions indicatethe presence of predominantly silt-sized material or very fine sand, provided thatthe amount of moisture is not excessive. Moist silt is difficult to roll into threadssince it crumbles easily.

(3) The most significant properties of clay are its cohesion and plasticity. If whenpressed together in the hands at a suitable moisture content the particles stick


MAY 2001 Page 3.35

together in a relatively firm mass, the soil shows cohesion. If it can be deformedwithout rupture (i.e. without losing its cohesion), it shows plasticity. Clay driesmore slowly than silt and sticks to the fingers; it cannot be brushed off dry. It hasa smooth feel, and shows a greasy appearance when cut with a blade. Dry lumpscan be broken, sometimes with difficulty, between the fingers, but cannot bepowdered. A lump placed in water remains intact for a considerable time.

(4) Clay does not exhibit dilatancy. Lumps shrink appreciably on drying, and showcracks which are the more pronounced the higher the plasticity of the clay. At amoisture content within the plastic range, clay can easily be rolled into threads of3 mm diameter (as in the plastic limit test) which for a time can support their ownweight. Threads of high - plasticity clay are quite tough; those of low-plasticityclay are softer and more crumbly.

(5) If it is important to know the composition of fine soils accurately then a particlesize distribution test should be carried out subsequently in the laboratory.

3.5.3.3 Organic soils

(1) Organic soils may be organic clay, silt or sand, or may be a form of peat.(2) Examination in the field will be by visual and manual inspection in the same way

as for other soils, paying particular attention to compactness and structure. Peatoften has a distinctive smell and low bulk density. Laboratory testing will benecessary to accurately determine relative proportions of organic and mineralmatter.

3.5.4 Methodology of description 3.5.4.1 General. In describing a soil, attention is given to a number of different aspects in a

methodical manner, determined using the techniques outlined in Section 3.5.3 above.These aspects are summarised as follows, and are used in the order given, as far as ispracticable. Descriptions made in the field may require to be modified subsequently inthe light of the results of laboratory tests, or when better facilities are available forinspection. The preferred order of description is conveniently remembered asMCCSSO :

a) Moisture conditionb) Consistency (compactness/strength)c) Colourd) Structuree) Soil typef) Origin

Examples of test forms 3.5.1 and 3.5.2 for use in the field are included at the end of thissection. The test forms refer to the various elements of description as explained indetail in 3.5.4.2 below.

3.5.4.2 Descriptive terms

(1) Moisture condition. The moisture condition of the sample can be indicted byuse of the following terms:

a) Dry : Soil will require the addition of water tob) Slightly moist : attain the optimum moisture content for

compaction (OMC).c) Moist : Near OMC for compactiond) Very moist : Will require drying to achieve OMCe) Wet : From below water table.


MAY 2001 Page 3.36

(2) Consistency. Consistency or compactness/strength of the soil is described using

different terms for different soil types. These terms and the field tests for them aregiven in Tables 3.5.1 to 3.5.5.

Table 3.5.1 Very coarse soils -boulders and cobbles

Term Field testLooseDense

By inspection of voids andparticle packing

Table 3.5.2 Coarse soils - gravels and sandsTerm Field test

Very loose Crumbles very easily when scraped withgeological pick.

Loose Can be excavated with a spade; 50 mmwooden peg can be easily driven.

Medium dense Between loose and dense.Dense Requires pickaxe or hoe for excavation; 50

mm wooden peg hard to drive.Slightly cemented For sands. Visual examination; pickaxe or

hoe removes soil in lumps which can beabraded.

Table 3.5.3 Fine soils - silts

Term Field testSoft or loose Easily moulded or crushed in the fingers.Firm or dense Can be moulded or crushed by strong

pressure in the fingers.Very soft Exudes between fingers when squeezed in

hand (like toothpaste).

Table 3.5.4 Fine soils - clays

Term Field testVery soft Comes out between fingers (like

toothpaste) when squeezes in hand.Soft Moulded by light finger pressure.Firm Can be moulded by strong finger pressure.Stiff Cannot be moulded by fingers. Can be

indented by thumb.Very stiff or hard Can be indented by thumbnail.

Table 3.5.5 Organic soils

Basic Soil Type Term Field testOrganic Clay, silt or sand Firm Fibres already

compressed together

Peats

Spongy Very compressible andopen structure

Plastic Can be moulded inhand, and smearsfingers.


MAY 2001 Page 3.37

(3) Colour. The colour of soil samples should be assessed in a freshly excavatedcondition. This colour may be different from a dried sample, and from the samplemixed with water. Under some circumstances it may be important to know thesedifferences.

It is preferable to use a standard colour chart such as that developed by Munsell.

If standard colour charts are not available, use colour descriptions which arereadily understood, e.g. red, brown, green, yellow, white black, pink etc. Thesecan be supplemented by the use of words like: light, dark etc. Soils can also beone colour mottled with another, or one colour blotched or veined with another.

(4) Structure. The soil being sampled may have a distinct structure and if so thisshould be recorded in the description. Tables 3.4.6 to 3.4.10 present guidelinesfor the descriptive terms to be used.

Table 3.5.6 Coarse and very coarse soils. Boulders, cobbles, gravels and sands

Term Field identificationHomogeneous Deposit consists essentially of one type.Interstratified Alternating layers of varying types or with bands or

lenses of other materials. Interval scale for beddingspacing may be used (see Table 3.5.7).

Heterogeneous A mixture of types.Weathered Particles may be weakened and may show concentric

layering.

Table 3.5.7 Scale of bedding spacing (see Table 3.5.6)

Term Mean spacing, mmVery thickly bedded Over 2000Thickly bedded 2000 to 600Medium bedded 600 to 200Thinly bedded 200 to 60Very thinly bedded 60 to 20Thickly laminated 20 to 6Thinly laminated Under 6

Table 3.5.8 Fine soils – silts and clays

Term Field identificationFissured Break into polyhedral fragments along fissures. Interval

scale for spacing of discontinuities may be used (seeTable 3.5.9).

Intact No fissures or joints.Homogeneous Deposit consists essentially of one type.Interstratified Alternating layers of varying types. Interval scale for

thickness of layers may be used (see Table 3.5.7).Weathered Usually has crumb or columnar structure.Slicken sided Indicates the presence of fissures with polished or

scratched surfaces.


MAY 2001 Page 3.38

Table 3.5.9 Scale of spacing of other discontinuities (see Table 3.5.8)

Term Mean spacing, mmVery widely spaced Over 2000Widely spaced 2000 to 600Medium spaced 600 to 200Closely spaced 200 to 60Very closely spaced 60 to 20Extremely closely spaced under 20

Table 3.5.10 Organic soils – peats

Term Field identificationFibrous Plant remains recognizable.Amorphous (form is lacking) Recognizable plant remains absent.

(5) Soil type

a) The basic soil type to be described, their limiting sizes and visualidentification are given in Table 3.5.11. In the description the predominant soiltype is written in capital letters, e.g. GRAVEL.

Typical grading curves which would be obtained on well graded, uniformlygraded and gap graded coarse soils are shown in Figure 3.5.1.


MAY 2001 Page 3.39


MAY 2001 Page 3.40

Table 3.5.11 Soil types

Basic soil type Particle size, mm Visual identificationBOULDERS

200Only seen complete in pit or exposures.

Ver

yC

oars

eso

ils COBBLES60

Often difficult to recover from boreholes.

coarse

20

Easily visible to naked eye; particle shape canbe described; grading can be described.

medium

6

Well graded : wide range of grain sizes, welldistributed. Poorly graded : not well graded.(May be uniform : size of most particles liesbetween narrow limits; or gap graded : anintermediate size of particle is markedly under-represented.

GRAVELS

fine2

coarse

0.6

Visible to naked eye; very little or no cohesionwhen dry; grading can be described.

medium

0.2

Well graded : wide range of grain sizes, welldistributed. Poorly graded : not well graded.(May be uniform : size of most particles liesbetween narrow limits; or gap graded : anintermediate size of particle is markedly under-represented.

C

oars

e so

ils

(ove

r 65

% s

and

and

grav

el s

izes

)

SANDS

fine0.06

SILTS coarse

0.02

Only coarse silt barely visible to naked eye;exhibits little plasticity and marked dilatancy :slightly granular or silky to the touch.Disintegrates in water; lumps dry quickly;possess cohesion but can be powdered easilybetween fingers.

medium0.006

fine0.002

Fin

e so

ils

(

over

35%

silt

and

cla

y si

zes)

CLAYS Dry lumps can be broken but not powderedbetween the fingers; they also disintegrate underwater but more slowly than silt; smooth to thetouch; exhibits plasticity but no dilatancy; sticksto the fingers and dries slowly; shrinksappreciably on drying usually showing cracks.Intermediate and high plasticity clays showthese properties to a moderate and high degree,respectively. Descriptions should include anindication of plasticity if possible.

ORGANIC CLAY,SILT or SAND

varies Contains substantial amounts of organicvegetable matter.

O

rgan

ic s

oils

PEATS varies Predominantly plant remains usually dark brownor black in colour, often with distinctive smell;low bulk density.


MAY 2001 Page 3.41

b) Many (most) soils exist as composite soil types, i.e. mixtures of basic soiltypes. Examples would be a slightly clayey GRAVEL, or a silty SAND. Inthese examples the clay and silt are secondary constituents. The secondaryconstituents are included in the description according to a set scale. Thisscale of proportions for secondary constituents for secondary constituents forcoarse soils is set out in Table 3.5.12 and for fine soils in Table 3.5.13.

c) Coarse and very coarse soils can be given a supplementary description fortheir shape and for the texture of their surface. Standard descriptive termsfor shape are given in Table 3.5.14, and for texture in Table 3.5.15. Figure3.5.2 shows typical shapes for descriptive purposes.

Table 3.5.12 Scale of secondary constituents with coarsesoils

Table 3.5.13 Scale of secondary constituents

Term % of clayor silt

Remarks

slightly clayey

slightly silty

GRAVELorSAND

- clayey

- silty

GRAVELor10.5

very clayey

very silty

GRAVELorSAND

Sandy GRAVEL

Gravelly SAND

Sand or gravel andimportant secondconstituent of the coarsefraction

5 to 15

under 5

15 to 35

Percentage of clayor silt has to beestimated in the field.

Note : For composite types described as:clayey : fines are plastic, cohesive:silty : fines non-plastic or of low plasticity

with fine soils

Term % of sandor gravel

sandy

gravelly

CLAYorSILT

35 to 65(Assessed by eye)

under 35(Assessed by eye)

- CLAY : SILT


MAY 2001 Page 3.42


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Table 3.5.14 Angularity and form of coarse particles

Term RemarksAngular Possessing well-defined edges formed at

the intersection of roughly planar faces.Subangular Corners slightly bevelled.Subrounded All corners rounded off.

Angularity

Rounded Fully water-worn or completely shaped byattrition.

Equidimensional All dimensions roughly equal.Flat (flaky) Having one dimension significantly

smaller than the other two dimensions.Elongated Having one dimension significantly larger

than the other two dimensions.Flat andelongated

See Figure 3.5.2.

Form

Irregular Naturally irregular, or partly shaped byattrition and having rounded edges.

Table 3.5.15 Surface texture of coarse soils Typical descriptive terms

roughsmooth

honeycombedpittedglassy

(6) Origin. This part of the description consists of information on the geologicalformation, age and type of deposit. This information may not always be availableto persons carrying out field descriptions but should be included where it isavailable. Examples of the kind of information to be included would be:

a) Girujan Clayb) Dihing Formationc) Tippam Groupd) River deposit (alluvium)e) Beach deposit (littoral)f) Lake deposit (lacustrine)


MAY 2001 Page 3.44

3.5.4.3 Examples

(1) Coarse soils

An example of a completed test sheet for coarse soils is shown as Form 3.5.1.

Two further examples of descriptions for coarse soils are given below:

Example 1 Example 2

(a) Moisture condition : damp moist

(b) Consistency : loose dense

(c) Colour : dark brown yellow

(d) Structure : homogeneous + thin lenses of soft

grey silty CLAY

(e) Soil Type : sandy rounded smoothtextured fine medium

and coarse (FMC)

GRAVEL

Fine and medium (FM)

SAND

(f) Origin : beach deposit Recent Alluvium

Composite description for Example 1 : Damp loose dark brown homogeneoussandy smooth textured rounded fine medium and coarse GRAVEL. BeachDeposit.

Composite description for Example 2 : Moist dense yellow fine and mediumSAND with thin lenses of soft grey silty CLAY.

(2) Fine soils

An example of a completed test sheet for fine soils is shown as Form 3.5.2.

Two further examples of descriptions for fine soils are given below:

Example 1 Example 2

(a) Moisture condition : wet dry

(b) Consistency : soft firm to stiff

(c) Colour : blue-grey grey mottled brown

(d) Structure : + closely spacedpartings of firm brown

SILT

widely fissured

(e) Soil Type : sandy CLAY

(high plasticity)

silty CLAY

(f) Origin : Recent Alluvium -

Composite description for Example 1 : Wet soft blue-grey sandy CLAY of highplasticity with closely spaced partings of firm brown SILT. Recent Alluvium.

Composite description for Example 2 : Dry firm to stiff grey mottled brown widelyfissured silty CLAY.


MAY 2001 Page 3.45

3.5.4.4 Standard symbols. Soils descriptions carried out as part of a site investigationprogramme can be shown in borehole and trial pit records in the form of symbols.Standard symbols for soils are presented in Figure 3.5.3.

Figure 3.5.3 Standard soils symbols

Note. Made ground means a soil which is artificially placed, e.g. in embankment.

An example of how these symbols might be used in a borrow area investigation isshown in Figure 3.5.4. Representing soil types in this manner should enable a clearerpicture to be obtained of the soils in the area being investigated. Such a representationshould be accompanied by a scaled plan to enable available quantities to becalculated.

A second example of the use of standard symbols is shown in Figure 3.5.5. This istaken from a site investigation report for a road project.

Made ground

Boulders and cabbles

Gravel

Sand

Silt

Clay

Peat

Silty sand

Note. Comsite soil types will be signified by combined symbols, e.g.


MAY 2001 Page 3.46


MAY 2001 Page 3.47


MAY 2001 Page 3.48


MAY 2001 Page 3.49

Chapter 4 Standard Test ProceduresDry Density – Moisture Content Relationship

MAY 2001 Page 4.1

CHAPTER 4

DRY DENSITY – MOISTURE CONTENT RELATIONSHIP

4.1 General Requirements

4.1.1 Introduction. Compaction is defined as the process of increasing soil unit weight byforcing soil solids into a tighter state and reducing the air voids and thus increasing thestability and supporting capacity of soil. This is accomplished by applying static ordynamic loads to the soil. Laboratory compaction tests provide the basis for controlprocedures used on earthworks, sub-grades and also for pavement works on site.

4.1.2 Scope. Based upon the site conditions, nature of the works, the type of soil and thetype of compaction equipment used, two types of tests are applied (1) Using rammermethods of compaction and (2) using vibrating methods of compaction.

4.1.3 Definitions and terminology. Definitions for the terminology used in compaction testsare given in Chapter 1.

The terminology used in compaction tests is illustrated in Figure 4.1.1.

Figure 4.1.1 Terminology used in compaction tests

4.1.4 Choice of compaction procedure

A 1L internal volume compaction mould is used when not more than 5% of the soilparticles are retained on a 20 mm sieve. Both the 2.5 kg and 4.5 kg rammer methodsmay be used. If there is a limited amount of particles up to 37.5 mm equivalent testsare carried out in the larger California Bearing Ratio (CBR) mould.

The second type of test makes use of a vibrating hammer and is intended mainly forgranular soils passing 37.5 mm test sieve, with not more than 30% retained on a 20mm test sieve. The soil is compacted into a CBR mould.

Maximumdry density

Moisture Content

Dry

den

sity

Mg/

m3

Compaction curve

Saturationline

Air void lines for a given particle density

Opt

imum

moi

stur

e co

nten

t

10%5%

0%

0


MAY 2001 Page 4.2

4.2 Sample Preparation

4.2.1 General. For soils containing particles not susceptible to crushing, one sample isrequired for test and it can be used several times after progressively increasing theamount of water.

For soils containing particles which are susceptible to crushing it is necessary toprepare separate batches of soil at different moisture contents. Consequently, a muchlarger sample is required. It may be necessary to carry out a trial compaction todetermine whether the soil is susceptible to crushing.

For stiff, cohesive soils, suggested methods are to shred the soil so that it could passthrough a 5 mm test sieve, or to chop it into pieces, e.g. to pass a 20 mm sieve.

4.2.2 Preliminary assessment of soil. An assessment of the soil is required in order todetermine which method of compaction should be used and the sample size required.

The first assessment is to decide if the soil is susceptible to crushing, i.e. whether itcontains weak particles which will crush during compaction with a 2.5 kg rammer. Ifsufficient sample is available it is preferable to use a method which assumes that thesoil susceptible to crushing.

The second assessment is to decide the approximate percentages (to an accuracy of±5%) by mass of particles passing the 20 mm and 37.5 mm sieves. Having determinedthe approximate percentages passing the 37.5 mm and 20 mm sieves, the compactiontest sample can be assigned to one of six grading zones. These are numbered 1 to 5and (x) and defined in Table 4.2.1.


MAY 2001 Page 4.3

Table 4.2.1 Summary of sample preparation methods

Gradingzone

Minimumpercentagepassing testsieves

Preparationprocedure Tablereference

Minimum massof prepared soilrequired

Type of

20 mm 37.5 (a) (b) (a) (b)

(1)

(2)

100%

95

100%

100

))) 4.2))

4.3

) kg) 6

kg15 1L

(3)

(4)

(5)

70

70

70

100

95

90

))) 4.4))

4.5

))) 16))

40 CBR

(X) Less Less (Tests not applicable)

(a) Soil particles not susceptible to crushing during compaction.(b) Soil particles susceptible to crushing during compaction.1L = one-litre compaction mould.CBR = CBR mould.

Table 4.2.1 also gives the method of sample preparation, the minimum mass of soilrequired and the type of mould to be used for the compaction test.

4.2.3 Preparation procedure. The procedure to be adopted depends on the grading zoneinto which the sample falls (see Table 4.2.1) and whether the soil is susceptible tocrushing.

The procedures are given hereafter in a series of tables, detailed as follows;

a) Table 4.2.2. Using 1L compaction mould for soils not susceptible to crushing.Grading Zones : 1 and 2.

b) Table 4.2.3. Using 1L compaction mould for soils susceptible to crushing. GradingZones : 1 and 2.

c) Table 4.2.4. Using CBR compaction mould for soils not susceptible to crushing.Grading Zones : 3, 4 and 5.

d) Table 4.2.5. Using CBR compaction mould for soils susceptible to crushing.Grading Zones : 3, 4 and 5.


MAY 2001 Page 4.4

Table 4.2.2 Sample preparation procedure Using 1L mould Soils not susceptible to crushingGrading zone

1 2 3 4 5Min. % passing 37.5 mm = 100%Min. % passing 20mm = 100%

Min. % passing 37.5 mm = 100%Min. % passing 20mm = 95%




If soil is too wet to process, air or oven dry at not more than 500C.Avoid drying completely.Gently break aggregation of soil.Determine moisture content. Weigh to 0.1% by mass the whole

sample and record the mass.Riffle/quarter to about 6 kgpassing 20 mm.

Remove and weigh to 0.1% bymass the material retained on 20mm sieve. Discard the material.Determine moisture content.Calculate additional water required

for 1st compaction point, e.g.sandy and gravelly soils start at4%-6%, for cohesive soils start at8%-10% below plastic limit.

Riffle/quarter to about 6 kgpassing 20 mm.

1L mould not suitable for this soilgrading



Add required water and mixthoroughly.

Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils).

Calculate additional water requiredfor 1st compaction point, e.g.sandy and gravelly soils start at4%-6%, for cohesive soils start at8%-10% below plastic limit.

Note : Care should be taken indrying samples which may sufferirreversible changes as a result.

Add required water and mixthoroughly

Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils)Note : Care should be taken indrying samples which may sufferirreversible changes as a result.Note : As an alternative, the wholesample could be compacted in aCBR mould. In this case, materialretained on 20 mm is notdiscarded.


MAY 2001 Page 4.5

Table 4.2.3 Sample preparation procedure Using 1L mould Soils not susceptible to crushingGrading zone






If soil is too wet to process, air or oven dry at not more than 500C.Avoid drying completely.Gently break aggregations of soil.Determine moisture content. Weigh to 0.1% by mass the whole

sample and record the mass.Riffle/quarter sample into 5 ormore representative samples,each of about 2.5 kg.

Remove and weigh to 0.1% bymass the material retained on 20mm sieve. Discard the material.Determine moisture content.Add required water and mix

thoroughly (see individual testmethods). Increments of 1%-2%are appropriate for sandy andgravelly soils, and of 2%-4% forcohesive soils.

Riffle/quarter sample into 5 ormore representative samples,each of about 2.5 kg.




Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils).Note : Care should be taken indrying samples which may sufferirreversible changes as a result.

Add required water and mixthoroughly (see individual testmethods). Increments of 1%-2%are appropriate for sandy andgravelly soils, and of 2%-4% forcohesive soils.

Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils)Note : Care should be taken indrying samples which may sufferirreversible changes as a result.Note : As an alternative, the wholesample could be compacted in aCBR mould. In this case, materialretained on 20 mm is notdiscarded.


MAY 2001 Page 4.6

Table 4.2.4 Sample preparation procedure Using CBR mould Soils not susceptible to crushingGrading zone






If soil is too wet to process, air or oven dry at not more than 500C. Avoid drying completely.Gently break aggregation of soil.Determine moisture content Weigh to 0.1% by mass the whole sample and record the mass.Riffle/quarter to about 15 kg. Remove and weigh the material

retained on 37.5 mm. Discard thismaterial.

Remove and weigh the materialretained on 37.5 mm. Discard thismaterial.

Determine moisture content.

Soils of this grading are moreusually compacted in 1L moulds,except when CBR tests are to becarried out.



Riffle/quarter to about 25 kg.

Replace this material by the samequantity of material of similarcharacteristics which passes 37.5mm and is retained on 20 mm.

Determine moisture content.Add required water and mixthoroughly.


Riffle/quarter to about 15 kg.


Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils) Store mixed material in sealed

container for minimum 24 h beforecompaction (particularly forcohesive soils)





Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils)Note : Care should be taken indrying samples which may sufferirreversible changes as a result.


MAY 2001 Page 4.7

Table 4.2.5 Sample preparation procedure Using CBR mould Soils not susceptible to crushingGrading zone






If soil is too wet to process, air or oven dry at not more than 500C. Avoid drying completely.Gently break aggregation of soil.Determine moisture content Weigh to 0.1% by mass the whole sample and record the mass.Riffle/quarter sample into 5 ormore representative samples eachof about 6 kg.

Remove and weigh the materialretained on 37.5 mm. Discard thismaterial.

Replace this material by the samequantity of material ofsimilar characteristicswhich passes 37.5mm and is retained on20 mm.

Determine moisture content. Determine moisture content.




Riffle/quarter sample into 5 ormore representative samples eachof about 6 kg.

Riffle/quarter sample into 5 ormore representativesamples each of about6 kg.

Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils)


Add required water and mixthoroughly (seeindividual testmethods). Incrementsof 1%-2% areappropriate for sandyand gravelly soils, andof 2%-4% for cohesivesoils.


Store mixed material in sealedcontainer for minimum 24 h beforecompaction (particularly forcohesive soils)

Store mixed material in sealedcontainer for minimum24 h beforecompaction(particularly forcohesive soils)


Note : Care should be taken indrying samples whichmay suffer irreversiblechanges as a result.


MAY 2001 Page 4.8

4.2.4 Modifying soil moisture content. When carrying out compaction tests it may benecessary to change the moisture content of the soil, either to a lower value, or to ahigher value. The required calculations are:

a) To decrease the moisture content from a value of x% to a value of y%, the mass ofwater required to be lost is;

x - y100 + x

x M grams

where, M is the mass of the wet soil

b) To increase the moisture content from a value of x% to a value of z%, the mass ofwater to be added is;

z - x100 + x

x M grams

4.3 Standard Compaction using 2.5 kg Rammer

4.3.1 Scope. This test method determines the optimum moisture content and maximum drydensity of a soil when compacted into a mould in three layers using a 2.5 kg rammerfalling through a height of 300 mm. In this method, 1L mould is used for soils passing20 mm sieve and CBR mould is used for soils containing not more than 30% by massof material on the 20 mm sieve which may include some particles retained on the 37.5mm sieve.

4.3.2 Apparatus. The following general apparatus is required for the test :

a) 2.5 kg compaction rammer (see Figure 4.3.1).b) Sieves of 20 mm and 37.5 mm, with receiver.c) Spatula or palette knife.d) Straight edge, e.g. a steel strip about 300 mm long, 25 mm wide, and 3 mm thick,

with one beveled edge.e) Sample tray of plastics or corrosion-resistant metal with sides, e.g. about 80 mm

deep.f) Apparatus for the determination of moisture content.g) Scoop.h) Additionally for test using 1L mould : a compaction mould similar to the one shown

in Figure 4.3.2; a balance readable to 1 g.i) Additionally for test using CBR mould : a compaction mould similar to the one

shown in Figure 4.3.3; a balance readable to 5 g.


MAY 2001 Page 4.9

350mm

4 holes6 mm dia

GUIDElength of travelof rammer= 300 mm

12 holes6 mm dia

50 mmdia

52 mmdia

48 mm

330 mm

RAMMERmass = 2.5 kg 25 g±

25 mm dia

2 mm rubbergasket

50 mmdia

50 mm

10 mm

115.5mm

10 mm

extensioncollar

pushfit

105 mm dia

118 mm dia

mouldbody

baseplate

three pins

three lugs

13 mm

180 mm dia or 150 mm square

Figure 4.3.1 BS 2.5 kg compaction rammer

Figure 4.3.2 BS 1 L compaction mould


MAY 2001 Page 4.10

580

mm

4 ho

les

6 m

m d

ia

GU

IDE

leng

th o

f tra

vel

of ra

mm

er=

450

mm

12 h

oles

6 m

m d

ia

60 m

mdi

a

52 m

mdi

a

128

mm51

0 m

m

RA

MM

ER

tota

l mas

s 4.

5 kg

50 k

g±

25 m

m d

ia

2 m

m ru

bber

gask

et

50 m

mdi

a

Figu

re 4

.4.1

B

S 4

.5 k

g co

mpa

ctio

n ra

mm

er

50 m

m

10 m

m

127

mm

10 m

m

exte

nsio

nco

llar push

fit

152

mm

dia

165

mm

dia

mou

ldbo

dy

base

plat

e

thre

e pi

ns

thre

e lu

gs

13 m

m

230

mm

dia

or

200

mm

squ

are

Fig

ure

4.3

.3

Type

s of

BS

CB

R c

omp

acti

on m

oul

ds

Two

lugs

50 m

m

152

mm

dia

exte

nsio

nco

llar

127

mm

152

mm

dia

10 m

m

mou

ld

body

deta

chab

leba

se p

late

scre

wth

read

162

mm

dia

168

mm

dia


MAY 2001 Page 4.11

4.3.3 Calibration of apparatus

4.3.3.1 Types of moulds. The standard sizes for compaction moulds are detailed in Table4.3.1.

Table 4.3.1. Standard sizes for compaction moulds

Type of mould Nominal dimensionsDiamet

mmHeight

mmVolume

cm3Height of

extension, mm‘One litre’

CBR

105

152

115.5

127

1000

2305

50 minimum

50 minimum

4.3.3.2. Mould factors. The volume of the mould can be determined using vernier calipers.Measure its internal diameter (D mm) and length (L mm) in places to 0.1 mm. Calculatethe mean dimensions, and the volume of the mould (V cm3) from the equation.

V = x D x Lπ 2

4

If necessary, mould factors can be determined. The use of these factors may makecalculations easier. Since the factors depend on physical measurements it is necessaryto recalculate the values whenever changes in the measurements are suspected.

4.3.3.2.1 Mould area factors. The mould area factor, F is the reciprocal of the cross-sectionalarea in square meters, i.e.

F D

= (1000)

sq.m2

-142π ( )

where, D = mould diameter in millimeters

Example

For the 1L compaction mould the mould area factor is :

F = (1000)

= x 90.703 = 115.49 sq.m2

-14

10512732π ( ).

4.3.3.2.2 Mould height factors. The mould height factor. H, is the same as the height of themould in millimetres. For the 1L mould, the mould height factor is 115.5.

4.3.3.2.3 Mould factor ratio

The mould factor ratio is calculated as FH

For the 1L mould this is calculated as 1.000

4.3.4 Preparation of sample. The sample should be prepared in accordance with therequirements of Tables 4.2.2 or 4.2.3 for soils with particles up to medium gravel size4.2.4 or 4.2.5 for soils with some coarse gravel size particles depending on whether the


MAY 2001 Page 4.12

soil is susceptible to crushing. When using Table 4.2.3 or 4.2.5, it can be useful to havemore than 5 prepared sub-samples, in case further points need to be established onthe compaction curve.

4.3.5 Test procedure

4.3.5.1 The mould including the base-plate is first weighed to an accuracy of 1 gm for mediumgravel and 5 gms for coarse gravel (m1). Measure the internal dimensions to 0.1 mmfor medium gravel and 0.5 mm for coarse gravel size.

4.3.5.2 Attach the extension (collar) to the mould and place the mould assembly on a solidbase, e.g. a concrete floor.

4.3.5.3 The prepared sample of moist material is divided into three approximately equalportions.

4.3.5.4 Sufficient material from the first portion is then placed in the mould so that the mould isabout a third full when the soil has been compacted. This first layer is then compactedusing 27 blows for 1L mould and 62 blows for CBR mould of the 2.5 kg rammerdropping from a controlled height of 300 mm. The blows should be evenly distributedover the surface of the material and care should be taken to ensure that soil does notstick to the face of the hammer, thus reducing the height of fall.

4.3.5.5 Material from the second and third portions is then placed in the mould, each portionbeing compacted as above. The purpose of this procedure is to compact the soil inthree equal layers and on completion, the mould should be completely filled. Onremoval of the collar, the top surface of the soil should be proud of the top rim of themould body by an amount not exceeding 6 mm. If the soil is below the top rim of themould or is proud of the mould by more than 6 mm, the test must be repeated.

4.3.5.7 The soil above the mould rim should then be struck off level with a metal straight edge.With some coarse-grained materials it may be difficult to obtain a smooth surface.Replace any coarse particles, removed in the leveling process, by finer material fromthe sample, well pressed in.

4.3.5.7 The mould, base-plate and soil are then weighed, to an accuracy of 1 gram for 1Lmould and 5 gram for CBR mould (m2).

4.3.5.8 Remove the compacted soil from the mould and place it on the metal tray. Take arepresentative sample for determination of moisture content.

4.3.5.9 For soils not susceptible to crushing break up the remainder of the soil, rub it throughthe 20 mm sieve and mix with the remainder of the prepared test sample. In case ofsoils susceptible to crushing, discard the remaining soil from each of the 5approximately 2.5 kg representative sub-samples.

4.3.5.10 Increase moisture 1% to 2% for sandy or gravelly soils and 2% to 4% for cohesive soilsand mix thoroughly into the soil. As the test progresses, the size of the increments canbe decreased to increase accuracy in determining the optimum moisture content.

4.3.5.11 Repeat steps 4.3.5.3 to 4.3.5.10 to give a total of at least 5 determinations. Themoisture contents shall include the optimum moisture content, at which the maximumdry density occurs, this point being as near to the middle of the range as is practicableto achieve.

Note. Tables 4.2.2 to 4.2.5 recommend that samples of prepared soil be allowed to“cure” for 24 h before test, particularly if they are cohesive. Good laboratory


MAY 2001 Page 4.13

practice should allow this is most cases. However, and in particular whentesting sandy or gravelly soils, it may be possible to reduce or omit thisrequirement altogether. In the latter case, an estimate can be made of thelikely optimum moisture content, and the first sub-sample made up andcompacted immediately at that moisture content, following the procedures in4.3.5.1 to 4.3.5.8.. The necessary weighings and calculations should berecorded on the test sheet. The compaction procedure is then repeated ontwo further sub-samples, at appropriate moisture contents above and belowthe estimated optimum. At this stage an estimate can be made of the drydensities of the specimens, using the calculated bulk densities and theassumption that the moisture contents are in fact what they were made up tobe. From this information it can be determined where the three points arelikely to lie on the final moisture content / dry density relationship curve, andthe remaining specimens can then be moistened and compacted accordingly.This method can achieve reliable results on suitable soils if carefully carriedout.

4.3.6 Calculation and expression of results

4.3.6.1 Calculate the internal volume of the mould. V (in cm3).

4.3.6.2 Calculate the bulk density, ρ (in Mg/m3) of each of the compacted specimens from theequation

ρ = m m

V2 1−

where, m1 is the mass of mould and base-plate (in g);m2 is the mass of mould, base-plate and compacted soil (in g).

Note. Where the height of the compacted soil specimen is the same as the height ofthe compaction mould body, e.g. in the case of the 2.5 kg and 4.5 kg rammermethods, the mould factors can be used to calculate the bulk density of thesoil as;

ρ = m m x FH2 1−

In the vibrating hammer test, where the height of the compacted soil specimen may bedifferent from the height of the compaction mould body the calculation then becomes

ρ = m m x F

H - h2 1−

Refer to Part 4.5 and Forms 4.3.1 to 4.3.4.

The dry density ρd of each compacted specimen is then calculated (in kg/m3) using theformula;

Dry density, ρ ρd = x 100

100 + w

Where, w is the moisture content of the soil.


MAY 2001 Page 4.14

The determined moisture content should be within 1% of the required moisture contentif the mixing and testing has been carried out correctly.

The graph of dry density vs moisture content is then plotted as in Figure 4.1.1. Thepoints should be joined by a curve of best fit.

The maximum dry density (MDD) and corresponding optimum moisture content (OMC)are then determined from the graph. Read off these values to three significant figures.

Note. The maximum on the curve may lie between two points, but when drawingthe curve, care should be taken not to exaggerate its peak.

4.3.6.3 If required, curves corresponding to air void contents can be plotted on the same graph(see Figure 4.1.1). These are calculated from the equation

ρ

ρ ρ

d

s

= 1 -

V100

1 -

w100

a

w

where, ρd is the dry density (in kg/m3);ρs is the particle density (in kg/m3);ρw is the density of water (in kg/m3), assumed equal to 1;Va is the volume of air voids in the soil expressed as a percentage of

the total volume of the soil (equal to 0%, 5%, 10% for the purposeof the example);

w is the moisture content (in %).

4.3.7 Report. The test report shall contain the following information :

a) the method of test used;b) the sample preparation procedure, and whether a single sample or separate

samples were used. In the case of stiff, cohesive soil the size of pieces to which thesoil was broken down shall be stated;

c) the experimental points and the smooth curve drawn through them showing therelationship between moisture content and dry density;

d) the dry density corresponding to the maximum dry density on the moisture content /dry density curve, reported as the maximum dry density to the nearest 0.01 (inMg/m3);

e) the percentage moisture content corresponding to the maximum dry density on themoisture content / dry density curve, reported as the optimum moisture content totwo significant figures;

f) the amount of stone retained on the 20 mm and 37.5 mm test sieves reported tothe nearest 1% by dry mass;

g) the particle density and whether measured (and if so the method used) orassumed.

Examples of completed test sheets are given in Forms 4.3.1 to 4.3.4.

In addition to the information above, the test sheets should contain full details of thesample description and location etc. The operator should sign and date the test sheets.


MAY 2001 Page 4.15


MAY 2001 Page 4.16

Form 4.3.2


MAY 2001 Page 4.17


MAY 2001 Page 4.18


MAY 2001 Page 4.19

4.4 Heavy Compaction using 4.5 kg Rammer

4.4.1 Scope. This type of compaction is widely used for pavement materials and also forearthworks and sub-grades if a high standard of compaction is specified.

This method may be carried out in the 1L compaction mould or in a CBR mould.

4.4.2 Apparatus, sample preparation and test procedure. The test is similar to thestandard compaction (2.5 kg rammer) as described earlier, the only differences beingthat the sample is compacted in 5 equal layers with the 4.5 kg rammer dropping from acontrolled height of 450 mm. The 4.5 kg rammer is shown in Figure 4.4.1. As previouslyeach layer still receives 27 blows / layer for a 1L mould and 62 blows / layer for a CBRmould. Calculation and reporting of results are identical to those for 2.5 kg rammercompaction test.

4.5 Vibrating Hammer Method

4.5.1 Scope. This test is applicable to granular soils containing no more than 30% by massof material retained on the 20 mm sieve, which may include some particles retained onthe 37.5 mm sieve. It is not generally suitable for cohesive soils. The principle is similarto that of the rammer procedures except that a vibrating hammer is used instead of adrop-weight rammer, and a larger mould (the standard CBR mould) is necessary.

4.5.2 Apparatus

a) Cylindrical metal mould, internal dimensions 152 mm diameter and 127 mm high(CBR mould). The mould can be fitted with an extension collar and base-plate. Themould is shown in Figure 4.3.3.

b) Electric vibrating hammer, power consumption 600-800 W, operating at afrequency in the range 25-60 Hz. For safety reasons the hammer should operateon 110V and an earth-leakage circuit breaker (ELCB) should be included in the linebetween the hammer and the mains supply.

c) Steel tamper for attaching to the vibrating hammer with a circular foot 145 mmdiameter (see Figure 4.5.1 a) and b)).

d) A balance readable to 5 g.e) 20 mm and 37.5 mm BS sieves and receiver.f) A straightedge, e.g. a steel strip about 300 mm long, 25 mm wide and 3 mm thick,

with one beveled edge.g) Depth gauge or steel rule reading to 0.5 mm.h) Apparatus for the determination of moisture content.i) Laboratory stop-clock reading to 1 s.j) A corrosion-resistant metal or plastic trays with sides, e.g. about 80 mm deep of a

size suitable for the quantity of material to be used.k) A scoop.l) Apparatus for extracting compacted specimens from the mould (optional).


MAY 2001 Page 4.20

Vibrating Hammer Assembly

Figure 4.5.1 (a)

Tamper for Vibrating Hammer Compaction Test

Figure 4.5.1 (b)


MAY 2001 Page 4.21

4.5.3 Calibration of apparatus

4.5.3.1 General. The vibrating hammer shall be maintained in accordance with themanufacturer’s instructions. Its working parts shall not be badly worn.

The calibration test described in 4.5.3.3 below shall be carried out to determinewhether the vibrating hammer is in satisfactory working order, and able to comply withthe requirements of the test.

4.5.3.2 Material. Clean, dry silica sand, from the (geological) Woburn Beds of the LowerGreensand in the Leighton Buzzard district of the UK. The grading shall be such that atleast 75% passes the 600 µm sieve and is retained on the 425 µm sieve. Dry and notpreviously used sand shall be used. This sand shall be sieved through 1 600 µm testsieve and the coarse fraction shall be discarded.

Note. This is the standard sand as described in the British Standard. Advice onsuitable suppliers can be obtained from BSI in the UK. Advice should besought from BRRL as to whether a suitable sand is available locally, toreduce dependence on costly imports.

4.5.3.3 Calibration test

a) Take a 5±0.1 kg sample of the specified in 4.5.3.2, which has not been usedpreviously and mix it with water in order to raise its moisture content to 2.5±0.5%.

b) Compact the wet sand in a cylindrical metal mould of 152 mm diameter and 127mm depth, using the vibrating hammer as specified in the section on apparatusabove.

c) Carry out a total of three tests, all on the same sample of sand, and determine themean dry density. Determine the dry density values to the nearest 0.002 Mg/m3.

Note. The operator can usually judge the required pressure to apply withsufficient accuracy after carrying out the check described in 4.5.4 below.

d) If the range of values in the three tests exceeds 0.01 Mg/ m3, repeat the procedure.Consider the vibrating hammer suitable for use in the vibrating compaction test ifthe mean dry density of the sand exceeds 1.74 Mg/m3.

Note. Advice should be sought from BRRL if a locally available replacement forthe Leighton Buzzard sand is used and the replacement does not achievea mean dry density of 1.74 Mg/m3.

4.5.3.3 Calibration of operator. Before being allowed to carry out the test the operator mustpractise with the apparatus in order to achieve the correct downward pressure requiredin the test. The downward force, including that resulting from the mass of the hammerand tamper should be 300-400 N. This force is sufficient to prevent the hammerbouncing up and down on the soil. The correct force can be determined by standing thehammer, without vibration, on a platform scale and pressing down until a mass of 30-40kg is indicated. With experience the pressure to be applied can be judged, but anoccasional check on the platform scale is advisable. If the hammer-supporting frame isused, the hand pressure required is much less but should be carefully checked.

4.5.5 Sample preparation. The procedure to be adopted depends on the grading zone intowhich the sample falls (see Table 4.2.1), and whether the soil is susceptible tocrushing. Full details of sample preparation methods are given in Tables 4.2.2 to 4.2.5.The quantities of soil required are indicated in Table 4.2.1.


MAY 2001 Page 4.22

4.5.6 Preparation of apparatus. See that the component parts of the mould are clean anddry. Assemble the mould, base-plate and collar securely, and weigh to the nearest 5 g(m1). Measure the internal dimensions of the assembly to 0.5 mm and calculate theinternal volume. The nominal dimensions of the mould give an area of cross-section of18, 146 mm2 and a volume of 2304.5 cm3 (say 2305 cm3) but these may changeslightly with wear. The inside height of the mould with collar is recorded (h1 mm).

It is particularly important to ensure the lugs and clamps holding the mould assemblytogether are secure and in good condition, in order to withstand the effects of vibration.If the mould has screw-on fittings, the threads must be kept clean and undamaged.Avoid cross-threading when fitting the base-plate and extension collar, and make surethat they are tightened securely as far as they will go without leaving any threadsexposed. Screw threads and mating surfaces should be lightly oiled before tightening.

Ensure that the vibrating hammer is working properly, in accordance with themanufacturer’s instructions. See that it is properly connected to the mains supply, andthat the connecting cable is in sound condition. The supporting frame if used, mustmove freely without sticking. The hammer should have been verified as described in4.5.3.3.

The tamper stem must fit properly into the hammer adapter, and the foot must fit insidethe CBR mould with the necessary clearance (3.5 mm all round).


4.5.7.1 Place the mould assembly on a solid base, such as a concrete floor or plinth. If the testis to be performed out of doors because of noise and vibration problems place themould on a concrete paved area, not on unpaved ground or on thin asphalt. Anyresilience in the base results in inadequate compaction.

4.5.7.2 For soils susceptible to crushing, prepare the soil to provide a sample of about 40 kgfrom which 5 (or more) separate batches of about 8 kg are obtained and made up todifferent moisture contents. It is not necessary, for soils not susceptible to crushing, tobe divided into 5 separate batches. Add a quantity of soil to the mould, such that aftercompaction the mould is one-third filled. A preliminary trial may be necessary toascertain the correct amount of soil. A disc of polyethylene sheet, of a diameter equalto the internal diameter of the mould, may be placed on top of the layer of soil. This willhelp to prevent sand particles moving up through the annular gap between the tamperand the mould.

4.5.7.3 Compact the layer with the vibrating hammer, fitted with the tamper for 60±2 s, applyinga firm pressure vertically downwards throughout.

The downward force of 300-400 N should only be applied by a practised operator (see4.5.4 above).

Repeat the above compaction procedure with a second layer of soil, and then with athird layer. The final thickness of the compacted specimen should be between 127 mmand 133 mm: if it is not, remove the soil and repeat the test.

4.5.7.4 After compaction remove any loose material from the surface of the specimen aroundthe edge of the mould collar. Lay the straight-edge across the top of the collar, andmeasure down to the surface of the specimen with the steel rule or depth gauge, to anaccuracy of 0.5 mm. Take readings at four points spread evenly over the surface, all atleast 15 mm from the side of the mould. Calculate the average depth (h2 mm). Themean height of the compacted specimen, h, is given by

h = (h - h mm1 2 )


MAY 2001 Page 4.23

where’ h1 = Height of mould.

4.5.7.5 Weigh the mould with the compacted soil, collar and base-plate to the nearest 5 g (m2).

4.5.7.6 Remove the soil from the mould and place on the tray. A jacking extruder makes thisoperation easy if fittings to suit the CBR mould are available. However, sandy andgravelly (non-cohesive) soil should not be too difficult to break up and remove by hand.

4.5.7.7 Take two representative samples in large moisture content containers for measurementof moisture content. This must be done immediately after removal from the mould,before the soil begins to dry out. The moisture content samples must be large enoughto give results representative of the maximum particle size of the soil. The average ofthe two moisture content determinations is denoted by w%.

4.5.7.8 For soils susceptible to crushing, repeat step 4.5.7.1 to 4.5.7.7 on each batch of soil inturn. For soil not susceptible to crushing break up the material on the tray and rub itthrough the 20 mm or the 37.5 mm sieve if necessary, mixing with the remainder of thesample. Add an increment of water so as to raise the moisture content by 1 to 2% (150-300 ml of water for 15 kg of soil). As the optimum moisture content is approached it ispreferable to add water in smaller increments.

4.5.7.9 Repeat stages 4.5.7.1 to 4.5.7.8 for each increment of water added. At least fivecompactions should be made, and the range of moisture contents should be such thatthe optimum moisture content is within that range. If necessary, carry out one or moreadditional test at suitable moisture contents.

Above a certain moisture content the soil may contain an excessive amount of freewater, which indicates that the optimum condition has been passed.

4.5.8 Calculation and expression of results. The following stages apply to both the aboveprocedures :

Calculate the bulk density ρ (in kg/m3), of each compacted specimen from the equation

ρ = m - m

Ah 10002 1

where, m1 = mass of mould, collar and base-plate;m2 = mass of mould, collar and base-plate with soil;h = height of compacted soil specimen = h1 – h2 mm;A = circular area of the mould (in mm2).

Calculate the density, ρd (in kg/m3), of each compacted specimen from the equation

ρρ

d = 100

100 + w

where, w, is the moisture content of the soil.

The results of the required calculations, as determinations of dry density and moisturecontent, are plotted as described in Part 4.3.6 and illustrated in Form 4.1.1 to 4.1.4.

Calculations for air voids can be calculated if required as detailed in Part 4.3.6.

4.5.9 Report. The requirements for reporting are as detailed in 4.3.7.

Chapter 5 Standard Test ProceduresCalifornia Bearing Ratio & Dynamic Cone Penetrometer

MAY 2001 Page 5.1

CHAPTER 5

STRENGTH TESTSCALIFORNIA BEARING RATIO AND DYNAMIC CONE PENETROMETER

5.1 California Bearing Ratio (CBR) Test

5.1.1 Introduction

5.1.1.1 General. The test is an empirical test which gives an indication of the shear strength ofa soil. The great value of this test is that it is comparatively easy to perform andbecause of its wide use throughout the world, there is a vast amount of data to assistwith the interpretation of results. The CBR test is essentially a laboratory test but insome instances the test is carried out on the soil in-situ.

5.1.1.2 Scope. The laboratory CBR test consists essentially of preparing a sample of soil in acylindrical steel mould and then forcing a cylindrical steel plunger, of nominal diameter50 mm, into the sample at a controlled rate, whilst measuring the force required topenetrate the sample.

A pictorial view of the general test arrangement is shown in Figure 5.1.1.

CBR values may vary from less than 1% on soft clays to over 150% on dense crushedrock samples.

Preparation of remoulded samples for the CBR test can be made in several ways.However, commonly used methods are described here:

(1) Static compression(2) Dynamic compaction by

(a) using 2.5 or 4.5 kg rammer and(b) using vibrating hammer.

5.1.2.1 Material. The CBR test is carried out on material passing a 20mm test sieve. If soilcontains particles larger than this the fraction retained on 20mm shall be removed andweighed before preparing the test sample. If this fraction is greater than 25% of theoriginal sample the test is not applicable. The moisture content of the specimen orspecimens can be adjusted as necessary following the procedure given in Chapter 4.The moisture content used is normally to the Optimum Moisture Content (OMC), butobviously this can be varied to suit particular requirements.

5.1.2.2 Mass of soil for test. When the density or air voids content of a compacted sample isspecified the exact amount of soil required for the test can be calculated as describedin a) or b) below. When a compactive effort is specified the mass of soil can only beestimated, as described in c) below.

a) Dry density specification. The mass of soil m1 (in g), required to just fill the CBRmould of volume Vm (in cm3) is given by the equation

dwm ρ)100(100V

= m1 +


MAY 2001 Page 5.2


MAY 2001 Page 5.3

where, w is the moisture content of the soil (in %); and pd is the specified drydensity (in Mg/m3).

b) Air voids specification. The dry density, ρd, (in Mg/m3), corresponding to an airvoids content of Va (in %) is given by the equation

ws

a

d

100w

+ 1

100V

- 1 =

ρρ

ρ

Where,Va is the air voids expressed as a percentage of the total volumes of soil ;ρs is the particle density (in Mg/m3);w is the soil moisture content (in %);ρw is the density of water (in Mg/m3), assumed equal to 1.

The corresponding mass of soil to just fill the CBR mould is calculated from theequation in (a) above.

c) Compactive effort specification. About 6kg of soil shall be prepared for each sampleto be tested. The initial mass shall be measured to the nearest 5g so that the massused for the test sample can be determined after compaction by difference, as acheck.

Note. Preliminary trials may be necessary to determine the required mass moreclosely.

5.1.2.3 Undisturbed samples. This method is very useful for testing of fine-grained cohesivesoils, but cannot be applied to non-cohesive materials or materials containing gravel orstones. Only the CBR moulds as described in 5.1.2.4(b) are suitable for undisturbedsampling.

5.1.2.4 Apparatus. The following apparatus is variously required to carry out the 2.5 kg, 4.5 kgand Vibrating hammer methods in Figure 5.1.2.

a) Test sieves of aperture sizes 20 mm and 5 mm.b) A cylindrical, corrosion-resistant, metal mould, i.e. the CBR mould, having a

nominal internal diameter of 152±0.5 mm. The mould shall be fitted with adetachable base-plate and a removable extension. The mould is shown in Figure4.3.3. The internal faces shall be smooth, clean and dry before each use.

c) A compression device (load press) for static compaction, (for 2.5 kg hammer).Horizontal platens shall be large enough to cover a 150mm diameter circle andcapable of a vertical separation of not less than 300 mm. The device shall becapable of applying a force of at least 300 kN.

d) Metal plugs, 152±0.5 mm in diameter and 50±1.0 mm thick, for static compaction ofa soil specimen (for 2.5 kg hammer). A handle which may be screwed into theplugs makes removal easier after compaction. The essential dimensions are shownin Figure 5.1.3. Three plugs are required for 2.5 kg hammer.


MAY 2001 Page 5.4


MAY 2001 Page 5.5

e) A metal rammer, (for 4.5 kg hammer). This shall be either the 2.5 kg rammer or the4.5 kg rammer, both as specified in Chapter 4, depending on the degree ofcompaction required. A mechanical compacting apparatus may be used providedthat it also complies with the requirements of that document.

f) An electric, vibrating hammer and tamper, as specified in Chapter 4 (for vibratinghammer).

g) A steel rod, about 16mm in diameter and 600 mm long.h) A steel straightedge, e.g. a steel strip about 300 mm long, 25 mm wide and 3mm

thick, with one beveled edge.i) A spatula.j) A balance, capable of weighing up to 25 kg readable to 5 g.k) Apparatus for moisture content determination, as described in Chapter 3.l) Filter papers, 150 mm in diameter, e.g. Whatman No. 1 or equivalent.

Figure 5.1.3 Plug for use with cylindrical mould in the CBR test (in mm).

5.1.2.5 Preparation of test sample using static compression

1. Preparation of mould

a) Weigh the mould with baseplate attached to the nearest 5 g (m2).b) Measure the internal dimensions to 0.5 mmc) Attach the extension collar to the mould and cover the base-plate with a filter

paper.d) Measure the depth of the collar as fitted, and the thickness of the spacer plug

or plugs, to 0.1 mm.

2. Preparation procedure

a) This procedure is for 2.5 kg hammer in Figure 5.1.2.b) Divide the prepared quantity of soil into three portions with a mass equal to

within 50 g of each other and seal each portion in an airtight container untilrequired for use.

c) Place one portion in the mould and level the surface. Compact to 1/3 the heightof the mould in the compression device using suitably marked steel spacerdiscs to obtain the required depth of sample (127/3 = 42 mm). The mould isthen removed from the compression device and the second portion of thematerial is added. This is then compressed to give a total sample depth to 2/3the height of the mould (i.e. 85 mm). Finally, the remainder of the sample is

∅ 150±0.5

50±1 Screw

thread


MAY 2001 Page 5.6

added and the mould is returned to the compression device until the finishedsample is just level with the top of the mould. Care should be taken not todamage the press by attempting to crush the steel mould when the sample islevel : always pay close attention to the load gauge. Except for some denseaggregates the force required for compaction should not be very large.

d) On completion of compaction weigh the mould, soil and base-plate to thenearest 5 g (m3).

e) Unless the sample is to be tested immediately, seal the sample (by screwing onthe top plate if appropriate) to prevent loss of moisture. With clay soils or soilsin which the air content is less than 5%, allow the sample to stand for at least24 h before testing to enable excess pore pressures set up during compressionto dissipate.

5.1.2.6 Preparation of sample using dynamic compaction

1. General. This method may be used if a static compression device is not available.If it is required to compact specimens to a density and moisture content other thanMaximum Dry Density and Optimum Moisture Content, it is preferable to use staticcompaction, as with dynamic compaction these can only be achieved by trial anderror.

Note. An alternative to compacting a single sample using a specified compactionmethod (see 5.1.2.6(3) below) and then carrying out a CBR test on it, is tocarry out a CBR test on each of the specimens made up during a normalcompaction test (in CBR moulds). This procedure gives a curve of varyingCBR with moisture content/dry density, an example is shown in Figure 5.1.8at the end of this document.

2. Preparation of mould. Follow the procedure given in 5.1.2.5(1) above, with theexception of 5.1.2.5(1)(d) .

3. Preparation procedure

3A. Using compaction rammers

a) This procedure is for 4.5 kg hammer in Figure 5.1.2b) The procedures for use in the CBR mould are summarised in Table 5.1.1

below.

Table 5.1.1 Dynamic compaction procedures for use in CBR mould

Test Method Mass ofRammer

(Kg)

Height ofDrop mm

Numberof Layers

Blowsper

Layer2.5 kg rammer method 2.5 300 3 62Intermediate compaction * 4.5 450 5 304.5 kg rammer method 4.5 450 5 62Vibrating hammer method ** - 3 -

* Recommended procedure to obtain a specimen density between that achievedby using the 2.5 kg and 4.5 kg rammer methods.

** See Chapter 4 for specification of vibrating hammer

c) Having decided which compaction method to use from Table 5.1.2, divide theprepared quantity of soil into three (or five) portions with a mass equal to


MAY 2001 Page 5.7

within 50 g of each other and seal each portion into an airtight container untilrequired for use.

d) Stand the mould assembly on a solid base, e.g. a concrete floor.e) Place the first portion of soil into the mould and compact it with the required

number of blows of the appropriate rammer. After compaction the layershould occupy about or a little more than one-third (or one-fifth) of the heightof the mould. Ensure that the blows are evenly distributed over the surface ofthe soil.

f) Repeat the process in (e) above using the other two (or four) portions of soil,so that the final of the soil surface is not more that 6mm above the top of themould body.

g) Remove the collar, trim the soil flush with the top of the mould with a scraper,and check with the steel straightedge that the surface is level.

h) Weigh the mould, soil and base-plate to the nearest 5 g (m3)i) Seal and store the sample as described in 5.1.2.5(2)(e)

3B. Using a vibrating hammer

a) This procedure is for Vibrating Hammer in Figure 5.1.2.b) Divide the prepared quantity of soil into three portions with a mass equal to

within 50 g of each other and seal each portion in an airtight container untilrequired for use, to prevent loss of moisture.

c) Stand the mould assembly on a solid base, e.g. a concrete floor or plinth.d) Please the first portion of soil into the mould and compact it using the

vibrating hammer fitted with the circular steel tamper. Compact for a period of60±2 s, applying a total downward force on the sample of between 300 N and400 N. The compacted thickness of the layer shall be about equal to or a littlegreater than one-third of the height of the mould.

e) Repeat 3B(d) of 5.1.2.6(3) above using the other two portions of soil in turn,so that the final level of the soil surface is not more than 6 mm above the topof the mould.

f) Remove the collar and trim the soil flush with the top of the mould with thescraper, checking with the steel straightedge.

g) Weigh the mould, soil and base-plate to the nearest 5 g (m3).h) Seal and store the sample as described in 5.1.2.5(2)(e) above.

3C. Preparation of undisturbed sample. Take an undisturbed sample from naturalsoil or from compacted fill by the procedure described in Chapter 2 using aweighed CBR mould fitted with a cutting shoe.

After removing the cutting shoe from the mould, cut and trim the ends of thesample so that they are flush with the ends of the mould body. Fill any cavitieswith fine soil, well pressed in.

Attach the base-plate and weigh the sample in the mould to the nearest 5 g (m3).Unless the sample is to be tested immediately, seal the exposed face with a plateor an impervious sheet to prevent loss of moisture.

5.1.2.7 Soaking

1. General. The test sample as prepared will normally represent the material shortlyafter compaction in the road works. However, if the material is likely to besubjected to an increase in moisture content, either from rainfall, ground-water oringress through the surfacing it is probable that its strength and, hence, CBR, willdrop as the moisture content increases. In an attempt to estimate these effectsCBR samples can be soaked in water for 4 days prior to penetration testing.


MAY 2001 Page 5.8

Some soils, especially heavy clays, are likely to swell during soaking andexcessive swelling may indicate that the soil is unsuitable for use as a sub-grade;it is, therefore, important to record the swell during soaking.

2. Apparatus. The following items are required in addition to the apparatus listed in5.1.2.4 above.

a) A perforated base-plate, fitted to the CBR mould in place of the normal base-plate (see Figure 5.1.4).

b) A perforated swell plate, with an adjustable stem to provide a seating for thestem of a dial gauge (see Figure 5.1.4).

c) Tripod, mounting to support the dial gauge. A suitable assembly is shown inFigure 5.1.4.

d) A dial gauge, having a travel of 25 mm and reading to 0.01 mm.e) A soaking tank, large enough to allow the CBR mould with base-plate to be

submerged, preferably supported on an open mesh platform.f) Annular surcharge discs, each having a mass known to ±50 g, an internal

diameter of 52-54 mm and an external diameter of 145-150 mm. As analternative, half-circular segments may be used. For practical purposes, thelatter are often easier to use.

g) Petroleum jelly.

Figure 5.1.4 Apparatus for measuring the swelling of a sample during soakingfor the CBR Test.

3. Test procedure

a) Remove the base-plate from the mould and replace it with the perforatedbase-plate.

b) Fit the collar to the other end of the mould, packing the screw threads withpetroleum jelly to obtain a watertight joint.

c) Place the mould assembly in the empty soaking tank. Place a filter paper ontop of the sample, followed by the perforated swell plate. Fit the requirednumber of annular surcharge discs around the stem on the perforated plate.

Note. One surcharge disc of 2 kg simulates the effect of approximately 70mm of superimposed construction on the sub-grade being tested.However, the exact amount of surcharge is not critical. Surchargediscs of any convenient multiples may be used.

Dial gauge mounting frame

Adjustablestem

Looking nut

Perforatedswell plate

CBR mouldbody

Perforatedbaseplate

Dial gauge

Surcharge rings

Extension collar

Sooking tank

Open mesh platform

Sample

Dial gauge

Surcharge ringsExtension collar


MAY 2001 Page 5.9

d) Mount the dial gauge support on top of the extension collar, secure the dialgauge in place and adjust the stem on the perforated plate to give aconvenient zero reading (see Figure 5.1.4)

e) The apparatus is then placed in a tank of clean water and the sample is keptsubmerged for 4 days and the dial gauge is read every 24 hours. Thedifference between the initial and final dial gauge reading gives the swell, S.The % swell is given by :

% Swell = S

127.0 x 100 =

S1.27

%

Where, S is in mm.

f) On completion of soaking surplus water is wiped from the sample which is re-weighed. The difference in weights before and after soaking is the weight ofwater absorbed, Ww. The % of water absorbed is give by :

% W

)m + (100 M = absorbed Water %

m

2W

Where Wm is original weight of sample and m2 is original moisture content.

g) Take off the dial gauge and its support, remove the mould assembly from theimmersion tank and allow the sample to drain for 15 min. If the tank is fittedwith a mesh platform leave the mould there to drain after emptying the tank. Ifwater remains on the top of the sample after draining it should be carefullysiphoned off.

h) Remove the surcharge discs, perforated plate and extension collar. removethe perforated base-plate and refit the original base-plate.

i) Weigh the sample with mould and base-plate to the nearest 5 g if the densityafter soaking is required.

j) If the sample has swollen, trim it level with the end of the mould and reweigh.k) The sample is then ready for test in the soaked condition.

5.1.2.8 Penetration test procedure

1. Apparatus. A general arrangement of apparatus is shown in Figure 5.1.5. Theapparatus consists of:

a) A cylindrical metal plunger, the lower end of which shall be of hardened steeland have a nominal cross-sectional area of 1935 mm2, corresponding to aspecified diameter of 49.65±0.10 mm. A convenient size would beapproximately 250 mm long.

b) A machine for applying the test force through the plunger, having a means forapplying the force at a controlled rate. The machine shall be capable ofapplying at least 45 kN at a rate of penetration of the plunger of 1 mm/min towithin ±0.2 mm/min.

c) A calibrated force-measuring device, usually a load ring or proving ring. Thedevice shall be supported by the cross-head of the compression machine soas to prevent its own weight being transferred to the test specimen (seeFigure 5.1.1)

Note. At least three force-measuring devices should be available, havingthe following ranges :

0 to 2 kN readable to 2 N for values of CBR up to 8%0 to 10 kN readable to 10 N for values of CBR from 8% to 40%


MAY 2001 Page 5.10

0 to 50 kN readable to 50 N for values of CBR above 40%

d) A means of measuring the penetration of the plunger into the specimen, towithin 0.01 mm. A dial gauge with 25 mm travel, reading to 0.01 mm andfitted to a bracket attached to the plunger is suitable. A general arrangementis shown in Figure 5.1.5. A dial gauge with a chisel edge to the stem anvil iseasier to use than one with a pointed stem anvil.

Note. A dial gauge indicating 1 mm/revolution is convenient since thespecified rate of penetration of 1 mm/min can be controlledconveniently by keeping the hand of the dial gauge in step with thesecond hand of a clock or watch. This is particularly convenient whenusing a non-motorised loading frame.

e) A stop-clock or stopwatch readable to 1 s.f) The CBR mould as described in Chapter 4.g) Surcharge discs as described in 5.1.2.7(2).

2. Procedure

a) Place the mould with base-plate containing the sample, with the top face ofthe sample exposed, centrally on the lower platen of the testing machine.

b) Place the appropriate annular surcharge discs on top of the sample.c) Fit into place the cylindrical plunger and force-measuring device assembly

with the face of the plunger resting on the surface of the sample. Make surethat the proving ring dial gauge is properly adjusted, i.e. that there is nodaylight between the bottom of the stem and the proving ring anvil.

Note. It may be necessary to move the crosshead up to allow the plunger tobe inserted through the surcharge discs and the stabilizer bar (iffitted). Be careful to lower the cross-head again in order to make surethat the lower platen and penetration dial gauge have enough travelleft before starting the test. This must be level before starting thepenetration test.

d) Apply a seating force to the plunger, depending on the expected CBR value,as follows:

For CBR value up to 5% apply 10 kNFor CBR value from 5% to 30%, apply 50 kNFor CBR value up to 30% apply 250 kN

Note. The number of proving ring dial gauge divisions corresponding to therequired seating load can be found from the calibration chart for thatproving ring. It is helpful to have the N/division value displayed oneach load ring. It is extremely important to ensure that themaximum allowable dial gauge reading for the proving ring isnever exceeded.

e) Record the reading of the force-measuring device as the initial zero reading(because the seating force is not taken into account during the test) or resetthe force measuring to read zero.

f) Secure the penetration dial gauge in position. Record its initial zero reading,or reset it to read zero. Make sure that all connections between plunger,crosshead, proving ring and penetration dial gauge assembly are tight.

g) Start the test so that the plunger penetrates the sample at the uniform rate of1±0.2 mm/min, and at the same instant start the timer.


MAY 2001 Page 5.11

h) Record readings of the force gauge at intervals of penetration of 0.25 mm to atotal penetration not exceeding 7.5 mm (see Form 5.1.2).

Note. If the operator plots the force penetration curve as the test is beingcarried out, the test can be terminated when the indicated CBR valuefalls below its maximum value. Thus if the CBR at 2.5 mm were seento be 6% but by 3.5 mm penetration it could be seen to have fallenbelow 6%, the test could be stopped and the result reported as:

CBR at 2.5 mm penetration = 6%CBR at 5.0 mm penetration = <6%

Dial gauge support

Dial gauge 25 travel(0.01divisions1per revolution)

Figure 5.1.5 General arrangement of apparatus for the CBR test

Surcharge rings

Detachable collar

All dimensions are in millimetres.This design has been found satisfactory, but alternative designs maybe used provided that the essential requirements are fulfilled.

Hardened steel end

Soil Sample152x 127 high

MouldTimer

49.65 0.1


MAY 2001 Page 5.12

i) If a test is to be carried out on both ends of the sample, raise the plunger andlevel the surface of the sample by filling in the depression left by the plungerand cutting away any projecting material. Check for flatness with thestraightedge.

j) Remove the base-plate from the lower end of the mould, fit it securely on thetop end and invert the mould. Trim the exposed surface if necessary. If thesample is to be soaked make sure that a perforated base-plate is used in thecorrect position.

k) If the sample is to be soaked before carrying out a test on the base follow theprocedure described in 5.1.2.7(3) above.

l) Carry out the penetration test on the base by repeating 5.1.2.8(2).m) After completing the penetration test or tests, determine the moisture content

of the test sample as follows:

(a) For a cohesive soil containing no gravel-sized particles and beforeextruding the sample from the mould, take a sample of about 350 gfrom immediately below each penetrated surface, but do not includefilling material used to make up the first end tested. Determine themoisture content of each sample.

Note. If the sample has been soaked the moisture content aftersoaking will generally exceed the initial moisture content.Because of the possibility of moisture gradients thedetermination of dry density from the moisture content aftersoaking may have little significance. If required, the drydensity after soaking can be calculated from the initial samplemass and moisture content and the measured increase inheight due to swelling.

(b) For a cohesionless soil or a cohesive soil containing gravel-sizedparticles, extrude the complete sample, break it in half and determinethe moisture contents of the upper and lower halves separately.


1. Force-penetration curve

a) Calculate the force applied to the plunger from each reading of the force-measuring device observed during the penetration test.

Note. Alternatively, readings of the force-measuring device may be plotteddirectly against penetration readings. Forces are then calculated onlyat the appropriate penetration values as in 5.1.2.6(1)(c).

b) Plot each value of force as ordinate against the corresponding penetration asabscissa and draw a smooth curve through the points.

The normal type of curve is convex upwards as shown by the curve labeledTest 1 in Figure 5.1.6 and needs no correction. If the initial part of the curve isconcave upwards as for Test 2 (curve OST) in Figure 5.1.6, the followingcorrection is necessary. Draw a tangent at the point of greatest slope, i.e. thepoint of inflexion, S, and produce it to intersect the penetration axis at Q. Thecorrected curve is represented by OST, with its origin at Q from which a newpenetration scale can be marked.


MAY 2001 Page 5.13

If the graph continues to curve upwards as for Test 3 in Figure 5.1.6, and it isconsidered that the penetration of the plunger is increasing the soil densityand therefore its strength, the above correction is not applicable.

c) Calculation of California Bearing Ratio. The standard force-penetration curvecorresponding to a CBR value of 100% is shown by the heavy curve in Figure5.1.7, and forces corresponding to this curve are given in Table 5.1.2. TheCBR value obtained from a test is the force read from the test curve (aftercorrection and calculation if necessary) at a given penetration expressed as apercentage of the force corresponding to the same penetration on thestandard curve. Curve representing a range of CBR values is included inFigure 5.1.7.

Penetrations of 2.5mm and 5mm are used for calculating the CBR value.From the test curve, with corrected penetration scale if appropriate, read offthe forces corresponding to 2.5 mm and 5 mm penetration. Express these asa percentage of the standard force at these penetrations, i.e. 13.2 kN and 20kN respectively. Take the higher percentage as the CBR value.

If the force-penetration curve is plotted on a diagram similar to Figure 5.1.7the CBR value at each penetration can be read directly without furthercomputation if the correction described in 5.1.2.9(1)(b) for test 2 is notrequired. The same diagram can be used for small forces and low CBRvalues if both the force scale (ordinate) and the labeled CBR values(abscissa) are divided by 10 as shown in brackets in Figure 5.1.7.

Table 5.1.2 Standard force-penetration relationships for 100% CBR

Penetration Forcemm2

2.54568

kN11.513.217.620.022.226.3

kgf*117213451793203822622680

*Standard force in kilonewton converted using factor of 9.807

Note. Older equipment may be calibrated in imperial units, in which case

CBR at 0.1 inches penetration = Test load (1bf)

3000 x 100%

CBR at 0.2 inches penetration = Test load (1bf)

4500 x 100%

2. Density calculations

a) Determine the internal volume of the mould, Vm (in cm3).

b) Bulk density. The initial bulk density, ρ (in kg/m3), of a sample compactedwith a specified effort (preparation methods 4.5 kg and vibrating hammer);see Figure 5.1.2, or of an undisturbed sample, is calculated from theequation:


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ρ = m - m

V3 2

m

where, m3 is the mass of soil, mould and base-plate (in g);m2 is the mass of the mould and base-plate (in g);Vm is the volume of the mould body (in cm3),

c) Dry density. The initial dry density, ρd (in kg/m3 ), of the sample is calculatedfrom the equation :

ρρ w+ 100

100 =

d

where, w is the moisture content of soil (in %).

If the dry density, ρds (in Mg/m3), of the soaked soil is required, calculate itfrom the equation:

ρρ

ds = 1 +

Ax1000 V

d

m

where,A is the area of cross section of the mould (in mm2)x is the increase in sample height after swelling (in mm).

Examples of completed calculations are given in Forms 5.1.1, 5.1.2 and5.1.3.

5.1.2.10 Report. The test report shall affirm that the test was carried out in accordance with thisPart of this standard. The results of tests on the top and bottom ends of the sampleshall be indicated separately.

The test report shall contain the following information:

a) the method of test used;b) force-penetration curves, showing corrections if appropriate;c) the California Bearing Ratio (CBR) values, to two significant figures. If the results

from each end of the sample are within ±10% of the mean value, the average resultmay be reported;

d) the initial sample density and the moisture content and dry density if required;e) the method of sample preparation;f) the moisture contents below the plunger at the end of each test, or the final

moisture contents of the two halves of the sample;g) whether soaked or not, and if so the period of soaking and the amount of swell.h) the proportion by dry mass of any over-size material removed from the original soil

sample before testing;i) information on the description and origin of the sample, as detailed on the test

forms.


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5.2 Dynamic Cone Penetrometer (DCP) Test

5.2.1 General. The dynamic cone penetrometer (DCP) test was developed by Transport andRoad Research Laboratory (TRRL), England. The DCP is an instrument designed forthe rapid in-situ measurement of the structural properties of existing road pavementsconstructed with unbound materials. It is also used for determining the in-situ CBRvalue of compacted soil sub-grade beneath the existing road pavement. Continuousmeasurements can be made down to a depth of 800 mm or, when an extension rod isfitted, to a depth of 1200 mm. Where pavement layers have different strengths theboundaries can be identified and the thickness of the layers determined.

Correlations have been established between measurements with DCP and CaliforniaBearing Ratio (CBR) so that results can be interpreted and compared with CBRspecifications for pavement design. Agreement is generally good over most of therange but differences are apparent at low values of CBR, especially for fine-grainedmaterials. A typical test takes only a few minutes and therefore the instrument providesa very efficient method of obtaining information which would normally require thedigging of test pits.

5.2.2 Apparatus. The DCP uses an 8kg weight dropping through a height of 575 mm and a60" cone having a diameter of 20mm. The apparatus is assembled as shown in Figure5.2.1. It has the following parts :

a) Handleb) Top Rodc) Hammer (8kg)d) Anvile) Handguard Cursorf) Bottom Rodg) 1 Meter ruleh) 60o Conei) Spanners and tommy bar are used to ensure that the screwed joints are

dept tight at all times.

The following joints should be secured with loctite or similar non-hardening threadlocking compound prior to use :

(i) Handle/top rod(ii) Anvil/bottom rod(iii) Bottom rod/cone

5.2.3 Procedure

a) After assembly, the zero reading of the apparatus is recorded. This is done bystanding the DCP on a hard surface, such as concrete, checking that it is verticaland then entering the zero reading in the appropriate place on the proforma (Form5.2.1).


MAY 2001 Page 5.22

Figure 5.2.1 Dynamic cone penetrometer assembly

600 INC

1960

mm

AP

PR

OX


MAY 2001 Page 5.23

b) The instrument is held vertical as shown in Figure 5.2.2 and the weight carefullyraised to the handle. Care should be taken to ensure that the weight is touching thehandle, but not lifting the instrument, before it is allowed to drop and that theoperator lets it fall freely and does not lower it with his hands.

Note. If during the test the DCP leaves the vertical no attempt should be made tocorrect this as contact between the bottom rod and the sides of the hole willgive rise to erroneous results.

c) It is recommended that a reading should be taken at increments of penetration ofabout 10mm. However, it is usually easier to take a scale reading after a setnumber of blows. It is therefore necessary to change the number of blows betweenreadings according to the strength of the layer being penetrated. For good qualitygranular bases readings every 5 or 10 blows are normally satisfactory but forweaker sub-base layers and sub-grades readings every 1 or 2 blows may beappropriate.

Note. There is no disadvantage in taking too many readings, however if readingsare taken too infrequently, weak spots may be missed and it will be moredifficult to identify layer boundaries accurately, hence important informationwill be lost.

d) After completing the test the DCP is removed by gently tapping the weight upwardsagainst the handle. Care should be taken when doing this as if it is done toovigorously the life of the instrument will be reduced.

Note 1. Penetration rates as low as 0.5 mm/blow are acceptable but if there is nomeasurable penetration after 20 consecutive blows it can be assumedthat the DCP will not penetrate the material. Under these circumstances ahole can be drilled through the layer using an electric or pneumatic drill orby coring. The lower layer can then be tested in the normal way. If onlyoccasional difficulties are experienced in penetrating granular materials itis worthwhile repeating any failed tests a short distance away from theoriginal test point.

2) Cone should be replaced when its diameter is reduced by 10 percent.

5.2.4 Calculation and expression of results. The results of the DCP test are usuallyrecorded on a field data sheet similar to that shown in Form 5.2.1. The results can theneither be plotted by hand Figure 5.2.3 or processed by computer. The boundariesbetween layers are easily identified by the change in the rate of penetration. Thethickness of the layers can usually be obtained to within 10 mm except where it isnecessary to core (or drill holes) through strong materials to obtain access to the lowerlayers. In these circumstances the top few millimeters of the underlying layer is oftendisturbed slightly and appears weaker than normal. Relationship between the DCPreadings and CBR can be obtained by the following equation:

1.35)(Pen

3700 =percent CBR - DCP

The Pen5 = Penetration in mm, every 5 blow interval. Relationship between the DCPreading and the CBR can also be found from Kleyn and Van Hearden graph as shownin Figure 5.2.4.


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Figure 5.2.2 Dynamic Cone Penetrometer in Action


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a) The method of test usedb) Data sheet shall be included (Form 5.2.1)c) Blows - Penetration depth curve (Figure 5.2.3) and CBR (%) value.

All other necessary information, needed by the client, should be added


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Form 5.2.1


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Chapter 6 Standard Test ProceduresDetermination of In-situ Density

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CHAPTER 6

DETERMINATION OF IN-SITU DENSITY

6.1 Introduction

In-situ density is widely used to control the field compaction of earthworks andpavement layers. There are a number of methods available for measuring in-situdensity but only the two common methods are considered here. These are the core-cutter method and the sand replacement method.

6.2 Sand Replacement Method

6.2.1 Introduction. The sand replacement method is the most widely used in-situ densitytest. Although the test takes slightly longer to perform than some other in-situ densitytests, the test may be carried out on most type of materials.

There are various types of sand replacement equipment in use, but all types havethe following essential features.

a) A sand container or bottleb) A valve to start or stop the flow of sandc) A core connected to the valve and intended to fit over the area being tested.d) A base plate which acts as a template during the excavation of the soil.

The stated size of the pouring cylinder relates to the diameter of the cone and thusthe diameter of the hole to be excavated. The three sizes commonly available are100 mm, 150 mm and 200 mm. The 100mm apparatus is mainly used for fine grainedsoils as used for earthworks and the 200mm apparatus is intended for coarsegrained materials as used in the sub-base and base layers.

6.2.2 Apparatus. The following apparatus is required for the test :

a) A pouring cylinder (Small or Large) (see Figure 6.2.1.)b) Suitable tools for excavating holes in compacted soil (bent spoon, scraper tool,

hammers, chisels and paint brush)c) Cylindrical metal calibrating container with an internal diameter of 200±5 mm and

internal depth of 250 mm fitted with a lip about 75 mm wide and about 5 mm thicksurrounding the open end for large pouring cylinder and internal diameter 100±2mm and internal depth of 150±3 mm fitted with a lip about 50 mm wide and about5 mm thick is required (see Figure 6.2.2).

d) Balance, readable to 10g for the large pouring cylinder method, or readable to 1g for the small pouring cylinder method.

e) Glass plate of 10mm thick and about 500mm square.f) Metal trays or containersg) Apparatus for moisture content determinationh) A metal tray about 500mm square and about 50mm deep with a 200mm diameter

hole in the centre for large pouring cylinder and about 300mm square and about40mm deep with a 100mm diameter hole in the centre.

i) Clean closely graded, preferably with rounded grains replacement sand. (100%passing 600µm sieve and 100% retained on the 75µm sieve).


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6.2.3 Calibrations

6.2.3.1 Calibration of apparatus. When the apparatus is used for a test a certain amountof sand is contained in the cone above the excavated hole. This weight of sand mustbe deducted from the total weight of sand used in the test in order to determine theexact weight of sand used to fill the hole. The apparatus must then be calibrated todetermine the weight of sand in the cone. As the weight of sand in the cone will varyslightly with the type of sand used, calibration of the apparatus should take placeeach time the sand is calibrated.

One minor complication is that generally the base-plate is left in place during the testand a small amount of sand is retained between the base-plate and the cone. In thiscase, the calibration of the apparatus should be carried out using both base-plateand cone. It is not normal to use the base-plate when calibrating the sand so, in thiscase, the calibration of the apparatus should be done with the cone only.

To calibrate the apparatus, it is partly filled with sand and weighed. The apparatus(with base-plate if required) is then placed on a flat glass plate and the valve isopened. When the cone is completely full of sand, the valve is closed and theapparatus is re-weighed. The difference between the two weights is the weight ofsand in the cone and base-plate if used. The calibration is normally repeated threetimes and the average value taken.

6.2.3.2 Calibration of sand. The sand should be stored in a clean container and protectedfrom rain and damp and should be airtight. The purpose of the calibration is todetermine the density of the sand being used. Each new batch of sand should becalibrated before use and existing sand should be calibrated weekly or monthlydepending on the frequency of use. The calibrating container is of the same diameteras the apparatus being used and has a depth similar to that of the hole excavated forthe test. To use the container, fill the apparatus first with sand and weigh it. Thenplace the cone over the calibration container and open the valve to allow the sand tofill the cone and the container. When the cone is completely full close the valve andreweigh the apparatus. The difference between these two weights is the weight ofsand in the container plus the weight of sand in the cone. The weight of sand in thecone is found from the calibration of apparatus and may be deducted from the totalweight of sand to give the weight of sand in the container. The container is thenemptied, weighed and then filled with clean water. Wipe off any surplus water on thesides of the containers with a clean cloth and reweigh the container plus water. Theweight of water in the container and thus its volume are then determined. Repeatthese measurements at least three times and calculate the mean values.

6.2.4. Excavation of test hole

6.2.4.1 Preparation of surface. Expose a flat area, approximately 600mm square(approximately 450mm square for the small cylinder method) of the soil to be testedand trim it down to a level surface. Brush away any loose material which is not part ofthat being tested. The surface should be as level as possible in order to reproducethe laboratory calibration conditions.

6.2.4.2 Excavation procedure

1) Lay the metal tray on the prepared surface with the hole over the portion of thesoil to be tested. Run a trowel or other sharp tool around the outside of the tray,marking square on the surface of the soil being tested. This will help to positionthe pouring cylinder during the later stages of the test. It is often helpful for thetray to be nailed to the ground to stop it moving during the excavation of the testhole.


MAY 2001 Page 6.5

2) Using the hole in the metal tray as a pattern, excavated a round hole,approximately 200 mm in diameter (100 mm for the small cylinder method) andthe depth of the layer to be tested up to a maximum of 250 mm deep (150 mm forthe small cylinder method). Do not leave loose material in the hole and do notdistort the immediate surround to the hole. Carefully collect all the excavated soilfrom the hole and determine its mass, mw to the nearest 10g (1 g for the smallcylinder method). Remove the metal tray before placing the pouring cylinder inposition over the excavated hole.

Note. Take care in excavating the hole to see that the hole is not enlarged bylevering the excavating tool against the side of the hole, as this willresult in lower densities being recorded.

3) Place a representative sample of the excavated soil in an airtight container anddetermine its moisture content, w. Alternatively, the whole of the excavated soilshall be dried and its mass md, determined.

4) Place the pouring cylinder filled with the constant mass of sand (m1) so that thebase of the cylinder covers the hole concentrically. This is assisted by the squarepreviously marked around the tray. Keep the shutter on the pouring cylinderclosed during this operation. Open the shutter and allow sand to run out; duringthis period do not vibrate the pouring cylinder or the surrounding area. When nofurther movement of the sand takes place, close the shutter. Remove the cylinderand determine the mass of sand remaining in it (m4) to the nearest 10 g (nearest1 g for the small cylinder method). For the small cylinder method this is easilydone by weighing the cylinder and remaining sand together.

6.2.5 Calculation and expression of results

6.2.5.1 Calculations

1) Calculate the mass of sand required to fill the calibrating container, ma (in g),from the equation:

ma = m1 - m3 - m2

wherem1 is the mass of [cylinder and] sand before pouring in the calibrating container(in g) :m2 is the mean mass of sand in cone (in g);m3 is the mean mass of [cylinder and] sand after pouring into the calibratingcontainer (in g).

2) Calculate the bulk density of the sand. ρa (in Mg/m3), from the equation :

ρa = ma

V

where, V is the volume of the calibrating container (in mL).

ρ


MAY 2001 Page 6.6

3) Calculate the mass of sand required to fill the excavated hole, mb (in g). from theequation:

mb = m1 - m4 - m2

where,m1 is the mass of [cylinder and] sand before pouring in the hole (in g) :m2 is the mean mass of sand in the cone (in g);m4 is the mean mass of [cylinder and] sand after pouring into the hole (in g)

4) Calculate the bulk density of the soil. ρ (in mg/m3). from the equation:

ρ ρ = mm

w

ba

wheremw is the mass of soil excavated (in g);mb is the mean mass of sand required to fill the hole (in g);ρa is the bulk density of the sand (in Mg/m3).

5) Calculate the dry density, ρd (in Mg/m3), from the equation:

w+100100

= ρ

ρd

where, w is the moisture content of the soil (in %).

6) Calculate the in-situ relative compaction (RC) of the tested layer from theequation :

%100 MDD

= RC d xρ

where,MDD is the Maximum Dry Density obtained from the compaction test used as thestandard for the particular layer. Note that the type of compaction test used isdependent on the type of material.

Example of completed calculations are shown in Forms 6.2.1 to 6.2.3.

6.2.6 Report. The correct test form must be used for the report. The report shall containthe following information:

a) The in-situ bulk and dry densities of the soil (in Mg/m3) to the nearest 0.01 inMg/m3.

b) The moisture content. as a percentage, to two significant figures.c) All other information required by the test form. e.g. sample origin, description etc.d) The operator should sign and date the test form.


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6.3 Core Cutter Method

6.3.1 Introduction. This method is only used on fine-grained cohesive soils which do notcontain stones. It is, therefore, very useful for control of earthworks and subgradematerials but is not suitable for coarse grained pavement materials. The testinvolves jacking or hammering a steel cylinder of known mass and volume into thesoil, excavating it and finding the mass of soil contained in the cylinder.

6.3.2 Apparatus. The following apparatus is required for the test :

a) Cylindrical steel core cutter. 130 mm long and of 100±2 mm internal diameter,with a wall thickness of 3mm beveled at one end, of the type illustrated in Figure6.3.1. The cutter shall be kept lightly greased.

Note. If the average density over a smaller depth is required, then theappropriate length of cutter should be used.

b) Steel dolly, 25 mm high and of 100 mm internal diameter, with a wall thickness of5mm, fitted with a lip to enable it to be located on top of the core cutter (seefigure 6.3.1).

c) Steel rammer.d) Balance, readable to 1 g.e) Palette knife, a convenient size is one having a blade approximately 200 mm long

and 30 mm wide.f) Steel rule, graduated to 0.5 mm.g) Short-handled hoe, or spade, and pickaxe.h) Straightedge, e.g. a steel strip about 300 mm long 25 mm wide and 3 mm thick,

with one beveled edge.i) Apparatus for moisture content determination.j) Apparatus for extracting samples from the cutter (optional).

6.3.2 Care and preparation of apparatus

6.3.2.1 Care of apparatus. The condition of the cutting edge should be frequently checkedas any damage will lead to inaccuracy in the test. A badly damaged edge may be re-formed on a lathe taking care to cut the new edge square to the long axis of themould. Any repair to the cutting edge will require the mould factor to be re-determined.

6.3.3.2 Preparation of apparatus

a) Calculate the internal volume of the core cutter in cubic centimetres from itsdimensions which shall be measured to the nearest 0.5 mm (Vc).

b) Weigh the cutter to the nearest 1 g (mc).c) Mould factor, To assist in the calculation of the bulk density of the soil it can be

useful to calculate a mould factor for each cutter, and to stamp or paint the value

on the mould. For the size of core cutter detailed above, the mould factor ratio FH

calculates as 0.979. This value would be used as a multiplier for the mass of wetsoil in the core cutter (in g).


MAY 2001 Page 6.11

Alternatively, a mould factor can be calculated as :

Mould Factor F = 4

x D x H(1000)

x (1000)2

3

π

F = 0.7854 x D x H(1000)

2

2

Where,D is the diameter of the mould in mm.H is the height of the mould in mm.

The value obtained from this calculation is used as a divisor to the mass of wetsoil in the core cutter (in g).


MAY 2001 Page 6.12


6.3.4.1 The area to be tested is first leveled and all loose material removed. The lightlygreased mould with driving dolly fixed is placed in position with the cutting edge onthe prepared surface.

6.3.4.2 The mould is then slowly driven into the soil by use of a jack or with a suitablerammer (see Figure 6.3.1). Take care not to rock the mould and drive the cutter untilonly about 10 mm of the dolly remains above the surface of the soil.

The use of a jack is to be preferred as this causes least disturbance to the soil.However, some form of reaction weight such as a vehicle is required. To use a jack, ablock of wood is first placed on the top of the dolly and a hydraulic or screw jack isthen placed between the wood block and the underside or the reaction weight(normally a jeep). The jack is then extended so that the mould is driven squarely intothe ground until only about 10mm of dolly is remaining above the surface. If driving iscontinued until the soil completely fills the mould and dolly, there is a danger ofcompressing the soil in the mould, thus giving incorrect results.

6.3.4.3 The mould, dolly and soil are then dug out of the ground using a spade. The soil inthe mould should not be disturbed during this operation.

6.3.4.4 The driving dolly should then be removed from the mould and the soil protruding fromeach end of the mould trimmed off using a straight edge. The mould and soil areweighed, ms.

6.3.4.5 The soil in the mould is then removed, crumbled and representative samples takenfor moisture content.

6.3.5 Calculation and expression of results. In principle, the bulk density of the soil.ρ ( in Mg / m3) , is calculated from the equation :

ρ = ms − m

Vc

c

where,ms is the mass of soil and core cutter (in g);mc is the mass of core cutter (in g);Vc is the internal volume of core cutter (in mL).

Alternatively, using the mould factor ratio (see Chapter 4), the bulk density of the soil,ρ ( in Kg / m3) , can be calculated from the equation :

HF

x m - m = csρ

As a second alternative, using the mould factor F, the bulk density of the soil,ρ ( in kg / m3) can be calculated from the equation :

ρ = ms − m

Fc

Value in kg/m3 are converted to Mg/m3 by dividing by 1000.


MAY 2001 Page 6.13

Calculate the dry density, ρd (Mg/m3) from equation :

ρρ

d = 100

100 + w

where, w is the moisture content of the soil (in %).

The in-situ bulk and dry densities of the soil (Mg/m3), are expressed to the nearest0.01 Mg/m3.

An example of a completed test calculation is given in Form 6.3.1 at the end of thisdocument.


a) the method of the test used;b) the in-situ bulk and dry densities of the soil in Mg/m3) to the nearest 0.01 Mg/m

3

;c) the moisture content, (in %), to two significant figures;d) all other details required by the test form regarding sample origin and

description etc;e) the operator should sign and date the test form.


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Chapter 7 Standard Test ProceduresTests For Aggregates And Bricks

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CHAPTER 7

TESTS FOR AGGREGATES AND BRICKS

7.1 Determination of Clay and Silt Contents in Natural Aggregates

7.1.1 Scope. This test covers the determination of the amount of material finer than the 75micron sieve by washing. Clay particles and other aggregate particles that aredispersed by the wash water, as well as water-soluble materials, will be removed fromthe aggregate during the test. In addition to the test which uses water only for thewashing of the material, there is another test in which a dispersing agent is used inassisting the loosening of the material finer than the 75 micron sieve. Unless otherwisestated water only will be used.

7.1.2 Method outline. A sample of the aggregate is washed in a prescribed manner usingwater. The decanted wash water, containing dissolved and suspended material, ispassed through the 75 micron test sieve. The loss in mass resulting from the washtreatment is calculated as a percentage of the original sample and is reported as thepercentage of material finer than the 75 micron sieve by washing.

7.1.3 Equipment

7.1.3.1 Balance, which shall be capable of weighing a mass of aggregate appropriate to themaximum size of aggregate and accurate to 0.1 g.

7.1.3.2 Test sieves. A nest of two sieve, the lower being the 75 micron test sieve and the upperbeing a sieve with openings in the range of 2.36 mm to 1.18 mm.

7.1.3.3 Container, which will permit the sample with water to be vigorously agitated without anyloss of aggregate or water.

7.1.3.4 Oven, of sufficient capacity to heat and maintain the temperature to 1100C plus orminus 50C.

7.1.4 Sampling. Sampling shall be in accordance with the test method described in Chapter2. Reduction of the bulk sample must also be carried out in order that the requiredmass of material for the test is obtained. After reduction, which will yield the testportion, the mass of the test portion shall comply with the values given in Table 7.1.1.

Table 7.1.1 Minimum mass of test portion

Nominal maximum size of aggregate Minimum mass, g2.36 mm5.00 mm10.0 mm20.0 mm28.0 mm40.0 mmLarger than 63.0 mm

10050010002500500050005000


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7.1.5 Material finer than the 75 micron sieve test

7.1.5.1 Procedure

a) Dry the test sample in the oven to constant mass at a temperature of 1100C plus orminus 50C. Determine the mass to the nearest 0.1% of the total mass of the testsample.

b) Place the sample in a container and add sufficient water to cover it. No detergent,or other substance shall be added to the water. Agitate the sample and water withsufficient vigour to result in complete separation of the particles finer than 75micron sieve from the coarser particles and to bring the fine material intosuspension. The use of a large spoon or other similar instrument to stir and agitatethe materials may be used. Immediately pour the wash water containing thesuspended and dissolved particles over the nested sieves so arranged that thecoarser sieve is at the top. Avoid decanting the coarser aggregates.

c) Add a second charge of water to the sample in the container, agitate, and decantas before, the operation being repeated as many times as is necessary for thewash water to be clear.

d) Return all material retained on the nested sieves by flushing to the washed sample.Dry the washed sample in the oven to constant mass at 1100C plus or minus 50Cand determine the mass of the sample to the nearest 0.1% of the original mass ofthe sample.

Note. Following the washing of the sample and flushing any materials retainedon the 75 micron sieve back into the container, no water should bedecanted from the container except through the 75 micron sieve. This isto avoid any accidental loss of material. Excess water from flushingshould be evaporated in the drying process.

7.1.5.2 Calculation. Calculate the amount of material passing the 75 micron sieve by washing,using the following expression:

A = 100 x (B – C) / B

Where,A is the percentage of material finer than the 75 micron sieve by washing.B is the original dry mass of sample in grams.C is the dry mass of sample in grams after washing.

7.1.5.3 Test Report. Report the amount of material passing the 75 micron sieve by washing tothe nearest 0.1%, except if the result is 10% or more, report to the nearest 1.0%.

Data sheets are given as Form 7.1.1 and 7.1.2.


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7.2 Particle Size Distribution of Aggregates

7.2.1 Dry sieving test

7.2.1.1 Introduction. This test is primarily used to determine the grading of materials proposedfor use as aggregates or being used as aggregates. The results are used to determinecompliance with the particle size distribution with applicable specification requirementsand to provide necessary data for the control of the production of various aggregateproducts and mixtures containing aggregates.

7.2.1.2 Scope. This test covers the determination of the particle size distribution (PSD) orsieve analysis of fine and coarse aggregate by sieving. An accurate determination ofthe amount finer than the 75 micron sieve cannot be achieved by this method. Testmethod 7.1.5 should be used to determine the amount of material finer than the 75micron sieve.

7.2.1.3 Equipment

a) Balance, of appropriate capacity for the size of sample and capable of accuracy to0.1% of the mass of the sample.

b) Test sieves. A complete nest of sieves in accordance with the sizes required by thespecification and which must comply with the relevant standards. Sieves withopenings larger than 125mm shall have a permissible variation in average openingof plus or minus 2% and shall have a nominal wire diameter of 8.0mm or larger. Aset of the sizes and apertures given in Table 7.2.1 will cover most applications ofthe method.

c) Mechanical sieve shaker (Optional).d) Oven, of appropriate size capable of maintaining a uniform temperature of 110ºC

plus or minus 5ºC.e) Trays and containers.

Table 7.2.1 Particulars of sieves for sieve analysis

Square perforated plate, 450 mm or300mm diameter

mm

Wire cloth, 300 mm or 200 mmdiameter

mm (unless stated)

75.063.050.037.528.020.014.010.06.305.00

3.352.361.701.18

850 micron600 micron425 micron300 micron212 micron150 micron75 micron


MAY 2001 Page 7.6

Table 7.2.2 Minimum mass of test portion required for sieve analysis

Nominal size of material mm Minimum mass of test portion Kg.63504028201410653

less than 3

503515521

0.50.20.20.20.1

7.2.1.4 Sampling. Sample the aggregate in accordance with test procedure described inChapter 2.1. The test portion shall comply with the values given in Table 7.2.2.Reduction of the sample shall be made in accordance with 2.9.1.1.

7.2.1.5 Procedure

a) If the test sample has not been subjected to testing using method 7.1 (material finerthan the 75 micron test sieve by washing), dry it to constant mass at a temperatureof 100ºC plus or minus 5ºC and determine the mass of it to the nearest 0.1% of thetotal original dry sample mass.

b) Select the sieve sizes suitable to furnish the information required by thespecification covering the material to be tested. Nest the sieves in order ofdecreasing opening size from top to bottom and place the sample, or portion of asample if it is to be sieved in more than one increment, on the top sieve. Agitate thesieves by hand or by mechanical means for a sufficient period, established by trialor checked by measurement on the actual sample, to meet the criteria foradequacy of sieving described in the note below.

Note. Adequacy of sieving criteria : Sieve for a sufficient period and in such

manner that, after completion, not more than 0.5% by mass of the totalsample passes any sieve during 1 minute of continuous hand sievingperformed as follows :

Hold the individual sieve, provided with a snug-fitting pan and cover, in a

slightly inclined position in one hand. Strike the side of the sieve sharplyand with an upward motion against the heel of the other hand at the rate ofabout 150 times per minute, turn the sieve about one-sixth of a revolution atintervals of about 25 strokes. In determining sufficiency of sieving for sizeslarger than the 4.75 mm sieve, limit the material on the sieve to a singlelayer of particles. If the size of the mounted testing sieves makes thedescribed sieving motion impractical, use 200mm diameter sieves to verifythe sufficiency of sieving.

c) Limit the quantity of material on a given sieve so that all particles have opportunity

to reach the sieve opening a number of times during the sieving operation. Forsieves with opening smaller than 4.75 mm the mass retained on any sieve at thecompletion of the sieving operation shall not exceed 6 kg/m2 , equivalent to 4 g/in2

of sieving surface. For sieves with opening 4.75 mm and larger, the mass in kg/m2

of sieving surface shall not exceed the product of (2.5) x (sieve opening inmillimeters).


MAY 2001 Page 7.7

Note. The 6 kg/m2 amounts to 194 g for the usual 200mm diameter sieve.

d) Determine the mass of each size increment by weighing to the nearest 0.1% of thetotal original dry sample mass. The total mass of the material after sieving shouldbe checked closely with original mass of sample placed on the sieves. If theamounts differ dry more than 0.3%, based on the original dry sample mass, theresults should not be used for acceptance purposes.

e) If the sample had previously been tested by 7.1.5 add the amount finer than the 75micron sieve determined by that method to the mass passing the 75 micron sieveby dry sieving of the same sample in this method.

7.2.1.6 Calculation. Calculate percentages passing, total percentages retained, orpercentages in various size fractions to the nearest 0.1% on the basis of the total massof the initial dry sample.

7.2.1.7 Report. The report shall include the following information:

a) Total percentage of material passing each sieve.b) Total percentage of material retained on each sieve.c) Report percentages to the nearest whole number, except if the percentage passing

the 75 micron sieve is less than 10%, it shall be reported to the nearest 0.1%.

A data sheet is given as Form 7.2.1.

7.2.2 Fineness modulus of fine aggregate

7.2.2.1 Using the procedure for sieve analysis of fine aggregate described in 7.2.1 above,calculate the fineness modules by adding the total percentages of material in thesample that is coarser than each of the following sieves (cumulative percentagesretained) and dividing the sum by 100.

Sieve size Sieve size

150 micron 4.75mm300 micron 9.5 mm600 micron 19.0mm1.1mm 37.5mm2.3mm and larger, increasing the ratio of 2 to 1

7.2.2.2 Report. Report the fineness modulus to the nearest 0.01.


MAY 2001 Page 7.8


MAY 2001 Page 7.9

7.3. Shape Tests for Aggregates

7.3.1 Flakiness index

7.3.1.1 Introduction. Flaky or elongated materials, when used in the construction of apavement, may cause the pavement to fail due to the preferred orientation that theaggregates take under repeated loading and vibration. It is important that the flakinessand elongation of the aggregate are contained to within permissible levels.

7.3.1.2 Scope. The scope of this test is to provide test methods for determining the flakinessindex of coarse aggregate. An aggregate is classified as being flaky if it has a thickness(smallest dimension) of less than 0.6 of its mean sieve size. The flakiness index of anaggregate sample is found by separating the flaky particles and expressing their massas a percentage of the mass of the sample tested. The test is not applicable tomaterials passing the 6.30 mm test sieve or retained on the 63.00 mm test sieve.

7.4.1.3 Equipment

a) A sample divider, of size appropriate to the maximum particle size to be handled oralternatively a flat shovel and a clean, flat metal tray for the quartering.

b) A ventilated oven, thermostatically controlled to maintain a temperature of 1050Cplus or minus 50C.

c) A balance of suitable capacity and accurate to 0.1% of the mass of the test portion.Balances of 0.5 kg, 5.0 kg, or 50 kg capacity may be required depending on thesize of aggregate and size of sample.

d) Test sieves.e) A mechanical sieve shaker (optional).f) Trays of adequate size, which can be heated in the oven without damage or

change in mass.g) A metal thickness gauge, of the pattern shown in Figure 7.3.1, or similar, or special

sieves having elongated apertures. The width and length of the apertures in thethickness gauge and in the sieves shall be within the tolerances given in Table7.3.3. The gauge shall be made from 1.5 mm thickness sheet steel.

7.3.1.4 Preparation of test portion. Produce a test portion that complies with Table 7.3.2. Drythe test portion by heating at a temperature of 1050C plus or minus 50C to achieve adry mass which is constant to within 0.1%. Allow to cool and weigh.

7.3.1.5 Procedure

a) Carry out a sieve analysis using the test sieves in Table 7.3.1. Discard allaggregates retained on the 63.0 mm test sieve and all aggregate passing the 6.30mm test sieve.

Table 7.3.1 Particulars of test sieves

Nominal aperture size (square hole perforated plate 450 mm or 300 mmDiameter)

63.0 mm50.0 mm37.5 mm28.0 mm20.0 mm14.0 mm10.0 mm6.3 mm


MAY 2001 Page 7.10


Nominal size of material

mm

Minimum mass of test portion afterrejection of oversize and undersizeparticles

kg

504028201410

35155210.5

Table 7.3.3 Data for determination of flakiness index

Aggregate size-fraction

mm


mm

Width of slot inthickness gaugeor special sieve

mm

Minimummass forsubdivision

kg

100% passing 100% retained

63.050.037.528.020.014.010.0

50.037.528.020.014.010.06.30

33.9±0.326.3±0.319.7±0.314.4±0.1510.2±0.157.2±0.14.9±0.1

5035155210.5

b) Weigh each of the individual size-fraction retained on the sieves, other than the63.0 mm and store them in separate trays with their size mark on the tray.

c) From the sums of the masses of the fractions in the trays (M1), calculate theindividual percentage retained on each of the various sieves. Discard any fractionwhose mass is 5% or less of M1. Record the mass remaining M2.

d) Gauge each fraction by using either of the procedures given in (i) or (ii) below.

(i) Using the special sieves, select the special sieve appropriate to the size-fraction under test. Place the whole of the size-fraction into the sieve andshake the sieve until the majority of the particles have passed through theslots. Then gauge the particles retained by hand.

(ii) Using the gauge, select the thickness gauge appropriate to the size-fractionunder test and gauge each particle of that size-fraction separately by hand.

e) Combine and weigh all the particles passing each of the gauge M3.

7.3.1.6 Calculation and expression of results. The value of the flakiness index is calculatedfrom the expression:

Flakiness Index = 100 x M3 / M2 Express the Flakiness Index to the nearest wholenumber.

Where, M2 is the total mass of test portionM3 is the mass of the flaky portion


MAY 2001 Page 7.11

7.3.1.7 Test Report. The test report shall affirm that the flakiness index test was performedaccording to the stated method and whether a sampling certificate was issued. Ifavailable the sampling certificate should be provided. The test report shall include thefollowing additional information:

a) Sample identificationb) Flakiness indexc) Sieve analysis obtained from this test.


7.3.2 Elongation index

7.3.2.1 Scope. The scope of this test is to provide test methods for determining the elongationindex of coarse aggregate. An aggregate is classified as being elongated if it has alength (greatest dimension) of more than 1.8 of its mean sieve size. The elongationindex of an aggregate sample is found by separating the elongated particles andexpressing their mass as a percentage of the mass of the sample tested. The test isnot applicable to materials passing the 6.30 mm test sieve or retained on the 50.00 mmtest sieve.

7.3.2.2 Equipment. The equipment used in the flakiness index are also used in the elongationindex test except a metal length gauge instead of a thickness gauge shown in Figure7.3.2.

Table 7.3.4 Particulars of test sieves

Nominal aperture size (square hole perforated plate 450 mm or 300 mmDiameter)

50.0 mm37.5 mm28.0 mm20.0 mm14.0 mm10.0 mm6.3 mm


Nominal size of material

mm

Minimum mass of test portion afterrejection of oversize and undersizeparticles

kg4028201410

155210.5


MAY 2001 Page 7.12


MAY 2001 Page 7.13

Table 7.3.6 Data for determination of elongation index


mm


mm

Width of slot inthickness gaugeor special sieve

mm

Minimum massfor subdivision

kg100% passing 100% retained

50.037.528.020.014.010.0

37.528.020.014.010.06.30

78.7±0.359.0±0.343.2±0.330.6±0.321.6±0.114.7±0.1

35155210.5

7.3.2.3 Preparation of test portion. Produce a test portion that complies with Table 7.3.4. Drythe test portion by heating at a temperature of 1050C plus or minus 50C to achieve adry mass which is constant to within 0.1%. Allow to cool and weigh.

7.3.2.4 Procedure

a) Carry out a sieve analysis using the test sieves in Table 7.3.5 or 7.3.6. Discard allaggregates retained on the 63.0 mm test sieve and all aggregate passing the 6.30mm test sieve.

b) Weigh each of the individual size-fraction retained on the sieves, other than the50.0 mm and store them in separate trays with their size mark on the tray.

c) From the sums of the masses of the fractions in the trays (M1), calculate theindividual percentage retained on each of the various sieves. Discard any fractionwhose mass is 5% or less of M1. Record the mass remaining M2.

d) Gauge each fraction as follows: select the length gauge appropriate to the size-fraction under test and gauge each particle separately by hand. Elongated particlesare those whose greatest dimension prevents them from passing through thegauge, and these are placed to one side.

e) Combine and weigh all the particles passing each of the gauges M3.

7.3.2.5 Calculation and expression of results. The value of the elongation index iscalculated from the expression:

Elongation Index = 100 x M 3 / M 2 Express the Elongation Index to the nearest wholenumber.

Where, M3 is the mass of test portion being elongatedM2 is the total mass of test portion

7.3.2.6 Test Report. The test report shall affirm that the elongation index test was performedaccording to the stated method and whether a sampling certificate was issued. Ifavailable the sampling certificate should be provided. The test report shall include thefollowing additional information:

a) Sample identificationb) Elongation indexc) Sieve analysis obtained from this test.



MAY 2001 Page 7.14


MAY 2001 Page 7.15

7.4 Fine Aggregate: Density and Absorption Tests

7.4.1 Introduction

7.4.1.1 Bulk specific gravity : Bulk specific gravity of the aggregate is a characteristicgenerally used for the calculation of the volume occupied by the aggregate in variousmixtures containing aggregate including Portland cement concrete, bituminousconcrete and other mixtures that are proportioned or analysed on an absolute volumebasis. It is also used in the computation of voids in aggregate and the determination ofmoisture in aggregate by displacement in water. Bulk specific gravity determined on thesaturated surface-dry basis is used if the aggregate is wet, that is, if its absorption hasbeen satisfied. Bulk specific gravity determined on the oven-dry basis is used forcomputations when the aggregate is dry or assumed to be dry.

7.4.1.2 Apparent specific gravity : Apparent specific gravity pertains to the relative density ofthe solid material making up the constituent particles not including the pore spacewithin the particles that is accessible to water. This value is not widely used inconstruction aggregate technology.

7.4.1.3 Absorption : Absorption values are used to calculate the change in the mass of anaggregate due to water absorbed in the pore spaces within the constituent particles,compared to the dry condition, when it is deemed that the aggregate has been incontact with water long enough to satisfy most of the absorption potential. Thelaboratory absorption is obtained after the aggregate has been submerged in water forapproximately 24 hours.

7.4.2 Scope. This test provides methods for determining the bulk and apparent densities(after submersion in water for 24h) of fine aggregate, the bulk specific gravity on thebasis of mass saturated surface-dry aggregate and water absorption of fine aggregate.

7.4.3 Equipment

a) Balance, of capacity not less than 3 kg, accurate to 0.5g and of such type and sizeas to permit the basket containing the sample to be suspended from the beam andweight in water.

b) Ventilated oven, thermostatically controlled to maintain the temperature at 105 ºCplus or minus 5 ºC.

c) Pycnometer , capable of holding 0.5 kg to 1.0 kg of material up to 10mm nominalsize and capable of being filled with water to a constant volume with an accuracy ofplus or minus 0.5 ml. The volume of the pycnometer shall be least 50% greaterthan the volume required to accommodate the sample.

d) Metal mould, in the form of a frustum of a cone 40 mm plus or minus 3mm diameterat the top, 90 mm plus or minus 3mm diameter at the bottom and 75 mm plus orminus 3 mm high. The metal shall be at least 900 micron thick.

e) Container, of sufficient size to contain the sample covered in water and to permitvigorous agitation without any loss of material or water.

f) 75 micron test sieve and a nesting sieve to protect the 75 micron sieve, e.g. a1.18mm sieve.

g) A metal tamper, of 340 g plus or minus 15 g and having a flat circular tamping face25 mm plus or minus in 3mm diameter.

h) A plain glass funnel (optional)i) A wide-mouthed glass vessel, Figure 7.4.1.

7.4.4 Preparation of test specimen

a) A sample of about 1 kg for material having a nominal size 10mm to 5mm inclusive,or about 500 g if finer than 5mm, shall be used. A duplicate sample is also required.


MAY 2001 Page 7.16


MAY 2001 Page 7.17

b) The sample shall be thoroughly washed to remove material passing the 75 micronsieve as follows :

i) Place the sample in the container and add enough water to it to cover it. Agitatevigorously the contents of the container and immediately pour the wash waterover the test sieves, which have previously been wetted on both sides andarranged with the coarser test sieve to top.

ii) The agitation shall be sufficiently vigorous to result in the complete separationfrom the coarse particles of all particles finer than the 75 micron sieve, and tobring the fine material into suspension in order that it will be removed bydecantation of the wash water. Avoid, as far as possible, decantation of coarsematerial. Repeat the operation until the wash water appears to be clean. Returnall material retained in the sieves to the washed sample.

7.4.5 Fine Aggregate Density and Absorption Test

7.4.5.1 Procedure using the pycnometer

a) Transfer the washed aggregate to the tray and add further water to ensure that thesample is completely immersed. Soon after immersion, remove bubbles ofentrapped air by gentle agitation with a rod.

b) Keep the sample immersed for 24h plus or minus 2h, the water temperature being20ºC plus or minus 5ºC for at least the last 20h of immersion. Then carefully drainthe water from the sample through the 75 micron sieve, covered by the protectivecoarser sieve, any material retained being returned to the sample.

c) Expose the aggregate to a gentle current of worm air to evaporate surface moistureand stir it at frequent intervals to ensure case of material finer than 5mm, it justattains a “free-running” condition. Refer Note 1 and to Figure 7.4.2 Weigh thesaturated and surface-dried sample, Mass (A). If the apparent density only isrequired, the draining and drying operations described above may be omitted,although for material finer than 5mm some surface drying is desirable to facilitatehandling.

d) Place the aggregate in the pycnometer and fill the pycnometer with water. Screwthe cone into place and eliminate any entrapped air by rotating the pycnometer onits side. Top up the pycnometer with water to remove any forth form the surfaceand so that the surface of the water in the hole is flat. Dry the pycnometer on theoutside and weight it. Mass (B)

e) Empty the contents of the pycnometer into a tray ensuring that all the aggregate istransferred. Refill the pycnometer with water to the same level as before, dry theoutside of it and weight it. Mass (C).

f) Carefully drain the water from the sample by decantation through the 75 micron testsieve and return any material retained to the sample. Place the sample in the tray,in the oven at a temperature of 105 C plus or minus 5 C for 24h plus or minus 0.5h,during which period it shall be stirred occasionally to facilitate drying. Cool to roomtemperature and weigh it, Mass (D).

Note 1. The “free-running” or “saturated surface-dry” condition of the fine

aggregate is sometimes difficult to identify and in order to help inidentification, two alternative methods are suggested for possible aids.

Method 1

After drying the sample with a stream of warm air allow it to cool to roomtemperature whilst thoroughly stirring it. Hold the mould with its larger diameter facedownwards on a smooth non-absorbent level surface. Fill the mould loosely withpart of the sample and lightly tamp 25 times through the hole at the top of themould with the prescribed tamper. Do not refill the space left after tamping . Gently


MAY 2001 Page 7.18


MAY 2001 Page 7.19

lift the mould clear of the aggregate and compare the moulded shape with thefigure in 7.4.2. If the shape resembles figure a) or b), there is still surface moisturepresent. Dry the sample further and repeat the test. If the shape resembles figurec), a condition close to the saturated surface-dry has been achieved. If the shaperesembles figure d), the aggregate has dried beyond the saturated surface-dry andis approaching the oven-dry condition. In this case, reject the sample and repeatthe test on a fresh sample.

Method 2

As an alternative to method 1, a dry glass funnel may be used to help determinethe “free-running” condition of aggregate finer than 5mm. With the funnel invertedover the sample tray pour some of the sample over the sloping sides by means of asmall scoop. if still damp, particles of the aggregate will adhere to the sides of thefunnel. Continue drying until subsequent pouring shows no sign of particles stickingto the glass.

7.4.5.2 Procedure using the wide-mouthed glass vessel. The procedure shall be the sameas with the procedure using the pycnometer except that in filling the jar with water itshall be filled just to overflowing and the glass plate slid over it to exclude any airbubbles.


a) Particle density

(i) The particle density on an oven-dried basis in (Mg/m3) is calculated from thefollowing expression.

D / ( A - ( B - C ) )

(ii) The particle density on a saturated and surface-dry condition in (Mg/m3) iscalculated from the following expression.

A / ( A - ( B - C ) )

(iii) The Apparent particle density in (Mg/m3) is calculated from the followingexpression.

D / ( D - ( B - C ) )

b) Water absorption

The water absorption (as percentage of dry mass) is calculated from the followingexpression.

100 (A - D ) / D

Where,A is the mass of saturated surface-dry sample in air, g.B is the mass of pycnometers or wide-mouthed glass vessel containing

sample filled with water, g.C is the mass of pycnometers or wide-mouthed glass vessel filled with

water only, g.D is the mass of oven -dried sample in air, g.



MAY 2001 Page 7.20

Form 7.4.1


MAY 2001 Page 7.21

7.5 Coarse Aggregate: Density and Absorption Tests

7.5.1 Definitions of terminology

7.5.1.1 Absorption – the increase in the mass of aggregate due to water in the pores of thematerial, but not including water adhering to the outside surface of the particles,expressed as a percentage of the dry mass. The aggregate is considered dry when ithas been maintained at 1050C plus or minus 50C for sufficient time to remove all.

7.5.1.2 Specific gravity – the ratio of the mass (or weight in air) of a unit volume of a materialto the mass of the same volume of water at stated temperature to the weight in air of anequal volume of gas-free distilled water at the same temperature.

7.5.1.3 Apparent specific gravity – the ratio of the weight in air of a unit volume of theimpermeable portion of aggregate at a stated temperature to the weight in air of anequal volume of gas-free distilled water at the same temperature.

7.5.1.4 Bulk specific gravity – the ratio of the weight in air of a unit volume of aggregate(including the temperature impermeable voids in the particles, but not including thevoids between the particles) at a stated temperature to the weight in air of an equalvolume of gas-free distilled water at the same temperature.

7.5.1.5 Bulk specific gravity (SSD) – the ratio of the mass in air of a unit volume ofaggregate, including the mass of water within the voids filled to the extent achieved bysubmerging in water for approximately 24 h (but not including the voids betweenparticles) at a stated temperature to the weight in air of an equal volume of gas-freedistilled water at the same temperature.

7.5.2 Equipment

a) Balance, of capacity not less than 3 kg, accurate to 0.5 g and of such type and sizeas to permit the basket containing the sample to be suspended from the beam andweighed in water.

b) Ventilated oven, thermostatically controlled to maintain the temperature at 1100Cplus or minus 50C.

c) A 4.75 mm test sieve and other sizes as needed.d) A sample container, such as a wire basket of 3.35 mm or finer mesh, or a bucket of

approximately equal breadth and height, with a capacity of 4 L to 7 L for 37.5 mmnominal maximum size aggregate or smaller, and a larger container, as needed, fortesting larger maximum size aggregate.

e) Water tank, in which the sample and container are placed for complete immersionwhile being suspended below the balance. It must be capable of maintaining thelevel of water constant.

7.5.3 Preparation of test specimen

7.5.3.1 Receive a sample sampled in accordance with test method 2.4 and reduce to therequired size as per method.

7.5.3.2 Reject all material passing the 4.75 mm test sieve of the test portion by dry sieving.Thoroughly wash the test portion to remove dust or other coatings from the surface. Ifthe coarse aggregate contains a substantial quantity of material finer than the 4.75 mmsieve, use the 2.36 mm test sieve in place of the 4.75 mm test sieve or, alternatively,separate the material finer than the 4.75 mm sieve and test that portion in accordancewith test method 7.4.


MAY 2001 Page 7.22

7.5.3.3 The minimum mass of the test portion is given in Table 7.5.1 below. In many instancesit may be desirable to test a coarse aggregate in several separate size fractions; and ifthe sample contains more than 15% retained on the 37.5 mm test sieve, test thematerial retained on the 37.5 mm sieve in one or more size fractions separately fromthe smaller size fractions. When an aggregate is tested in separate size fractions theminimum mass of test sample for each fraction shall be the differences between themasses prescribed for the maximum and minimum sizes of the fractions.

Table 7.5.1

Nominal maximum size, mm Minimum mass of test sample, kg

12.5 or less

19.0

25.0

37.5

50

63

75

2

3

4

5

8

12

18

7.5.4 Coarse aggregate density and absorption test

7.5.4.1 Procedure. A sample of not less than 2 kg of aggregate shall be tested. Aggregateswhich were artificially heated shall not normally be used. If such material is used, thefact shall be stated in the report. Two tests shall be performed.

a) Place the prepared sample in the wire basket and immerse it in water at atemperature of 200C plus or minus 50C with a cover of at least 50 mm of waterabove the top of the basket.

b) Immediately after immersion remove the entrapped air by lifting the wire basketabout 25 mm above the base of the water tank and letting it drop 25 times at a rateof about once per second. The basket and aggregate shall remain in water for 24 hplus or minus 0.5 h.

c) After this period weigh the basket and aggregate at a temperature of 200C plus orminus 50C. Record the mass to the nearest 1 g or 0.1% of the sample mass,whichever is greater, Mass B.

d) Remove the test sample from the water and roll it in a large absorbent cloth until allvisible film of water is removed. Wipe the larger particles individually. A warmstream of air may be used to assist in the drying operation. Take care to avoid theevaporation of water from the pores of the aggregate during the operation ofsurface-drying. Determine the mass of the sample in the saturated surface-drycondition, record the mass A.

e) Dry the test sample to constant mass in the oven at 1050C plus or minus 50C, (24 hplus or minus 0.5 h will suffice), cool in air at room temperature until the aggregatehas cooled to a temperature that is comfortable to handle. Weigh the dry aggregateand record as mass D.

f) Weigh the wire basket in water at the specified temperature and record the weightas mass C.


MAY 2001 Page 7.23


a) Bulk specific gravities

The bulk specific gravity (saturated surface-dry) on a saturated and surface-drycondition in (Mg/m3) is calculated from the following expression.

A / (A – (B – C))

(i) The bulk specific gravity on the oven-dry basis (Mg/m3) is calculated from thefollowing expression.

D / (A – (B – C))

The apparent specific gravity (Mg/m3) is calculated from the followingexpressions.

D / (D – (B – C))

Where,A is the mass of the saturated surface-dry sample in air, g.B is the apparent mass in water of the basket containing the sample of

saturated aggregate, g.C is the apparent mass in water of the basket, g.D is the mass of the oven-dried aggregate in air, g.

(ii) Average specific gravity values.

When the sample has been tested in separate size fractions the averagevalue for bulk specific gravity, bulk specific gravity (SSD), or apparent specificgravity can be computed as the weighted average of the values as computedabove, using the following expression.

G = 1

P / 100 G + P / 100 G + ....... P / 100 G1 1 2 2 n n

Where,G is the average specific gravity. All forms of specific gravity can

be expressed in this manner.G1, G2 … Gn is the appropriate specific gravity values for each fraction

depending on the type of specific gravity being averaged.P1, P2 … Pn is the mass percentages of each size fraction present in the

original sample.

Note. If the user wishes to express the specific gravity in terms of density,then the value for the specific gravity, which is dimensionless, ismultiplied by the density of water at 40C, the temperature at whichwater is considered to have a density of 1000 kg/m3.

b) Absorption

The water absorption (as percentage of dry mass) is calculated from the followingexpression.

100 (A – D) / D


MAY 2001 Page 7.24

Where, A is the mass of the saturated surface-dry sample in air, g.D is the oven-dry mass of the sample in air, g.

(i) Average Absorption Value

When the sample has been tested in separate size fractions the averageabsorption value can be computed as the weighted average of the values ascomputed above, using the following expression.

A = P1A1 / 100 + P2A2 / 100 + ……. + PnAn / 100

Where,A is the average absorption percent.A1, A2 … An is the absorption percentages for each fraction.P1, P2 … Pn is the mass percentages of each size fraction present in the

original sample.

7.5.4.3 Acceptability of results. If the difference between any two test results falls outside therange of the values given in Table 7.5.2, the test results shall not be used foracceptability purposes and the tests shall be repeated.

Table 7.5.2 Precision

Single operator Acceptable range of two results

Bulk specific gravity (dry)Bulk specific gravity (SSD)Apparent specific gravityAbsorption percent

0.0250.0200.0200.025

7.5.4.4 Report

a) Report specific gravity results to the nearest 0.01, and indicate the type of specificgravity, whether bulk, bulk (SSD), or apparent.

b) Report the absorption result to the nearest 0.1%.

A data sheet is given in Form 7.5.1.


MAY 2001 Page 7.25

Form 7.5.1


MAY 2001 Page 7.26

7.6 Aggregate Impact Value

7.6.1 Scope. The aggregate impact value gives a relative measure of the resistance of theaggregate to sudden shock or impact.

The particular purpose which an aggregate is meant to serve requires the aggregate tohave a particular strength which is usually stated in the specification. This test providesa method for measuring this strength.

7.6.2 Method outline. A test specimen, of chosen fractions, is compacted in a standardisedmanner, into an open steel cup. The specimen is then subjected to a number ofstandard impacts from a dropping weight. The impacts break the aggregate to a degreewhich is dependent on the aggregate’s impact resistance. This degree is assessed by asieving test on the impacted specimen and is taken as the aggregate impact value.

7.6.3 Sampling. The sample used for this test shall be taken in accordance with Chapter 2.

7.6.4 Equipment

7.6.4.1 Impact testing machine. The machine shall be of the general form shown in Figure7.6.1, have a total mass of between 45 kg and 60 kg and shall have the following parts:

a) A circular metal base, with a mass of between 22 kg and 30 kg, with a plane lowersurface of not less than 300 mm diameter and shall be supported on a level andplane concrete or stone block floor at least 450 mm thick. The machine shall beprevented from rocking during operation of the machine.

b) A cylindrical steel cup, having an internal diameter of 102 mm plus or minus 0.5mm and an internal depth of 50 mm plus or minus 0.25 mm. The walls shall be notless than 6 mm thick and the inner surfaces shall be case hardened. The cup shallbe rigidly fastened at the centre of the base and be easily removed for emptying.

c) A metal hammer, with a mass of between 13.5 kg and 14.0 kg, the lower end ofwhich shall be cylindrical in shape, 100.0 mm plus or minus 0.5 mm diameter and50 mm plus or minus 0.15 mm long, with a 1.5 mm chamfer at the lower edge, andcase hardened. The hammer shall slide freely between vertical guides so arrangedthat the lower part of the hammer is above and concentric with the cup.

d) Means for raising the hammer, and allowing it to fall freely between the verticalguides from a height of 380 mm plus or minus 5 mm on to the test sample in thecup, and means for adjusting the height of fall within 5 mm.

e) Means for supporting the hammer whilst fastening or removing the cup.

7.6.4.2 Square-hole perforated plate test sieves, of sizes 14.0 mm and 10.0 mm and a woven-wire 2.36mm test sieve.

7.6.4.3 A cylindrical metal measure, of sufficient rigidity to retain its form under rough usageand with an internal diameter of 75 mm plus or minus 1 mm and an internal depth of 50mm plus or minus 1 mm.

7.6.4.4 A tamping rod, made out of straight iron or steel bar of circular cross section, 16 mmplus or minus 1 mm diameter and 600 mm plus or minus 5 mm long, with both endshemispherical.

7.6.4.5 A balance, of capacity not less than 500 g and accurate to 0.1 g.

7.6.4.6 A ventilated oven, thermostatically controlled at a temperature of 1050C plus or minus50C.


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7.6.4.7 A rubber mallet, a metal tray of known mass and large enough to contain 1 kg ofaggregate and a brush with stiff bristles.

7.6.4.8 Additional equipment for testing aggregate in a soaked condition.

a) Drying cloths or absorbent paper, for the surface drying of the aggregate.b) One or more wire-mesh baskets, with apertures greater than 6.5 mm.c) A stout watertight container in which the basket may be immersed.

7.6.5 Preparation of test portions and specimens

7.6.5.1 Test portions. Reduce laboratory samples to test portions of sufficient mass toproduce 3 specimens of 14 mm to 10 mm size fraction.

Table 7.6.1. Guide to minimum mass of test portions required to obtain a suitablemass of material to determine the aggregate impact value

Grade of the aggregate Minimum mass of test portion

All-in aggregate 40 mm max. sizeAll-in aggregate 20 mm max. sizeGraded aggregate 40 to 5 mmGraded aggregate 20 to 5 mmGraded aggregate 14 to 5 mm

20 kg15 kg12 kg8 kg5 kg

7.6.5.2 Test specimen in a dry condition

a) Sieve the entire dried test portion on the 14 mm and the 10 mm test sieve toremove the oversize and undersize fraction. Divide the resulting 14 mm to 10 mmsize fractions to produce 3 test specimens each of sufficient mass to fill themeasure when it is filled by the procedure in 7.6.5.2(c).

b) Dry the test specimens by heating at a temperature of 1050C plus or minus 50C fora period of not more than 4 h. Cool to room temperature before testing.

c) Fill the measure to overflowing with the aggregate using a scoop. Tamp theaggregate with 25 blows of the rounded end of the tamping rod, each blow beinggiven by allowing the tamping rod to fall freely from a height of about 50 mm abovethe surface of the aggregate and the blows being distributed evenly over thesurface.

Remove the surplus aggregate by rolling the tamping rod across, and in contactwith, the top of the container. Remove by hand any aggregate that impedes itsprogress and fill any obvious depressions with added aggregate. Record the netmass of aggregate in the measure and use the same mass for the second testspecimen.

7.6.5.3 Test specimens in a soaked condition

a) Prepare the test portion as in 7.6.5.1 except that the test portion is tested in the as-received condition and not oven-dried. Place test specimen in a wire basket andimmerse it in the water in the container with a cover at least 50 mm of water abovethe top of the basket. Remove entrapped air by lifting the basket 25 mm above thebase of the container and allowing it to drop 25 times at a rate of approximatelyonce per second. Keep the aggregate completely immersed in water at all timesand for the next 24 h plus or minus 2 h and maintain the water temperature at 200Cplus or minus 50C.


MAY 2001 Page 7.29

b) After soaking, remove from the water and blot the free water from the surface usingthe absorbent cloths. Prepare for testing as described in 7.6.5.2 immediately afterthis operation.

7.6.6 Aggregate impact value

7.6.6.1 Procedure

a) Test specimens in a dry condition

(i) Fix the cup firmly in position on the base of the impact machine and place thewhole of the specimen in it and then compact by 25 strokes of the tampingrod. Adjust the height of the hammer so that its lower face is 380 mm plus orminus 5 mm above the aggregate in the cup and then allow it to fall freely onto the aggregate. Subject the test specimen to 15 such blows each blowbeing delivered at an interval not less than 1 s.

(ii) Remove the crushed aggregate by holding the cup over a clean tray andhammering on the outside with the rubber mallet until the crushed aggregatefalls freely on to the tray.

Transfer fine particle adhering to the inside of the cup and to the surface ofthe hammer to the tray by means of the stiff bristle brush. Weigh the tray andthe aggregate and record the mass of the aggregate to the nearest 0.1 g(M1).

(iii) Sieve the whole of the specimen on the 2.36 mm test sieve until no furthersignificant amount passes during a further period of 1 min. Weigh and recordthe mass of the fractions passing and retained on the sieve to the nearest 0.1g (M2 and M3) respectively and if the total mass (M2 + M3) differs from theinitial mass (M1) by more than 1 g, discard the result and test a furtherspecimen.

(iv) Repeat the procedure from (i) to (iii) above inclusive using a secondspecimen of the same mass as the first specimen.

b) Test specimens in a soaked condition

(i) Follow the test procedure described in 7.6.6.1(a) except that the number ofblows of the hammer to which the aggregate is subjected, is the number ofblows which will yield between 5% and 20% of fines when this value iscalculated using procedure in 7.6.6.2.

(ii) Remove the crushed specimen from the cup and dry it in the oven at atemperature of 1050C plus or minus 50C either to constant mass or for aminimum period of 12 h. Allow to cool and weigh to the nearest 1 g andrecord this mass M1. Complete the procedure described in (ii) of 7.6.6.1(a)starting at the stage where the specimen is sieved on the 2.36mm test sieve.

7.6.6.2 Calculation and expression of result

a) Calculate the aggregate impact value (AIV) expressed as a percentage to the firstdecimal place for each test specimen from the following expression.

(AIV) = 100 x M2 / M1

Where,M1 is the mass of the test specimen in grams.M2 is the mass of the material passing the 2.36mm test sieve in grams.


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b) Aggregate in the soaked condition.

(i) Calculate the mass of fines, m, expressed as a percentage of the total massfor each test specimen from the following expression.

M = 100 x M2 / M1

Where,M1 is the mass of the oven-dried test specimen in grams.M2 is the mass of the oven-dried material passing the 2.36mm test sieve

in grams.

(ii) Calculate the AIV expressed as a percentage to the first decimal place foreach test specimen from the following expression.

(AIV) = 15 m/ n

Where, n is the number of hammer blows to which the specimen issubjected.

7.6.7.3 Results. Calculate the mean of the two values determined in (a) or (b) of 7.6.6.2 to thenearest whole number. Report the mean as the aggregate impact value, unless theindividual results differ by more than 0.15 times the mean value. In this case repeat thetest on two further specimens, calculate the median of the four results to the nearestwhole number and report the median as the aggregate impact value.

A data sheet is given in Form 7.6.1.


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7.7 Aggregate Crushing Value and 10% Fines Value

7.7.1 Aggregate Crushing Value (ACV)

7.7.1.1 Introduction. One of the requirements, for the suitability of aggregates forconstruction, is the ability of the aggregate to resist crushing. The Aggregate CrushingValue gives a relative measure of the resistance of the aggregate to crushing under agradually applied compressive load.

7.7.1.2 Scope. The particular purpose which an aggregate is meant to serve requires theaggregate to have a particular strength. This strength is usually stated in thespecification. This test provides a method for measuring this strength. This method isnot suitable for testing aggregates with a crushing value higher than 30, and in thiscase the ten percent fines value is recommended.

7.7.1.3 Method outline. A test specimen, of chosen fractions, is compacted in a standardisedmanner, into a steel cylinder fitted with a freely moving plunger. The specimen is thensubjected to a standard loading regime applied through the plunger. This actioncrushes the aggregate to a degree which is dependent on the aggregate’s crushingresistance. This degree is assessed by a sieving test on the crushed specimen and istaken as the Aggregate Crushing Value.

7.7.1.4 Sampling. The sample used for this test shall be taken in accordance with Chapter 2.

7.7.1.5 Equipment

a) Steel cylinder, open-ended, of nominal 150mm internal diameter with plunger andbase-plate of the general form and dimensions shown in Figure 7.7.1 and given inTable 7.7.1. The surface in contact with the aggregate shall be machined and casehardened, and shall be maintained in a smooth condition.

Table 7.7.1 Principal dimensions of cylinder and plunger apparatus

Component DimensionsSee Figure 7.7.1

Nominal 150 mminternal diameterof cylinder, mm

Nominal 75 mm internaldiameter of cylindermm

Cylinder Internal diameter, AInternal diameter, BMinimum wall thickness, C

154±0.5 mm125 to 140 mm16.0 mm

78±0.5 mm70.0 to 85.0 mm8.0 mm

Plunger Diameter of piston, DDiameter of stem, EOverall length of piston plusstem, FMinimum depth of piston, GDiameter of hole, H

152±0.5 mm>95 to = or <D

100 to 115 mmNot less than 25.020.0±0.1 mm

76.0±0.5 mm>45.0 to = or <D

60.0 to 80.0 mmNot less than 19.010.0±0.1 mm

Base-plate Minimum thickness, ILength of each side of square,J

10 mm

200 to 230 mm

10 mm

110 to 115 mm

b) A cylindrical metal measure, of sufficient rigidity to retain its form under roughusage and with an internal diameter of 115 mm plus or minus 1 mm and an internaldepth of 180 mm plus or minus 1 mm.

c) A tamping rod, made out of straight iron or steel bar of circular cross section. 16mm plus or minus 1 mm diameter and 600 mm plus or minus 5 mm long, with bothends hemispherical.

d) A balance, of capacity not less than 3 kg and accurate to 1 g.


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Figure 7.7.1 Outline form of cylinder and plunger apparatus for the aggregate crushingvalue and ten percent fines test

e) A ventilated oven, thermostatically controlled at a temperature of 1050C plus orminus 50C.

f) A rubber mallet, a metal tray of known mass and large enough to contain 3 kg ofaggregate and a brush with stiff bristles.

g) Square-hole perforated plate test sieves, of sizes 14.0 mm and 10.0 mm and anovenware 2.36 mm test sieve.

h) A compression testing machine, capable of applying any force up to 400 kN at auniform rate of loading so that the force is reached in 10 min.

7.7.1.6 Preparation of test portions and specimens

a) Test portions. Reduce laboratory samples to test portions of sufficient mass toproduce 3 specimens of 14 mm to 10mm size fractions.

b) Sieve the entire dried test portion on the 14mm and the 10mm test sieve to removethe oversize and undersize fraction. Divide the resulting 14mm to 10 mm size


MAY 2001 Page 7.34

fractions to produce 3 test specimens each of sufficient mass that the depth of thematerial in the cylinder is approximately 100 mm after tamping.

c) Dry the test specimens by heating at a temperature of 1050C plus or minus 50C fora period of not more than 4 h. Cool to room temperature and record the mass of thematerial comprising the test specimen.

Table 7.7.2 Guide to minimum mass of test portions required to obtain asuitable mass of material to determine the Aggregate CrushingValue.

Grade of the aggregate Minimum mass of test portionAll-in aggregate 40 mm max. sizeAll-in aggregate 20 mm max. sizeGraded aggregate 40 to 5 mmGraded aggregate 20 to 5 mmGraded aggregate 14 to 5 mm

60 kg45 kg40 kg25 kg15 kg

7.7.1.7 Procedure

a) Place the cylinder of the test apparatus in position on the base-plate and add thetest specimen in three layers of approximately equal depth, each layer beingcompacted to 25 strokes from the tamping rod distributed evenly over the surfaceof the layer and dropping from a height approximately 50 mm above the surface ofthe aggregate. Carefully level the surface of the aggregate and insert the plungerso that it rests horizontally on this surface. Ensure that the plunger is free to move.

b) Place the apparatus, with the test specimen prepared as described in 7.7.1.6(c)and plunger in position, between the platens of the testing machine and load it asuniform a rate as possible so that the required force of 400 kN is reached in 10 minplus or minus 30 s.

c) Release the load and remove the crushed aggregate by holding the cylinder over aclean tray of known mass and hammering on the outside with the rubber malletuntil the crushed aggregate falls freely on to the tray. Transfer fine particle adheringto the inside of the cylinder and to the surface of the hammer to the tray by meansof the stiff bristle brush. Weight the tray and the aggregate and record the mass ofthe aggregate to the nearest 1g (M1).

d) Sieve the whole of the specimen on the 2.36mm test sieve until no furthersignificant amount passes during a further period of 1 min. Weight and record themass of the fractions passing and retained on the sieve to the nearest 1g (M2 andM3) respectively and if the total mass (M2 + M3) differs from the initial mass (M1) bymore than 10g, discard the result and test a further specimen.

e) Repeat the procedure from (a) to (b) above inclusive using a second specimen ofthe same mass as the first specimen.

7.7.1.8 Calculation and expression of result. Calculate the Aggregate Crushing Value (ACV)expressed as a percentage to the first decimal place, of the mass of fines formed to thetotal mass of the test specimen from the following expression.

(ACV) = 100 x M2 / M1

Where,M1 is the mass of the test specimen in grammes.M2 is the mass of the material passing the 2.36mm test sieve in grammes.


MAY 2001 Page 7.35

7.7.1.9 Results. Calculate the mean of the two values determined to the nearest wholenumber. Report the mean as the Aggregate Crushing Value, unless the individualresults differ by more than 0.07 times the mean value. In this case repeat the test ontwo further specimens, calculate the median of the four results to the nearest wholenumber and report the median as the Aggregate Crushing Value.


7.7.2 10% Fines Value Test

7.7.2.1 Scope. The particular purpose which an aggregate is meant to serve requires theaggregate to have a particular strength. This strength is usually stated in thespecification. This test provides a method for measuring this strength. This method issuitable for testing both strong and weak aggregate passing a 14.0 mm test sieve andretained on a 10.0 mm test sieve.

7.7.2.2 Method outline. A test specimen, of chosen fractions, is compacted in a standardisedmanner, into a steel cylinder fitted with a freely moving plunger. The specimen is thensubjected to a standard loading regime applied through the plunger. The action crushesthe aggregate to a degree which is dependent on the aggregate’s crushing resistance.This degree is assessed by a sieving test on the crushed specimen. The procedure isrepeated with various loads to determine the maximum force which generates a givensieve analysis. This force is taken as the ten percent fines value (TFV).

7.7.2.3 Sampling. The sample used for this test shall be taken in accordance with Chapter 2.

7.7.2.4 Equipment. The equipment required for this test is identical to the equipment requiredfor the ACV test as described in 7.7.1.5.

a) Additional equipment for testing aggregate in a soaked condition.b) Drying cloths or absorbent paper, for the surface drying of the aggregate.c) One or more wire-mesh baskets, with apertures greater than 6.5 mm.d) A stout watertight container in which the basket may be immersed.

7.7.2.5 Preparation of test portions and specimens

a) Test portions

Reduce laboratory samples to test portions of sufficient mass to produce 3specimens of 14 mm to 10mm size fraction. Use Table 7.7.1 for a guide to the minimum mass of test portion required to obtaina mass of material to determine the aggregate 10% fines value.

b) Test specimen in a dry condition

(i) Sieve the entire dried test portion on the 14 mm and the 10 mm test sieve to

remove the oversize and undersize fraction. Divide the resulting 14 mm to 10mm size fractions to produce 3 test specimens each of sufficient mass suchthat the depth of the material in the cylinder is approximately 100 mm aftertamping.

(ii) Dry the test specimens by heating at a temperature of 1050C plus or minus50C for a period of not more than 4 h. Cool to room temperature beforetesting. Record the mass of the material comprising the test specimen.


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c) Test specimens in a soaked condition

(i) Prepare the test portion as in 7.7.1.6(b) except that the test portion is testedin the as-received condition and not oven-dried. Place test specimen in a wirebasket and immerse it in the water in the container with a cover at least 50mm of water above the top of the basket. Remove entrapped air by lifting thebasket 25 mm above the base of the container and allowing it to drop 25times at a rate of approximately once per second. Keep the aggregatecompletely immersed in water at all times and for the next 24 h plus or minus2 h and maintain the water temperature at 200C plus or minus 50C.

(ii) After soaking, remove from the water and blot the free water from the surfaceusing the absorbent cloths. Carry out the test procedure immediately after thisoperation.

7.7.2.6 Procedure: Aggregates in dry condition

a) Place the cylinder of the test apparatus in position on the base-plate and add thetest specimen in three layers of approximately equal depth, each layer beingcompacted to 25 strokes from the tamping rod distributed evenly over the surfaceof the layer and dropping from a height approximately 50 mm above the surface ofthe aggregate. Carefully level the surface of the aggregate and insert the plungerso that it rests horizontally on this surface. Ensure that the plunger is free to move.

b) Place the apparatus, with the test specimen and plunger in position, between theplatens of the testing machine and load it as uniform a rate as possible so as tocause a total penetration of the plunger in 10 min plus or minus 30 s ofapproximately:

(i) 15 mm for rounded or partially rounded aggregates (uncrushed gravels). (ii) 20 mm for normal crushed aggregate. (iii) 24 mm for vesicular (honeycombed) aggregates.

c) Record the force (f) applied to produce the required penetration. Release the loadand remove the crushed aggregate by holding the cylinder over a clean tray ofknown mass and hammering on the outside with the rubber mallet until the crushedaggregate falls freely on to the tray. Transfer fine particle adhering to the inside ofthe cylinder and to the surface of the hammer to the tray by means of the stiffbristle brush. Weigh the tray and the aggregate and record the mass of theaggregate used to the nearest 1 g (M1).

d) Sieve the whole of the specimen on the 2.36 mm test sieve until no furthersignificant amount passes during a further period of 1 min. Weigh and record themass of the fractions passing and retained on the sieve to the nearest 1 g (M2 andM3) respectively and if the total mass (M2 + M3) differs from the initial mass (M1) bymore than 10 g, discard the result and test a further specimen.

If the percentage of the material (m) passing the sieve, calculated from theexpression: M = 100 x M2 / M1 does not fall within the range 7.5% and 12.5%, test afurther specimen, using an adjusted maximum test loading to bring the percentageof fines within the range and record the value of (m) obtained.

e) Repeat the complete test procedure with the same mass of aggregate at the sameforce that gives percentage fines value within the range 7.5% and 12.5%.

7.7.2.7 Procedure; aggregates in a soaked condition

a) Follow the procedure described in 7.7.2.6(a) except that after the crushedspecimen has been removed from the cylinder, dry it in the oven at a temperature


MAY 2001 Page 7.37

of 1050C plus or minus 50C either to constant weight or for a minimum of 12 h.Allow the dried material to cool and weigh to the nearest 1 g (M1). Complete theprocedure 7.7.2.6(d) and 7.7.2.6(e).

7.7.2.8 Calculation and expression of result

a) Calculate the force F (in kN), to the nearest whole number, required to produce10% fines for each test specimen, with the percentage of material passing in therange of 7.5% to 12.5%, from the following expression:

F = 14 f / (m + 4)

Where,f is the maximum force in kN.m is the percentage of material passing the 2.36 mm test sieve at the maximum

force.

b) Calculate the mean of the two results to the nearest 10 kN or more or to thenearest 5 kN for forces of less than 100 kN. Report the mean as the aggregate10% fines value, unless the individual results differ by more than 10 kN or by morethan 0.1 times the mean value. In this case repeat the test on two furtherspecimens, calculate the median of the four results to the nearest whole numberand report the median as the aggregate 10% fines value.



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7.8 Tests for Bricks

7.8.1 Introduction. Since bricks are made from variable naturally occurring materials, careshould be exercised in placing too much importance on the test results obtained on asingle sample. For test results to be meaningful and useful in the evaluation of materialproperties the tests have to be carried out according to the prescribed method andperhaps even more importantly the samples have to represent the materials beingtested.

7.8.2 Determination of dimensions

7.8.2.1 Size. The standard dimensions of common bricks shall be:

Length Width Depth / Height

240 mm 115 mm 70 mm

7.8.2.2 Size of voids

a) Solid bricks shall not have holes, cavities or depressions.b) Cellular bricks shall not have holes, but may have frogs or cavities not exceeding

20% of the gross volume of the brick.c) Perforated bricks shall have holes not exceeding 25% of the gross volume of the

brick. The area of any one hole shall not exceed 10% of the gross area of the brick.d) Frogged bricks shall have depressions in one bed. Frog size should not exceed

130 mm x 50 mm x 10 mm.

7.8.2.3. Variation. Small variation in the dimension shall be permissible to the following extentonly :

Table 7.8.1

Specified Dimension Maximum Permissible Variation

Over 50 mm and upto 75 mm ±1.5 mm




7.8.2.4 Dimensional deviations. The overall measurements of 24 bricks shall not fall outsidethe limits given in Table 7.8.2. In addition, the size of any individual brick shall notexceed the size given in 7.8.2.

Table 7.8.2

Sizes Overall measurement of 24 bricks

Maximum Minimum

240 mm

115 mm

70 mm

5880 mm

2910 mm

1710 mm

5680 mm

2810 mm

1650 mm

7.8.2.5 Procedure for measuring dimensions

a) Take 24 bricks. Remove any blisters, small projections or loose particles of clayadhering to the brick. Place the bricks in contact with each other in a straight line


MAY 2001 Page 7.40

upon a level surface, using the appropriate arrangement for each work size shownin Figure 7.8.1.

b) Measure the overall dimension (Length, width or height) to the nearest millimeter,using an in extensible measure long enough to measure the whole row at one time,results recorded in Form 7.8.1.

Note. Alternatively, the sample may be divided in half to form 2 rows of 12 bricks.Measurement of each row is made separately and the results are summedup.

7.8.3 Relative density and absorption

7.8.3.1 Introduction. The relative density of bricks may be measured using the saturatedsurface-dry (SSD) method used for the determination of density of cores and concretespecimens.

7.8.3.2 Density. The density of bricks is defined as the average density of 10 bricks sampledaccording to this test method and tested on the SSD basis.

7.8.3.3 Water absorption. The test method for the determination of water absorption in thisstandard is the 5 h boiling test.

7.8.3.4 Equipment. The equipment required for this test is listed below:

a) Ventilated drying oven with automatic control capable of maintaining a constanttemperature of 110 – 1150C.

b) Water tank, provided with a grid to ensure free circulation of water betweenmasonry units and the bottom of the tank.

c) Balance capable of weighing to an accuracy of 0.1% of the mass of the specimen.

7.8.3.5 Preparation of specimens

a) Use 10 bricks sampled in accordance with this test procedure.b) Dry the specimen to constant mass in the oven at a temperature of between 110

and 1150C. When cool, weigh each specimen to an accuracy of 0.1% of its mass.


a) Place the 10 specimens in a single layer in a tank of water immediately afterweighing, so that the water can circulate freely on all sides of them. Leave a spaceof about 10 mm between bricks and the sides of the tank.

b) Heat the water to boiling point in approximately 1 h.c) Boil for 5 h continuously, and then allow to cool to room temperature by natural loss

of heat for not less than 16 h or more than 19 h.d) Remove the specimens, wipe off the surface water with a damp cloth and weigh.

When wiping perforated bricks, shake them to expel water that might otherwise beleft in the perforations.

e) Complete weighing any one specimen within 2 min after its removal from the water.

7.8.3.7 Calculation of water absorption. Calculate the water absorbed by each specimen. A,expressed as a percentage of the dry mass, using the following expression.

A = 100 x (wet mass – dry mass) / dry mass

Calculate the average of the water absorption’s of the 10 specimens to the nearest0.1%. A data sheet is given as Form 7.8.2.


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7.8.3.8 Maximum permissible water absorption. The water absorption shall in no case begreater than the water absorption for the appropriate class of brick given in Table 7.8.3below.

Table 7.8.3 Classification of bricks by compressive strength and waterabsorption

Grade Compressive Strength Water absorptionfor 10 bricks (%)

Average for 12 halvedbricks (N/mm2)

Minimum forindividual halved

bricks (N/mm2)A

B

C

28

17.5

10.5

21.1

14

8.4

10

12

16

7.8.4 Compressive strength determination

7.8.4.1 Introduction. The compressive strength of bricks shall in no case be less than thecompressive strength for the appropriate class of brick given in Table 7.8.3.

When bricks are to be broken for use as road making, aggregate tests such as the LosAngles abrasion, aggregate crushing strength and aggregate impact value may give amore satisfactory indication of their suitability for use.

7.8.4.2 Equipment. The equipment required for the determination of compressive strength ofbrick is listed below:

1. Testing machine, compatible with the testing machine required for testing concretespecimens and capable of applying the rate of loading specified in the testprocedure.

Testing machine requirements:

It shall be equipped with two permanent ferrous bearing platens whichshall be at least as large as any plywood packing or, where such packingis not being used, the bedding faces of the specimens being tested.

The upper machine platen shall be able to align freely with the specimensas contact is made but the platens shall be restrained by friction or othermeans from tilting with respect to each other during loading.

The lower compression platen shall be plain, non-tilting bearing block.

The testing face of the platen shall be hardened and shall have:

a) a flatness tolerance of plus or minus 0.05 mmb) a parallelism tolerance for one face of each platen with respect to the

other of 0.10 mm.c) a surface texture not greater than 3.2 micron


MAY 2001 Page 7.45

7.8.4.3 Preparation of specimen. Twelve bricks taken at random from sample shall be halvedand one half from each whole brick used for determining the compressive strength. Theoverall dimension of each bedding face shall be measured to the nearest of 1.3 mmand the area of the face having smaller area shall be taken as the area of the bricks fortesting the compressive strength.


a) Bricks with frogs

1) Immerse the bricks in water at room temperature for 24 hours. They shall thenbe removed and allow to dry at room temperature for about 5 minutes.

2) Then fill the frogs with cement-sand mortar with a ratio of 1:11/2. Sand shouldbe clean and well graded and passing through 3.35 mm sieve. Trowel themortar off flush with surface of the bricks.

3) After filling the frogs, store the bricks under the damp sacks for 24 hours andthen immerse in water for 6 days before bricks are considered ready for testing.After seven days of filling the frogs, take out the specimens and wipe off themoisture with damp cloth.

4) Then place the specimen with flat surface horizontally and the mortar filled facefacing upwards between two plywood sheets of 3-ply, normally 3 to 4 mm thickand carefully centered between the plates of the compression testing machine.

5) Then apply the load axially at a uniform rate of 14 N/mm2 per minute, untilfailure. The failure shall be deemed to have occurred when no further increasein the load is registered with unchanged rate of moving head travel.

6) Calculation of compressive strength: Obtain the strength of each specimen bydividing the maximum load obtained during loading by the appropriate area ofthe bed face. Record the strength in N/mm2 to the nearest 0.1 N/mm2.Calculate the average of the 12 compressive strengths and report it to thenearest 0.1 N/mm2

.

b) Solid bricks / bricks with a frog intended to be laid downwards / perforatedbricks / cellular bricks

Immerse the brick in water for 6 days or saturate the brick by boiling as describedin water absorption test. Then follow the 7.8.4.4(a)(4) and 7.8.4.4(a)(5).

c) Solid bricks with cavities

Fill the cavities with capping compound or mortar mix and immerse in water for 6days and then follow 7.8.4.4(a)(4) and 7.8.4.4(a)(5).

d) Brick with holes

No capping compound is used and holes remain empty. Immerse the brick in waterfor 6 days, take out and wipe off the moisture and then follow 7.8.4.4(a)(4) and7.8.4.4(a)(5).

7.8.4.5 Calculation of compressive strengths

Strength = Maximum load in Newton / net area of brick in mm2.

For bricks with holes, net area of brick = Gross area of brick – area of holes.Gross area = Length of brick x width of brick.


MAY 2001 Page 7.46

Area of hole = 4

d

2

π where d is the diameter of the hole

Note. When bricks are to be used as crushed aggregate, for in a blend as unfoundmaterial, the necessity to determine the compressive strength accurately as itis when the bricks are to be used in load-bearing walls, is not so critical (see7.8.4.1)

7.8.4.6 Report. Report the compressive strength in a data sheet to the nearest 0.1 N/mm2. Datasheets are given as Forms 7.8.3 and 7.8.4.

Chapter 8 Standard Test ProceduresTests On Cement

MAY 2001 Page 8.1

CHAPTER 8

TESTS ON CEMENT

8.1 Fineness of Cement

8.1.1 Introduction. This simple test is not intended to indicate the true fineness of acement as may be determined by apparatus for measuring the specific surface, but itis intended to give an indication of any hydration in the cement which has led to theformation of small pieces of hardened material. If a sample of cement contains anyhardened lump of cement, it is clearly unsuitable for structural work and should berejected without further test.

8.1.2 Apparatus

a) 75 micron sieveb) Balance (accuracy 0.01g)

8.1.3 Preparation of sample. The sample should be taken from at least 10 different bagsand divided by means of quartering or riffling. About 100 grams of cement isrequired. Care should be taken in handling the sample to ensure that no crushing ofparticles takes place.


a) The sample should be weighed to the nearest 0.1 grams, Weight A and thensieved a little at a time on a 75 micron sieve. Care should be taken to preventloss of cement dust during loading and the sieve should be nested between a lidand a receiver whilst sieving. Sieving of any portion should not continue forlonger than 4 minutes and not more than 25 grams of cement should be placedon the sieve at any time. A bristle brush should be used to clean the mesh asrequired.

b) The material retained on the sieve from each portion should be collected insuitable dishes. There should be no cement dust adhering to the retainedmaterial. If necessary, the retained material should be re-sieved to remove fines.The total weight of material retained, Weight B, is determined.

c) To check that no significant weight of dust has been lost, the weight of thematerial in the receiver, Weight C, should be determined.

8.1.5 Calculation

Weight A' = Weight B + Weight C

Loss of material during test = Weight A - Weight A'

The loss in weight should not exceed 0.5% of the original weight.

Percentage retained on the 75 micron sieve = Weight B

x 100%WeightA

8.1.6 Reporting of results. The percentage retained on the 75 micron sieve should bereported to the nearest 1 percent.


MAY 2001 Page 8.2

8.2 Setting Time of Cement

8.2.1 Introduction

The setting times of cement give an indication of how long the cement will remainworkable when used in a concrete mix. If the cement has deteriorated or wasoriginally defective, it may take an excessive time to set.

8.2.2 Apparatus

The apparatus used for the test is the standard Vicat apparatus as shown in Figure8.2.1. The apparatus is essentially a simple penetrometer, the sample of cementpaste being placed in the mould below the sliding weight. The weight may be variedby placing calibrated weights within the stem and three different penetration devicesmay be fitted to the underside of the weight. The total sliding weight including thepenetration attachments should be 300 ± lg.


a) The sample must be mixed with the correct amount of water to give a standardconsistency. The standard consistence is determined by means of the Vicatapparatus fitted with the plunger, a 10mm diameter blunt-ended, metal cylinderweighing 9.0± 0.5. g.

b) The freshly mixed cement paste is placed in the mould and levelled off with atrowel. The plunger is brought into contact with the surface of the paste and thenreleased.

c) The paste is at the correct consistence when the plunger penetrates to a points5± 1 mm. from the bottom of the mould. The depth of penetration is shown on thescale. Fresh samples of paste with varying water contents should be tested untilthe desired consistence is achieved.

d) Normally, a weight of water between 26 and 33 percent of the weight of the drycement is required to obtain the standard consistence.

Note. Note that the procedure of determining consistence should not takelonger than about 5 minutes.


a) A fresh sample of cement paste of standard consistence should be placed in themould and levelled off using a trowel.

b) The initial set needle should be fitted to the apparatus, this needle is a blunt-ended cylinder of diameter 1.13 mm. and weighing 9.0 ± 0.5g. with the needle inposition the sliding portion of the apparatus should weight 300 grams. The weightshould be checked prior to the start of the test.

c) To determine the initial setting time the needle is brought into contact with thesurface of the cement paste and released. Initially the needle will penetratecompletely through the paste to the base of the mould, but the test is repeated atregular intervals at different points on the surface until the needle onlypenetrates to within 5 ± 1 mm. of the base of the mould. The time elapsed frominitially mixing the cement with water until the desired penetration is reached isthe initial setting time.


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d) To determine the final setting time the final set needle is fitted to the apparatus.The final set needle is a cylindrical blunt-ended needle which is fitted with a metalcollar which is hollowed out to leave a 5 mm. diameter cutting edge 0.5 mm.behind the tip of the needle. The weight should be 9.0 ± 0.5 g.

e) The needle is brought gently into contact with the surface of the paste andreleased. This operation is repeated at intervals until the tip of the needle marksthe paste but the cutting edge does not come into contact with the paste. Thetime elapsed from initial mixing of the cement and water until this stage is reachedis the final setting time.

Note 1. For ordinary Portland cement the initial time of setting is not less than45 minutes and the final time of setting is not more than 375 minutes byVicat test.

Note 2. It should be noted that the setting times will be reduced as thetemperature of the paste increases, and the temperature of the testshould be maintained at 30 ± 20C to give consistent results. To preventpremature hardening of the surface of the paste, the humidity shouldexceed 90%; this may be achieved by covering the apparatus with adamp, but not dripping, towel between determinations.

8.2.5 Reporting of results

The initial setting time should be reported to the nearest 5 minutes and the finalsetting time should be reported to the nearest 30 minutes. The temperature of thetest should be stated.


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8.3 Compressive Strength of Cement

8.3.1 General Requirements

8.3.1.1 Scope: The strength of cement is determined by compressive strength tests, on100mm concrete cubes, or 70.7mm mortar cubes, made with specified coarse andfine aggregates, in the case of the 100mm concrete cubes and specified sand in thecase of the 70.7 mortar cubes, mixed by a machine and compacted manually with acompacting bar.

Note. The water/cement ration is 0.60 (C1, Table 8.3.1) for all cements exceptsuper sulphated and high alumina, for which values of 0.55 (C2 Table8.3.1) and 0.45 (C3 Table 8.3.1) respectively are used.

Table 8.3.1 Mixes for concrete cubes (in grams)Mix type Material Proportion

by massMass for6 cubes

Mass for 9cubes

Mass for12 cubes

C 1CementSandCoarseagg.Water

1.02.53.50.60

2200±555007700±101320±5

3200±5800011200±101920±5

4200±51050014700±102520±5


1.02.53.50.55

2200±555007700±101210±5

3200±5800011200±101760±5

4200±51050014700±102310±5


1.01.8752.6250.45

2940±555007700±101320±-5

4270±5800011200±101920±5

5600±51050014700±102520±5

8.3.1.2 Apparatus

8.3.1.2.1 Moulds

a) Construction and assembly. The sides of the mould shall be made fromferrous metal. The mould shall include a removable ferrous metal base plate. Allparts shall be robust enough to prevent distortion. Before assembly for use, thejoints between the sides of the mould and between the sides and the base plateshall be thinly coated with oil or grease to prevent loss of water. The wholeassembly when completed must be rigidly held together in such a manner as toprevent leakage from the mould. The internal faces of the mould shall be thinlycoated with release agent to prevent adhesion of the concrete.

Tolerances: The dimensional deviations shall be as follows:

i) Dimensions: The internal depth of the mould when assembled and thedistance between the two pairs of opposite internal faces, shall be 100 mmplus or minus 0.15 mm for the 100mm moulds and 70.7 mm plus or minus0.1mm for the 70.7 mm moulds

ii) Flatness: The flatness tolerance for each internal side face whenassembled shall be 0.03mm wide for the both the 70.7mm and the 100mmmoulds. The flatness tolerance for the joint faces, for the top and bottom


MAY 2001 Page 8.6

surfaces of the assembled mould sides and the top surface of the baseplate shall be 0.06mm wide.

iii) Squareness: When assembled, the squareness tolerance for each internalside face with respect to the adjacent internal side face and top of the baseplate shall be 0.5 mm wide for the both the 70.7 mm and the 100 mmmoulds.

iv) Parallelism: When assembled, the parallelism tolerance for the top surfaceof the mould with respect to the top surface of the base plate shall be1.0mm wide both for the 70.7mm and the 100mm moulds.

v) Surface texture: The surface texture of each internal side face shall notexceed 3.2 micron when determined in accordance with BS 1134 both forthe 70.7 mm and the 100 mm moulds.

8.3.1.2.2 Scoop, approximately 100mm wide.

8.3.1.2.3 Square mouthed shovel, size 2 BS 3388.

8.3.1.2.4 Plasterer’s steel float.

8.3.1.2.5 Compacting bar weighing 1.8 plus or minus 0.1 kg, at least 380mm long and having aramming face of 25 plus or minus 0.5mm square.

8.3.1.2.6 Mixer. The concrete mixer shall be of suitable capacity to mix a concrete batch inone operation. It shall comprise a rotating mixing pan with contra-rotating mixingpaddle and a scraper blade as shown in Figure 8.3.1 and Figure 8.3.2. The mixingpan shall rotate at 18 plus or minus 1r/min. The mixing paddle shall rotate at 90 plusor minus 5 r/min. The mixer shall preferably be fitted with an automatic timing deviceotherwise a stopwatch should be provided.

8.3.1.2.7 Tank. The tank shall contain clean tap water which shall be replace at least every 7days with water at the specified temperature.

8.3.1.2.8 Compression testing machine. Over the scale range used, the machine shall becapable of applying the load at a rate of about 0.25 N/mm2 per second for the 100mmconcrete moulds and at a rate of about 0.60Mpa for the 70.7mm mortar moulds andshall comply with grade 1 of BS 1610.

8.3.1.3 Temperature and humidity conditions. The temperature throughout the entiretest procedure should be controlled at 200C with permitted variations as shown inTable 8.3.2. The minimum relative humidity shall be as given in Table 8.3.2.

Table 8.3.2 Temperature and humidity conditions.

Situation Permitted temperatureVariation, 0C

Minimum RelativeHumidity

%Mixing roomMoist curingchamberWater curing tankWater curing tank

±2±1±1±2

5090-

50


MAY 2001 Page 8.7

Form 8.3.1


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MAY 2001 Page 8.9

Figure 8.3.3 : Typical Vibration Machine for compacting MortarCubes


MAY 2001 Page 8.10

8.3.1.4 Preparation of samples. The specimens shall be prepared as follows:

8.3.1.4.1 Number of cubes. Make batches of six, nine, or twelve cubes for testing at thespecified ages.

8.3.1.4.2 Aggregates. The coarse aggregate and sand shall comply.

8.3.1.4.2.1 Standard coarse aggregate for concrete cubes (100mm 70.7mm moulds).

a) Scope. The coarse aggregate shall consist of clean, substantially free fromdust and dry crushed granite, in one fraction, 10mm to 5mm nominal size,30Kg of aggregate is required for sampling purposes and it shall be reduced,using a sample divider, to six sub-samples of about 500g each.

b) Grading. The coarse aggregate shall comply with the grading requirementsof the table below:

Test sieve10.00mm5.00

Percentage passing sieve90 - 100 0 - 10

Sieve the coarse aggregate on 10 mm and 5 mm and 5 mm sieves with square holesso that it is substantially free from oversized particles.

8.3.1.4.3 Standard sand to be used with standard coarse aggregate for makingconcrete cubes

a) Scope. Natural silica sand in five fractions. Each fraction shall comply withthe grading requirements of table 5. For each fraction of sand, 8kg sand arerequired for sampling purposes and the sand shall be reduced using asample divider to six sub-sample of about 500g each.

b) Grading. The sand shall comply with the grading requirements of Table 8.3.3below:

Table 8.3.3 Grading of sand fractions for concrete cubes 100mm or 70.7 mm

Fraction A Fraction B Fraction C Fraction D Fraction E

Test sieve % passing % passing % passing % passing % passing3.35 mm 100 100 100 100 1003.35-2.36 mm 90-100 100 100 100 1002.36-1.18mm 0-10 90-100 100 100 1001.18mm-600 mic 0 0-10 90-100 100 100600mic-300mic 0 0 0-10 90-100 100300mic-150mm 0 0 0 0-15 85-100150-90 mic 0 0 0 0 0-1575 mic 0 0 0 0 0


MAY 2001 Page 8.11

8.3.2 Compressive Strength Procedure using the 100 mm Concrete Moulds

8.3.2.1 Proportionship of materials. The masses of the individual materials for batches ofsix, nine of twelve cubes are given in Table 8.3.1 and 8.3.4.

Table 8.3.4 Mass for individual fractions of sand (in grams)Fraction Mass for 6

cubesMass for9 cubes

Mass for12 cubes

A (2.36-1.18mm)B (1.18-600 micron)C (600 micron-300 micron)D (300 micron-150 micron)

550±51100±51650±51375±5

800±51600±52400±52000±5

1050±52100±53150±52625±5

8.3.2.2 Mixing. Place the weighed materials in the mixer in the following order:

1. Sand, 2. Cement, 3. Coarse aggregate

Hold the mixing water ready and start the mixer. After 15s add the water uniformlyduring the next 15s, and then continue mixing for a total time of 180 plus or minus 5s.After the machine mixing, turn the concrete over in the pan a few times with a trowelto remove any slight segregation.

8.3.2.3 Compacting: Half fill the cube moulds as quickly as possible. Compact each mouldwith exactly 35 strokes of the compacting bar, uniformly distributed over the crosssection of the mould. Place a further quantity of concrete in each mould to form thetop layer and compact similarly. Then strike off the top of each cube and smooth withthe trowel so that the surface or the concrete is level with the top of the cube.Complete the entire operation within 15 minutes from the completion of the mixing.

8.3.2.4 Storage of specimens. Immediately after preparation, place the moulds in singlelayer on a layer on a level surface in a moist curing chamber. In order to reduceevaporation, cover the exposed top of the cubes with a flat impervious sheet makingcontact with the upper edge of the mould. After 24h plus or minus 0.5h mark thecubes for later identification and remove from the moulds. Immediately submerge allspecimens, except the ones to be tested at 24h, in the tank and arrange in such away that the temperature variation specified in Table 1 is not exceeded. Leave thecubes in the tank until just prior to the test but ensure that the temperature of thewater in the tank is maintained at 200C plus or minus 20C.

Specimens to be tested at 24h are marked and demoulded 15 min to 20 min beforethe test and are covered with a damp cloth so that they remain in a moist condition. Ifthe concrete has not achieved sufficient strength after 24h to be handled without fearof damage, delay the demoulding for a further 24h but state this in the test report.

8.3.2.5 Testing of specimens. Determine the compressive strength of the cubes, under thetemperature and relative humidity conditions specified in Table 8.3.2 for thecompression testing room, at the specified age, calculated from the time that waterwas added to the materials, by the applying load without shock in the testingmachine. Ensure that all surfaces of the cube are clean and that no grit or any otherparticle rests on the surface receiving the load and centre the cube on the lowerplaten and ensure that the load will be applied to the two opposite cast faces of thecube. The rate of loading shall be about 0.25 N/mm2 per second using the auxiliaryplatens.


MAY 2001 Page 8.12

Test the specimens within the following limits:

24h plus or minus 0.5h3 days plus or minus 1.0h7 days plus or minus 2.0h28 days plus or minus 4.0h

8.3.2.6 Calculation. Calculate the average of the individual results of the set of threespecimens tested at the same age, and express the result to the nearest 0.5N/mm2. Ifone result within the same set varies by more than 5% of the average of the set,discard the result and recalculate the average of the remaining results. If more thanone result varies by more than 5% from the average, discard the set of results.

8.3.2.7 Report. Report the individual results and the average compressive strength to thenearest 0.5N/mm2, indicating if any result has been discarded.

8.3.3 Compressive Strength of Mortar Cubes using the 70.7 mm Mortar Cubes

The strengths of cement is determined by compressive strengths tests on 70.7mmmortar cubes, made with specified sand, mixed by hand and compacted by means ofa standard vibration machine. The equipment required for this test has beendescribed in the general requirements for the compressive strengths of cement using100mm concrete moulds. In addition to the equipment above there is a requirementfor a vibrations machine. A typical vibration machine as shown in Fig. 8.3.3 issuitable. The temperature and humidity conditions required for the test are identicalto those in the test for the compressive strengths of cement using 100mm concretemoulds.

8.3.3.1 Standard sand to be used for making mortar cubes.

8 kg of sand are required for sampling purposes and it shall be reduced using thesample divider into sub-samples of about 500g each.

The moisture content of the sand shall not exceed 0.1% by dry mass using the oven-dry method.

The grading of the sand shall be such that all of it passes 850 micron test sieve andthe proportion by mass passing the 600 micron test sieve shall not exceed 10%.

The sand shall show a loss of mass not exceeding 0.25% on extraction with hothydrochloric acid when determined in the following methods:

8.3.3.2 Method

Dry a sample of little over 2g of the sand at a temperature of 1050C plus or minus50C for a period of 1 h.

Weigh a quantity of about 2g of the dried sand to an accuracy of plus or minus0.001g into a porcelain dish and add 20ml of 1 M hydrochloric acid and 20ml ofdistilled water. Heat the dish on a water bath for 1h, filter the contents, and wash wellwith hot water.

Dry the sand, ignite it in a covered crucible, cool it and weigh it again. The loss inmass shall be expressed as a percentage of the original mass of sample.


MAY 2001 Page 8.13

8.3.3.3 Proportioning. The mass of cement, sand and water for each cube is given in Table8.3.5.

Table 8.3.5 Mixes for mortar cubes:Mix type Material Proportions by

massMass for 1 cube

V 1CementSandWater

1.03.00.40

185±1555±174±1

8.3.3.4 Mixing. Before mixing, clamp the assembled mould on the table of the vibrationmachine and attach the hopper to the top of the mould. Mix the mortar for each cubeseparately on a non-porous surface that has been wiped clean with a damp cloth. Mixthe cement and the sand dry, for 1 min, by means of the two trowels. Then add thewater and mix the whole for 4 min with the two trowels.

8.3.3.5 Compacting. Please the whole of the mortar in the hopper of the mould by means ofa suitable scoop as quickly as possible and compact by vibration for a period of 120splus or minus 5s.

8.3.3.6 Storage. Storage of samples is identical with the procedure for test using 100mmconcrete cubes.

8.3.3.7 Testing. The testing of the 70.7mm mortar cubes is the same procedure as thetesting used for the 100mm concrete cubes except that the rate of loading shall be0.60/Nmm2 per second. Calculations and reporting are identical to the correspondingsections of test using the 100mm concrete cubes.

Chapter 9 Standard Test ProceduresTests On Concrete

MAY 2001 Page 9.1

CHAPTER 9

TESTS ON CONCRETE

9.1 Slump Test

9.1.1 Scope

The strength of concrete of a given mix proportion is seriously affected by the degreeof its compaction. It is therefore important that the consistency of the mix is such thatthe concrete can be transported, placed and finished sufficiently easily and withoutsegregation. A concrete satisfying these conditions is said to be workable.Workability is a physical property of the concrete depending on the external andinternal friction of the concrete matrix; internal friction being provided by theaggregate size and shape and external friction being provided by the surface onwhich the concrete comes into contact with.

Consistency of concrete is another way of expressing workability but it is moreconfined to the parameters of water content. Thus concrete of the same consistencymay vary in workability. One test which measures the consistency of concrete is theslump test. It does not measure the workability of concrete but it is very useful indetecting variations in the uniformity of a mix of given nominal proportions.

Mixes of stiff consistency have zero slump. In this dry range no variation can bedetected between mixes of different workability. In a lean mix with a tendency toharshness a true slump can easily change to the shear slump or even to collapse.Different values of slump can be obtained from different samples of the same mix.Despite the limitations, the slump test is very useful on site as a check on the day-to-day or hour-to-hour variations in the materials being fed into the mixer.

An increase in slump may mean, for instance, that the moisture content of aggregatehas unexpectedly increased; another cause would be a change in the grading ofaggregate, such as a deficiency in sand. Too high or too low a slump givesimmediate warning and enables the mixer operator to remedy the situation.

9.1.2 Apparatus

9.1.2.1 Mould. A mould made of metal not readily attacked by cement paste and not thinnerthan 1.5mm. The interior of the mould should be smooth and free from projectionssuch as protruding rivets and shall be free from dents. The mould shall be in the formof a hollow frustum of a cone having the following dimensions:

a) diameter of base = 200mm plus or minus 2mmb) diameter of top = 100mm plus or minus 2mmc) height = 300mm plus or minus 2mm.

The base and top shall be open and parallel to the axis of the cone. The mould shallbe provided with two handles at two-thirds of the height, and with foot pieces toenable it to be held steady. A mould which can be clamped to the baseplate isacceptable, provided that the clamping arrangement can be released withoutmovement of the mould.


MAY 2001 Page 9.2

9.1.2.2 Scoop, approximately 100mm wide.

9.1.2.3 Sampling tray, 1.2m x 1.2m x 50mm deep made from minimum 1.6mm thick non-corrodible metal.

9.1.2.4 Square mouthed shovel, size 2 in accordance with BS 3388.

9.1.2.5 Tamping rod, made out of straight steel bar of circular cross section. 16mmdiameter, 600mm long with both ends hemispherical.

9.1.2.6 Rule, graduated from 0mm to 300mm at 5mm intervals.

9.1.3 Performing Slump test

9.1.3.1 Procedure. Commence the slump test as soon as possible after sampling ofconcrete as per standard procedure described in Chapter 2.

9.1.3.2 Preparation of sample for test. Empty the sample from the container onto thesampling try. Thoroughly mix the sample by shovelling to form a cone on thesampling tray. and turning this over to form a new cone, the operation beingrepeated three times. When forming the cone deposit each shovelful of the materialon the apex of the cone so that the portions which slide down the sides aredistributed as evenly as possible and so that the centre of the cone is not displaced.Flatten the third cone by repeated vertical insertion of the shovel across the apex ofthe cone, lifting the shovel clear of the concrete after each insertion.

9.1.3.3 Test. Ensure that the internal surface of the mould is clean and damp but free fromexcessive moisture before commencing the test. Place the mould on a smooth,horizontal, rigid and non-absorbent surface free from vibration and shock.

Hold the mould firmly against the surface below. Using the scoop fill the mould inthree layers, each approximately one-third of the volume of the mould when tamped.Tamp each layer with 25 strokes of the tamping rod, the strokes being distributeduniformly over the cross section of the layer. Tamp each layer to its full depth,ensuring that the tamping rod does not forcibly strike the surface below whentamping the first layer and only passes through the second and top layers into thelayers below. Heap the concrete above the mould before the top layer is tamped.After the top layer has been tamped strike off the concrete level with the top of themould with a sawing and rolling motion of the tamping rod. With the mould still helddown, clean from the surface below any concrete which might have fallen onto it.

Remove the mould from the concrete by raising it vertically, slowly and carefully, in 5seconds to 10 seconds, in such manner as to impart minimum lateral or torsionalmovement to the concrete. The entire operation from start to finish shall be carriedout without interruption and shall be completed within 150 seconds. Immediately afterthe mould is removed, measure the slump to the nearest 5mm by using the rule todetermine the difference between the height of the mould and of the highest point ofthe specimen being tested.

Note. The workability of a concrete mix changes with time due to the hydration ofthe cement, and loss of moisture.


MAY 2001 Page 9.3

9.1.3.4 Expression of result

9.1.3.4.1 General. The test result is only valid if it yields a true slump. The slump should bereported to the nearest 5mm and the type of slump (i.e. true, shear or collapse)should be stated as shown in Figure 9.1.1 a), b) and c).

9.1.3.4.2 Precision. For slump measurements made on concrete taken from the samesample, the repeatability is 15mm at the 95% probability level, for normal concretehaving a measured slump within the range of 50mm to 75mm.

9.1.4 Report

The following information shall be included in the report:

a) Name of testing agencyb) Clientc) Contract named) Location of concrete in structuree) Supplier of concretef) Date and time of testg) Time of completion of testh) Location of testi) Time lapsed from sampling to commencement of testj) Form of slump, whether true, shear or collapsek) Measure of true slumpl) Name and signature of sampler and tester

A form of reporting the slump test results is shown in Form 9.1.1.

Figure 9.1.1

a)Intact and symmetrical b) Shear c) Collapse

True Slump Shear Collapse


MAY 2001 Page 9.4


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9.2 Crushing Strength of Concrete

9.2.1 Introduction

Crushing tests are universally used for determining the strength of concrete and thestandard test measures the crushing strength at an age of 28 days after mixing.Because of the time delay in obtaining the test results for concrete crushing strength,it is often very difficult or expensive to take remedial action if the test results areunsatisfactory. It is, therefore, essential to continuously control all aspects ofconcrete production so that the concrete very rarely fails in crushing strength tests.

Crushing strength tests may be carried out on either cylinders or cubes made instandard moulds, cured under standard conditions and crushed in a standardmanner. Any variations in the methods of manufacture, curing or testing may affectthe final results and all these aspects require careful control.

9.2.2 Scope

The results of this test may be used as the basis of concrete proportioning, mixingand placing operations; determination of compliance with specification, control forevaluating effectiveness of admixtures and similar uses. There are only minordifferences in test methods between cubes and cylinders and they are, therefore,considered together.

9.2.3 Testing machine

Crushing machines may vary from small hand-operated models to large power-drivenuniversal test machines. In the large majority of machines, the load is applied by ahydraulic jack and the load is measured by a pressure gauge calibrated directly inunits of force.

Even a small crushing machine is likely to be one of the most expensive pieces ofequipment in the laboratory and it should be maintained strictly in accordance withthe manufacturer’s instruction. In general, it should be installed in a dry place andshould be kept clean at all times. The hydraulic reservoir or pump should befrequently topped up with the correct grade of hydraulic oil, (the use of ordinarymotor oil may quickly ruin the machine). The maximum load on the gauge shouldnever be exceeded and the machine should not be left under load for a prolongedtime. Any oil leaks should be quickly reported and appropriate repairs carried out. Awell maintained machine should last many years.

The accuracy of new crushing machines will vary somewhat with the type of machine,a smaller machine may be expected to give less accurate results than a high-qualityuniversal test machine. If machines are used frequently at loads close to their designcapacity, their accuracy will suffer and it is a wise precaution to only use machines atloads up to 75 percent of their design capacity.

With age the calibration of a machine may vary and all machines should periodicallybe re-calibrated using a load cell or a number of standard test specimens, aproportion of which are tested on a fully-standardised machine. If a replacement loadgauge is fitted to a machine, re-calibration must be carried out.

The steel platens on a crushing machine are designed to withstand very highstresses, they should, however, occasionally be checked for damage and the ballseating of the upper platen should be checked for cleanliness and freedom ofmovement.


MAY 2001 Page 9.6


Samples for crushing strength tests should truly represent the concrete used in theworks and must, therefore, be taken throughout the period when work is in progress.It will be clear that if all specimens are made from only one batch of concrete this mayrepresent only a small fraction of the concrete used in the pour. If, however, onespecimen is made from each of a number of different batches of concrete throughoutthe day the specimens will be more representative of the average concrete used inthe pour.

Samples for testing should be taken at random times throughout the day and it isbest for the mix to be batted before any indication is given that tests are to be made.It is very easy for a mixer operator to produce ‘a good mix’ especially for the tests; thepurpose of quality control testing is, however, to determine the true strength of thetypical material used in the works.

The samples for crushing strengths may be collected in a similar manner as forworkability test (slump test). In fact, it is usual procedure to test part of the sample forworkability and part for crushing strength.

The specimens should be prepared immediately after sampling.

9.2.5 Making test cubes and cylinders

Concrete cube or cylinder moulds are made of steel or cast iron and of sufficientstrength to resist deformation, the inside faces and ends are machined to givesmooth surfaces and tight fitting joints. The moulds are made in two halves which bolttogether for ease of removing the samples and cleaning. Cylinder moulds arenormally 150 mm in diameter and 300 mm high; cube moulds normally have 150mmsides. The moulds sit on heavy baseplates which are fastened to the moulds byclamps.

There should be no dirt or hardened mortar on the faces or the flanges of the mouldsbefore assembly, otherwise the sections will not fit together closely. These faces mustbe thinly coated with mould oil to prevent leakage during filling, and a similar oilshould be provided between the contact surfaces of the bottom of the mould and thebase. The inside of the mould must also be oiled to prevent the concrete fromsticking to it. The sections must be bolted tightly together and the mould held downfirmly on the baseplate. Any excess oil should be removed by wiping with a soft clothas this may be detrimental to the concrete.

The concrete should be placed in the mould using a scoop, taking care to ensure theconcrete does not segregate. The concrete should be placed in layers, each layerbeing compacted before placing another layer. The purpose of the procedure is toachieve full compaction (i.e. maximum density); a drier mix may, therefore, need morecompaction than a wet mix. The following procedures are considered the minimumrequirements to ensure full compaction; dry mixes may require considerably morecompaction than the minimum shown: -

Cubes: - Place concrete in three layers giving each layer at least 35 blows of a 25mmsquare blunt-ended tamping rod.

Cylinders: - Place concrete in three layers, each approximately one-third the volumeof the mould, giving each layer 25 strokes of a 16mm diameter round-ended tampingrod of 600mm length.


MAY 2001 Page 9.7

As an alternative to the above procedures vibration may be used to fully compact thespecimen. This may be done either on a vibrating table or using an immersionvibrator.

On completion of compaction, excess concrete should be removed with a steel floatand the surface floated off level with the top of the mould. It is preferably for thefinished surface to be slightly proud of the mould especially if the mix is very wet.Care should be taken when floating off the top surface to ensure the surface is notdevoid of fines or contains too much mortar, as far as possible the top surface shouldbe of a similar consistency to the concrete in the mould.

The moulds should not be moved at all within the first four hours after casting and itis preferable to leave them undisturbed for 24 hours. The reference number of thespecimen may be marked on the surface of the concrete once this has started to set.

9.2.6 Curing specimens

The conditions under which a specimen is cured can cause substantial variations inthe final strength of the concrete. For example, a normal concrete cured entirely inair, will have a strength at 28 days about half that of the same mix cured in water.Similarly, a specimen cured in water at 130C will have a strength at 7 days about 70%of that of the same mix cured in water at 460C. Because of these variations, it isessential that all specimens are cured in a similar manner if strengths are to becompared.

Immediately after casting, the moulds should be covered with damp hessian (jutebags), the hessian should not be so wet as to allow water to fall on the surface of thespecimen. It is a good practice to raise the hessian off the surface of the concrete bymeans of small pieces of wood. The moulds and hessian should then be covered witha sheet of polythene to prevent drying out. The polythene should completely enclosethe moulds and be weighted down at the edges with bricks or stones. If polythene isnot available, the hessian must be kept damp at all times. The moulds should not beexposed to direct sunlight.

After 24 ± ½ hours, the specimens should be uncovered and removed from themoulds. The concrete is still weak at this stage and should be handled carefully. Toremove from the mould, loosen all the bolts and clamps, slide off the baseplate andthen tap the mould gently to free the specimen. On removal from the mould, thespecimen should be put straight into a tank of clean water. It will not normally bepossible to control the water temperature other than by shielding from direct sunlightbut it should be normally within the range 25 to 350C. In the case of laboratory testsfor trial mixes etc., the temperature should be maintained at 30± 10C. The watershould be changed at least once a month.

It should be noted that in the USA and Europe the standard curing temperature is200C. In Bangladesh it is not normally possible to attain this temperature withoutartificial cooling and a standard temperature of 300C is used. This temperaturedifference has only a minor effect on 28-days strengths but results in a higherstrength at 7 days. Care should, therefore, be taken when comparing test results withtypical values given in reference books and papers.

9.2.7 Transporting specimens

In many cases it will be necessary to transport cubes and cylinders from the site to acentral laboratory where they are to be crushed. Specimens must not be transported


MAY 2001 Page 9.8

during the first 24 hours after casting and, if possible, reduce the risk of damageduring transit.


MAY 2001 Page 9.9

Immediately prior to transport, the specimen should be removed from the curing tankand completely wrapped in hessian which should be at least two layers thick. Thehessian and specimen should then be completely soaked with water and placed in apolythene bag which should be firmly sealed. A ticket containing details of thespecimen should be placed in the bag.

As an alternative to a polythene bag, the specimen may be placed in an airtight tin.Occasionally, purpose-made curing cans may be available, these have a spongelining which is thoroughly wetted prior to inserting the specimen, thus dispensing withthe need for hessian. The whole purpose in transporting is to keep the specimen wetat all times and to prevent physical damage during the journey. If the specimens areto be transported by lorry or over rough roads, additional protection may be required.On reaching the laboratory, the specimens should be immediately placed in a tank ofwater to complete the period of curing.

9.2.8 Testing specimens

On completion of the required period of curing, the specimens are removed from thewater, allowed to drain and surface-dried, using a soft cloth.

The weight of the saturated surface-dry specimen is then determined, weight a. Theweight of the sample in water is then taken by use of wire basket suspended from asuitable balance and immersed in a tank of water, weight b.

Any burrs or edges on the sides of the specimen should then be removed using acarborundam block.

The sample may now be tested. In the case of cubes, the sample is placed in thecrushing machine on its side so that the two faces in contact with the platens of themachine are faces which were in contact with the polished steel sides of the mould,they should, therefore, be perfectly plane and smooth. Cylinders must, however, betested in an upright position and the upper surface has only been float- finished. Ifthe cylinder was crushed with the upper surface directly in contact with the platen ofthe test machine, the test result would almost certainly give a low result as the uppersurface will be in contact with the machine at a number of high spots and compactstress patterns will be developed. It is, therefore, standard procedure to capspecimens prior to test.

Capping may be done by a number of methods but the two most commonly used areneat cement and capping compounds. Using neat cement the cylinder is cappedshortly after casting. During casting, the wet concrete should be left about 3mm.below the top of the mould. After at least 4 hours when the concrete has initially set,the mould is topped up with a neat cement paste. The cement paste should havebeen allowed to stand for some time prior to use, to allow some of the initialshrinkage to take place; it should not, however, have started to harden. To obtain aperfectly smooth surface the cement paste is finished off level with the top of themould using a flat piece of glass which is slid across the top surface. It is sometimeuseful to apply a thin layer of graphite grease to the glass to aid sliding, somepractice may be required before a perfectly smooth surface can be achieved. Thespecimen is then cured as usual.

Using capping compound, the cylinder is capped immediately prior to testing. Thecapping compound may be pure sulphur or preferably a mixture of sulphur and milledfired clay (brick dust). The compound is heated in a metal pot until molten, when aportion is removed with a ladle, and poured onto a polished steel plate. The cylinder


MAY 2001 Page 9.10

is then gently lowered onto the compound and rotated to ensure the face iscompletely


MAY 2001 Page 9.11

covered. A special jig is normally used for this purpose, this ensures the cylinder iskept absolutely vertical during the capping operation. Once cool, the compound isimmediately ready for use. After testing, compound may be recovered by re-heating.

The capped cylinder is placed in the crushing machine. Specimens should be testedin a saturated surface-dry condition.

The steel platens of the crushing machine are brought together until they just touchthe upper and lower surfaces of the specimen. The specimen should be central onthe platens and the upper platen should be free to rotate so that any smalldifferences in alignment between the upper and lower surfaces of the specimen maybe accounted for.

The crushing machine should be fitted with a guard to contain the specimen onfracture.

The load is then applied to the specimen at a constant rate to give an increase instress on the specimen of 0.2 to 0.4 N/mm2/sec. On automatic machines the rate ofloading may be shown by a load pacer, but on manual machines, pacing should bedone using a stopwatch. It is a good practice to overlay the dial with a clear plasticsheet with times corresponding to each dial gauge reading shown. Note that, as thesample begins to fail the actual speed of the platens must be increased to maintainthe same rate of application of load.

The rate of loading has a significant effect on the test result in that, too quick a ratewill give a high result and too slow a rate will give low results, it is, therefore,important to maintain the correct rate.

The specimen is considered to have failed when the load begins to decrease, eventhough the operator is still attempting to maintain the rate of loading. Prior to thiscondition, small decreases in the load may take place and after a short time the loadagain increases, this re-orientation of the specimen close to failure may bedisregarded. The maximum load attained during the test should be recorded. Someof the satisfactory and unsatisfactory of failures are shown in Figure 9.2.1 and Figure9.2.2.

9.2.9 Calculation

It is usual to test cubes and cylinders on a daily basis and the test results for a day’swork may be recorded on a sheet such as Form 9.2.1.

The volume of the specimen is give by: -

Volume c = (weight a - weight b) ml

Where, weight a, is weight of SSD specimen in air (grams) and weight b, is weight ofSSD specimen in water (grams).

The density of the concrete is give by: -

Density = WeightVolume

= ac

gm / ml

= ac

x 1000 kg / cu.m


MAY 2001 Page 9.12

The stress on the specimen is given by: -

Stress = Maximum test load

Cross - sectional area of specimen

In the case of a cube, the cross sectional area = L2.

In the case of a cylinder the cross sectional area = π D2

4Where L is length of side of a cube, D is diameter of a cylinder.

The final results of a batch of cubes may be given on a form as shown in Form 9.2.2.


The crushing strength of the concrete should be reported to the nearest N/mm2 andthe density of the hardened concrete should be reported to the nearest to kg/cu.m.

The test report should include at least the following information:

a) Name of testing agencyb) Clientc) Contractor’s named) Contract namee) Date and time specimens madef) Age of specimen at testg) Method of compacting specimensh) Sample identification numberi) Conditions of curing and storagej) Supplier of concretek) Date concrete delivered to sitel) Location of concrete in structurem) Slump of concreten) Maximum load at failureo) Density of specimenp) Appearance of concreteq) Description of failurer) Name of samplers) Name of testert) Any other information


MAY 2001 Page 9.13

NOTE. All four exposed faces are cracked approximately equally, generally with littledamage to faces in contract with the platens.


MAY 2001 Page 9.14

Form 9.2.1


MAY 2001 Page 9.15

Form 9.2.2

Chapter 10 Standard Test ProceduresTests For Bitumen & Bituminous Materials

MAY 2001 Page 10.1

CHAPTER 10

TESTS FOR BITUMEN & BITUMINOUS MATERIALS

10.1 Bitumen Penetration Test


10.1.1.1 Scope. This is a basic test for determining the grades of bitumen. In effect, the test isan indirect determination of high temperature viscosity and low temperature stiffness.The scope of this is to provide a method for determining the consistency of semi-solidand solid bituminous materials in which the sole or major constituent is either bitumenor tar pitch.

10.1.1.2 Definition. The penetration of bituminous material is its consistency expressed asthe distance in tenths of a millimeter that a standard needle penetrates vertically intoa specimen of the material under specified conditions of temperature, load andduration of loading.

Grades of straight-run bitumen are designated by two penetration values, forexample, 40/50, 60/80, 80/100 etc.; the penetration of an actual sample of thebitumen in any grade should fall between the lower and upper value given.

10.1.1.3 Apparatus

a) The test apparatus consists of a right frame which holds the needle spindle in avertical position and allows it to slide freely without friction. A dial gaugecalibrated in millimeters measures the penetration. The total weight of the needleand spindle must be 50 ± 0.05 grams and facilities for adding additional weightsof 50 ± 0.05 grams and 100 ± 0.05 grams must be provided. The surface onwhich the sample container rests must be flat and at right angles to the needle.

b) A penetration needle made of fully hardened and tempered stainless steel of1.00mm in diameter and 50mm in length, with one end ground to a truncatedcone as shown in Figure 10.1.1. The needle is held by brass or stainless steelferrule. The test is shown diagrammatically in Figure 10.1.1.

c) The sample is placed in a metal or glass flat bottom container of the followingdimensions:-

For penetrations below 200 mm:Diameter 55 mmInternal depth 35 mm

For penetrations between 200 and 350 mmDiameter 70 mmInternal depth 45 mm

The sample and dish are brought to the required temperature in a water bathwhich is maintained at a temperature within ±0.1/oC of the test temperature. Thesample container must be placed on a perforated shelf which is between 50 and100 mm below the surface of the water.


MAY 2001 Page 10.2

Figure 10.1.1 Penetration needle

100 gms.

100 gms.

AFTER 5 SECSSTART

DIAL GAUGE READSPENETRATION (in mm)

Penetration Test

Penetration Needle

1.00 to 1.02 mm

START

Approximately 50.8 mm (2’)

Approx. 6.35 mm

0.14 to 0.16 mm840’ to 940’0 0


MAY 2001 Page 10.3

d) To maintain the sample at the correct temperature during the test, a glasstransfer dish is used. This dish of at least 350 ml capacity is fitted with a suitablesupport to hold the sample container firm and level during testing.

e) A stopwatch is required to measure the time of penetration.


a) A sample of bitumen is first heated carefully in an oven or on a hotplate until ithas become sufficiently fluid to pour. When using a hotplate, the bitumen shouldbe stirred as soon as possible to prevent local overheating. In no case should thetemperature be raised more than 900C above the softening point, and samplesmust not be heated for more then 30 minutes.

b) When sufficiently fluid a portion of the sample is poured into the sample containerto a depth of at least 10mm greater than the depth to which the needle isexpected to penetrate.

c) The sample is then covered loosely to protect against dust, and allowed to cool inthe atmosphere between 15 and 300C for 1 to 1½ hours for the small containerand 1½ to 2 hours for the large container.

d) After cooling in air, the sample containers together with the transfer dishesshould be placed in the water bath at the required temperature, for a period of 1to 1½ hours for the small container and 1½ to 2 hours for the large container.

10.1.3 Conditions of test

The test is normally carried out at a temperature of 250C with the total weight of theneedle, spindle and added weights being 100 grams, the needle is released for aperiod of 5 seconds. If it is not possible to obtain these conditions or if there arespecial circumstances, one of the following alternative conditions may be used:-

Temperature,0C (0F)

Total slidingweights, grams

Time,seconds

0 (32)4 (39.2)46.1 (115)

20020050

60605

It will be noted that, to obtain the standard temperature of 250C in Bangladesh,cooling of the water bath is normally required, it may, therefore, be more convenientin many cases to use a temperature of 46.10C.


a) The needle should be examined for damage or surface roughness; it should bedry and clean. To ensure the needle is perfectly cleaned, it should be wiped witha cloth soaked in toluene or another suitable bitumen solvent and then dried witha clean cloth.

b) The clean needle should be inserted into the penetrometer apparatus and thetotal sliding weight made up to the required value, if necessary by addingadditional weights. For example, if 100 grams is required, and the needle andspindle weigh 50 grams, an additional weight of 50 grams must be added.

c) The sample container is then placed in the transfer dish complete with water atthe required temperature from the constant temperature bath, the sample beingcompletely covered with water at all times. The transfer dish is then placed on thestand of the apparatus.


MAY 2001 Page 10.4

d) The penetrometer needle is then slowly lowered until it just touches the surface ofthe sample. This point is best judged by using a strong source of light anddetermining the point where the tip of the needle just meets its image reflected bythe surface of the sample. The initial dial gauge reading is taken.

e) The needle is then released for the specified time and re-locked immediately atthe end of the period. Care should be taken not to disturb or jolt the apparatuswhen releasing the needle, if this occurs or the sample moves, the test must berepeated. The final dial gauge reading is taken.

f) The transfer dish should then be returned to the water bath and a clean needlefitted to the machine. The test is then repeated on the same sample. Thisprocedure is repeated so that at least 3 determinations are made on eachsample, taking care that each point is at least 10mm from the side of the samplecontainer and at least 10mm from the other determinations. If the penetrationexceeds 200mm, the needles should be left in the sample until all threedeterminations have been completed.

10.1.5 Calculation

The penetration is given by:

Penetration = (Initial dial gauge reading (mm) - Final dial gauge reading (mm)) x 10

A typical worksheet is shown as Form 10.1.1.

The three penetration values obtained on the sample must agree to within thefollowing limits:-

PenetrationMaximum difference between highestand lowest determination

0 to 49

2

50 to 149

4

150 to 249

6

250

8

If the differences exceed the above values, the results are ignored and the test mustbe repeated on the second sample. If the differences are again exceeded by thesecond sample, the results must be ignored and the test completely repeated.

If the determinations are within the above tolerances, the penetration is quoted asthe average of the individual results.

10.1.6 Test report

The report shall contain at least the following information:

a) Identification of the material testedb) A reference to the test method used.c) A statement of any deviation from the method stated for 25C/100g/5 seconds.d) The test resulte) Date of test.


MAY 2001 Page 10.5


MAY 2001 Page 10.6

10.2 Bitumen Softening Test

10.2.1 General Requirements

10.2.1.1 Scope. An alternative to the penetration test for checking the consistency ofbitumen, is the ring and ball softening point test. The scope of this test is to provide amethod for determining the consistency of semi-solid and bituminous materials inwhich the sole or major constituent is either bitumen or tar pitch.

10.2.1.2 Definition. The softening point of a bituminous material is the temperature at whichthe material attains a certain degree of softness under specified conditions of test.

10.2.1.3 Equipment. The equipment required to carry the penetration test in the laboratoryare listed below:

a) A steel ball having a diameter of 9.3 mm and weighing 3.5g ± 0.05g.b) Tapped ring, made of brass (see Figure 10.2.1) shall be used for referee

purposes. For other purposes either a straight ring (Figure 10.2.2) or ashouldered ring (Figure 10.2.3) may be used.

c) A convenient form of ball contouring guide (Figure 10.2.4)d) Ring holder made of brass or other metal (see Figure 10.2.5)e) Bottom plate made of brass or other metal (see Figure 10.2.6)f) A thermometer (capacity 1000C and accuracy 0.1 0C)g) A water bath of heat-resistant glass and conforming to the dimensions given in

Figure 10.2.7, the rings being supported in a horizontal position. The bottom ofthe bulb of the thermometer shall be level with the bottom of the rings and within10mm of them but not touching them. A 600 ml beaker is suitable.

h) Distilled water for materials of softening points of 800C and glycerol for materialsof higher softening point.

i) Stirrer.


The sample obtained in accordance with section 2.7 is heated carefully in an oven oron a hotplate until it has become sufficiently fluid to pour. When using a hotplate, thebitumen should be stirred as soon as possible, to prevent local over-heating. In nocase should the temperature be raised more than 900C above the expected softeningpoint and samples must not be heated for more than 30 minutes. The brass rings tobe used for the test are placed on a flat smooth brass plate, which has been coatedimmediately prior to use, with a thin covering of a mixture of glycerin and china clay.The coating is to prevent the bitumen sticking to the plate.

When the bitumen is sufficiently fluid to pour, the rings should be filled with bitumen.A tight excess of bitumen should be used. The bitumen is allowed to cool for aminimum of 30 minutes. If the bitumen is soft at room temperature, it must be cooledartificially for a further 30 minutes. After cooling the excess material on the top of thespecimen must be cut off cleanly using a moral palette knife.

If further specimens are to be prepared or the test repeated, it is essential to useclean containers and to use bitumen which has not been previously heated.


MAY 2001 Page 10.7

6.25

- 6.

45

2

17.4 - 17.6 DIA20.54 - 20.7 DIA

18.9 - 19.1 DIA

15.78 - 15.96 DIA

Figure 10.2.1 Tapered Ring Material Brass

15.76 - 15.96

20.5 - 20.7

19 MIN. 2

6.25

- 6.

45

OPTIONALSHOULDER

Figure 10.2.2 Straight Ring

2.7

- 2.

9

2

6.15

- 6.

45

19.74 - 19.94

22.9 - 23.1

18.9 - 19.1

15.76 - 15.96

Figure 10.2.3 Shoulder Ring

All dimensions in millimetres.


MAY 2001 Page 10.8

GUIDE FITS ONTOP OF RING(FIG. 1 OR 2) TOPOSITION THE BALLON CENTRE OFSAMPLE

Figure 10.2.4 Recommended Form of Ball Centring Guide

76

67

2 HOLES 6 DIA

HOLE 5.5 DIA

2 HOLES 19.2 DIA

1.59

1.59

Figure 10.2.5 Ring Holder

Figure 10.2.6 Base

2 HOLES TAP 2 BA

OUTLINE DIMENSIONSAS FIG. 10.2.5

Dimensions in millimetres (inches).


MAY 2001 Page 10.9

Figure 10.2.7 Assembly of ring-and-ball apparatus for two rings (stirrer not shown)

THERMOMETER 1P60COR 1P61C

STEEL BALL 9.53 (3/8“) DIAWEIGHT 3.45-3.55 g

SHOULDERED RING FIG. 10.2.3

RING HOLDER FIG. 10.2.5

BASE FIG. 10.2.6

LIQUIDLEVEL

120

5025

20-3

0

All DIMENSIONS IN MILLIMETRES

85 ID


MAY 2001 Page 10.10


The apparatus is assembled with the rings, ball centering guides and thermometer inposition and the beaker is filled with water to a depth of not less than 102mm and notmore than 108mm. The water used for the test must be distilled and allowed to cool ina stoppered flask, this is to prevent air bubbles forming on the specimen during thetest. The initial water temperature must be 5 ± 10C and this temperature must bemaintained for 15 minutes, placing the beaker in a bath of iced water if necessary.

On completion of the 15-minute period, the steel balls are positioned using forceps,and heat is applied to the beaker, preferably with a gas burner, at such a rate thatthe water temperature rises at 50C per minute. The rate of temperature rise is criticaland if after the first 3 minutes the rise varies from the 50C in any minute period, bymore than ± 0.50C, the test must be abandoned.

As the temperature rises, the balls will begin to cause the bitumen in the rings to sagdownwards, the water temperature at the instant the bitumen touches the bottomplate is taken for each ball. If the two temperatures differ by more than 10C, the testmust be repeated using fresh samples.

10.2.3 Calculation

The ring and ball softening point is simply the average of the two temperatures atwhich the bitumen just touches the bottom plate. A typical data sheet is shown asForm 10.2.1.

10.2.4 Test report

The report shall contain at least the following information:

a) Identification of the material tested.b) A reference to the test method used.c) A statement offends deviation from the method.d) The test result [softening point is reported to the nearest 0.20C]e) Date of test


MAY 2001 Page 10.11


MAY 2001 Page 10.12

10.3 Specific Gravity Test of Bitumen

10.3.1 Introduction

It is often required to know the specific gravity of straight run and cut-back bitumenfor purposes of calculating rates of spread, asphaltic concrete mix properties etc.

The standard specific gravity test is carried out at a temperature of 250C. However, ifcooling facilities are not available, a temperature of 350C may be used, although thismust be clearly stated in the result. For some purposes the specific gravity atelevated temperatures is required, as it is not possible to measure this directly anapproximate value may be obtained by calculation using the value determined at alower temperature.

10.3.2 Apparatus

a) The apparatus for the test consists of a standard pycnometer as shown in Figure10.3.1.

Figure 10.3.1 Suitable Pycnometers

b) A constant temperature water bath is also required.c) A 600 ml glass beaker.

22 to 26 mm.

1.0 to 2.0 mm.

4.0 to 6.0 mm.

22 to 26 mm.

1.0 to 2.0 mm.

4.0 to 6.0 mm.


MAY 2001 Page 10.13


The sample obtained in accordance with Chapter 2 is heated carefully in an oven oron a hotplate until it has become sufficiently fluid to pour. When using a hotplate, thebitumen should be stirred as soon as possible to prevent local overheating. In nocase should the temperature be raised more than 900C the softening point andsample must not be heated for more than 30 minutes.


a) The clean, dry pycnometer, complete with stopper, should be weighed to thenearest 0.001 gram., weight A.

b) A 600 ml glass beaker should be partly filled with freshly boiled distilled waterwhich has been allowed to cool in a stoppered flask. The beaker should then beimmersed to a depth of at least 100mm. in a water bath which is maintained at therequired temperature ± 0.10C for a period of at least 30 minutes. The top of thebeaker should be above the level of the water in the bath.

c) The weighed pycnometer should then be filled with the boiled distilled water andthe stopper placed loosely in position, taking care to expel all air from thepycnometer. The pycnometer should then be submerged in the beaker of waterto a depth above the stopper of at least 40mm and the stopper firmly pushed intoposition. The beaker and pycnometer must remain in the water bath for at least30 minutes after which the pycnometer is removed. The top of the pycnometershould first be dried with one stroke of a dry clean cloth and the remainder of thepycnometer is then dried as quickly as possible prior to weighing, weight B. Notethat if a droplet of water forms on the stopper after drying, the stopper should notbe re-dried, the volume of water in the pycnometer on immediately, leaving thewater is the required value, any subsequent changes should not affect the result.On completion of weighing the pycnometer should be thoroughly dried.

d) The pycnometer is then filled about three quarters full with the sample of bitumen.The bitumen should be carefully poured into the pycnometer ensuring that no airbecomes trapped below the bitumen and there are no air bubbles in the sample.The sample should be poured into the center of the pycnometer so that the sidesor neck of the pycnometer above the level of the bitumen are not contaminated.The pycnometer and bitumen should then be allowed to cool in air for a period ofat least 40 minutes, after which the weight is determined, weight C.

e) The pycnometer is then topped up with the boiled distilled water and the stopperloosely placed in position, taking care to expel all air from the pycnometer. Thepycnometer should then be submerged in the beaker of water to a depth abovethe stopper of at least 40mm and the stopper firmly pushed into position. Thebeaker and pycnometer must remain in the water bath for at least 30 minutesafter which the top and sides of the pycnometer are dried as before, prior toweighing, weight D.

f) At least two separate determinations should be made.

10.3.5 Calculation

The specific gravity of the bitumen is given by:

S.G = (C - A)

(B - A) - (D - C)

The average value of two or more results should be quoted.


MAY 2001 Page 10.14

A typical calculation sheet is included as Form 10.3.1.

The specific gravity is valid only at the temperature of the test. If, however, thespecific gravity is required at other temperature, the following approximaterelationship should be used:-

S.G at temperature, T = (S.G at test temperature, t) - (0.0006 x (T-t))


The specific gravity of the bitumen should be reported to three decimal places,together with the temperature of the test.

If the specific gravity is calculated for any other temperature, the fact that this is anapproximate calculated value should be stated.


MAY 2001 Page 10.15

10.4 Bitumen Extraction Tests


10.4.1.1 Introduction. The properties of bituminous materials are dependent on the amountof bitumen used to coat the constant components of the mix. Properties likedurability, compactibility, rutting, bleeding, ravelling, ageing, etc., are all propertiesthat are controlled by the amount of bitumen in the mix.

10.4.1.2 Equipment. The equipment required for this test for a number of methods, are given

under the appropriate test method used.

10.4.1.3 Safety. This test may involve hazardous materials, operation and equipment. Safetyprecautions must be exercised at all times. The inhalation of solvent fumes may beparticularly harmful and therefore it is advised that the area where the extraction testis carried out is well ventilated and that an adequate extractor fan is provided.

10.4.1.4 Calibrations. The scales used in this test must bear a valid certificate of calibration

when in use. Calibrations should be carried out at intervals not exceeding twelvemonths.

10.4.1.4.1 Balances and weights. Balances should be calibrated using reference weights

once every twelve months.

a) Balances should be checked daily before use by two point checks using stableweights of mass appropriate to the operating range of the balance.

b) Recalibration at a frequency of less than twelve months is necessary if the dailybalance check indicates a fault or the balance has been serviced.

10.4.1.4.2 Volumetric glassware. In-house calibration by weighting the amount of purewater that the vessel contains or delivers at a measured temperature is acceptablewhen used in conjunction with the corrections in BS 1797 and balances andweights that are in calibration and are traceable.

Where the test method specifies class B glassware it is permissible to useuncalibrated class A glassware.

10.4.1.4.3 Centrifuges. It should be checked and recorded that the centrifuge is capable ofproducing sufficient acceleration. See section 10.4.2.2.2.1.k).

The centrifuge speed controls should be calibrated at the speed of rotation at leastevery six months using a traceable tachometer.

10.4.1.4.4 Pressure gauges. Pressure gauges should be calibrated at least once every sixmonths using a certified reference gauge.

10.4.1.4.5 Time. Calibration should be performed on all timing devices at least once everythree months.

10.4.1.4.6 Thermometry. For this test stamped, mercury-in-glass thermometers conformingto BS 593 are sufficient.

10.4.1.4.7 Test sieves. Only test sieves with valid calibrations should be used.


MAY 2001 Page 10.16

10.4.1.4.8 Bottle rotation machine. The speed of rotation of the bottles should becalibrated at least once per year.

10.4.1.4.9 Solvents : Solvents should comply with the relevant applicable standardappropriate to the type of solvent used.

10.4.1.5 Consumables. Solvents used in this test, depending on the method used, arenormally 1,1,1 - trichloroethane, trichloroethylene, methyl chloride or methylenechloride. All solvents are harmful when inhaled for prolonged periods of time.

10.4.1.6 Sample preparation

a) If the mix is not soft enough to separate with a spatula, place it in a large, flat panand warm in a 110°C plus or minus 5°C oven only until it can be handled orseparated. Split or quarter the material until the required mass of the sample isobtained.

b) The size of the test sample shall be governed by the nominal maximum size of theaggregate in the mix. The mass of the sample must comply with the values givenin Table 10.4.1

Table 10.4.1Nominal maximum aggregate size,mm

Minimum mass of sample, kg

4.759.5

12.519.025.037.5

0.51.01.52.03.04.0

Note. When the sample in the test specimen exceeds the capacity of theequipment used, for the particular method used, the test specimen maybe divided into suitable increments, all increments tested, and theresults appropriately combined for calculation of bitumen content.

Note. If tests are to be performed on the recovered bitumen it is necessary todetermine the moisture content of the mixture. Refer to section 10.4.1.7for the determination of water content in a mix.

10.4.1.7 Determination of Water Content

10.4.1.7.1 Apparatus

A suitable apparatus is shown in Figure 10.4.1. The apparatus should be calibratedand traceable as recommended in section 10.4.1.4.

10.4.1.7.1.1 Cylindrical container. It should be made from a non-corrodible or brass gauzeof about 1 mm to 2 mm aperture size, or alternatively, a spun copper tube with aledge at the bottom on which a removable brass gauze disc rests. The containeris retained. By any suitable means, in position in the top two-thirds of metal pot.The pot is flanged and fitted with a secure cover and suitable jointing gasket. Thecover is held in position so that the joint between the container and the cover issolvent tight. The essential features of the construction are shown in Figures10.4.2 and 10.4.3.


MAY 2001 Page 10.17

Figure 10.4.1 Assembled apparatus for the hot extractor method

Cylindrical container(see figure 10.4.2)

Metal pot(see figure 10.4.3)

A stopcock may befitted at A if required

Graduated receiver

Water cooledreflux condenser

A


MAY 2001 Page 10.18

Figure 10.4.2 Cylindrical container for the hot extractor method

10 ∅ A 10

B

A From 120 mm to 200 mm as appropriateB From 120 mm to 250 mm as appropriate

All dimensions are in millimetres


MAY 2001 Page 10.19

Figure 10.4.3 Brazed brass welded steel pot for the hot extractor method

Brass or welded steelouter pot

A5

A From 150 mm to 230 mm as appropriateB From 200 mm to 400 mm as appropriateAll dimensions are in millimetres and are for guidance only.

NOTE. This design has been found satisfactory but alternative designs may be employed.

B

35 Three pegs to takegauge cylinder

20

Gasket ring

35

60 30

Six or eight slots equallyspaced around circumferenceto take swivelling bolts

453Brass or weldedsteel cover


MAY 2001 Page 10.20

10.4.1.7.1.2 Graduated receiver. This must conform to the requirements of type 2 of BS756, or a receiver of similar type, suitable for use with solvents of higher densitythan water, but fitted with a stop cock so that the water may be drawn off into aCrow receiver as necessary. The receivers must be fitted with ground glassjoints; in this case an adaptor may be necessary to connect the receiver to thecover of the pot.

10.4.1.7.1.3 Water-cooled reflux condenser with the lower end ground at an angle ofapproximately 450 to the axis of the condenser.

10.4.1.7.1.4 Heater such as an electric hotplate.

10.4.1.7.1.5 Solvent; trichloroethylne free from water.

10.4.1.7.2 Procedure

10.4.1.7.2.1 Take part of the sample that was put aside during the sample reduction for thedetermination of water content and divide it into two portions by quartering.Retain one portion in a closed container.

10.4.1.7.2.2 Weigh the other portion to the nearest 0.05% and place it in a well ventilatedoven at 1100C plus or minus 100C for one hour.

Reweigh this portion and if the loss in mass is less than 0.1% no further action isrequired.

10.4.1.7.2.3 If the loss in mass exceeds 0.1% weigh the portion that was retained and transferit to a dry hot extractor pot. Alternatively place the sample in a gauze containerbefore transferring it to the extractor pot.

10.4.1.7.2.4 Add sufficient solvent to permit refluxing to take place and then bolt on the coverwith a dry gasket in position. Fit the receiver and condenser in place.

Ensure an adequate flow of water through the condenser and heat to give asteady reflux action.

10.4.1.7.2.5 Continue heating until the volume of water in the receiver remains constant.

10.4.1.7.2.6 Measure the volume of water and record its mass.

10.4.1.7.2.7 Calculation and expression of results

Calculate the water content as a percentage by mass of either original sample tothe nearest 0.1% or the dried portions to the nearest 0.1%.

10.4.1.7.2.8 Reporting of results

Report the results as indicated in 10.4.2.3.

10.4.2 Bitumen Extraction Test

10.4.2.1 Scope. This is a quality control test which provides methods of extracting thebitumen from the mixed material. The results obtained from the methods herein maybe affected by the age of the material tested. For best results it is recommended thatthese tests be carried out on mixtures and pavements shortly after their preparation.


MAY 2001 Page 10.21

10.4.2.2 Test methods 10.4.2.2.1 Method A; Centrifuge method 10.4.2.2.1.1 Equipment

The equipment required for this test method are listed below:

a) Oven, capable of maintaining the temperature at 110° C plus or minus 5°Cb) Pan, flat and of appropriate size to heat the test specimens.c) Balance or scales capable of weighing a sample to an accuracy of 0.05% of

its mass.d) Extraction apparatus, consisting of a bowl and an apparatus in which the

bowl may be revolved at controlled variable speeds up to 3600 revolutionsper minute. Refer to Figure 10.4.4.

Note. Accessories must be fitted to the apparatus for catching anddisposing of the solvent. The apparatus preferably shall be installedin a hood or an effective surface exhaust system to provideventilation.

Note. Similar apparatus of larger size from the apparatus shown in Figure10.4.4 may be used.

e) Filter rings, felt or paper, to fit the rim of the bowl.

10.4.2.2.1.2 Procedure

a) Weigh the sample of mixed material to the nearest 0.05% of its mass andweigh the oven dried filter ring to the nearest 0.01g. Sample size shouldcomply with the requirements of Table 10.4.1.

b) Determine the moisture content of the material (if required ) in accordancewith the method stipulated in 10.4.1.7.

c) Place the test portion in the bowl.d) Cover the test portion in the bowl with trichloroethylene or other approved

solvent and allow sufficient time for the solvent to disintegrate the testportion but time must not exceed 1 hour. Place the bowl with the sampleand solvent in the extraction apparatus. Dry the filter ring to a constantweight in an oven at 110°C plus or minus 5°C and fit it round the edge ofthe bowl. Clamp the cover on the bowl tightly and place a container underthe drain outlet of the apparatus to collect the extract.

e) Start the centrifuge revolving slowly and gradually increase the speed to amaximum of 3600 rev/min until the solvent ceases to flow from the drain.Allow the machine to stop and add 200ml (or more as appropriate for massof sample) trichloroethylene and repeat the procedure (not less than threetimes). Use sufficient solvent so that the extract is very nearly clear. Thecollected extract may be used for other tests.

f) Carefully transfer the filter ring and all the residual aggregate in thecentrifuge bowl into a tarred metal pan. Dry in air until the fumes dissipate,and then to a constant mass in an oven at 110°C plus or minus 5°C.Scrape all the filter which might have adhered to the filter into the residualaggregate and weight the filter and aggregate to the nearest 0.01gseparately.


MAY 2001 Page 10.22

Figure 10.4.4 Extraction Unit Bowl (Method A)

157.2 D.152.4 D.

203.2 D.

247.7 D.

35.730.2

1 2 7. 0

9.5

28.6 55.6

57.2

6.4 56.4

5.6

NOTE. See table 3 for dimensional equivalent.

All dimensions are in millimetres.

COVER PLATE 1 REG. CAST ALLUMINUM

BURNISH ALL OVER

BOWL 1 REG. CAST ALLUMINUM

BURNISH ALL OVER

41.3 D.

108.0 D.247.7 D.

4.8

7.9 9.5


MAY 2001 Page 10.23

10.4.2.2.1.3 Calculation. Calculate the bitumen content using the equation:

Bitumen content in grammes = ((W1 - W2) - (W3 + W4)) / (W1 - W2)

Where, W1 is the total weight of the test portion, in grammesW2 is the weight of water in test portion in grammesW3 is the weight of the extracted mineral aggregate in grammesW4 is the mass of the mineral matter in the extract.

10.4.2.2.1.4 Expression of results. The bitumen content may be expressed as apercentage of weight of bitumen with respect total weight of mix or with respectto total aggregate in the mix.

Bitumen content % by weight of total mix = (bitumen content in grammes / W1) x100

or, Bitumen content % by weight of total aggregate = (bitumen content ingrammes / (W2 + W3)) x 100

Note. The residue of aggregate and filler may be used in the graduation ofthe sample.

10.4.2.2.2 Method B; Extraction bottle method

10.4.2.2.2.1 Equipment

a) Metal bottles of capacity appropriate to the size of sample being tested, e.g.600ml, 2.51, 71, 121, with wide mouths and suitable closures.

Note. Bottles should not be filled to more than three - quarters full.

b) Bottle roller which can rotate the bottles about their longitudinal axes at aspeed of 20 plus or minus 10 rev / min.

c) Pressure filter of appropriate size and an air pump for supplying oil - free airat a pressure of at least 2 bar.

d) Filter papers to fit the pressure filtere) Volumetric flasks of appropriate capacity, e.g. 250ml, 500ml, 11, 21.f) A set test sievesg) Balance capable of weighing a sample to an accuracy of 0.01% of its massh) Sample divider.i) Trays that can be heated without change in mass in which to dry recovered

aggregate.j) Solvent; either dichloromethane (methylene chloride) or trichloroethylene.k) Centrifuge.

1. A typical centrifuge carries four buckets fitted with centrifuging tubes ofat least 50 ml capacity and is capable of an acceleration of between1.5 x 104 m/s2

2. The tubes should be closed with caps such that no loss of solventoccurs during centrifuging.

3. The times of centrifuging should be obtained from figure 10.4.6 ofsection 10.4.2.2.2.2 after calculating the acceleration, a in m/s2

developed in the machine in accordance with the following equation:

a = 1.097 n2 x 10-5

Where,


MAY 2001 Page 10.24

n, is the angular velocity measured in revs. per min.r is the radius in millimeters to the bottom of the tubes (internal) whenrotating.

l) Recovery apparatus comprising a water bath with an electric heatercapable of maintaining boiling water in the bath throughout the recoveryprocedure, round-bottomed flasks of 200ml or 250 ml capacity, a pressuregauge, a vacuum reservoir and a method of maintaining a reducedpressure, e.g. a vacuum pump. Refer to Figure 10.4.5.

Figure 10.4.5 Recovery apparatus showing necessary features

m) Balance accurate to 0.001 g for weighing the flasks.n) Stopclock or watcho) Containers resistant to solvent attack each with narrow neck and tight fitting

resealable lid.p) Desiccator to store the extraction flasks before weighing.

10.4.2.2.2.2 Procedure

a) Weigh a test sample to the nearest 0.05% of its mass and place it in themetal bottle. To the same accuracy weigh sufficient silica gel to absorbany water present and add it to the bottle. The mass of the silica gelshould be equal to the mass of water estimated to be present in thesample. The mass of the sample should comply with the requirements ofTable 10.4.1.

b) Measure and record the temperature of the solvent immediately prior toadding the required volume to the sample. The volume required shall givea solution of between 2% and 4% concentration of soluble binder.

Note. To estimate the total volume V of solvent required use thefollowing formula :


MAY 2001 Page 10.25

V = M SE / CS

Where, M is the mass of sample in grammes.SE is the estimate percentage of soluble binder in the sampleCS is the required concentration of solution in %.

The estimated volume V is rounded to the nearest 250 ml.

c) Close the bottle, and roll on the bottle rolling machine for the specifiedtime indicated in Table 10.4.2 and Table 10.4.2a.

Table 10.4.2. Time required for extraction (extraction Bottle method : binderdetermination by difference)

Type of material Tars min Bitumens MinMacadams other than dense, close, medium orfine graded.Macadams containing ut-back bitumens.

30 10

Rolled asphalt, dense tar surfacing, dense,close, medium and fine graded macadamscontaining penetration grade bitumens

60 20

Table 10.4.2a. Time required for extraction (extraction Bottle method : binder directlydetermined)

Type of material Tars min Bitumens MinMacadams other than dense, close, medium orfine graded.Macadams containing ut-back bitumens.

30 10

Rolled asphalt, dense tar surfacing, dense,close, medium and fine graded macadamscontaining penetration grade bitumens

60 20

d) Remove the closed bottle from the rolling machine and stand it upright forabout 2 minutes to allow the bulk of the mineral matter to settle fromsuspension. Remove the stopper carefully and immediately transfer about500ml of liquor to a clean dry pouring bottle. Transfer to the centrifugetube sufficient liquid such that after centrifuging is complete there isenough solution to provide duplicate aliquot portions. Seal the remainderin the pouring bottle until aliquot portions are satisfactorily obtained. Sealthe centrifuge tubes and centrifuge for the appropriate time given inFigure 10.4.6.


MAY 2001 Page 10.26

30000

29000

28000

27000

26000

25000

24000

23000

22000

21000

20000

19000

18000

17000

16000

15000

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Centrifuging time (minutes)

Figure 10.4.6 Acceleration / time relationship for centrifuges

Note. From here on the work is done in duplicate.

e) Dry a flask and weigh it to the nearest 0.001g.f) Measure a sufficient amount of the centrifuged solution into the flask,

using the burette to give a residue of 0.75g of soluble binder afterevaporation of the solvent. Immediately prior to transfer from thecentrifuge tube into a burette measure and record the temperature of thesolution.

Note 1. The difference between the temperature o f the solvent whenmeasured in accordance with (b) and the temperature of thebinder solution when measured in accordance with (f) should notexceed plus or minus 3°C.

2. If the temperature of (f) is outside the range of plus or minus3°C of the temperature of the solvent gentle heating or coolingof the solution is permitted provided evaporation of the solvent isprevented.

Note. An estimate of the volume v of solution (aliquot portion) requiredis given by the following formula.

V = (100 x V) / ( M SE )

Where,V is the total volume of solventM is the mass of the sample in grammes.SE is the estimated percentage of soluble binder in the sample


MAY 2001 Page 10.27

Volume V is rounded to the nearest 5 ml.

g) Remove the solvent from the binder solution by connecting the flask tothe recovery apparatus, immersing the flask to approximately half itsdepth in boiling water, and distilling off the solvent. While the distillation isproceeding , gently shake the flask with a rotary motion so that the binderis deposited in a thin film layer on the walls of the flask. Do not allowpressure above atmospheric to develop in the flask during theevaporation of the solvent. Note. It is recommended that the distillation be carried out under

reduced pressure. If reduced pressure is used the pressureshould not be less than 600mbar.

h) At this stage frothing usually occurs, Proceed as follows :h.1) For penetration grade bitumen and tars reduce the pressure to between

180mbar and 220mbar in 1 min. to 2 min. and maintain at this pressurefor a further 3 min. to 4 min.

h.2) For cut-back bitumen allow the pressure to increase to approximatelyatmospheric pressure and then reduce in to between 550mbar in 1 min.to 2 min. and maintain at this pressure for a further 3 min. to 4 min.

i) Remove the flask from the bath and admit air to the apparatus to increasethe pressure to atmospheric. Wipe the flask dry and disconnect it, takingcare to prevent the entry in to the flask of any water that may havecollected at the joint between the flask and the stopper.

Remove all traces of solvent that remain in the flask by a gentle current ofclean, oil-free and water-free air at ambient temperature. Insert the airsupply into the tube to below mid-depth. Clean the outside of the flaskand remove any rubber adhering to the inside of the flask neck if rubberbungs are used.

j) Cool the flask in a desiccator and weigh to the nearest 0.001g. If themass of the soluble binder recovered is not between 0.75g and 1.25g,repeat the procedure from (e) to (i). If the difference between theduplicate recoveries is greater than 0.02g reject and repeat theprocedure from (e) to (i).

10.4.2.2.2.3 Calculations

Calculate the soluble binder content S (%) of the mass of the original drysample by means of the following equation :

S = 10,000 (z V) / v M ( 100 - P ) ( 1 -z/dv )

Where,M is the mass of undried sample in grammes.z is the average mass of binder recovered from each of two aliquot portions in

grammes.V is the total volume of solvent in millilitres.v is the volume of each aliquot portion in millilitresd is the relative density of the binderP is the percentage by mass of water in the undried sample. See 10.4.1.7.


MAY 2001 Page 10.28

10.4.2.2.2.4 Washing of mineral aggregate

10.4.2.2.2.4.1 (filler directly determined)

a) After removing sufficient solution for the determination of the solublebinder content, pour the liquid contents of the extraction bottle (includingfine matter in suspension but taking care not to carry over any aggregate)through a 75 micron test sieve protected by a 1.18mm test sieve andthrough the funnel into the pressure filter.

b) Fit the pressure filter with a filter paper.c) Pass the liquid through the filter paper under air pressure of at least 2

bar.d) Dry the sample by evaporation to constant weight.

The sample is now ready for the gradation test.

10.4.2.2.2.4.2 (filler determined by difference)

a) After removing sufficient solution for the determination of the solublebinder content, pour the liquid contents of the extraction bottle (includingfine matter in suspension but taking care not to carry over any aggregate)through a 75 micron test sieve protected by a.1.1m test sieve to waste.

b) Shake the aggregate remaining in the bottle with further quantity ofsolvent (about half the quantity of solvent used originally). Immediatelyafter shaking pour the solution through the nest of sieves, ensuring noloss of mineral matter. Repeat this process until no discoloration of thesolvent is visible. At this point transfer the bulk of the contents of thebottle to a tray of suitable size and rinse the bottle once more to removeas much of the mineral matter as possible and pour the final washingsthrough the 75 micron test sieve.

c) Dry the sample by evaporation test.

The sample is now ready for the gradation test.

10.4.2.2.2.5 Adjustments of soluble binder content and material passing 75 microntest sieve found on analysis.

When assessing the composition of the mixture, adjust the found soluble binderand filler contents to correspond with the mid-point of the grading passing a2.36 mm test sieve for rolled asphalt and a 3.35 mm test sieve for coatedmacadam.

Use Table 10.4.3 for roadbase, basecourse and regulating course asphaltmixtures, Table 10.4.4 for wearing course asphalt mixtures and Table 10.4.5 forcoated macadam roadbase and basecourse mixtures.


MAY 2001 Page 10.29

Table 10.4.3 Adjustment values for roadbase, basecourse, and regulatingcourse asphalt mixtures.

Deviation of foundaggregate gradingfrom mid-pointpassing 2.36mm testsieve

Correction tocontent of solublebinder

Correction to contentof aggregate passing75 micron test sieve.

0 to 0.3 0 00.4 to 1.1 0.1 0.11.2 to 1.8 0.2 0.11.9 to 2.5 0.3 0.22.6 to 3.4 0.4 0.33.5 to 4.1 0.5 0.44.2 to 4.9 0.6 0.45.0 to 5.6 0.7 0.55.7 to 6.4 0.8 0.66.5 to 7.1 0.9 0.67.2 to 7.8 1.0 0.77.9 to 8.7 1.1 0.88.8 to 9.4 1.2 0.99.5 to 10.2 1.3 0.9

10.3 to 10.9 1.4 1.011.0 to 11.7 1.5 1.0

Table 10.4.4 Adjustment values for wearing course asphalt mixturesDeviation of foundaggregate gradingfrom mid-pointpassing 2.36mm testsieve



0 to 0.4 0 00.5 to 1.5 0.1 0.11.6 to 2.6 0.2 0.22.7 to 3.7 0.3 0.33.8 to 4.8 0.4 0.44.9 to 5.9 0.5 0.56.0 to 7.0 0.6 0.67.1 to 8.0 0.7 0.78.1 to 9.1 0.8 0.89.2 to 10.2 0.9 0.9

10.3 to 11.3 1.0 1.011.4 to 12.2 1.1 1.1


MAY 2001 Page 10.30

Table 10.4.5 Adjustment values for coated macadam roadbase andbasecourse mixtures where the mid-point of the range of thepercentage passing the 3.35mm sieve lies between 30% and50%

Deviation of foundaggregate gradingfrom mid-pointpassing 2.35mm testsieve



0 to 0.4 0 00.5 to 1.4 0.1 0.11.5 to 2.4 0.2 0.32.5 to 3.4 0.3 0.43.5 to 4.4 0.4 0.64.5 to 5.4 0.5 0.75.5 to 6.4 0.6 0.96.5 to 7.4 0.7 1.07.5 to 8.4 0.8 1.28.5 to 9.4 0.9 1.39.5 to 10.4 1.0 1.5

10.4.2.3 Reporting of results

The report shall contain at least the following information :

a) The testing laboratory.b) A unique serial number for the test report.c) The name of the client.d) Description and identification of the sample.e) Whether or not the sample was accompanied by a sampling certificate.

An example data sheet is given as Form 10.4.1.


MAY 2001 Page 10.31


MAY 2001 Page 10.32

10.5 Flash Point and Fire Point Tests of Bitumen

10.5.1 Introduction

Flash point of bitumen is the temperature at which, it’s vapour will ignite temporarilyduring heating, when a small flame is brought into contact with the vapour. Theknowledge of this point is of interest mainly to the user, since the bitumen must notbe heated to this point. The flash point tells the critical temperature at and abovewhich suitable precautions are required to be taken to eliminate the danger of fireduring heating. This temperature, however, is well below that at which the bitumen willburn. The latter temperature is called the fire point.

10.5.2 Definitions

Flash point. It is the lowest temperature at which the vapour of a bituminous materialmomentarily takes fire in the form of a flash, under specified conditions of test.

Fire point. It is the lowest temperature at which bituminous materials ignite and burnunder specific conditions of test.

10.5.3 Scope

This method covers the determination of the flash and fire points, by Cleveland OpenCup Tester, of petroleum products and other liquids, except fuel oils and thosematerials having an open cup flash point below (79 C) as determined by theCleveland Open Cup Tester.

10.5.4 Apparatus

a) Cleveland Open Cup Apparatus - This apparatus consists of the test cup, heatingplate, test flame applicator and heater, thermometer support, and heating platesupport, all conforming to the following requirement:

Test Cup- of brass conforming to the dimensional requirements shown in Figure10.5.3. The cup may be equipped with a handle.

Heating Plate - A brass, cast iron, wrought iron, or steel plate with a center holesur-rounded by an area of plane depression, and a sheet of hard asbestos boardwhich covers the metal plate except over the area of plane depression in whichthe test cup is supported. The essential dimensions of the heating plate areshown in Fig. 10.5.2., however, it may the square instead of round, and the metalplate may have suitable extensions for mounting the test flame applicator deviceand the thermometer support. The metal bead, may be mounted on the plate sothat it extends through and slightly above a suitable small hole in the asbestosboard.

Note. The sheet of hard asbestos board which covers the heating plate maybe extended beyond the edge of the heating plate to reduce draftsaround the cup. The F dimension given is intended for gas apparatus.For electrically heated apparatus the plate shall be of sufficient size tocover the top of the heater.

Test Flame Applicator - The device for applying the test flame may be of anysuitable design, but the tip shall be 1.6 to 5.0 mm or 0.06 to 0.20 in. in diameterat the end and the orifice shall have an approximate diameter of 0.8 mm or 0.031in. The device for applying the test flame shall be so mounted to permit automaticduplication of the sweep of the test flame, the radius of swing being not less than


MAY 2001 Page 10.33

150 mm or 6 in. and the center of the orifice moving in a plane not that 2.5 mm or0.10 in. above the cup. A bead having a diameter of 3.8 to 5.4 mm or 0.15 to0.21 in. may be mounted in a convenient position on the apparatus so the size ofthe test flame can be compared to it.

Heater - Heat may be supplied form any convenient source. The use of a gasburner of alcohol lamp is permitted, but under no circumstances are products ofcombustion or free flame to be allowed to come up around the cup. An electricheater controlled by a variable voltage transformer is preferred. The source ofheat shall be centered under the opening of the heating plate with no localsuperheating. Flame-type heaters may be protected from drafts or excessiveradiation by any suitable type of shield that does not project above the level ofthe upper surface of the asbestos board.

Thermometer Support - Any convenient device may be used which will hold thethermometer in the specified position during a test and which will permit easyremoval of the thermometer form the test cup upon completion of a test.

Heating Plate Support - Any convenient support will hold the heating plate leveland steady may be employed.

One form of the assembled apparatus, the heating plate, and the cup areillustrated in Figures 10.5.1, 10.5.2 and 10.5.3 respectively.

Filling Level Gauge - A device to aid in the proper adjustment of the samplelevel in the cup. It may be made of suitable metal with at least one projection, butpreferably two for adjusting the sample level in the test cup to 9 to 10 mm (0.35 to0.39 in.) below the top edge of the cup. A hole 0.8 mm (1 / 32 in.) in diameter, thecenter of which is located not more than 2.5 mm or 0.10 in. above the bottomedge of the gage, shall be provided for use in checking the center position of theorifice of the test flame applicator with respect to the rim of the cup. (Figure10.5.4 shows a suitable version.)

b) Shield - A shield 460 mm (18 in.) square and 610 mm (24 in.) high and having anopen front is recommended.

c) Thermometer.

10.5.5 Preparation of apparatus

a) The apparatus is supported on a level steady table in a draft-free room orcompartment. The top of the apparatus is shielded from strong light by anysuitable means to permit ready detection of the flash point. Tests in a laboratoryheed (Note 1.) or any location where drafts occur are not to be relied upon.

Note 1. With some samples whose vapours or products of pyrolysis areobjectionable, it is permissible to place the apparatus with a shield in ahood, the draft of which is adjustable so that vapours may be withdrawnwithout causing air currents over the test cup during the final 56 C (100F) rise in temperature prior to the flash point.


MAY 2001 Page 10.34

Figure 10.5.1 Cleveland open cup apparatus

B

C

TEST CUP

HEATINGPLATE

THERMOMETERASTM NO. 11C

1P 28C

D

RADIUSTEST FLAMEAPPLICATOR

A

FMETAL BEAD

TO GASSUPPLY

HEATER (FLAME ORELEC. RESIST. TYPE)

E

A - DIA. OF APLICATORB - DIA. OF TIPC - DIA. OF ORIFICED - RADIUS OF SWINGE - INSIDE BOTTOM OF CUP TO BOTTOM OF THERMOMETERF - DIA. OF OPTIONAL COMPARISON BEAD

-1.6(0.8 APPROX.)150

(6.4 APPROX.)

3.8

5.05.0

-

5.4

-0.06(0.031 APPROX.)6

(0.25 APPROX.)

0.15

0.200.20

-

0.21

MILLIMETRESMIN MAX

INCHESMIN MAX


MAY 2001 Page 10.35

Figure 10.5.2 Heating Plate

B

D

E

F

C

METAL THERMALINSULATION

A

MILLIMETRES INCHES

MIN MAX MIN MAX6.4 NOMINALA 0.25 NOMINAL0.5B 1.0 0.02 0.046.4 NOMINALC 0.25 NOMINAL54.5D - DIAMETER 2.1569.5E - DIAMETER 70.5 2.74 2.78150 NOMINALF - DIAMETER 6 NOMINAL

56.5 2.22


MAY 2001 Page 10.36

Figure 10.5.3 Cleveland Open Cup

I

450

JBRASS

HG

C

FILLINGMARK

D

E F

B

A

MILLIMETRES INCHES

MIN MAX MIN MAX67.5A 69 2.66 2.7262.5B 63.5 2.46 2.502.8C 3.6 0.11 0.144 APPROX.D - RADIUS 0.16 APPROX.32.5E 34 1.28 1.349F 10 0.35 0.391.8G 3.4 0.07 0.132.8H 3.6 0.11 0.1467I 70 2.60 2.7597J 101 3.8 4.0


MAY 2001 Page 10.37

Figure 10.5.4 Filling Level Gauge

F

E

D

A/2

B

AC

G

D

MILLIMETRES INCHES

100 4203.2309 - 100.8 DIA.(2.5 MM ABOVE)BOT TOM EDGE10

ABCDEF

G

3/41/81-1/40.35 - 0.391/32 DIA.(0.10 IN. ABOVEBOTTOM EDGE)3/8

NOMINALNOMINALNOMINALNOMINAL

NOMINAL

MAXIMUMNOMINAL


MAY 2001 Page 10.38

b) The test cup is washed with an appropriate solvent to remove any oil or traces ofgum or residue remaining from a previous test. If any deposits of carbon arepresent, they should be removed with steel wool. The cup is flashed cold waterand dry for a few minutes over an open flame, on a hot plate, or in an oven toremove the last traces of solvent and water. The cup is cooled to at least 56 C(100 F) below the expected flash point before using.

c) The thermometer is supported in a vertical position with the bottom of the bulb6.4 mm (1/4 in.) from the bottom of the cup and located at a point halfway betweenthe center and side of the cup on the diameter perpendicular to the arc (or line)of the sweep of the test flame and on the side opposite to the test frame burnerarm.

10.5.6 Procedure

a) The cup, is filled at any convenient temperature (Note 2) not exceeding 100 C or180 F above the softening point, so that the top of the meniscus is at the fillingline. To aid in this operation, a Filling Level Gauge (A7) may be used. If too muchsample has been added to the cup, remove the excess, using a pipette or othersuitable device; however, if there is sample on the outside of the apparatus,empty, clean and refill it. Any air bubbles on the surface of the sample (Note 3)are destroyed.

Note 2. Viscous samples should be heated until they are reasonably fluidbefore being poured into the cup. For asphalt cement, the temperatureduring heating must not exceed 100 C or 180 F above the expectedsoftening point. Extra caution must be exercised with liquid asphalt’swhich should be heated only to the lowest temperature at which theycan be poured.

Note 3. The sample cup may be filled away from the apparatus provide thethermometer is preset with the cup in place and the sample level iscorrect at the beginning of the test. A shim 6.4 mm (1/4 in) thick is usefulin obtaining the correction distance from the bottom of the bulb to thebottom of the cup.

b) The test flame is lighted and adjusted to a diameter of 3.8 to 5.4 mm (0.15 to0.21 in.).

c) Heat is applied initially so that the rate of temperature rise of the sample is 14 to17 C (25 to 30 F) per minute. When the sample temperature is approximately 56C (100 F) below the anticipated flash point, decrease the heat so that the rate oftemperature rise for the 28 C (50 F) before the flash point is 5 to 6 C (9 to 11 F)per minute.

d) Starting at least 28 C (50 F) below the assumed flash point, the test flame isapplied when the temperature read on the thermometer reaches each successive2 C (5 F) mark. The test flame is passed across the center of the cup, at rightangles to the diameter which passes through the thermometer. With a smooth,continuous motion apply the flame either in a straight line or along thecircumference of a circle having a radius of at least 150 mm or 6 in. The center ofthe test flame must move in a plane not more than 2.5 mm or 0.10 in. above theplane of the upper edge of the cup passing in one direction first, then in theopposite direction the next time. The time consumed in passing the test flameacross the cup shall be about 1 s. During the last 17 C (30 F ) rise in temperatureprior to the flash point, care must be taken to avoid disturbing the vapours in thetest cup by careless movements or breathing near the cup.


MAY 2001 Page 10.39

Note 4. If a skin should form before the flash or fire point is reached, move itcarefully aside with a small spatula or stirring rod and continue thedetermination.

e) The observed flash point is recorded as the temperature read on thethermometer when a flash appears at any point on the surface of the oil, but donot confuse the true flash with the bluish halo that sometimes surrounds the testflame.

f) To determine the fire point, continue heating so that the sample temperatureincreases at a rate of 5 to 6 C (9 to 11 F). The application of the test flame iscontinued at 2 C (5 F) intervals until the oil ignites and continues to burn for atleast 5 s. Record the temperature at this point as the fire point of the oil.

10.5.7 Correction for barometric pressure

If the actual barometric pressure at the time of the tests is less than 715 mm ofmercury, it is recorded and the appropriate correction is added from the followingtable to the flash and fire points, as determined.

Barometric Pressuremm of Mercury

Correction deg C deg F

715 to 665 2 -

715 to 635 - 5

664 to 610 4 -

635 to 550 - 10

609 to 550 6

10.5.8 Calculation and report

1. The observed flash point or fire point, or both is corrected in accordance with10.5.7.

2. The corrected flash point of fire point, or both is reported as the Cleveland OpenCup Flash Point or Fire Point, or both.

10.5.9 Precision

The following data should be used for judging the acceptability of results (95 percentconfidence.)

Duplicate results by the same operator should be considered suspect if they differ bymore than the following amounts:

RepeatabilityFlash point ..................................................................................................8 0C (150F)Fire point .................................................................................................….8 0C (150F)


MAY 2001 Page 10.40

10.6 Viscosity Test of Bitumen

10.6.1 Introduction

Viscosity is reverse of fluidity. It is a measure of the resistance to flow. Higher theviscosity of liquid bitumen, the more nearly it approaches a semi-solid state inconsistency. Thick liquid is said to be more viscous than a thin liquid of the roadpavement. The bitumen binders of low viscosity, simply lubricate the aggregateparticles instead of providing a uniform thin film for binding action, similarly highviscosity does not allow full compaction and the resulting mix exhibits heterogeneouscharacter and thus low stability values.

Saybolt Furol viscosity test is used to determine viscosity of liquid bitumens.

10.6.2 Scope

In this test, time in seconds is noted for 60 ml of the liquid bitumen at specifiedtemperature to flow through an orifice of a specific size. The higher the viscosity ofthe bitumen more time will be required for a quantity to flow out.

10.6.3 Apparatus

a) Saybolt Viscometer and Bath.

Viscometer- The viscometer, illustrated in Figure 10.6.1 shall be constructedentirely of corrosion resistant metal, conforming to dimensional requirements shownin Figure 10.6.1. The orifice tip, Universal or Furol may be constructed as areplaceable unit in the viscometer. Provide a nut at the lower end of the viscometerfor fastening it in the bath. Mount vertically in the bath and test the alignment with aspirit level on the plan test; a small chain or cord may be attached to the cork tofacilitate rapid removal.

Bath- The bath serves both as a support to hold the viscometer in a vertical positionas well as the container for the bath medium. Equip the bath effective insulation andwith an efficient stirring device Provide the bath with a coil for heating and coolingand with thermostatically controlled heaters capable on maintaining the bath withinthe functional precision given in Table 10.6.2. The heaters and coil should be locatedat least 3 in. (75 mm) from the viscometer. Provide a means for maintaining the bathmedium at least 6 mm (0.25 in.) above the overflow rim. The bath media are given inTable 10.6.2.

b) Withdrawal Tube, as shown in Figure 10.6.2 or other suitable device.c) Thermometer Support. One suitable design is shown in Figure 10.6.3d) Saybolt Viscosity Thermometers, as listed in Table 10.6.1.e) Bath Thermometers - Saybolt Viscosity thermometers, or any other temperature-

indicating means of equivalent accuracy.f) Filter Funnel, as shown in Figure 10.6.4 equipped with interchangeable 850 µm

(N0. 20), 150µm (N0. 100) and 75µm (N0. 200) wire-cloth inserts meeting therequirements of M 92 with respect to the wire cloth Filter funnels of a suitablealternate design may be used.

g) Receiving Flask, as shown in Figure 10.6.5h) Timer, graduated in tenths of a second, and accurate to within 0.1% when tested

over a 60min interval. Electric timers are acceptable if operated on a controlledfrequency circuit.


MAY 2001 Page 10.41

Table 10.6.1 Saybolt Viscosity Thermometer

ThermometerStandard TestTemperature,C (F)

ThermometerNo. Range C (F)

SubdivisionC (F)

21.11 (70) 17C (17F) 19 to 27 0.1 (0.2)(66 to 80)

25.0 (77) 17C (17F) 19 to 27 0.1 (0.2)(66 to 80)

37.8 (100) 18C (18F) 34 to 42 0.1 (0.2)(94 to 108)

50.0 (122) 19C (19F) 49 to 57 0.1 (0.2)(120 to 134)

54.4 (130) 19C (19F) 49 to 57 0.1 (0.2)(120 to 134)

60.0 (140) 20C (20F) 57 to 65 0.1 (0.2)(134 to 148)

82.2 (180) 21C (21F) 79 to 87 0.1 (0.2)(174 to 188)

98.9 (210) 22C (22F) 95 to 103 0.1 (0.2)(204 to 218)

Table 10.6.2 Recommended bath Media

StandardTestTemperature,C (F)

Recommended Bath Medium

Max TempDifferential,C (F)

Bath TemperaturesControl FunctionalPrecision, C (F)

21.1 (70) Water ± 0.05 (0.10) ± 0.05 (0.10)25.0 (77) Water ± 0.05 (0.10) ± 0.05 (0.10)37.8 (100) Water, or oil of 50 to 70 SUS

viscosity at 37.80C± 0.15 (0.25) ± 0.05 (0.10)

(1000F)50.0 (122) Water, or oil of 120 to 150 SUS

viscosity at 37.80C± 0.20 (0.35) ± 0.05 (0.10)


viscosity at 37.80C± 0.30 (0.50) ± 0.05 (0.10)


viscosity at 37.80C± 0.50 (1.0) ± 0.05 (0.10)

82.2 (180) Water, or oil of 120 to 150 SUSviscosity at 37.80C

± 0.80 (1.5) ± 0.05 (0.10)

(1000F)98.9 (210) Oil of 330 to 370 SUS viscosity at

37.80C± 1.10 (2.0) ± 0.05 (0.10)

*Maximum permissible difference between bath and sample temperatures at time of the test.


MAY 2001 Page 10.42

Figure 10.6.1 Saybolt Viscometer with Furol or Fice

Cork Stopper

Bottom of Bath

6 Min.

Level of Liquidin Bath

29.7 0.2 ± (1.17 0.01)±

32.5 0.5 ± (1.28 0.02)±

88Min.

(3.47)

OverflowRim

125 1 ± (4.92 0.04)±

(0.354)9.00

(0.124 0.008)3.15 0.02

±±

(0.169 0.012)4.3 0.3

±±

(0.882 0.04)12.25 0.1

±±

Furol Tip

All dimensions are in millimitres (inches)


MAY 2001 Page 10.43

Figure 10.6.2 Withdrawal Tube for Use with Saybolt Viscometer

¼ IN. NPSPIPE CAP

SILVERSOLDERED

6.4 (0.25)0 D

4.8 (0.19) 1 D

3.2 (0.13) 0 D

38 (1

.5)

127

(5.0

)

1.6 (0.06) 1 D

Note : All dimensions are in millimetres (inches)


MAY 2001 Page 10.44

Figure 10.6.3 Thermometer Support

15.4 (0.63)

7.9 (0.31)

15.9(o.63)

76 (3.0)

9.5 (0.37)

4.8 (0.19)

17.5 (0.69)



MAY 2001 Page 10.45

Figure 10.6.4 Filter Funnel for Use with Saybolt Viscometer

WIRECLOTH

A A

95 (3.75)

51 (2

.0)

6.4

(0.2

5)

33 (1.3)

8SPRINGCLIP

WIRECLOTH1.6 (0.06)

13(0.5)

23(0

.91)


22

(0.8

7)


MAY 2001 Page 10.46


a) A Furol orifice tip is used for residual materials with efflux times greater than 25 sto give the desired accuracy.

b) The viscometer is thoroughly cleaned with an appropriate solvent of low toxicity;then all solvent is removed from the viscometer and its gallery. The receivingflask is cleaned in the same manner.

Note 1. The plunger commonly supplied with the viscometer should never beused for cleaning; its use might damage the overflow rim and walls ofthe viscometer.

c) The viscometer and bath are set up in an area where they will not be exposed todrafts or rapid changes in air temperature, and dust or vapours that mightcontaminate a sample.

d) The receiving flask (Figure 10.6.5) is placed beneath the viscometer so that thegraduation mark on the flask is from 100 to 130 mm (4 to 5 in.) below the bottomof the viscometer tube, and so that the stream of oil will just strike the neck of theflask.

Figure 10.6.5 Receiving Flask

e) The bath is filled to least 6 mm (1/4 in.) above the overflow rim of the viscometerwith an appropriate bath medium selected from Table 10.6.2

f) Adequate stirring and thermal control are provided for the bath so that thetemperature of a test sample in the viscometer will not vary more than ± 0.05 C (±0.10 F) after reaching the selected test temperature.

g) Viscosity measurements should not be made at temperatures below the dew pointof the room's atmosphere.

5810±

60 0.05 mlat 20C±

0

11 max.

10 1 ID at Graduation Mark±

3 min3 min

Less Than 55

Note. All dimensions are in Millimetres


MAY 2001 Page 10.47

h) For calibration and referee tests, the room temperature is kept between 20 and30 0C (68 and 86 0F), and the actual temperature is recorded. However roomtemperatures up to 38 0C (100 0F) will not introduce errors in excess of 1%.

10.6.5 Calibration and standardization

1. The Saybolt Furol Viscometer is calibrated at intervals of not more than 3years by measuring minimum efflux time of 90s at 50 0C (122 0F) of anappropriate viscosity oil standard, following the procedure given in Section10.6.6

Saybolt Viscosity Standards - The approximate Saybolt viscosity’s are shownin Table 10.6.3.

Table 10.6.3 Saybolt Viscosity Oil standard

Viscosity Oil Standards SUS at 37.80C(1000F)

SUS at 98.90C(2100F)

SFS at 500C(1220F)

S3 36 … …S6 46 … …S20 100 … …S60 290 … …S200 930 … …S600 … 150 120

Standards Conforming to ASTM Saybolt Viscosity Standards -Theviscosity standards may also be used for routine calibrations at othertemperatures as shown in Table 10.6.3. Other reference liquids, suitable forroutine calibrations may be established by selecting stable oils covering thedesired range and determining their viscosities in a viscometer calibrated with astandard conforming to ASTM requirements.

Routine Calibrations- The viscosity standards may also be used for routinecalibrations at other temperatures as shown in Table 10.6.3.

2. The efflux time of the viscosity oil standard shall equal the certified Sayboltviscosity value. If the efflux time differs from the certified value by more than0.2% calculate a correction factor, F for the viscometer as follows:

F = V/t

Where,V = certified Saybolt viscosity of the standard, andt = measured efflux time at 500C (122 0F)

Note 2. If the calibration is based on a viscosity oil standard having and effluxtime between 200 and 600 s, the correction factor applies to allviscosity levels at all temperatures.

3. Viscometers or orifices requiring corrections grater than 1.0% shall not be usedin referee testing.


MAY 2001 Page 10.48

10.6.6 Procedure

a) The bath temperature is established and controlled at the selected testtemperature. Standard test temperatures for measuring Saybolt Furol viscosity’sare 25.0, 37.8 50.0, and 98.9 0C (77, 100, 122, and 210 0F).

b) A cork stopper is inserted having a cord attached for its easy removal, into theair chamber at the bottom of the viscometer. The cork shall fit tightly enough toprevent the escape of air, as evidenced by the absence of oil on the cork when itis withdrawn later as described.

c) If the selected test temperatures is above room temperature, the test may beexpedited by preheating the sample in its original container to not more than 1.70C (3.0 0F) above the test temperature.

d) The sample is stirred well, then strain it through a wire cloth of appropriate meshdirectly into the viscometer until the level is above the overflow rim. The wirecloth shall be 150µm (No. 100) mesh except as noted in T 59 (Testing EmulsifiedAsphalt) and Note 3.

e) For liquid asphaltic road materials having highly volatile components such as therapid curing and medium curing cut-backs, preheating in an open container shallnot be permitted.

The material shall be poured at room temperature into the viscometer of if thematerial is too viscous to pour conveniently at room temperature, it shall bewarmed sufficiently by placing the sample in the original container in a 50 0C (1220F) water bath for a few minutes prior to pouring. Filtering through a wire clothshall be omitted.

For tests above room temperature, greater temperature differential thanindicated in Table 10.6.2 be permitted during the heating period, but the bathtemperature must be adjusted to within the prescribed limits prior to the finalminute of stirring during which the temperature of the sample remains constant.

Note 3. The viscosity of steam-refined cylinder oils, black lubrication oils,residual fuel oils and similar waxy products can be affected by theprevious thermal history. The following preheating procedure should befollowed to obtain uniform results for viscosity below 95 0C (200 0F).

To obtain a representative sample, heat the sample in the originalcontainer to about 50 0C (122 0F) with stirring and shaking. Probe thebottom of the container with a rod to be certain that all waxy materialsare in solution. Pour 100 ml into a 125 ml Erlenmeyer flask. Stopperloosely with a cork or rubber stopper. Immerse the flask in a bath ofboiling water for 30 min. Mix well, remove the sample from the bath, andstrain it through a 0.07µm (No. 200) sieve directly into the viscometeralready in the thermostat bath. Complete the viscosity test within 1 hr.after preheating.

f) The sample in the viscometer is stirred with the appropriate viscositythermometer equipped with the thermometer support (Fig. 10.6.3) a circularmotion at 30 to 50 rpm is used in a horizontal plane. When the sampletemperature remains constant within 0.05 C (0.10 F) of the test temperatureduring 1 min of continuous stirring, the thermometer is removed.

Note 4. Never attempt to adjust the temperature by immersing hot or coldbodies in the sample. Such thermal treatment might affect the sampleand the precision of the test.


MAY 2001 Page 10.49

g) The tip of the withdrawal tube is immediately placed (Fig. 10.6.2) in the gallery atone point, and suction is applied to remove oil until its level in the gallery is belowthe overflow rim. Do not touch the overflow rim with the withdrawal tube; theeffective liquid head of the sample would be reduced.

h) The receiving flask must be in proper position; then the cork is snapped form theviscometer using the attached cord and the timer is started at the same instant.

i) The timer is stopped instant the bottom of the oil meniscus reaches thegraduation mark on the receiving flask. The efflux time is recorded in seconds tothe nearest 0.1 s.


1. The efflux time is multiplied by the correction factor for the viscometer in 2 of10.6.5.

2. The corrected efflux time is reported as the Saybolt Furol viscosity of the oil atthe temperature at which the test was made.

3. Values to the nearest whole second are reported.


MAY 2001 Page 10.50

10.7 Distillation of Cut-Back Asphaltic (Bituminous)

10.7.1 Introduction

By this procedure, the amount of the more volatile constituents in cut-back asphalticproducts are measured. The properties of the residue after distillation are notnecessarily characteristic of the bitumen used in the original mixture nor of theresidue which may be left at any particular time after application of the cut-backasphaltic product. The presence of silicone in the cut-back may affect the distillationresidue by retarding the loss of volatile material after the residue has been pouredinto the residue container.

10.7.2 Scope

This test is used for the distillation of cut-back asphaltic (bituminous) products.

10.7.3 Apparatus

a) Distillation Flask, 500 ml side-arm, having the dimensions shown in Figure 10.7.1.

Figure 10.7.1 Distillation Flask

b) Condenser, standard glass-jacketed, of nominal jacket length from 200 to 300mm and overall tube length of 450 ± 10 mm (see Figure 10.7.2).

c) Adapter, heavy-wall (1 mm) glass, with reinforced top, having an angle ofapproximately 1050. The inside diameter at the large end shall be approximately18 mm, and at the small end not less than 5 mm. The lower surface of theadapter shall be on a smooth descending curve from the larger end to thesmaller. The inside line of the outlet end shall be vertical, and the outlet shall becut or ground (not fire-polished) at an angle of 45 ± 5 deg to the inside line.

d) Shield, 22 gauge sheet metal, line with 3-mm asbestos or high temperature lightweight flexible ceramic insulation, and fitted with suitable transparent heat

25 1.2 mm. 1.D.±

75 3±

100.

5 m

m. 1

.D.

±

1.0

to 1

.5 m

m. W

all

220 5.0 mm.

±

105

3 m

m.

±

135

5 m

m.

±

102 2.0 mm.0.D.

±


MAY 2001 Page 10.51

resistant non-discoloring windows, of the form and dimensions shown in Figure10.7.3 used to protect the flask from air currents and to reduce radiation. Thecover (top) shall be made in two parts of 6.4-mm (1/4 in.) milboard.

e) Shield and Flask Support- Two 150 by 150 mm sheets of 1.18 mm nickel-chromemesh wire gauze on opening (16 mesh) on tripod or ring.

f) Heat Source - Adjustable Terrill-type gas burner or equipment.g) Receiver - A 100 ml Crow receiver conforming to British Standard No. 658: 1962

(see Figure 10.7.4).

Figure 10.7.2 Distillation Apparatus

Receiver

BlottingpaperNot less

than 25.4Water Jacketedcondenser

12.5mm

Stand

Burner

Chimney

6.5 mm

Flask

Shield

Window

23 mm

Two sheetswire gauge

ThermometerCork Stopper

15 mm

450 mm

600 to 700 mm

Tight Ground Glassor Cork Joints


MAY 2001 Page 10.52

Figure 10.7.3 Shield

Figure 10.7.4 Crow receivers of capacity 25, 50 and 100 ml

41 2 mm±

117

3 m

m±

823

mm

±

Shield

16 2 mm±

117 2 mm±

3.2 0.3 mm±12.3 2 mm±

6.4

0.5

mm

± 30 10 mm±148 3 mm±

Cover in Two Parts

Windows

148 3 mm±

Flanged Open-End CylinderMade of 22-Gauge Sheet Metal Linedwith 3 mm Asbestos LiningRiveted to Metal.

Two Windows areProvided at Right Anglesto the End Slot.


MAY 2001 Page 10.53

h) Residue Container - A 240 ml (8 oz. seamless metal container with slip on coverof 75 ± 5 mm in diameter, and 55 ± 5 mm in height.

Caution : Provide a cover suitable in size and material to extinguish a flame in the240 ml (8 oz) tin box if the residue flames after pouring.

i) Thermometer.j) Balance as required.

10.7.4 Sampling

a) The sample is thoroughly, stirred warming if necessary, to ensure homogeneitybefore removal of a portion for analysis.

b) If sufficient water is present to cause foaming or bumping, dehydrate a sample ofnot less than 250 ml by heating in a distillation flask sufficiently large to preventfoaming over into the side arm. When foaming has ceased, the distillation isstopped. If any light oil has distilled over, separate and pour this back into theflask when the contents have cooled just sufficiently to prevent loss of volatile oil.The contents of the flask is thoroughly mixed before removal for analysis.


a) The mass of 200 ml of the sample is calculated from the specific gravity of thematerial at 15.6 0C (60 0F). This amount is weighed ± 0.05 g into the 500 ml flask.

b) The flask is placed in the shield supported by two sheets of gauze on a tripod orring. The condenser tube is connected to the tabulator of the flask with a tightcork joint. The condenser is clampped so that the axis of the bulb of the flaskthrough the center of its neck is vertical. The adapter is adjusted over the end ofthe condenser tube so that the distance from the neck of the flask to the outlet ofthe adapter is 650 ± 50 mm (see Figure10.7.2).

c) The thermometer is inserted through a tightly fitting cork in the neck of the flaskso that the bulb of the thermometer rests on the bottom of the flask. Thethermometer is raised 6.4 mm (1/4 in.) from the bottom of the flask using the scaledivisions on the thermometer to estimate the 6.4 mm (1/4 in.) distance above thetop of the cork.

d) The burner is protected by a suitable shield or chimney. The receiver is placedso that the adapter extends at least 25mm but not below the 100 ml mark. Thegraduate is covered closely with a piece of blotting paper, or similar material,suitably weighted, which has been cut to fit the adapter snugly.

e) The flask, condenser tube, adapter, and receiver shall be clean and dry beforestarting the distillation. The 240 ml (8 oz.) residue container is placed on its coverin an area free from drafts.

f) Cold water is passed through the condenser jacket. Warm water is used ifnecessary to prevent formation of solid condense in the condenser tube.

10.7.6 Procedure

a) The temperatures to be observed are corrected in the distillation if the elevationof the laboratory at which the distillation is made deviates 500 ft (150 m) or morefrom sea level. Corrected temperatures for the effect of altitude are shown inTable 10.7.1 and 10.7.2. If the prevailing barometric pressure in millimeters ofmercury is known, correct to the nearest 1 0C or 2 0F the temperature to beobserved with the corrections shown in Table 10.7.3. Do not correct for theemergent stem of the thermometer.


MAY 2001 Page 10.54

Table 10.7.1 Corrected FractionationTemperatures for VariousAltitudes, Deg C

Table 10.7.2 Corrected FractionationTemperatures for VariousAltitudes, Deg C

Elevationabove SeaLevel. ft (m)

Fractionation Temperatures forVarious Altitudes. deg C

Elevationabove sealevel. ft (m)

Fractionation Temperatures forVarious Altitudes. deg C

-1000 (-305) 192 227 363 318 362

-1000 (-305) 377 440 503 604 684

-500 (-152) 191 226 261 317 361

-500 (-152) 375 438 502 602 682

0(0) 190 225 260 316 360

0(0) 374 437 500 600 680

500 (152) 189 224 259 315 359

500 (152) 373 436 498 598 678

1000 (305) 189 224 258 314 358

1000 (305) 371 434 497 597 676

1500 (457) 188 223 258 313 357

1500 (457) 370 433 495 595 675

2000 (610) 187 222 257 312 356

2000 (610) 369 431 494 593 673

2500 (762) 186 221 256 312 355

2500 (762) 367 430 492 592 671

3000 (914) 186 220 255 311 354

3000 (914) 366 429 491 590 669

3500 (1067) 185 220 254 310 353

3500 (1067) 365 427 490 588 667

4000 (1219) 184 219 254 309 352

4000 (1219) 364 426 488 587 666

4500 (1372) 184 218 253 308 351

4500 (1372) 363 425 487 585 665

5000 (1524) 183 218 252 307 350

5000 (1524) 361 423 485 584 663

5500 (1676) 182 217 251 306 349

5500 (1676) 360 422 484 582 661

600 (1829) 182 216 250 305 349

600 (1829) 359 421 483 581 660

6500 (1981) 181 215 250 305 348

6500 (1981) 358 420 481 580 658

7000 (2134) 180 215 249 304 347

7000 (2134) 357 418 480 578 656

7500 (2286) 180 214 248 303 346

7500 (2286) 356 417 479 577 655

8000 (2438) 179 213 248 302 345

8000 (2438) 355 416 478 575 653

Table 10.7.3 Factors Calculating Temperature Corrections

Nominal Temperatures.deg C (deg F)

Correction per 10 mm Difference inPressure, deg C (deg F)

160 (320) 0.514 (0.925175 (347) 0.531 (0.957)190 (374) 0.549 (0.989225 (437) 0.591 (1.063)250 (482) 0.620 (1.166)260 (500) 0.632 (1.138)275 (527) 0.650 (1.170)300 (572) 0.680 (1.223)


MAY 2001 Page 10.55

315.6 (600) 0.698 (1.257)325 (617) 0.709 91.277)360 (680) 0.751 (1.351)

• To be subtracted in case the barometric pressure is below 760 mm Hg: to beadded in case barometric pressure is above 760 mm Hg.

Correction = (Observed Pressure - 760) x Correction per mmThe correction per mm=1/10 the correction per 10 mm given the Table 10.7.3

Example : Barometric observation temperature 260 C (500 F).Celsius Correction = (748-760) x 0.0632 = 0.758Temperature = 260 - 0.758 = 259 C (rounded to nearest 10C)Fahrenheit Correction = (748 - 760) x 0.1138 = 1.366Temperature = 500 - 1.366 = 498 F (rounded to nearest 20F)

b) Heat is applied so that the first drop of distillate falls from the end of the flaskside-arm in 5 to 15 min. Conduct the distillation so as to maintain the followingdrop rates, the drop count to be made at the tip of the adapter:

50 to 70 drops per minute to 260 0C (500 0F)20 to 70 drops per minute between 260 and 316 C (500 and 600 0F)Not over 10 minutes to complete distillation from 316 to 360 C (600 to 680 0F)

c) The volumes of distillate are recorded to the nearest 0.5 ml in the receiver at thecorrected temperatures. If the volume of distillate recovered is critical, usereceivers graduated in 0.1 ml divisions and immersed in a transparent bathmaintained at 15.6 ± 3 C (60 ± 5 0F).

Note 1. Some cut-back asphaltic products yield no distillate or very little distillateover portions of the temperature range to 316 0C (600 0F). In this caseit becomes impractical to maintain the above distillation rates. For suchcases the intent of the method shall be met if the rate of rise oftemperature exceeds 5 0C (9 0F)/min.

d) When the temperature reaches the corrected temperature of 360 0C (680 0F), theflame is extinguished and the flask and thermometer are removed. With the flaskin a pouring position, the thermometer is removed the contents is immediatelypoured into the residue container. The total time form cutting off the flame tostarting the pour shall not exceed 15 s. When pouring, the side-arm should besubstantially horizontal to prevent condense in the side-arm from being returnedto the reside.

Note 2. The formation of skin on the surface of a residue during cooling entrapsvapors which will condense and cause higher penetration results whenthey are stirred back into the sample. If skin begins to form duringcooling, it should be gently pushed aside. This can be done with aspatula with a minimum of disturbance to the sample.

e) The condenser is allowed to drain into the receiver and record the total volume ofdistillate collected as total distillate to 360 0C (680 0F).

f) When the residue has cooled until fuming just ceases, it is thoroughly stirred andpoured into the receptacles for testing for properties such as penetration,


MAY 2001 Page 10.56

viscosity, or softening point. Proceed as required by the appropriate IP methodfrom the point that follows the pouring stage.

g) If desired, the distillate, or the combined distillates from several tests, maybe submitted to a further distillation.


a) Asphaltic Residue - Calculate the percent residue to the nearest 0.1 asfollows:

R = [(200 - TD)/200] x 100

Where,R = residue content, in volume percent, andTD = total distillate recovered to 360 0C (680 0F), ml.Report as the residue from distillation to 360 0C (680 0F), percent volume bydifference.

b) Total Distillate - Calculate the percent total distillate to the nearest 0.1as follows:

TD percent = (TD/200) x 100

Report as the total distillate to 360 0C (680 0F), volume percent.

c) Distillate Fractions

i) Determine the volume percentages of the original sample by dividingthe observed volume (in milliliters) of the fraction by 2. Report to thenearest 0.1 as volume percent as follows:

Up to 190 0C (374 0F)Up to 225 0C (437 0F)Up to 260 0C (500 0F)Up to 316 0C (600 0F)

ii) Determine the volume percentages of total distillate by dividing theobserved volume in millilitres to 360 0C (680 0F) and multiply by 100.Report to the nearest 0.1 as the distillate, volume percent of totaldistillate to 360 0C (680 0F) as follows :

Up to 190 0C (374 0F)Up to 225 0C (437 0F)Up to 260 0C (500 0F)Up to 316 0C (600 0F)

d) Where penetration, viscosity, or other tests have been carried out, reportwith reference to this method as well as to any other method used.

10.7.8 Precision

The following criteria shall be used for judging the acceptability of results (95percent probability):


MAY 2001 Page 10.57

a) Repeatability - Duplicate values by the same operator shall not beconsidered suspect unless the determined percentages differ by more than1.0 volume percent of the original sample.

b) Reproducibility - The values reported by each of the two laboratories shallnot be considered suspect unless the reported percentages differ by morethan the following:

Distillation Fractions, volume percent of the original sample :Up to 175 0C (347 0F) 3.5above 175 0C (347 0F) 2.0Residue, Volume percentage by difference from the original sample 2.0


MAY 2001 Page 10.58

10.8 Float Test of Bitumen

10.8.1 Scope

This test is used to determine the floating time of bituminous materials.

10.8.2 Apparatus

a) Float - The float (Figure 10.8.1 is made of aluminium or aluminium alloy inaccordance with the following requirements :

Min. Normal Max.Weight of float, g ................................. 37.70 37.90 38.10Total height of float, mm ..................... 34.00 35.0 36.0Height of rim above lower side ofshoulder mm ........................................ 26.5 27.0 27.5Thickness of shoulder, mm ................. 1.3 1.4 1.5Diameter of opening, mm ..................... 11.0 11.1 11.2

b) Collar - The collar (Figure 10.8.1) is made of brass in accordance with thefollowing requirements :

Min. Normal Max.Weight of collar, g ................................ 9.60 9.80 10.00Over all height of collar, mm ................ 22.3 22.5 22.7Inside diameter at bottom, mm ............. 12.72 12.82 12.92Inside diameter at top, mm ............. 9.65 9.70 9.75

The top of the collar shall screw up tightly against the lower side of the shoulder.

c) Calibration of Assembly - The assembled float and collar, with the collar filled flushwith the bottom and weighted to a total weight of 53.2 g, shall float upon water withthe rim 8.5 ± 1.5 mm above the surface of the water. This adjustment of the totalweight of the assembly is for the purpose only of calibrating the depth ofimmersion in the testing bath. Dimension of the apparatus additional to thoserequired above are given in Figure 10.8.1.

d) Thermometer - Having a rang of - 2 to + 80 0C or + 30 to + 180 0F.e) Water Bath - 185 or more millimetres in its smallest lateral dimension and

containing water 185 or more millimetres in depth. The height of the containerabove the water shall be 100 or more millimetres. The bath may be heated byeither a gas or electric heater. A stand or other suitable support shall beavailable to hold the thermometer in the proper position in the bath during thetest.

f) Water bath at 5 0C - A water bath of suitable dimensions maintained at 5.0 ± 1.00C, which may be accomplished by means of melting ice.

g) Heater - An oven or hot plate, heated by electricity or gas, for melting samples fortesting.

h) Trimmer - A spatula or steel knife of convenient size.i) Plate - The plate shall be made of non-absorbent material of convenient size and

of sufficient thickness to prevent deformation. The plate shall be flat so that thebottom surface of the collar touches it throughout.

j) Timer - A stop watch or other timer graduated in divisions of 1 s or less.


MAY 2001 Page 10.59

Methods of sampling and testing

Figure 10.8.1 Float Test Apparatus

10.8.3 Procedure

a) The brass collar is placed with the smaller end down on the plate which has beenpreviously coated with a suitable release agent (Note 1).

Note 1. Mixtures of glycerine and dextrine or talc (3 grams glycerine to about 5grams dextrine or talc has been used satisfactorily), Dow-CorningSilicone Stop-Cock Grease, or castor oil-Versamid 900 [100:1 mixtureby weight heated to 204 to 232 0C (400 to 450 0F) and stirred untilhomogeneous] have proven suitable. Other release agents may beused provided results obtained are comparable to those obtained whenusing one of the above .

b) The sample shall be completely melted at the lowest possible temperature thatwill bring it to a sufficiently fluid condition for easy pouring, excepting creosote-oil

Thermometer

Float Tester

HotBath

Tripod

BunsenBurner

Standard Support

11.1 0.1 mm±

92.0 2.0 mm±

53.6

mm

Ra

d.

Tapered to make Weight

95 m

m

Rad.12.0 0.5 mm±

Float(Aluminum)

1.4 0.1 mm±

27.0

0.5

mm

±35

.01.

0 m

m±

9.700.05 mm

±1.40 0.10 mm±

Tapered to make Weight

1.40 0.10 mm

± 12.120.10 mm

±

Collar(Brass)

22.5

0.2

mm

±3 m

mWeight of Float,Weight of Collar,

37.90 0.20 g±9.80 0.20 g±

Assembly


MAY 2001 Page 10.60

residues, which shall be mixed and poured at a temperature of 100 to 125 0C. Stirthe sample thoroughly until it is homogeneous and free from air bubbles thenpour it into the collar in any convenient manner until slightly more than level withthe top.

c) Asphalt and Asphalt Products - Asphalt and asphalt products are cooled to roomtemperature for 15 to 60 min. then place them for 5 min in the water bath at 5 0C,after which trim the surplus material flush with the top of the collar by means of aspatula or steel knife that has been slightly heated. Then the collar and plate areplaced in the water bath at 5 0C and leave them in this bath for not less than 15nor more than 30 min.

d) The water is heated in the testing bath to the temperature at which the test is tobe made. This temperature shall be accurately maintained without stirring, andshall at no time throughout the test be allowed to very more than 0.5 0C from thetemperature specified. The temperature shall be determined by immersing thethermometer with the bottom of the bulb at a depth of 40 ± 2 mm below the watersurface.

e) After the material to be tested has been kept in the water bath at 5 0C for notless than 15 nor more than 30 min remove the collar with its contents from theplate and screw into the aluminum float. The assembly is completely immersed for1 min in the water bath at 5 0C. Then the water is removed inside of the float andimmediately float the assembly on the testing bath. Lateral drift of the assemblyshall be permitted, but no spinning motion shall be intentionally imparted thereto.As the plug of material becomes warm and fluid, it is forced upward and out of thecollar until the water gains entrance into the saucer and causes it to sink.

f) The time, in seconds, between placing the apparatus in the water and the waterbreaking through the material shall be determined by means of a stop watch orother timer, and shall be taken as a measure of the consistency of the materialunder examination.

10.8.4 Precautions

Special precautions should be taken to insure that the collar fits tightly into the floatand to see that there is no seepage of water between the collar and float during thetest.


MAY 2001 Page 10.61

10. 9 Marshall Stability and Flow

10.9.1 Introduction

The Marshall test method is widely used for the design and control of asphalticconcrete and hot rolled asphalt materials, it cannot be applied to open texturedmaterials such as bitumen macadam. Materials containing aggregate sizes larger than20 mm, are liable to give erratic results.

The full Marshall method is a method of bituminous mix design in addition to being aquality control test. The details given below related mainly to its use as a qualitycontrol test. The suitability of materials for the design of Marshall asphalt requires thata numbers of tests are performed on the materials. Tests normally performed are:

1. Asphalt :

(a) Penetration (b) Viscosity (c) Solubility (d) Specific gravity (e) Fire & flash point(f) Softening point.

2. Aggregates :

(a) Percent wear (b) Unit weight (c) Sieve analysis (d) Specific gravity (e)Absorption.

The preliminary mix designs, the scheme for analysing aggregate will begoverned, to some extent, by method of producing the gradation duringconstruction.

10.9.2 Scope

The basic Marshall test consists essentially of crushing a cylinder of bituminousmaterial between two semi-circular test heads and recording the maximum loadachieved (i.e. the stability) and the deflection at which the maximum load occurs (i.e.the flow).

In common with many other tests, the bulk of the work is involved in preparing thesamples for testing.

10.9.3 Apparatus

The samples are prepared in 100 mm diameter moulds which are fitted with a baseand collar (Figure 10.9.1) the sample is compacted using a hammer consisting of asliding weight which falls onto a circular foot (Figure 10.9.2) during compaction themould is held on a hardwood block which is rigidly fixed to a concrete base (Figure10.9.3).

The sample is removed from the mould using an extraction plate and press (Figure10.9.1) and heated to the test temperature of 60° C in a water bath.

The cylindrical specimens are tested on their sides between test heads similar tothose shown in Fig. 10.9.4. The flow is measured with a dial gauge and the stability ismeasured with a proving ring. A motorised load frame is required for the test.


MAY 2001 Page 10.62

Figure 10.9.1 Marshall Test Compaction and Extraction Equipment

∅ 114.3

∅ 101.6 0.1±

71.5

∅ 12.7 ∅ 106.8 0.1±

∅ 99

63.5

∅ 38R 9.5 spherical seating

Extraction plateExtension collar

∅ 101.6 0.1±

∅ 106.4 0.1±

89

12.7

12.7

∅ 114.3

Mould cylinder∅ 106.8 0.1±

86

12.7

∅ 114.3

Extraction collar

∅ 104.8∅ 125.4

∅ 100.8 0.1±18.25

5.6Mould baseDimensions are in millimetres.

12.7


MAY 2001 Page 10.63

Figure 10.9.2 Marshall Compaction Hammer

∅ 55

Handle screwed and pinned

∅ 98.513

28

3

∅ 45

25

70

80

305

981

457

∅ 15.875

Sliding mass 4.535 kg457 free fall

Mandatory requirements

Diameter of foot 98.50.125Length of free fall 457Mass of sliding mass 4.535 kg(Other dimensions are approximate)

±

Rod-nut screwed and rivetedon end

Finger guard

Compression springFree length 51Wire diameter 3.175Mean diameter 27.0 - 28.6Number of coils 4

Foot screwed and locked

Hard face


MAY 2001 Page 10.64

Figure 10.9.3 Marshall Compaction Pedestal

Guide Post

Spring

Angle-housing welded tounderface of steel plateto ensure permanentcentering of assembly

Recess in concretebase of permanentcentering of timberblock or angle-housingbolted to concrete base450 x 450 x 200

NOTE. A suitable framework issecured to the pedestal to ensurethat the compaction hammer is kept vertical.

Dimensions are in millimetres.

Mould baselocating pegs

Concreteblock

200

25

450 square

Barrel strainers(Min. Dia. 6.35)

Wood block200 x 200 x 450

Steel plate300 x 300 x 25

Sample mould

Hinge post

Clamp ring


MAY 2001 Page 10.65

Figure 10.9.4 Marshall Testing Heads

Lower testing headBaseFace hardenedor plated andpolished

6.35

450

19 min.

Upper testing head

101.6 0.1±

9.5

9.5

Swinging plate for dial gauge

Dimensions are in millimetres.

NOTE. Frequent checks oninner radius of segments and onalignment of guide posts arenecessary as high loads maypermanently distort the testinghead.

Lug for dial gauge

Dial gauge

76

12.7 Guide pinsand brushes


MAY 2001 Page 10.66

10.9.4 Sampling

Due to the various uses which may be made of Marshall tests, the materials for testmay be obtained in one of the following forms:

a) 100 mm diameter bituminous cores cut from an existing pavement using a corecutting machine.

b) Ready-mixed bituminous material obtained from a mixing plant or at the point oflaying, and sampled in accordance with Chapter 2.

c) A sample of mixed aggregate obtained from the mixing plant together with aseparate sample of bitumen obtained from the storage tank at the mixing plant inaccordance with Chapter 2.

Note. A sample of mixed aggregate may be obtained from a mixing plant bybatching the specified aggregate weights into the mixer but not allowingany bitumen to be batched. The aggregate sample is then dischargedinto a clean lorry where it may be sampled in accordance with Chapter2.

d) Samples of the various sized aggregates in use at the mixing plant sampled inaccordance with Chapter 2 together with a separate sample of bitumen sampledin accordance with Chapter 2.

In the case of a sample of type (a), the core may be tested without furtherpreparation. It must, however, be of the correct diameter and height. It is doubtfulif samples obtained in this manner give results which are closely comparable tolaboratory compacted specimens; however, the taking of cores is a valuable wayto check the compacted density of the ‘as laid’ material and the small amount ofadditional work in determining the stability and flow is justified. If the densitiesobtained form cores (or sand replacement tests) are significantly below those oflaboratory compacted specimens, attention should be paid to the methods oflaying and compacting.

For many quality control purposes samples of type (b) are the most useful asthey may be conpacted, after re-heating in an oven to the required temperature.The delay between initial mixing and compacting should be as short as possible.With this type of sample separate test on the mixed aggregate will be required todetermine the void content.

It is essential to make frequent checks on the combined aggregate from anasphalt plant. The most important factors to be checked are the aggregatetemperature at the time of mixing and the grading of the mixed aggregate. It may,therefore, be convenient to obtain separate samples of aggregate and bitumen(type (c) sample) and mix them in the required proportions in the laboratory. Asthe aggregate will be discharged from the mixer in a dry state, there isconsiderable risk of segregation and the greatest care should be taken inobtaining a representative sample. If there are reasons to suspect that thebitumen at the mixing plant has been overheated, it may be worth while to checkthe penetration as excessive heating hardens the bitumen. One particular use ofthis method of sampling is that if some adjustment is required to the bitumencontent, a number of samples may be made at various bitumen contents todetermine which is the most satisfactory.

To maintain the quality of a bituminous material, it is necessary to check, atregular intervals, the various sizes of aggregate for grading, cleanliness, shape,strength etc. If it is required to study the effects of varying the aggregate, orbitumen proportions, it will be necessary to obtain separate samples of each


MAY 2001 Page 10.67

aggregate size to be used in addition to a sample of the bitumen (a type (d)sample).

10.9.5 Sample Preparation

If necessary, the aggregates should be oven-dried at 150°C before testingcommences. (Sample types (c) and (d)).

For samples of type (d) it is first necessary to combine the various sample sizes togive the required grading for the mixed aggregate. Several different gradings may betried if a full Marshall mix design is to be carried out.

When it is required to determine the most satisfactory bitumen content, given asample of mixed aggregate, an initial estimate of the required bitumen content can bemade from a knowledge of the compacted density of the Mixed Aggregate (CDMA).The CDMA is most conveniently determined using a standard 100 mm. diametercompaction mould and a 2.5 kg compaction hammer. The sample of dry aggregate iscompacted in the mould in four layers, each layer being given 20 blows of thehammer. The density of the aggregate is then calculated in an identical manner to thebulk density in a compaction tests. The average of two determinations is taken as theCDMA, as shown in Form 10.9.1.

It is also necessary to carry out separate determinations of the specific gravity of themixed aggregate (SGMA), and the specific gravity of bitumen.

The voids in mixed aggregate VMA are then determined from the formula:

VMACDMA

SGMAX=

−(SGMA100%

The VMA should normally be between 17 and 20% for a satisfactory mix. An initialestimate of the optimum bitumen content (B) is obtained from the formulae :

BVMA VIM x S G Bitumen

CDMA100 =−( ) . .

Where, B100 is expressed in parts per 100 parts of mixed aggregate (p.h.a) and

VIM = the specified percentage of air voids in the compacted mix.

Note. In bitumen calculations, it is usual to express all densities and specificgravities in gram/ml; gram/cc or Mg/cu.m.

Having completed the required tests on the mixed aggregates, the bituminousmaterial is then produced by mixing the aggregates with the bitumen in the correctproportions.

For each test specimen, the required weight of mixed aggregate is weighed out andplace in an oven at the temperature shown in the following Table 10.9.1 (Column 2) :


MAY 2001 Page 10.68


MAY 2001 Page 10.69

Table 10.9.1 Temperatures required in the preparation of moulded specimens

1 2 3 4 5Bindergrade pen

Temperature

(in mm) Heatedaggregate

Heatedbinderbitumen

On Completion ofmixing (approx.)

Immediatelyprior tocompaction(max. - min.)

°C °C °C °C80 - 100 155 150 140 136 - 13260 - 70 160 155 145 141 - 13740 - 50 165 160 150 146 - 142

The amount of aggregate required for each specimen is in the region of 1000 - 1500grams, but the exact amount must be determined by an initial trial.

There specimens are required for each bitumen content and the aggregate should beheated in the oven for at least 2 hours.

The weight of bitumen required for each specimen should be weighed out into a smallmetal container, and heated to the temperature shown in the Table 10.9.1 (Column3), using an oven or a hot plate. When using a hot plate, the bitumen should bestirred whenever possible to prevent local overheating and heating should notcontinue for longer than 30 minutes. The temperature should be maintained for atleast 10 minutes. When pouring a sample of bitumen it is inevitable that some bitumenadheres to the sides of the container, to account for this, it is useful to beat a sampleof bitumen in the container and pour this away, thus coating the sides of the containerbefore adding the exact weight of bitumen required for the specimen, the weight ofbitumen adhering to the sides of the container will vary only slightly each time it isemptied. To establish the exact weight of bitumen used, the weight of the containershould be taken before heating and after pouring.

The heated aggregate and bitumen should be thoroughly mixed together as quicklyas possible. Mixing may be by hand or in a mechanical mixer. In either case the mixingpan and tools should be heated prior to use so that the temperature of the sample ismaintained. When all the aggregate is evenly coated with the bitumen, the sampleshould be removed from the mixing pan and compacted as quickly as possible.

When using a sample of mixed bituminous material (type (b)), this should be dividedinto the required specimen weights as quickly as possible after sampling and thenbrought back to the required mixing temperature by heating in an oven. The time ofheating will depend on the initial temperature of the sample and should not exceedone hour. On removal from the oven, the sample should be compacted as soon aspossible.

The compaction moulds, collars and bases should be cleaned, lightly oiled andplaced in an oven, at the temperature shown in column 5 of the Table 10.9.1, for aperiod of at least one hour. The hammer base should also be heated in a similarmanner.

The base, mould and collar should then be assembled and a 100 mm. diameter discof tough non-absorbent paper (such as greaseproof) placed in the base of the mould.The whole of the mixed material is then transferred into the mould as quickly aspossible and levelled by prodding with a spatula 15 times round the perimeter and 10times over the interior of the sample. At the end of this process, the upper surface of


MAY 2001 Page 10.70

the sample should be slightly domed. At this stage the temperature should bechecked, using a previously warmed thermometer, to save time, and must be withinthe range shown in column 5, Table 10.9.1.

A disc of non-absorbent paper is then placed on the top of the sample, the mouldassembly is placed on the compaction pedestal and located in the mould clamp.

Compaction is then given to the top of the sample using 50 blows of the hammer. Thehammer must be maintained perfectly vertical during this operation and the rate ofcompaction should be about 60 - 70 blows per minute.

On completion of 50 blows, the collar and base are carefully removed, the mould isturned over and the base and collar re-fixed so the bottom of the sample is nowfacing upwards. The assembly is re-fixed in the pedestal mould holder and givenanother 50 blows of the hammer.

On completion of compaction, the collar is removed and the mould and base areimmersed in cold water for at least 15 minutes.

When completely cool the base is removed and the sample ejected from the mouldusing the extraction apparatus. The specimen must be extracted from the mouldwithout shock or distortion. Any burrs may be removed with a spatula or sharp knife.

The specimen should be placed on a flat surface and the average height measured,preferably with a dial gauge, the height must be between 62.0 and 65.0 mm. (2.7/16”- 2.9/16) otherwise the sample should be discarded.

The specimen is then dried with a cloth and stored on a piece of absorbent paper ona flat surface for at least 16 hours. Ensure the different specimens are clearlymarked.

The mould, base and collar should be thoroughly cleaned before re-use or storage.

10.9.6 Measurement of Density

Prior to testing, it is necessary to determine the density of the density of thespecimen, this is done by weighing in water.

The weight of the dry specimen is first determined to an accuracy of 0.1 grams.Weight C.

The specimen is then weighed in water, weight d, using a wire basket suspended froma suitable balance. Care should be taken to ensure that there are no air bubblesattached to the wire basket or the specimen prior to weighing.

These weights are recorded on the data sheet Form 10.9.2 and the calculationsrelating to volume and voids in the mix may then be completed.


MAY 2001 Page 10.71


MAY 2001 Page 10.72

From the weight of bitumen and aggregates used in the mix, the proportion of binder iscalculated as follows:

Proportion of binder,Weight of bitumenWeightof mixedaggregate

x 100...(a) B =

Where B is expressed in parts of bitumen per 100 parts of aggregate (p.h.a) . This isthe most convenient method of expressing binder content.

The binder content as a true percentage of the mixed material, is given by:

BWeight of bitumen

Weight of x'

(

mixed aggregate) + (Weight of bitumen) = 100%

Note that

BB

b'( )

% ............... ( ) B x =+

100100

Where, B is in p.h.a.

From the weight in air and weight in water :

Total Volume of specimen, V = (Weight c - Weight d) x S.G. water = (Weight c - Weight d) ml .......... (f)

The density of the compacted specimen is then given by, Compacted density of mix,

CDMWeight C

Vgram / ml ....................... (g)=

The maximum theoretical density of the specimen if there were no air voids would be:

Max. theoretical specimen density,

' X '100

% BitumenS . G . Bi tumen

% AggregateS . G . M .A

=+

or, ' X'100

B'S.B.Bitumen

(100 B')S.G.M.A

gram / ml..................(h)

=+

−

From the above results it is possible to derive a number of factors concerning thevolumetric proportions of the mix and the void content:

Volume of binder, V = B' x CDM

S.G. Bitumen % .............. (i)

(as % of total volume)

b


MAY 2001 Page 10.73

Volumeof aggregate VB

S G M Ajagg,

( '). . .

%..............( ) x CDM

=−100

Volumeof air voids, VIM (100 Vb V ) %..................(k)

(as % of total volume)agg= − −

The voids in the mixed aggregate are given by :

VMA = (100 - Vagg) % ............... (l)

and this value may be compared with that calculated previously using the CDMA.

The percentage of voids filled with bitumen are given by :

VFB = 100 x V

VMAb % ....................................................... (m)

and the percentage of air voids in the compacted mix,

VIM = 100 x ( 1 - CDM

X' ') % ........ (n)

This alternative method of calculating VIM may be used as a check. The values of VIMachieved should be compared with the specified value.

If the test is being repeated using a number of different bitumen contents, it is usualto plot, graphs of compacted density of mix, CDM, Voids in Mix, VIM, and Voids filledwith bitumen, VFB, against binder content, B.


On completion of density measurements, the specimens are heated in athermostatically controlled water bath at a temperature of 60 ± 0.5°C for a period of60 minutes the specimens should be completely immersed in the water.

The inside faces of the testing heads should be thoroughly cleaned and the guiderods lightly oiled, so that the upper head slides freely. The heads should then beimmersed in the water bath at 60 ± 0.5°C so they are heated to the correct testtemperature.

It is important that the test is carried out quickly and efficiently such that the total timebetween removing the specimen from the water bath and completion of the testshould not exceed 40 seconds. It is, therefore, essential that the test machine,gauges etc., are all prepared ready for use before removing the specimens from thewater bath.

On completion of the heating period, the specimen and heads should be quicklyremoved from the bath and the specimen placed on its side centrally in the lower testhead, the upper head is then located on the slides and brought into contact with thespecimen. The whole assembly is then placed on the test machine directly below theplunger.

The deformation dial gauge should be placed into position and either zeroed or theinitial reading taken. The load ring dial gauge should previously have been zeroed.

The load is then applied to the specimen by the machine at a rate of 50.8 mm/minute± 5%. The reading on the load ring gauge should be observed and the instant theload stops increasing, the machine should be switched off. The maximum load gauge


MAY 2001 Page 10.74

reading should be taken. The corresponding reading on the deformation (flow) gaugemay then be taken.

The heads should be wiped clean before testing further specimens.

10.9.8 Calculation

The calculations concerned with densities and voids have already been described insection 10.9.6

From the maximum load gauge reading, the maximum load applied may bedetermined using a calibration chart or proving ring factor. This is the measuredstability.

It will be noted that the height of the specimen may vary somewhat and the measuredstability will tend to increase as the height of the specimen increases. To reduce allmeasurements to a common height of 63.5 mm. (21/2 ins.) a stability correction factoris applied to the measured value such that:

Correctedstability = ( )Measured stability x (Adjustment factor)

The adjustment factor is determined from the specimen volume in accordance withFigure 10.9.5. The stability is expressed in kN (or 1bf).

The flow value is simply the reading on the deformation gauge at the point ofmaximum load, and is expressed in mm. (or 0.01 inch).

A useful factor in the assessment of mix quality is the stability to flow ration which isgiven by :

Stability flowCorrected stability

Flow ratio =

The stability to flow is expressed in kN/mm or lb/(0.01 inch). The average value of thethree specimens should be quoted.

As mentioned previously the Marshall test is often carried out as a mix designprocedure and specimens will be made at various bitumen contents to determinewhich is the most satisfactory (i.e. the optimum binder content).

To determine the optimum binder content graphs of CDM, VIM, VFB, Stability andFlow against binder content are normally plotted as shown in Figure 10.9.6.

The values of some these factors may be specified and the most satisfactory valuesfor the other factors are generally known; it is, therefore, possible to obtain the mostdesirable bitumen content relating to each of these factors from the relevant graph.These values are not likely to be exactly the same, but are generally fairly close. Theoptimum bitumen content may than be determined by taking an average of thesedifferent values.


MAY 2001 Page 10.75


The stability should be reported to the nearest 0.1 kN (20 lbsf) and the flow should bereported to the nearest 0.5 mm. (0.01inch).

The bitumen content of the specimen, the grade of bitumen and the proportions of thevarious aggregate sizes used should be given.

Height of specimen,

mm

Volume of specimen,ml

Stability correctionfactor

62 502 - 503 1.04

504 - 506

507 - 509

510 - 512

1.03

1.02

1.01

63.5 513 - 517 1.00

515 - 520

512 - 523

524 - 526

0.99

0.98

0.97

65 527 - 528 0.96

Figure 10.9.5 Correction factors for stability values with variations in height or volume


MAY 2001 Page 10.76

Figure 10.9.6 (10.9.8) Marshall Test Results

Binder Content(p.h.a.)

Max CDM 6.4Max Stab 6.6VIM - 5% 6.3VFB - 80% 7.1Flow II 6.4Mean 6.6 p.h.a.

Hence optimum bindercontent = 6.6 p.h.a.

2.1

2.2

2.3

Density (CDM)

4.5 5.0 5.5 6.0 6.5 7.0 7.5500

1000

1500

2000

4.5 5.0 5.5 6.0 6.5 7.0 7.5

Binder Content (pha) Binder Content (pha)

Stability (Lbs)

5

7

4.5 5.0 5.5 6.0 6.5 7.0 7.560

70

80

90

4.5 5.0 5.5 6.0 6.5 7.0 7.5

Binder Content (pha) Binder Content (pha)

Voids Filled with Bitumen (V.F.B.)

4

6

8Voids In Mix (V.I.M.)

10

20

4.5 5.0 5.5 6.0 6.5 7.0 7.5

Binder Content (pha)

5

15

25Flow (0.01)

30


MAY 2001 Page 10.77

10.10 Bulk Specific Gravity of Compacted Bituminous Mixtures Test


10.10.1.1 Scope

This test provides a method of measuring the compaction of a compacted bituminousmixture in terms of its bulk specific gravity. The bulk specific gravity may be used incalculating the unit mass of the mixture.

The specimen may be a laboratory moulded bituminous mixture or from bituminouspavements. The mixture may be wearing course, binder course, hot mix or levellingcourse.

10.10.1.2 Apparatus

a) Balance, capable of weighing a sample in air and water and of ample capacityappropriate for the sample weights. The balance should be capable of weighingto an accuracy of at least 0.0001 kg.

b) Water bath, for immersing the specimens in water while suspended under thebalance, equipped with an overflow outlet for maintaining the water levelconstant.

c) Thermometer, for measuring the temperature of the water in the water bath.d) A steel wire brush.e) Volumeter, calibrated to 1200 ml or appropriate capacity depending on the size of

the test sample.

10.10.1.3 Preparation of specimens

a) Clean the specimen well to remove any dust particles adhering to it, remove anygrease, oil and other matter from it.

b) Using a wire brush, scub the surface of the specimen to remove any particles thatmay come loose during the immersion of the specimen in water.

c) The temperature of the specimen should be in close proximity to roomtemperature.

d) Dry the specimen to a constant mass.e) If the specimen is a core consisting of more than one layer of the same material

the core may be split into its different layers tested separately and averaging theresult.

f) If the specimen is a core consisting of more than one layer of different materialsthe core must be split into its different layers and each layer must be testedseparately.

10.10.2 Bulk specific gravity of compacted bituminous mixtures test

10.10.2.1 Methods

a) Method A

Dry the specimen to constant mass and record its dry mass A. Immerse thespecimen in water at 25° C for 4 min plus or minus 1 min and record the mass,C of the specimen in water. Remove the specimen from the water, quickly dampdry the specimen by blotting with a damp cloth and determine the surface - drymass, B of the specimen.

Note. Constant mass shall be defined as the mass at which further drying at52°C plus or minus 3° C does not alter the mass by more than 0.05%.


MAY 2001 Page 10.78

Recently moulded laboratory specimens which have not beenexposed to moisture do not require drying. Samples saturated withwater should be dried overnight at the specified temperature and thenweighed at 2 hourly drying intervals.

Note. The sequence of the testing operations may be changed to expeditethe test result. For example, first the immersed mass, C can be taken,then the surface-dry mass, B and finally the dry mass, A.

a.1) Calculations : Calculate the bulk specific gravity of the specimen as follows,round and report the value to the nearest 0.001 kg :

Bulk Sp. Gr. = A / ( B - C )

WhereA = dry mass of specimen in kg. in air.B = mass of surface - dry specimen in kg. in airC = Mass of specimen in water in kg.

Calculate the percent water absorbed by the specimen (on volume basis) asfollows :

Percent water absorbed = ( B - A ) / ( B - C )

b) Method B

Dry the specimen to constant mass and record the dry mass. Immerse in waterbath and let saturate for at least 10 min. At the end of the 10 Minute period filla calibrated volumeter with distilled water at 25° C plus or minus 1°C. Removethe immersed and saturated specimen from the water bath, quickly damp drythe specimen surface by blotting with a damp cloth and quickly as possibleweigh the specimen.

Place the weighed saturated specimen into volumeter and let stand for at least60 seconds. Bring the temperature of the water in the volumeter to 25° C plusor minus 1° C, and cover the volumeter ensuring that water escapes throughthe overflow. Wipe the volumeter dry and weigh the volumeter and contents.

b.1) Calculations

Calculate the bulk specific gravity of the specimen as follows, round and reportthe value to the nearest 0.001 kg.

Bulk Sp. Gr. = A / ( B + D - E )

WhereA = dry mass of specimen in kg. in air.B = mass of surface-dry specimen in kg. in airD = mass of volumeter filled with at 25° C plus or minus

1° C water in kg.E = mass of volumeter filled with the specimen and water at 25°C

plus or minus 1° C, in kg.


MAY 2001 Page 10.79

Calculate the percent water absorbed by the specimen (on volume basis) asfollows :

Percent water absorbed = ( B - A ) / ( B + D - E )

c) Method C (Rapid test)

This method can be used for specimens which are not required to be saved orwhich may contain large amounts of water. Specimens obtained from coring orsawing do contain water and should be tested using this method.

The testing procedure shall be as given in method A or method B except thesequence of operations. The dry mass of the specimen is determined last, asfollows :

After the original mass in air, mass in water, and surface - dry mass have beendetermined, place the sample in a large flat tray and place the tray in an ovenat 110° C plus minus 5° C for only long enough, for the asphalt aggregateportion of the sample to be able to be separated into fractions not greater thanabout 6.4 mm. Place the separated specimen into the oven again and dry toconstant mass. Cool the specimen to room temperature and weight the mass A.

c.1) Calculations

The calculations of method A or method B are valid for this method, Forms10.10.1 and 10.10.2.

10.10.2.2 Expression of result

Duplicate results from the same operator should be accepted if the two results do notdiffer by more than 0.02.

10.10.2.3 Report

The test report should include at least the following information :

a) Name of testing agencyb) Client namec) Contractor named) Contract namee) Location sample was takenf) Type of sampleg) Number of layers in sampleh) Sample identification numberi) Method of testing usedj) Date sample takenk) Date sample testedl) Date sample reportedm) Name of testern) Signature of tester


MAY 2001 Page 10.80


MAY 2001 Page 10.81


MAY 2001 Page 10.82

10.11 Maximum Theoretical Specific Gravity of Paving


10.11.1.1. Introduction

10.11.1.2 Scope

This test provides methods for calculating the specific gravity of bituminous pavingmixtures when the mixtures contains no air voids.

10.11.1.3 Apparatus

a) Balance of ample capacity to provide readings for the appropriate samples ofuncompacted bituminous materials and to provide sensitivity to 1.0g. For the bowldetermination method the balance should be equipped with a suitable suspensionapparatus and holder to permit weighing the sample while suspended from thecentre of the scale pan of the balance.

b) Container which shall be either a glass, metal, or plastic bowl or a volumetric flaskhaving capacity of at least 1000ml. The container shall be sufficiently strong towithstand a partial vacuum and shall have covers as follows: (i) for use with abowl, a cover fitted with a rubber gasket and a hose connection, (ii) for use withthe flask, a rubber stopper with a hose connection. The hose opening shall becovered with a small piece of fine wire mesh to minimise the possibility of loss offine material, The top surfaces of all containers shall be smooth and adequatelyplane.

c) Thermometer which should be calibrated, of the liquid-in-glass total immersiontype, of suitable range with graduations at least every 0.10C.

d) Vacuum pump or water aspirator, for evacuating air from the container.e) Water bath, for use with the bowl, which shall be suitable for immersing in water

while suspended under the balance and equipped with an overflow outlet formaintaining a constant water level. For use with the flask, a constant temperaturewater bath.

10.11.1.4 Calibrations

Calibrate the volumetric flask by accurately determining the mass of water 250Crequired to fill it.

10.11.1.5 Sample Preparation

a) Samples should obtained as per Chapter 2.b) The size of the test sample shall be governed by the nominal maximum aggregate

size of the mixture and conform to the requirements of Table 10.11.1. Samplelarger than the capacity of the container may be divided into smaller increments,tested and the results appropriately combined.


MAY 2001 Page 10.83

Table 10.11.1

Nominal maximum sizeof aggregate mm

Minimum mass of Sample

25.0 2.519.0 2.012.5 1.59.5 1.04.75 0.5

10.11.2 Maximum theoretical specific gravity of paving mixtures; test

10.11.2.1 Procedure

a) Separate the particles of the sample, taking care not to fracture the mineralparticles, so that the particles of the fine aggregate portion are not larger than6.5 mm. If the mixture is not sufficiently soft to be separated manually, place it inflat pan and warm it in an oven only until it can be so handled.

b) Cool the sample to room temperature, place it in the flask or bowl, and determineits mass to the nearest 1.0g.

c) After the mass determination, add sufficient water at approximately 250C to coverthe sample.

d) Remove entrapped air by subjecting the contents to a partial vacuum of 4.0 kPa(30 mm Hg) pressure for 15 minutes plus or minus 2 minutes. Agitate thecontainer and contents either continuously by mechanical device or manually byvigorous shaking in a rotary motion at intervals of about 2 minutes.

e) Bowl determination. Suspend the bowl and contents in water at 250C plus orminus 10C and determine its mass after 10 plus or minus 1 min. immersion.

f) Flask determination. Fill the flask with water and bring the contents to atemperature of 250C plus or minus 10C in a constant-temperature water bath.Determine the mass of flask (filled) and contents 10 plus or minus 1 minutes aftercompleting step a) of 10.11.2.1.

Note. In the absence of a constant-temperature water bath, determine thetemperature of the water within the flask. Determine the mass of flask(filled) and contents 10 plus or minus 1 minutes after completing step a of10.11.2.1. Make the appropriate density correction to 250C using thecurves in Figures 10.11.1 and 10.11.2.

10.11.2.2 Calculation

Calculate the maximum theoretical specific gravity of the sample as follows:

1) Bowl determination.

Specific Gravity = A / ( A – C ) (1)

Where,A is the mass of dry sample in air in grammes.C is the mass of sample in water in grammes.

2) Flask determination


MAY 2001 Page 10.84

Specific Gravity = A / ( A + D - E ) (2)

Where,A is the mass of dry sample in air in grammes.D is the mass of flask filled with water at 250C in grammes.E is the mass of flask filled with water and sample at 250C in grammes.

10.11.2.3 Equation for Figure 10.11.1 curves

Sp. Gr. = A / (( A+F) – (G+H) x dw / 0.9970 (3)

Where,A = mass of dry sample in air in grammesF = mass of pycnometer filled with water at test temperature in grammesG = mass of pycnometer filled with water and sample at test temperature in

grammes.H = correction for thermal expansion of bitumen in grammes. See Figure

10.11.2.dw = density of water at test temperature. Curve D in Figure 10.11.1, Mg/m3

0.9970 = density of water at 250C, Mg/m3

The ratio (dw / 0.09970) is curve R in Figure 10.11.1.

10.11.2.4 Reporting

The test is acceptable if two consecutive results from the same operator in the samelaboratory do not differ by more than 10Kg/m3 or, if two results from different operatorin a different laboratory do not differ by more than 20 kg/m3.

The report example shown in Form 10.11.1 should include at least the followinginformation:

a) Name of testing agencyb) Name of clientc) Name of contractd) Sample identificatione) Sample type and numberf) Date sample was takeng) Date sample was testedh) Name of person who tested the samplei) Date the result was reportedj) Any other comments.


MAY 2001 Page 10.85

Figure 10.11.1 Curves D and R for Eq.3

Figure 10.11.2 Correction Curves for Thermal Expansion of Bitumen H, in Eq..3


MAY 2001 Page 10.86

Chapter 11 Standard Test ProceduresSteel Reinforcement Tests

MAY 2001 Page 11.1

CHAPTER 11

STEEL REINFORCEMENT TESTS

11.1 General Requirements

11.1.1 Introduction

Reinforcing bars are used in reinforced concrete and are one of the main parts ofR.C.C. structure. For that reason, quality of plain and deformed bars should bechecked specially for yield, ultimate strength and elongation (ductility). The mostimportant test is the tensile strength test. But sometimes bending test is also done.Tension test provides information on the strength and ductility of materials underuniaxial tensile stresses. This information may be useful in comparisons of materials,alloy development, quality control and design under certain circumstances. Bend test isalso a method for evaluating ductility but it cannot be considered as a quantitativemeans of predicting service performance in bending operations. The severity of thebend test is primarily a function of the angle of bend and inside diameter to which thespecimen is bent and of the cross-section of the specimen.

Plain round, hot rolled, mild steel bars are commonly used as reinforcement in concretein Bangladesh. Reinforcing bars with various surface protrusions are also used.Reinforcing steel used in road structures must have yield and ultimate tensile strengthas specified later.

This chapter covers the dimensions of reinforcing bars, tensile strength and bendingprocedure.

11.1.2 Terminology

11.1.2.1 Definitions

(1) Deformed bar. Steel bar with protrusions; a bar that is intended for use asreinforcement in reinforced concrete construction.

(2) Discontinuous yielding. A hesitation or fluctuation of force observed at the onsetof plastic deformation due to localized yielding. (The stress-strain curve need notappear to be discontinuous.)

(3) Lower yield strength. The minimum stress recorded during discontinuousyielding, ignoring transient effects.

(4) Upper yield strength. The first stress maximum (stress at first zero slope)associated with discontinuous yielding.

(5) Yield point elongation. The strain (expressed in percent) separating the stress-strain curves first point of zero slope from the point of transition from discontinuousyielding to uniform strain hardening.

11.1.3 Dimensions of reinforcing bar

The steel bars should be made straight and ends should be plain surface perpendicularto the longitudinal axis before measuring weight and length. Length should be sufficient(provided it does not exceed the capacity of balance) for rods of large diameter forbetter result. The length of the properly prepared sample to be measured in mm. Theweight (W) to be taken in gm. Then the average diameter of the bar can be found as:


MAY 2001 Page 11.2

Average bar diameter (mm) = 12.736 x WL

Actual diameters of many bars available in the market are less than their stateddiameters. Care must therefore be exercised in procuring steel from local markets.Standard diameters and other physical properties of standard plain round bars aregiven in Table 11.1.1.

Table 11.1.1 Dimensions of Standard Reinforcing Bars

NominalDiameter

Actual Diameter Cross SectionalArea

Perimeter Mass / Unit-Length

mm (in) mm (in) mm2 (in2) mm (in) kg/m (1b/ft)6

10

12

16

19

22

25

29

32

(1/4)

(3/8)

(1/2)

(5/8)

(3/4)

(7/8)

(1)

(11/3)

(11/4)

6.350

9.525

12.700

15.875

19.050

22.225

25.400

28.575

32.260

(0.250)

(0.375)

(0.500)

(0.625)

(0.750)

(0.875)

(1.000)

(1.128)

(1.270)

32.26

70.79

129.03

200.00

283.87

387.10

509.68

645.16

819.35

(0.05)

(0.11)

(0.20)

(0.31)

(0.44)

(0.60)

(0.79)

(1.00)

(1.27)

20.07

29.97

39.88

49.78

59.94

69.85

79.76

89.92

101.35

(0.79)

(1.18)

(1.57)

(1.96)

(2.36)

(2.75)

(3.14)

(3.54)

(3.99)

0.248

0.560

0.994

1.552

2.235

3.042

3.973

5.059

6.403

(0.167)

(0.376)

(0.668)

(1.043)

(1.502)

(2.044)

(2.670)

(3.400)

(4.303)

11.1.4 Requirements of deformed bar

Deformed bars are of many sizes. From size no. 10 to size no. 55 in metric units aregiven in Table 11.1.2 and from size no. 3 to size no. 18 in FPS units are given in Table11.1.3.


MAY 2001 Page 11.3

Table 11.1.2 Deformed Bar Designation Numbers, Nominal Masses, NominalDimensions and Deformation Requirements as per ASTM A 615-M(Metric Units)

Nominal Dimension Deformation Requirement, mm

BarDesignatio

n No.

Mass

kg/m

Diameter

mm

Cross-Sectional

Areamm2 Max. Av. Min. Av.

Max. Gap(chord of12.5% ofNominal

Perimeter)1015202530354555

0.7851.5702.3553.9255.4957.85011.77519.625

11.316.019.525.229.935.743.756.4

100200300500700

100015002500

7.911.213.617.620.925.030.639.4

0.450.720.981.261.481.792.202.55

4.46.37.79.9

11.714.017.222.2

Note. • The nominal dimensions of a deformed bar are equivalent to those of aplain round bar having the same mass per meter as the deformed bar.

• Bar designation numbers approximate the number of millimetres of thenominal diameter of the bar.

Table 11.1.3 Deformed Bar Designation Numbers, Nominal Masses, NominalDimensions and Deformation Requirements as per ASTM A 615-M(FPS Units)

Nominal Dimension Deformation Requirement, mm

BarDesignation No.

NominalMass

1b/ft

Diameter

in

Cross-Sectional

Areain2 Max.

Av.Min. Av.

Max. Gap (ChordSpacing Height of12.5% of Nominal

Perimeter)

3456789

10111418

0.3760.6681.0431.5022.0442.6703.4004.3035.3137.65013.600

0.3750.5000.6250.7500.8751.0001.1281.2701.4101.6932.257

0.110.200.310.440.600.791.001.271.562.254.00

0.2620.3500.4370.5250.6120.7000.7900.8890.9871.1851.580

0.0150.0200.0280.0380.0440.0500.0560.0640.0710.0850.102

0.1430.1910.2390.2860.3340.3830.4310.4870.54006480864

Note. • The nominal dimensions of a deformed bar are equivalent to those of aplain round bar having the same weight per foot as the deformed bar.

• Bar numbers are based on the number of eighths of an inch included inthe nominal diameter of the bar.

11.1.4.1 Requirements for deformation

(1) Deformations shall be spaced along the bar at substantially uniform distances.The deformations on opposite sides of the bar shall be similar in size and shape.


MAY 2001 Page 11.4

(2) The deformations shall be placed with respect to the axis of the bar so that theincluded angle is not less than 450. Where the line of deformations forms anincluded angle with the axis of the bar of from 450 to 700 inclusive, thedeformations shall alternately reverse in direction on each side, or those on oneside shall be reversed in direction from those on the opposite side. Where the lineof deformation is over 700, a reversal in direction is not required.

(3) The average spacing or distance between deformations on each side of the barshall not exceed seven tenths of the nominal diameter of the bar.

(4) The overall length of deformations shall be such that the gap between the ends ofthe deformations on opposite side of the bar shall not exceed 12.5% of thenominal perimeter of the bar. Where the ends terminate in a longitudinal rib, thewidth of the longitudinal rib shall be considered the gap. Where more than twolongitudinal ribs are involved, the total width of all longitudinal ribs shall notexceed 25% of the nominal perimeter of the bar. Furthermore, the summation ofgaps shall not exceed 25% of the nominal perimeter of the bar. The nominalperimeter of the bar shall be 3.14 times the nominal diameter.

(5) The spacing, height, and gap of deformations shall conform to the requirementsprescribed in Table 11.1.2 and 11.1.3.

11.1.4.2 Measurement of deformations

(1) The average spacing of deformations shall be determined by dividing a measuredlength of the bar specimen by the number of individual deformations andfractional parts of deformations on any one side of the bar specimen. A measuredlength of the bar specimen shall be considered the distance from a point on adeformation to a corresponding point on any other deformation on the same sideof the bar. Spacing measurements shall not be made over a bar area containingbar making symbols involving letters or numbers.

(2) The average height of deformations shall be determined from measurementsmade on not less than two typical deformations. Determinations shall be basedon three measurements per deformation, one at the centre of the overall lengthand the other two at the quarter points of the overall length.

(3) Insufficient height, insufficient circumferential coverage, or excessive spacing ofdeformations shall not constitute cause for rejection unless it has been clearlyestablished by determinations on each lot tested that typical deformation height,gap or spacing do not conform to the minimum requirements prescribed inSection 11.1.4.1. No rejection may be made on the basis of measurements iffewer than ten adjacent deformations on each side of the bar are measured.

Note. A lot is defined as all the bars of one bar number and pattern and patternof deformation contained in an individual shipping release or shippingorder.

11.1.5 Tensile requirements

(1) The material, as represented by the test specimens, shall conform to therequirements for tensile properties prescribed in Table 11.1.4 (metric) and inTable 11.1.5 (FPS).

(2) The percentage of elongation shall be as prescribed in Table 11.1.4


MAY 2001 Page 11.5

Table 11.1.4 Tensile requirements as per ASTM A 615-M (Metric Units)

Parameter RequirementsGrade 300 Grade 400

Tensile Strength (minimum), Mpa

Yield Strength (minimum), Mpa

Elongation (minimum) in 200 mmgauge, %, for the bar size of:

#10#15#20#25#30#35#45#55

500

300

1112------

600

400

998777--

Note. Grade 300 bars are furnished only in sizes 10 through 20.

Table 11.1.5 Tensile requirements as per ASTM A 615-M (FPS Units)

Parameter RequirementsGrade 40 Grade 60 Grade 75

Tensile Strength (minimum), psi

Yield Strength (minimum), psi

Elongation (minimum) in 8 inchgauge, %, for the bar size of:

#3#4, 5, 6#7, 8

#9, 10#11, 14, 18

70,000

40,000

1112---

90,000

60,000

99877

100,000

75,000

----6

Note. Grade 40 bars are furnished only in sizes 3 through 6.Grade 75 bars are furnished only in sizes 11, 14 and 18.

11.1.6 Bending requirements

The bend-test specimen shall withstand being bent around a pin without cracking onthe outside of the bent portion. The requirements for degree of bending and sizes ofpins are prescribed in Table 11.1.6. (metric units) and in Table 11.1.7 (FPS units).

Table 11.1.6 Bend test requirements as per ASTM A 615-M (Metric Units)

Bar Size Pin Diameter for Bend TestGrade 300 Grade 400

#10, 15#20#25

#30, 35#45, 55 (900)

3.5d5d---

3.5d5d5d7d9d


MAY 2001 Page 11.6

Table 11.1.7 Bend test requirements as per ASTM A 615-M (FPS Units)

Bar Size Pin Diameter for Bend TestGrade 40 Grade 60 Grade 75

#3, 4, 5#6

#7, 8#9, 10

#11#14, 18 (900)

3.5d5d----

3.5d5d5d7d7d9d

----

7d9d

Note. Test bends 1800 unless noted otherwise.‘d’ is the nominal diameter of the specimen.

11.1.7 Permissible variation in mass

The permissible variation shall not exceed 6% under nominal mass. Reinforcing barsare evaluated on the basis of nominal mass. In no case shall the overpass of any barbe the cause for rejection.

11.1.8 Finish

(1) The bars shall be free of detrimental surface imperfections.(2) Rust, seams, surface irregularities, or mill scale shall not be cause for rejection,

provided the mass, dimensions, cross-sectional area, and tensile properties of ahand wire brushed test specimen are not less than the requirements of thisspecification.

(3) Surface imperfections other than those specified above shall be considereddetrimental when specimens containing such imperfections fail to conform toeither tensile or bending requirements.

11.1.9 Test specimens

(a) Tension test

1) For round reinforcing bars, full size test specimens should be used. The totallength of the specimen shall be at least equal to the gauge length plus thelength required for the full use of the grips employed. The test specimen mustbe straight.

2) Orientation of test specimen for longitudinal test : The lengthwise axis of thespecimen should be parallel to the direction of the greatest extension of thesteel during rolling or forging. The stress applied to a longitudinal tension testspecimen is in the direction of greatest extension. The unit stressdetermination shall be based on the nominal bar cross-sectional area.

(b) Bend test

The bend test specimen shall be the full section of the bar as rolled.

11.1.10 Number of tests

(a) For bar size no. 10 to 35, inclusive, one tension test and one bend test shall bemade of the largest size rolled from each batch. If however, material from onebatch differs by three or more designation numbers, one tension and one bendtest shall be made from both the highest and lowest designation number of thedeformed bars rolled.

(b) For bar sizes nos. 45 and 55, one tension test and one bend test shall be madeof each size rolled from each batch.


MAY 2001 Page 11.7

11.1.11 Retest

1) If any tensile property of any tension test specimen is less than that specified,and any part of the fracture is outside the middle third of the gage length asindicated by scribe scratches marked on the specimen before testing, a retestshall be allowed.

2) If the results of an original tension specimen fail to meet the minimumrequirements and are within 14 MPa of the required tensile strength, within 7 MPaof the required yield point, or within two percentage units of the requiredelongation, a retest shall be permitted on two random specimens for each originaltension specimen failure from the lot. If all results of these retest specimens meetthe specified requirements, the lot shall be accepted.

3) If a bend test fails for reasons other than mechanical reasons or flaws in thespecimen as described in 11.1.11(4) and 11.1.11(5) below, a retest shall bepermitted on two random specimens from the same lot. If the results of both testspecimens meet the specified requirements, the lot shall be accepted. The retestshall be performed on test specimens that are at air temperature, but not lessthan 160C.

4) If any test specimen fails because of mechanical reasons such as failure oftesting equipment or improper specimen preparation, it may be discarded andanother specimen taken.

5) If any test specimen develops flaws, it may be discarded and another specimenof the same size bar from the same batch substituted.


MAY 2001 Page 10.87

10.12 Spray Rate of Bitumen

10.12.1 General

When carrying out surface dressing work using a motorised bitumen distributor, it isnecessary to measure the rate of spread of the bitumen. Too low a rate of spray willresult in chippings not adhering to the surface and too high a rate of spray will leadto ‘fatting up’ of the surface in addition to being uneconomic.

There are two basic types of bitumen distributor, those which supply bitumen at aconstant pressure to the spray bar and those in which the pressure on the spray baris directly coupled to the vehicle’s engine speed.

The former type is generally to the preferred as changes in the bitumen spray ratemay be made simply by adjusting the speed of the vehicle, the higher the speed thelower the rate of spray. With the second type the distributor, it is only possible tochange the rate of spray by engaging a different gear, the spray rate can, therefore,only be adjusted in steps, increasing the speed of the vehicle purely increases thepressure on the bar and the spray rate remains virtually constant.

It should be noted that the rate of spray will be seriously affected by the grade ofbitumen used and the temperature of the bitumen. The specified temperature for theparticular grade of bitumen in use must be strictly maintained. The jets on the spraybar of a distributor are designed to operate at a given viscosity and, hence, hardergrades of bitumen (lower penetrations) must be heated to higher temperatures thansofter grades, or cut-back bitumens. Some bitumen emulsions may be sprayedwithout heating.

The tray test is a simply field test which measures the rate of spray and allowsadjustments in the speed of the vehicle (or the gears) to be made for subsequentruns. The apparatus consists simply of a number of aluminium trays, 200 mm. squareand about 5 mm. deep. A balance is required for weighing the trays.

Although the tray test will measure the rate of spray from a particular part of thespray bar, it cannot account for variations along the bar. It is essential that all the jetsare fully cleaned and operating freely and that the bar is level and at the correctheight.

10.12.2 Test Procedure

The clean dry trays are numbered on the underside and weighted. Usually 5 traysare used for each test and to allow time for cleaning at least 10, and preferably 15trays, are required for quality control work.

The trays are then placed on the prepared road surface in a random pattern in frontof the distributor lorry. The trays should be spaced out along the whole length to besprayed and should cover the full width of the spray bar, excepting the very edgeswhere there is no overlap on the jets. Obviously the trays must not be placed in thepath of the distributor wheels, as the distributor is normally only moving at walkingpace the position of the trays may be adjusted as the lorry approaches.

Immediately after spraying the trays should be carefully lifted from the surface with apair of tongs or pliers and re-weighed.

To enable the trays to be removed, it is usually necessary to spread a few chippingson to the surface of the bitumen to allow the operative to reach the tray without


MAY 2001 Page 10.88

damaging the surface. Immediately after removing the tray, the area of road underthe tray should be covered in not bitumen from a bitumen pouring can.

After use, the trays should be thoroughly cleaned, using a solvent such as diesel,kerosine or petrol, this operation should be carried out in an open space away fromfires or other sources of heat. Any damaged trays should be repaired and checkedfor dimensional accuracy. The trays should be re-weighed each time, before use.

If it is required to measure the rate of spread of chippings laid on the bitumen, thesame procedure may be used but larger sized trays will give more accurate results. Afew chippings should be spread in the bitumen under the trays to prevent thebitumen contaminating the underside of the trays.

10.12.3 Calculation

Weight of bitumen in tray, W = (Weight of tray + Bitumen) – (Weight of tray) grams

Area of tray ,ALenght1000

x breadth1000

sq. meter

Where length and breadth are in millimetres

Spray rate = WA

grams sq metre/ .

WA

Kg sq metreW

blitres

sq metre1000 1000/ .

/.

= A

Where b is density of bitumen at road temperature(Normally taken as 1.0)

Typical results are shown as Form 10.12.1.

10.12.4 Reporting of Results

The individual results should be reported to the nearest 0.1 kg/sq.metre.

The speed of the distributor, the grade of bitumen, the temperature of spraying andthe detailed position of the test should be given.


MAY 2001 Page 10.89

Form 10.12.1


MAY 2001 Page 11.8

11.2 Tension Test of Steel Reinforcing Bar

11.2.1 Scope

The tension test relates to the mechanical testing of steel products subjects amachined or full-section specimen of the material under examination to a measuredload sufficient to cause rupture. These test methods cover the tension testing ofmetallic materials in any form at room temperature, specifically, the methods ofdetermination of yield strength, yield point elongation and tensile strength.

Note. Room temperature shall be considered to be 10 0C to 38 0C unless otherwisespecified.

11.2.2 Apparatus

a) Testing machine : Universal compression / tension machine motorised. Capacityminimum 100-kN for compression and 500 kN for tension, 220-240V, 50 Hz, 1phase. Suitable for tension testing of reinforcing base up to 25 mm diameter. Allaccessories for tension testing including universal grip holders to be includedduring procurement of the machine.

b) Gripping devices

General : Various types of gripping devices may be used to transmit themeasured load applied by the testing machine to the test specimens. To ensureaxial tensile stress within the gauge length, the axis of the test specimen shouldcoincide with the centre line of the heads of the testing machine.

Loading : It is the function of the gripping or holding device of the testing machineto transmit the load from the heads of the machine to the specimen under test.The essential requirement is that the load shall be transmitted axially. Thisimplies that the centres of the action of the grips shall be in alignment, in so far aspracticable, with the axis of the specimen at the beginning and during the test,and that bending or twisting be held to a minimum. Gripping of the specimen shallbe restricted to the section outside the gauge length.

Wedge Grips : Testing machines usually are equipped with wedge grips. Thesewedge grips generally furnish a satisfactory means of gripping long specimens ofductile metal. For proper gripping, it is desirable that the entire length of theserrated face of each wedge be in contact with the specimen.

c) Other Apparatus

i) Double Pointed Centre Punch or Scribe Marks: For marking of roundspecimen.

ii) Special Scale : For direct reading of % elongation (for particular gaugelength) special pointed scale may be used. Minimum division of 0.5% issufficient for this purpose.

iii) Extensometer : Extensometer with gauge length equal to or shorter thanthe nominal gauge length of the specimen is used to determine the yieldphenomenon.

iv) Slide calipers.


MAY 2001 Page 11.9

11.2.3 Speed of testing

1) Rate of straining : The allowable limits for rate of straining shall be specified inmeters per meter per second. Some testing machines are equipped with pacingor indicating devices for the measurement and control of rate of straining, but inthe absence of such a device the average rate of straining can be determinedwith a timing device by observing the time required to effect a known increment ofstrain.

2) Rate of stressing : The allowable limits for rate of stressing shall be specified inMPa per second. Many testing machines are equipped with pacing or indicatingdevices for the measurement and control of the rate of stressing, but in theabsence of such a device the average rate of stressing shall be determined with atiming device by observing the time required to apply a known increment ofstress.

Note. Speed of testing can affect test values because of the rate sensitivity ofmaterials and the temperature-time effects.

3) Elapsed time : The allowable limits for the elapsed time from the beginning offorce application (or from some specified stress) to the instant of fracture, to themaximum force, or to some other stated stress, shall be specified in minutes orseconds. The elapsed time can be determined with timing device.

4) When determining yield properties : Unless otherwise specified, any convenientspeed of testing may be used up to one half the specified yield strength or yieldpoint, or up to one quarter the specified tensile or ultimate strength, whichever issmaller. The speed above this point shall be within the limits specified. If differentspeed limitations are required for use in determining yield strength, yield point,tensile strength, elongation, and reduction of cross-sectional area they should bestated in the product specifications. In the absence of any specified limitations onspeed of testing the following general rules apply.

a) The speed of testing shall be such that the loads and strains used inobtaining the test results are accurately indicated.

b) During the conduct of the test to determine yield strength or yield point, therate of stress application shall not exceed 12 MPa/sec.

5) When determining tensile strength : After the yield strength point has beendetermined, the speed may be increased to correspond to a maximum strain rateof 0.01 m/m/s. The extensometer and strain rate indicator may be used to set thestrain rate prior to its removal. If the extensometer and strain rate indicator arenot used to set this strain rate, the speed should be set not to exceed 0.01 m/m ofthe length of the reduced section (or distance between the grips for specimensnot having reduced sections) per second.

11.2.4 Gauge length, marking.

The gauge should be five times the diameter (unless otherwise specified). Roundspecimens are gauge marked with a double pointed centre punch or scribe marks. Thegauge points shall be approximately equidistant from the centre of the length of section.


MAY 2001 Page 11.10

Figure 11.1.1 Tension test specimen


a) Measure the diameter of the specimen by the weight method described in section11.1.3 or by slide calipers.

b) Record extensometer constant and gage length.c) Fix the specimen at the centre of the properly placed grip of the machine.d) Fix the extensometer with the specimen.e) After completion of all arrangements as per requirement (described earlier) and

setting the speed of machine, etc. switch the machine on. Load is increasedgradually until the specimen fails by tensile force.

Note. If any test specimen fails because of mechanical reasons such as failureof testing equipment or improper specimen preparation, it may bediscarded and another specimen taken.

f) Then determine the yield and ultimate strength and elongation etc. Methods ofdetermination of these tensile properties are described in section 11.2.6.

11.2.6 Determination of tensile properties

11.2.6.1 Yield Point : Yield point is the first stress in a material, less than the maximumobtainable stress, at which an increase in strain occurs without an increase in stress asshown in Figure 11.2.2. Yield point is intended for application only for materials thatmay exhibit the unique characteristic of showing an increase in strain without anincrease in stress. For this type of material, the stress-strain diagram is characterisedby a sharp knee or discontinuity. Yield point can be determined as described below.

a) ‘Drop of the Beam’ or ‘Halt of the Pointer Method (method commonly used):

In this method apply an increasing load to the specimen at a uniform rate. Whena lever and poise machine is used, keep the beam in balance by running out thepoise at approximately steady rate. When the yield point of the material isreached, the increase of the load will stop. However, run the poise a trifle beyondthe balance position, and the beam of the machine will drop for a brief but atappreciable interval of time. When a machine equipped with a load-indicating dial

W

G

R

L

AB B

C

L = Overall lengthA = Length of reduced sectionB = Length of grip sectionC = Dia of grip sectionW = Dia of reduced sectionG = Gauge lengthR = Radius of fillet


MAY 2001 Page 11.11

is used, there is a halt or hesitation of the load-indicating pointer corresponding tothe drop of the beam. Note the load at the “drop of the beam” or the “half of thepointer” and record the corresponding stress as the yield point.

b) Autographic Diagram Method (alternative to 11.2.6.1(a) if such device isavailable):

When a sharp-kneed stress-strain diagram is obtained by an autographicrecording device, take the stress corresponding to the top of the knee, or thestress at which the curve drops as the yield point.

11.2.6.2 Yield Strength : Yield strength is the stress at which a material exhibits a specifiedlimiting deviation from the proportionality of stress to strain. This is shown in Figure11.2.2. In a simplified way the stress corresponding to the yield-point may be taken asthe ‘Yield-Strength’. In the ‘Halt of the Pointer’ method or when the stress-stressdiagram is not available, the ‘Yield-Strength’ is calculated by dividing the load at yield-point by the original cross-sectional area.

11.2.6.3 Tensile/Ultimate Strength : The stress corresponding to the maximum point of thestress-train diagram is the ‘Tensile Strength’ or ‘Ultimate Strength’. This is shown inFigure 11.2.2. When the stress-strain diagram is not available; calculate the ‘TensileStrength’ or ‘Ultimate Strength’ by dividing the maximum load the specimen sustainsduring a tension test by the original cross-sectional area of the specimen.

Figure 11.2.2 Yield and Ultimate Strength in the Stress-Strain Diagram in an AutographicRecording Device

11.2.6.4 Elongation

a) Fit the ends of the fractured specimen carefully and measure the distancebetween the gauge marks to nearest 0.25 mm (0.01 in.) for gauge lengths of 50mm and under, and to the nearest 0.5 percent of the gage length for lengths over50 mm. A percentage scale reading to 0.5 percent of the gauge length may beused. The elongation is the increase in length of the gauge length, expressed asa percentage of the original gage length. In reporting elongation values, give boththe percentage increase and the original gauge length.

b) If any part of the fracture takes place outside of the middle half of the gagelength, the elongation value obtained may not be representative of the material. If

TENSILE / ULTIMATESTRENGTH

YIELD-STRENGTH(In a simplified way)

Stre

ss

Strain

Yield-point


MAY 2001 Page 11.12

the elongation so measured meets the minimum requirements specified, nofurther testing is indicated, but if the elongation is less than the minimumrequirements, discard the test and retest.

11.2.7 Rounding of test data

In the absence of a specified procedure for rounding the test data, it is recommendedto use the Table 11.2.1 for rounding the test result.

Table 11.2.1 Recommended Values for Rounding Test Data

Parameter Range Rounded Vale0 to <500 MPa 1 MPa

Yield/Ultimate Strength500 to <1000 MPa 5 MPa

≥ 1000 MPa 10 MPa

Elongation 0 to <10% 0.5 %

≥ 10 % 1%

Note. Round test data to the nearest integral multiple of the values in this table. Ifthe data value is exactly midway between two rounded values, round to thehigher value.

11.2.8 Replacement of specimens

A test specimen may be discarded and a replacement specimen selected from thesame lot of material in the following cases:

a) the original specimen had a poor surfaceb) the original specimen had the wrong dimensionsc) the test procedure was incorrectd) the fracture was outside the gage lengthe) for elongation determinations, the fracture was outside the middle half of the gage

length, orf) there was a malfunction of the testing equipment


11.2.9 Report

Test information to be reported shall include the following when applicable:

1) Material and sample identification2) Yield strength3) Yield point4) Tensile strength5) Elongation (report both the original gage length and the percentage increase).


MAY 2001 Page 11.13


MAY 2001 Page 11.14

11.3 Bend Test of Reinforcing Bar

11.3.1 Scope. This test method is used for evaluating ductility. Unless otherwise specified itshall be permissible to age bend test specimen. The time-temperature cycle employedmust be such that the effects of previous processing will not be materially changed. Itmay be accomplished by aging at room temperature 24 to 48h or in shorter time atmoderately elevated temperatures by boiling in water, heating in oil or in an oven.

11.3.2 Test method. Bend the test specimen at room temperature to an inside diameter, asdesignated by the applicable product specifications, to the extent specified with majorcracking on the outside of the bent portion.

11.3.2.1 (1) Procedure. The bend test shall be made on specimens of sufficient length toensure free bending and with apparatus which provides:

a) Continuous and uniform application for force throughout the duration of thebending operation.

b) Unrestricted movement of the specimen at points of contact with the apparatusand bending around a pin free to rotate.

c) Close wrapping of the specimen around the pin during the bending operation.

(2) Other acceptable, more severe methods of bend testing, such as placing aspecimen across two pins free to rotate and applying the bending force with afixed pin, may be used. When failures occur under more severe methods, retestshall be permitted under the bend test method prescribed in 11.3.2.1(1) above.

(3) A field bend test may be done which is similar to 11.3.2.1(2) above. This is alsoan acceptable method. The sample is placed between two or three fixed pins insuch a way that it is free to rotate. Then bending force is applied uniformity. If thesample specimen withstands this force without cracking on the outside of the bentportion, then it is considered to be acceptable in respect of bending.

Note. Sometimes in the work site the bending of reinforcement (plain bar) isdone with beating. This should be strictly prohibited.

(4) When re-testing is permitted by the product specification, the following shallapply:

a) Sections of bar containing identifying roll marking shall not be used.b) Bar shall be so placed that longitudinal ribs lie in a plane at right angles to

the plane of bending.

11.3.3 Report

If the bending around the pin could be done without cracking on the outside of the bentportion the result is ‘satisfactory’. If cracking was found on the outside of the bentportion, it would be considered that the rod did not meet the bending requirements andthe result is ‘unsatisfactory’.



MAY 2001 Page 11.15

Form 2.2.1

BANGLADESH ROAD RESEARCH LABORATORY SAMPLE RECORD CARD

Contract :

Sample no.Origin of sample :

Date of sampling

Borehole / Trial pit no. :Depth of sample : From m

To m

Description of soil :

Moisture content container nos. :

Adjacent in-situ test / undisturbed sample :

Special Instructions / Remarks :

Name and Designation of Sampler :

Type of test Position / depth of test Sheet no. Result

Form 2.3.1

SAMPLING CERTIFICATE OF BRICKS

Name of testing Client Contractor's Contract Date of samplingagent name

Manufacturer Consignment Batch number / lot no. Number of bricks in lot.

Sample number Number of Date of manufacture Testes requiredbricks in sample Date delivered

Name and designation of sampler Date tested Signature

Form 2.4.1

SAMPLING CERTIFICATE OF AGGREGATES

Name of testing Client Contractor's Contract Date of samplingagent name

Manufacturer Description of material

Identification number Location material was sampled

Sample number Number of Tests requiredsamples

Name and designation of sampler Date tested Signature

Any other information

Form 2.6.1

CERTIFICATE OF SAMPLING : CEMENT / FRESH CONCRETE

Testing agency Client Contract name

Location in structure Sample number Batch number

Temperature of concrete Ambient temperature Name and designation of sampler

Date of sampling Concrete grade Signature

Tests required :

Any other comments :

Form 3.1.1

BANGLADESH ROAD RESEARCH LABORATORY MOISTURE CONTENTDETERMINATION

Contract : Sample No.

Date of samplingDescription of soil :

Type / origin of sample : Method of drying : Oven / Sand bathDrying temp. 0C

Container No.

Position of sample

Mass of wet soil + container (m2) g

Mass of dry soil + container (m3) g

Mass of moisture (m4 = m2 - m3) g

Mass of container (m1) g

Mass of dry soil (m5 = m3 - m1) g

Moisture content %

Average moisture content %

Date of test :

Contract : Sample No.Date of sample


Type / origin of sample : Method of drying : Oven / Sand bathDrying temp. 0C

Container No.

Position of sample

Mass of wet soil + container (m2) g

Mass of dry soil + container (m3) g

Mass of moisture (m4 = m2 - m3) g

Mass of container (m1) g

Mass of dry soil (m5 = m3 - m1) g

Moisture content %

Average moisture content %

Date of test :Name and Designation

Operator Checked Approved

Name and DesignationOperator Checked Approved

w = mm

x 1004

5

w = mm

x 1004

5

Form 3.2.1

BANGLADESH ROAD RESEARCH LABORATORY ATTERBERG LIMITS TEST(Cone penetrometer method)

Contract

Origin of sample

Description of soil

Date of Test:

Test Plastic Limit Liquid Limit1 2 3 4

Container No.

Mass of cont. + wet soil g

Mass of cont. + dry soil g

Mass of moisture g

Mass of container g

Mass of dry soil g

Moisture content %

Average %

Summary

% of total sample passing

425mm sieve %

Liquid limit (LL) %

Plastic limit (PL) %

Plasticity Index (PI) %

Operator Checked ApprovedRemarks

Name and Designation

Con

e Pe

netra

tion

mm

Moisture Content %

2

14

16

18

20

22

24

2

12

Sample No. ___________

Date of Sample ________

Sample preparation *

as receivedwashed on 425 mm sieveair dried at ................ oCoven dried at ............. oCnot known

* Delete as appropriate

Liquid LimitTest No. 1 2 3 4Final dial gauge mm

reading

Initial dial gauge mm

reading

Average mm

penetration

28

26

24

22

20

18

16

14

12

Form 3.2.1

BANGLADESH ROAD RESEARCH LABORATORY ATTERBERG LIMITS TEST(Casagrande Method)

Contract

Origin of sample

Description of soil

Date of Test:_____________

Test Plastic Limit Liquid Limit

Container No. No. of Blows

Wt. of cont. + wet soil g

Wt. of cont. + dry soil g

Wt. of moisture g

Wt. of container g

Wt. of dry soil g

Moisture content %

Average %

Summary

% of total sample passing

425mm Sieve %

Liquid Limit (LL) %

Plastic Limit (PL) %

Plasticity Index (PI) %

Linear Shrinkage (LS) %

If LL or PL cannot be determined

use PI = 2.13 x LS = %

Remarks ______________________________________

______________________________________

______________________________________

Operator Checked Approved


10 15 20 25 30 35 40 45 50

Moi

stur

e C

onte

nt %

Number of Blows

Sample No._____________

Date of sample _________

Sample preparation *

as receivedwashed on 425 mm sieve air dried at _______ 0C oven dried at _______ oC not known

* Delete as appropriate

Form 3.3.1

BANGLADESH ROAD RESEARCH LABORATORY PARTICLE SIZE DISTRIBUTIONSTANDARD WET SIEVING METHOD


Origin of sample : Date of Sample


Initial dry mass g

SIEVE SIZEactual

75 mm63 mm50 mm37.5 mm28 mm20 mm

Passing 20 mmtotal (check with m1)riffledriffled and washed m4

=

14 mm10 mm6.3 mm5 mm

Passing 5 mmtotal (check with m4)riffled

=

3.35 mm2 mm1.18 mm600 µm425 µm300 µm212 µm150 µm75 µm

Passing 75 µm ME

Total (check with m6)Remarks :

Date of test :


m3

correctedMass retained g Percentage

retainedCumulativepercentage

Approved

m1

m5

m6

CheckedOperator

(m1)

m passing

m2

100mm1

Correction factor mm

=2

3


x mm

=2

3

5

6

Form 3.3.2

BANGLADESH ROAD RESEARCH LABORATORY PARTICLE SIZE DISTRIBUTIONDRY SIEVING METHOD




Initial dry mass g

SIEVE SIZEactual

75 mm63 mm50 mm37.5 mm28 mm20 mm


=

14 mm10 mm6.3 mm5 mm


=

3.35 mm2 mm1.18 mm600 µm425 µm300 µm212 µm150 µm75 µm

Passing 75 µm ME

Total (check with m5)Remarks :

Date of test :

m1

m4

m5

CheckedOperator

(m1)

m passing

m2


m3

correctedMass retained g Percentage

retainedCumulativepercentage

Approved

100mm1


=2

3


x mm

=2

3

4

5

Form 3.3.3

BANGLADESH ROAD RESEARCH LABORATORY PARTICLE SIZE DISTRIBUTION CHART

Contract Job ref. no Sample No.



200 150 100 72 52 36 25 18 14 10 7 3/16" 1/4" 3/8" 1/2" 3/4" 1" 11/2" 2" 21/2" 3" 4"

75 105 150 210 300 425 600 850 1.70 2.36 3.15 4.75 6.30 9.50 12.50 19.00 25.00 37.50 50.00 63.00 75.00 100.00 MILLIMETRES

100 0

90 10

80 20

70 30

60 40

50 50

40 60

30 70

20 80

10 90

0 100

Remarks : Operator Checked Approved

MEDIUM COARSECOBBLES


SAND GRAVELFINE MEDIUM COARSE FINE

PE

RC

EN

TA

GE

PA

SS

ING

PE

RC

EN

TA

GE

RE

TA

INE

D

BS SIEVE NUMBERS APERTURE SIZE IN INCHES

0.06 0.2 0.6 2 6 20 60 100 MM

1.18

1/8"

Form 3.5.1

BANGLADESH ROAD RESEARCH LABORATORY SOILS DESCRIPTIONCOARSE SOILS

Contact : Sample No.


Date of Test :

1 MOISTURE Section 3.5.4.2(1)

CONDITION Moist Very moist Wet

2 CONSISTENCY Table 3.5.1

Table 3.5.2

3 COLOUR Section 3.5.4.2(3)

4 STRUCTURE Table 3.5.6

Table 3.5.7

5 SOIL TYPE Table 3.5.12

Table 3.5.14

Table 3.5.15

Figure 3.5.1

Table 3.5.11

6 ORIGIN Section 3.5.4.2(6)

Remarks :

FULL

DESCRIPTION

Note : * Circle as appropriate Name and Designation of Operator

Component STP Reference

Slightly moistDry

Description *

Sl. Cemented

Very loose Loose

Medium dense Dense

Very dense

Sand

Cobbles

Gravel

Boulders

Form 3.5.2

BANGLADESH ROAD RESEARCH LABORATORY SOILS DESCRIPTIONFINE SOILS

Contact : Sample No.


Date of Test :

1 MOISTURE Section 3.5.4.2(1)

CONDITION Moist Very moist Wet

2 CONSISTENCY Table 3.5.3

Table 3.5.4

Table 3.5.5

3 COLOUR Section 3.5.4.2(3)

4 STRUCTURE Table 3.5.7

Table 3.5.8

Table 3.5.9

Table 3.5.10

5 SOIL TYPE Table 3.5.13

Table 3.5.11

6 ORIGIN Section 3.5.4.2(6)

Remarks :

FULL

DESCRIPTION

Note : * Circle as appropriate Name and Designation of OperatorOperator

Very soft Soft

Firm Stiff

Very stiff / hard

SILT CLAY PEAT

Firm Spongy Plastic

Component STP Reference

Slightly moistDry

Description *

Standard Test Procedure RHD.bd

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