Mord specifications for low volume roads

MORD Specifications for Low Volume Roads

Presentation outline• Pavements and requirements• Road Construction Materials and tests • Embankment Requirements• Subgrade Requirements• Granular Sub Bases, Bases &

Surfacing Requirements• Bituminous Surfacing Courses

Requirements

Pavement• A pavement is a man-made structure whose

primary function is to spread the load of a vehicle sufficiently that the underlying soil can support it without excessive deformation.

Types and Choice of Pavements

Load Distribution

Requirements of Pavements Structural Requirements

Traffic loads Load repetition Climatic variables (rainfall &

temperature) Environmental factors

Riding comfort Economic operation Safe operation

Functional Requirements

Road Construction Materials

soil

Aggregates, and

Bituminous Materials

Tests on soils

Tests for Soil with IS codesType of test Test MethodWater Content IS 2720-2 (1973)

Free Swell Index Of Soil IS 2720-40 (1977)

Plastic Limit Of Soil IS 2720-5 (1985)

Liquid Limit Of Soil IS 2720-5 (1985)

Particle Size Distribution Of Soil IS 2720-4 (1985)

The Specific Gravity Of Soil IS 2720-3-1 (1980)

The In-Situ Dry Density Of Soil By Sand Replacement Method IS 2720-28 (1974)

The In-Situ Dry Density Of Soil By Core Cutter Method IS 2720-29 (1975)

The Maximum Dry Density And The Optimum Moisture Content Of Soil IS 2720-7 (1980)

DRY/WET SIEVE ANALYSIS

Sieve Shaker

LIQUID LIMIT TEST

Liquid Limit Device with Accessories

Compaction test

Compaction Mould and Rammers

CBR TEST

FIELD DENSITY BY SAND REPLACEMENT METHOD

Suitable for coarse grained compacted soils

FIELD DENSITY BY CORE-CUTTER METHOD

Suitable for fine grained soils

Embankment ConstructionSuitable Material

1. Soil, moorum, gravel, a mixture of these or other

material approved by the Engineer.

2. It shall be free from logs, stumps, roots, rubbish, etc

3. The size of coarse material shall not ordinarily exceed 75

mm when placed in embankment

4. The maximum particle size not more than 2/3 of the

compacted layer thickness.

Minimum Density Requirement For Suitability Of EmbankmentType of Work Max. laboratory dry unit weight

(IS:2720, Part 7)(a)Embankment not subject to

1) flooding height upto 3 m 2) height more than 3 m

Not less than 14.4 kN/m3Not less than 15.2 kN/m3

(b) Embankment subject to flooding

Not less than 15.2 kN/m3

Type of work / Material Relative compaction % of maximum laboratory dry density obtained by standard proctor test as per IS:2720(Part 7)

Embankment Not less than 90% - 95%Expansive Clays 90% - 95%

Unsuitable Materials

• Material from swamps, marshes and bogs

• Peat, log, stump and perishable material; soil classified as OL,

OI, OH or Pt as per IS:1498.

• Materials susceptible to spontaneous combustion

• Clay having liquid limit exceeding 70 and plasticity index

exceeding 45

• Material with salts resulting in leaching action e.g. sodic soils (pH

> 8.5)

• Expansive clay with free swelling index exceeding 50 per cent

Embankment Construction


Unsuitable Materials

• Materials in a frozen condition

• Fill materials with a soluble sulphate content

exceeding 1.9 gm of sulphate, (expressed as SO3)

per litre.

• Material with a total sulphate content (expressed

as SO3) exceeding 0.5 per cent by mass.


Construction Operations• Setting out• Dewatering• Stripping of topsoil• Preparing foundation• Spreading and Moisture control• Compaction• Repairs of damages caused by rain/spillage of water• Embankment around structures

Subgrade Construction• Soil, moorum, gravel, a mixture of these or any other

approved material.

• Material considered unsuitable for embankment

construction shall not be used for sub-grade.

• The material for subgrade shall be non-expansive in nature

• Where an expansive clay with acceptable “free swelling

index” value is used as a fill material in embankment, the

sub-grade and top 500 mm portion of the embankment just

below the sub-grade shall be non-expansive in nature.

Subgrade Construction• The size of coarse material in the soil shall ordinarily not

exceed 50 mm when placed in the subgrade.

• Any fill material which yields a maximum dry laboratory unit

weight of less than 16.5 kN/m3 determined as per IS:2720

(Part 7) shall be considered unsuitable for use in subgrade.

• Moisture content: +1% or -2% of OMC

• Relative Compaction: 100%

Existing sub grade: • If sub grade CBR is less than 2%, a capping layer of 100mm

thick with 10% CBR soil is to be provided and a CBR of 2% is to be taken for crust design

Subgrade Construction

Construction operations• Setting out• Dewatering• Stripping of Top soil• Spreading • Moisture control• Compaction

Tests on aggregates

Tests for Aggregates with IS codesProperty of Aggregate Type of Test Test Method

Crushing strength Crushing test IS : 2386 (part 4)

Hardness Los Angeles abrasion test IS : 2386 (Part 5)

Toughness Aggregate impact test IS : 2386 (Part 4)

Durability Soundness test IS : 2386 (Part 5)

Shape factors Shape test IS : 2386 (Part 1)

Specific gravity and porosity

Specific gravity test and water absorption test IS : 2386 (Part 3)

Adhesion to bitumen Stripping value of aggregate IS : 6241-1971

Abrasion testing Internal Dia 700mm, and Length

500mm Abrasive Charges of Cast Iron

with 48mm Dia weighing 390 - 445 gms

Quantity of Aggregates 5 – 10 Kg (Depending upon the size of aggregates taken)

Cylinder Speed 30 – 33 Rpm No. of Revolutions 500 – 1000

(Depending upon the size of the aggregates taken)

Passing 1.7mm sieve

AGGREGATE IMPACT TESTING

• Material passing 12.5 mm sieve and retained on 10 mm sieve• 3 Layers in measuring cylinder, each layer given 25 tamping• Transfer entire material at once to test cylindrical cup, 25 tamping• 15 blows with hammer• Material passing 2.36 mm sieve• Impact value = ( W2 / W1 ) * 100

• Surface Courses……… max 30%• Base courses…………..max 40%• Sub-base courses…….max 50%

SHAPE OF AGGREGATES

Angular Particle

Elongated Particle

Flaky particle

Thickness Gauge Length Gauge

CRUSHING TEST

Metal Measures and Tamping Rods

Specific Gravity and Water Absorption test

Buoyancy Balance With Accessory

Granular/Gravel Sub-Base• Natural sand, moorum, gravel, crushed stone, crushed slag,

brick metal and kankar.

• Min CBR 20%

• Wet AIV < 50% layer thickness :100mm compacted with

smooth wheeled roller ,225 mm compacted with vibratory

roller.• Should free from organic or deleterious materials.• The granular subbase materials shall conform to the

gradings.

Granular Sub-base

IS Sieve Size Per cent by Weight Passing the IS Sieve

Grading I Grading II Grading III75 mm 100 - -53 mm - 100 26.5 mm 55-75 50-80 1009.50 mm - - -4.75 mm 10-30 15-35 25-452.36 mm - - -0.425 mm - - -

0.075 mm < 10 < 10 < 10

Table :Grading for granular sub-base materials

On clayey subgrades where otherwise drainage condition are encountered,

the percent passing IS Sieve 0.075 mm shall not exceed 5

Where naturally occurring gravel is specified for sub-base it shall conform to following grading.

Sieve Designation Per cent by Weight Passing the IS Sieve Grading I Grading II

53 mm 100 -

37.5 mm 100 -

26.5 mm 75-95 -

19.0 mm 80-100 -

9.5 mm 40-75 55-80

4.75 mm 30-60 40-60

425 µ 15-30 15-30

0.075 < 15 < 15

The subbase gravel should have minimum CBR of 20 %

Physical Requirements of Materials for Sub-baseClimate Liquid limit Plasticity

IndexRemarks

Rain fall >1000 mm < 35 <10 up to 1 msa

Rain fall < 1000 mm <40 <15 to 1 msa

All areas respect of rain fall

<25 <6 Design Traffic > 1 msaWet AIV Shalll not exceed 50

The subbase shall have a min soaked CBR of 20 at FDDWhen Locally available morrum are used in the GSB it shall be ensured through adeqate test son represenative samples thatall the requirements meets.

Note: Subbase materials req CBR is not met within economical leads than satisfying all the Grading and other requirements 15 CBR is allowed.

Gravel/Soil-aggregate Base And Surface Course

• Natural gravel/ soil-aggregate or blended with suitable

aggregate fractions of stone, gravel, moorum, sand or

combination of these materials depnding of grading

requirement.

• Wet Aggregate Impact Value (IS:5640) shall not exceed 40

and 30 when used in base and 30 when used in surfacing.

• Flakiness Index (IS:2386 Part I) shall not exceed 25

percent when used in base and 20 when used in surfacing.

Gravel/Soil-aggregate Base And Surface Course– In high rainfall areas (annual rainfall of 1500 mm or

above), coastal areas and where local soils are salt infested, if the water absorption value of the coarse aggregate is greater than 2 percent, the Soundness test shall be carried out on the material delivered to the site as per IS:2386 (Part 5).• Loss with Sodium Sulphate, 5 cycles : 12 per cent

maximum• Loss with Magnesium Sulphate, 5 cycles : 18 per

cent maximumFine aggregates material passing 4.75 mm sieve shall consist of natural or crushed sand and fine mineral particles.

Gravel/Soil-Agg Base and Surface Course

IS Sieve desperation Per cent by Weight Passing IS SieveGrading A Grading B Grading C

53 mm 100 37.5 mm 97–100 100 26.5 mm 97–100 10019 mm 67–81 97–1009.5 mm 56–70 67 – 794.75 mm 33–47 39–53 47 – 59425 µ 10–19 12–21 12 – 2175 µ 4.0-15 4.0–15 4.0–15

The Liquid Limit shall not exceed 25 and PI shall not exceed 6.

Grading requirements for soil-aggregate mixtures for sub-base/base

Sieve size % by mass passing IS sieve Grading designation nominal maximum size

80 mm 40 mm 20 mm80 mm 100

40 mm 97-100 100

20 mm 60-80 80-100 100

10 mm 45-65 55-80 80-100

4.75 mm 30-50 40-60 50-75

2.36 mm - 30-50 35-60

600 µm 10-30 15-30 15-35

75 µm 5-15 5-15 5-15

Grading requirement for surface gravel

IS Sieve Designation

Per cent by Weight Passing IS Sieve

26.5 mm 100

19 mm 97–100

4.75 mm 41 – 71

425 µm 12-28

75 µm 9 – 16

Grading and plasticity index requirements for surface course

Gravel/Soil aggregate for surface course should satisfy

Climate Liquid limit Plasticity Index

High Rain fall >1500 mm

35 4-9

Med Rain fall 750-1500mm

40 6-15

Low rain fall<750 mm

55 15-30

IS SievePercent by mass

passing designated sieve nominal

maximum size 10 mm

10 mm 100

4.75 mm

80-100

2.36 mm

50-80

1.18 mm

40-65

600 µm -

300 µm 20-40

75 µm 10-25

Lime treated soil for improved subgrade/ sub base

• The PI of the soil to be treated should generally be higher than 10.

• Lime for lime-soil stabilization work shall be commercial dry lime slaked at site or pre-slaked lime delivered to the site in suitable packing

• The lime shall have purity of not less than 70% by weight of CaO when tested in accordance with IS:1514

• The water to be used for lime stabilization shall be clean and free from injurious substances. Potable water shall be preferred.

Table : Lime Content For Different Type Of Soil

Soil type required Alluvial soils and Moorum (PI : 10-15) 3%

Clays/ BC soil of medium plasticity (PI : 15-30) 3-5%

Highly expansive Clays (PI : over 30 ) 5-6%

Table : Soil Pulverisation Requirements For Lime Stabilization

Is sieve Minimum % by weight passing the IS sieve

26.5 mm 1005.6 mm 80

CEMENT TREATED SOIL SUBBASE AND BASE

• Sand, gravel, laterite, kankar, brick aggregate, crushed rock, slag or flyash or combination of these.

• For use in base course, the Liquid limit and Plasticity Index shall not exceed 45% and 20%.

• Cement: Cement shall comply with the requirements of IS:269, 455 or 1489

• Water: The water for cement stabilization shall be clean and free from injurious substances

• For use in base and sub-base courses, minimum 7-day unconfined compressive strength of 2.76 MPa and 1.7 MPa respectively is required.

CEMENT TREATED SOIL SUBBASE AND BASE

Soil type required Sands/Sandy soils/Soil-Gravels 3-5 %

Silts/Silty clays of low P1 (<15) 4-8%

Clays/black cotton soils 8-15%

Table : Cement content for different type of soil

IS Sieve % by weight passing within the rangeSub- base base

53.0 mm 100

37.5 mm 95-100

19.0 mm 45-100

9.5 mm 35-100

4.75 mm 25-100

600 micron 8-65

300 micron 5-40

75 micron 0-10

Table : Grading limits of material for stabilization with cement

WBM as Sub-Base /Base /Surfacing: Physical Reqs• Water absorption of aggregate > 2 %

Soundness test.• Aggregates like brick bats, kankar, laterite etc.

which get softened in presence of water shall be tested for Aggregate Impact Value under wet conditions in accordance with IS:5640.

Test Sub-base Base SurfacingAI value < 50 < 40 < 30

Flakiness index < 30 < 25 < 20Loss with

Sodium Sulphate < 12% < 12% < 12%Loss with

Magnesium Sulphate

< 18% < 18% < 18%

Grading No. Size Range IS Sieve Designation Per cent by weight passing

1. 90 mm to 45 mm 125 mm 100

90 mm 90-100

63 mm 25-60

45 mm 0-15

22.4 mm 0-5

2. 63 mm to 45 mm 90 mm 100

63 mm 90-100

53 mm 25-75

45 mm 0-15

22.4 mm 0-5

3. 53 mm to 22.4 mm 63 mm 100

53 mm 95-100

45 mm 65-90

22.4 mm 0-10

11.2 mm 0-5

Grading requirements of coarse aggregate for WBM

Grading Classification

Size of Screenings IS Sieve Designation

Per cent by weight passing the IS Sieve

A. 13.2 mm 13.2 mm 100

11.2 mm 95-100

5.6 mm 15-35

180 micron 0-10

B. 11.2 mm 11.2 mm 100

5.6 mm 90-100

180 micron 15-35

Grading for screenings

To fill in voids , generally consist of same materials as the coarse aggregatesEconomic considerations are so warrant predominately non plastic materials (other than rounded river borne) may be used for this purpose and Liquid limit and PI of such materials 20 and 6 respectively. In soft aggregates screening should omitted – likely to crush under rollers.

Wet Mix Macadam Base• Coarse aggregate shall be crushed stone and shall conform to the requirements.• Thickness of the single compacted WMM shall not be < 75 mm.• The Compacted thickness of a single layer of the base course may be up to 200 mm.

Test Test Method Requirements

AIV Value IS:2386 40 % (maximum )

Flakiness Index IS :2386 25 % (maximum )

If water absorption value of coarse aggregate is greater than 2 %, soundness test shall be carried out.

IS Sieve Designation

Maximum percent by weightPassing the sieve

53.00 mm 10045.00 mm 95-10026.50 mm -22.40 mm 60-8011.20 mm 40-604.75 mm 25-402.36 mm 15-30

600 micron 8-2275 micron 0-8

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

Optimum Moisture Content :Optimum Moisture Content shall be determined in accordance with IS:2720 (Part 7)

Table : Grading Requirements

WET MIX MACADAM

The shoulder material should be selected earth with maximum laboratory dry unit weight not less 16.5 kN/m3 . LL and PI not to exceed 25 and

6 respectively

Shoulder

Local material for road construction

• Locally available soils and aggregates

• Transport cost and Economic consideration.

• Construction aspects for the use of these materials are similar to the conventional quality materials.

Sl.No.

State of Occurrence of Material

Manner of Use in the Pavement

Test/Quality Requirements

1.

Kankar, Laterite, Dhandla etc. found

in blocks or large discrete particles.

As WBM without screenings/filler after breaking the material, broadly meeting the required sizes.

Wet Aggregate Impact Value( IS:5640) not to exceed 50, 40 and 30 when used in sub-base, base and surfacing respectively.

2.

Naturally occurring gravels without appreciable amount ofsoil.

Directly as a granular layer for sub-base/base course.

PI should not exceed 6 when used in lower courses. Evaluated for strength by soaked CBR.

3.

Soil-gravel with appreciable amount of soil.

Directly as soil-gravel for sub-bas e /base.

The material should be well-graded and the PI restricted as for Sl. No. 2 above. Evaluated for strength by soaked CBR value.

Lime- flyash stabilised soil sub-baseTable : Chemical Requirements For Flyash As A Pozzolana

Table : Physical Requirements For Flyash As A Pozzolana

•Lime should have a purity of not less than 70% by weight of CaO when tested as per IS:1514.Quick lime which has been pre-slaked at site should be used within 7 days. Slaked lime supplied in airtight bags should not be stored for more than 3 months.• Soil should have a PI between 4 and 20; soil with PI more than 20 may be used provided strength requirements are satisfied.• Water should be free from injurious salts, organic matter and other deleterious matter. Potable water is satisfactory.

Aggregate gradation requirement for Crusher Run

Macadam 53mm max size

IS Sieve, mm

Per cent passing by weight

53 mm max size63 10045 87 - 100

22.4 50 - 855.6 25 – 45

0.710 10 - 250.090 2 - 9

MORD - Crusher Run Macadam 53 mm maximum size

AIV < 30% and FIV < 25% for coarse aggregates. LL < 25% & PI < 6%

400-20, Aggregate gradation requirement for Crusher Run Macadam 37.5mm max size

IS Sieve, mm

Per cent passing by weight

37.5 mm max size63 --45 100

22.4 90 - 1005.6 35 - 55

0.710 10 - 300.090 2 - 9

Crusher Run Macadam 37.5mm maximum size

AIV < 40% and FIV < 25% for coarse aggregates. LL < 25% & PI < 6%

Bitumen tests

Tests for Bitumen with IS codesType of test Test Method

Penetration Test IS: 1203-1978Ductility test IS: 1208-1978

Softening Point test IS: 1205-1978

Specific gravity test IS: 1202-1978

Viscosity test IS: 1206-1978

Flash and Fire Point test IS: 1209-1978

Float Test IS: 1210-1978

Determination of water content IS: 1211-1978

Determination of Loss on heating IS:1212-1978

PENETRATION TEST

PENETROMETER

PENETRATION TEST

DUCTILITY TEST

BRIQUETTE MOULD

DUCTILITY TEST

DUCTILITY TESTING MACHINE

SOFTENING POINT TEST

RING AND BALL APPARATUS

SOFTENING POINT TEST

SPECIFIC GRAVITY TEST

FLASH POINT TEST

VISCOSITY TEST

STRIPPING TEST

Prime Coat Over Granular Base

• Application of single coat low viscosity liquid bituminous materials to non bituminous porous granular surface prepared to spread the bituminous treat mix.

• The primer shall be cationic bitumen emulsion ss1 grade and it shall not be applied to wet surface/ during dust/foggy/rainy and windy.

Type of Quantity per 10sqm

Surface (kg)

WBM /WMM 7-10Stabilized Base 9-12Gravel base 12-15

Table: Type And Quantity Of Cutback Bitumen Primer

Weather and seasonal limitations• Shall not be applied to a wet surface or during a dust storm or when the weather is foggy, rainy or windy or when the temperature in the shade is less than 10 degrees Celsius.• Surface should be free from standing water and shall be just damp.

Type of surface Type of cutback

Rate of spray(kg/m^2)

WMM/WBM MC 30 0.6-0.9Mechanical stabilized soil base, lime stabilized soil, soil cement and lime cement base

MC 70 0.9-1.2

Gravel base , crusher run macadam and crushed rock base

MC 250 1.2-1.5

Tack coat

Type of Surface Quantity of emulsion per sqm area (kg)

Normal Bituminous surfaces 0.20 to 0.25

Dry and hungry bituminous surfaces 0.25 to 0.30

Granular (primed) 0.25 to 0.30

Cement Concrete Pavement 0.30 to 0.35

Binder for Tack Coat:Rapid setting bituminous emulsion Grade RS-1 complying with IS:1887 as specified in Contract. For sites at sub-zero temperature: Cutback Bitumen (Medium Curing Grade) asper IS:217.

Table : Rate of application of Binder

BITUMINOUS MACADAM• A paving bitumen of viscosity graded complying

with IS:73• Crushed rock, crushed gravel or other hard

material retained on the 2.36 mm sieve.• Clean, hard, durable, of cubical shape , free from

dust and soft or friable matter , organic or other deleterious substance.

Lowest daily mean Air temperature, °C

Highest daily mean Air temperature °C

Less than 20 °C 20 to 30 °C More than 30 °C

More than -10 °C VG -10 VG -20 VG -30

-10 °C or lower VG -10 VG -10 VG -20

BITUMINOUS MACADAM

Property Test Specification

Particle shape Flakiness index (IS:2386 Part 1) Max. 25 %

Strength Aggregate Impact Value (IS:2386 Part 4)

Max. 30 %

Durability Soundness (IS:2386 Part 5) Sodium sulphate Max. 12 %

Magnesium sulphate Max. 18 %

Water absorption Water Absorption (IS:2386 Part 3) Max. 2 %

Stripping

Coating and stripping of bitumen

aggregatemixture. (IS:6241)

Minimum retainedcoating 95 %

Physical requirement for aggregates for bituminous macadam

Composition of bituminous MacadamIS Sieve (mm) Cumulative Per cent Passing

by weight of Total Aggregate26.5 10019 90-10013.2 56-884.75 16-362.36 4-190.3 2-100.075 0-5Bitumen content, % by weight of total mixture

3.3-3.5

Bitumen Viscosity Grade VG-10 to VG-30

BITUMINOUS MACADAM

Surface dressingBitumen:• Viscosity grade bitumen (IS 73)• Modified bitumen (IS 15462)• Rapid setting bitumen emulsion (IS 8887)





-10 °C or lower VG -10 VG -10 VG -20

Surface dressing




Max. 30 %




Stripping




Physical requirement for aggregates for Surface dressing

GRADING REQUIREMENTS FOR CHIPS FOR SURFACE DRESSING

IS Sieve Designation (mm)

Cumulative percent by weight of total aggregate passing for the following nominal sizes(mm)19 13 10 6

26.5 100 501 502 50319 85-100 100 504 50513 0-40 85-100 100 5069.5 0-7 0-40 85-100 1006.3 507 0-7 0-35 85-1004.75 508 509 0-10 5103.35 511 512 513 0-352.36 0-2 0-2 0-2 0-100.6 514 515 516 0-20.075 0-1.5 0-1.5 0-1.5 0-1.5Minimum 65% by weight of aggregate

Passing 19mm retained 13.2mm

Passing 13.2 mm retained 9.5 mm

Passing 9.5mm retained 6.3 mm

Passing 6.3 mm retained 3.35 mm

20 mm Open graded Premix Surfacing using Bitumen




Max. 30 %



Water absorption Water Absorption (IS:2386 Part 3)

Max. 1 %

Stripping

Coating and stripping of

bitumen aggregatemixture. (IS:6241)


Table : Physical requirements of stone aggregate

Aggregate Quantity(a) Nominal size 13.2 mm (passing 22.4

mm sieve and retained on 11.2 mm sieve)

0.18 m3

(b) Nominal size 11.2 mm (passing 13.2 mm sieve and retained on 5.6 mm sieve)

0.09 m3

Total 0.27 m3

Binder (a) For 0.18 m3 of 13.2 mm nominal size

stone at 52 kg bitumen per m 3

9.5 kg

(b) For 0.09 m3 of 11.2 mm nominal size stone at 56 kg bitumen per m 3

5.1 kg

Total 14.6 kg

Binder: The binder shall be a viscosity grade bitumen of suitable grade and Satisfying the Requirements of IS:73

Table : Quantities of material required for 10 m^2 area

20 mm cold mixed Open graded Premix carpet• The binder for premix carpet shall be bitumen emulsion of Medium

Setting (MS) grade complying with IS:8887 and having a bitumen content of 65% minimum by weight.

• Physical requirements of stone aggregate same as Open graded Premix Surfacing using Bitumen

Aggregate Quantity(a) Nominal size 13.2 mm (passing

22.4 mm sieve and retained on 11.2 mm sieve)

0.18 m3

(b) Nominal size 11.2 mm (passing 13.2 mm sieve and retained on 5.6 mm sieve)

0.09 m3

Total 0.27 m3

Cationic bitumen Emulsion 20-23 kg

Quantities of material required for 10 m^2 area

Mix Seal Surfacing





-10 °C or lower VG -10 VG -10 VG -20

• The fine aggregates shall be crushed rock, quarry sand, natural gravel/sand or a mixture of both free from organic and deleterious substances

• Binder: The binder shall be a viscosity grade bitumen of suitable grade and Satisfying the Requirements of IS:73

Mix Seal Surfacing




Max. 30 %




Stripping




Table : Physical requirements of stone aggregate

Mix Seal Surfacing

IS sieve designation (mm)

Cumulative percent by weight passing

Type A Type B

13.2 — 100

11.2 100 88 -100

5.6 52 -88 31 -52

2.8 52 -88 5 -25

0.090 0 -5 0 -5

Aggregate Gradation

Seal coat• The seal coat shall be any of the three

types mentioned below:• Type A : Liquid seal coat comprising of

an application of layer of bituminous binder followed by a cover of stone chips.

• Type B : Premixed seal coat comprising of a thin application of fine aggregate premixed with bituminous binder.

• Type C : Premixed seal coat comprising of an application of 6.7 mm size stone chips premixed with bituminous binder.

Type of seal coatPer 10 sq m area

Bitumen in kg Bituminous Emulsion in kg

Type A 9.8 12 to 14Type B 6.8 10 to 12Type C 4.5% by weight of total

mix9 to 11

Table : Quantity And Gradation Requirement Of Aggregate For Seal Coat

Type of seal coat Quantity of aggregate requiredper 10 sqm

area

Gradation requirement

100% passing sieve 100 % retained sieve designation designation

Type A 0.09 cum 11.2 mm 2.36 mmType B 0.06 cum 2.36 mm 180 micronsType C 0.09 cum 9.5 mm 2.36 mm

Table : Quantities of binder required for seal coat

Thank you

Mord specifications for low volume roads

Technology

Transcript of Mord specifications for low volume roads