L13-TVM_Pavement Materials & Desirable Propoties_27 & 28-09-06

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Pavement MaterialsPavement Materials

&&Desirable PropertiesDesirable Properties

ByDr. Tom. V. Mathew

IIT Bombay



TVM Highway materials 2

Overview

Pavement materials

Soil (sub-grade, embankment)

Aggregates(coarse, fine)

Binders (Bitumen, cement)




Soil

Soil is all unindurated mineral material lying above rock

strata including air, water, and organic matter

It is non-homogeneous and porous

Properties greatly influenced by moisture, density and

compaction

A number of pavement failure is attributed to soil failures




Soil

Soil is a very essential highway material

1. Soil sub grade is part of the pavement

structure; the design and behaviour of

pavement depends to a great extent on the subgrade properties

2. Soil is one of the principal materials of

construction in stabilized soil base and sub

base and also in embankment construction

±




Properties of soil

Shape of soil particles (bulky, flaky)

Particle size classification (clay, silt, sand, gravel)

Grain size distribution (sedimentation analysis for <75m)

Porosity and void ratio

Soil density (dry and wet density)




Properties of soil

Moisture-density relationship (Proctor density, OMC)

Chemical properties (Organic matter, minerals, pH)

Soil-water (Capillary water, water table)

Physical properties (Permeability, compressibility, shearresistance)




Properties of soil

Atterberg limits (Index properties)

Liquid Limit (LL): Moisture content at which statechanges from viscous liquid to plastic solid

Plastic Limit (PL): Moisture content at which statechanges from plastic solid to semi solid state

Plasticity Index (PI): Range during which it acts asplastic PI = LL – PL

Liquidity Index LI= (NMC – PL) / PI




Liquid Limit




Plastic limit




Desirable Properties

(soil as a highway material)

Stability: Adequate stability to resist permanentdeformation under loads

Incompressibility: Minimum variation in volumeensures minimum differential expansion andstrength values

Permanency of Strength: Should retain desiredsub-grade support i.e. resistance to weathering




Continue….

Minimum changes in volume and stability

under adverse conditions of weather and

ground water

Good drainage: Essential to avoid excessive

moisture retention and to reduce thepotential frost action

Ease of compaction: Ensures higher drydensity and strength under particular typeand amount of compaction




Bitumen is a petroleum product obtained by the

distillation of petroleum crude

Bitumen is a hydrocarbon material of either natural or

pyrogenous origin, found in gaseous, liquid,

semisolid or solid form

Highway construction: hydrocarbon material which

are cementitious in character

Bitumen




Bitumen

1. Natural product (lake asphalt, rock asphalt)

2. Fractional distillation of petroleum

a. Asphalt cement (Penetration grade)

b. Oxidised asphalt (softening point grade)

c. Liquid asphalt

3. Tar: destructive distillation of coal




1. Normal Bitumen

Production

The portion of bituminous material present in petroleummay widely differ depending on the source

Almost all the crude petroleum's contain considerable

amounts of water along with crude oil

Hence the petroleum should be dehydrated before thedistillation




Petroleum distillation Flow Chart




Petroleum distillation




Types of Distillation Processes

Fractional distillation

In the fractional distillation the various volatileconstituents are separated at successively highertemperatures without substantial chemical change

The fractions obtained yield gasoline, naphtha,

kerosene and lubricating oil and the residue would bepetroleum bitumen

Destructive distillationThe material undergoes chemical changes under theapplication of extreme heat and pressure




Steam distillation

1. Steam distillation is employed to produce

steam refined petroleum bitumen without

causing chemical change

2. When the residue is distilled to a definite

consistency without further treatment it is

called as Straight-run Bitumen

Types of Distillation Processes




It should be fluid enough at the time of mixing to

coat the aggregate evenly by a thin film

It should have low temperature susceptibility

It should show uniform viscosity characteristics Bitumen should have good amount of volatiles in

it, and it should not lose them excessively when

subjected to higher temperature

Desirable Properties of Bitumen




The bitumen should be ductile and not brittle

The bitumen should be capable of being heated to thetemperature at which it can be easily mixed without anyfire hazards

The bitumen should have good affinity to the aggregate and should not be stripped off in the continuedpresence off water

Desirable Properties of Bitumen




2. Cutback BitumenBitumen, the viscosity of which has been reduced

by a volatile dilutent

For use in some constructions like, surfacedressings, some type of bitumen macadam andsoil-bitumen stabilization, it can be mixed at low

temperatures

Thus to increase fluidity at lower temperaturesbitumen is blended with a volatile solvent

After the use of cutback, the volatiles getevaporated and binding property gets developed




Continue….

The viscosity of cutback and the rate atwhich it hardens on the road depend on the

characteristics and quantity of both bitumenand volatile oil used as the dilutent

Types: classification based on rate of curing

or hardening after application

1. Rapid Curing (RC)2. Medium Curing (MC)

3. Slow Curing (SC)




Viscosity of Cutbacks

60 to 100RC-5, MC-5 & SC-5

14 to 45RC-4, MC-4 & SC-4

25 to 75RC-3, MC-3 & SC-3

10 to 20RC-2, MC-2 & SC-2

50 to 100RC-1, MC-1 & SC-1

25 to 75RC-0, MC-0 & SC-0

10mmorifice40oC

10mmorifice25oC

4mm orifice25oC

Viscosity in seconds in tar viscometer

Type and grade ofCutback




Continue….

Grade designated by figure which follows initialseg. RC-1, RC-2, MC-1, MC-2, SC-1, SC-2 etc

Lower grade cutbacks like RC-0, RC-1 etc.would contain higher proportion of solvent

RC-0 & MC-0: 45% solvent, 55% bitumen

RC-5 & MC-5: 15% solvent, 85% bitumen




Continue….

Rapid Curing Cutbacks are bitumen's, fluxed or cutback with apetroleum distillate such as naphtha or gasoline which will

rapidly evaporate after use

Medium Curing Cutbacks are bitumen fluxed to greater fluidityby blending with an intermediate-boiling-point solvent likekerosene or light diesel oil

Slow Curing Cutbacks are obtained either by blending bitumen

with high-boiling-point gas oil, or by controlling the rate of flowand temperature of the crude during the first cycle of refining




3. Bituminous Emulsion

A liquid product in which substantial amount ofbitumen is suspended in a finely divided condition inan aqueous medium and stabilized by means of oneor more suitable materials.

Two phase system, one liquid being dispersed as fineglobules in the other

Bitumen is broken up into fine globules and keptsuspended in water

Small proportion of an emulsifier is used to facilitatethe formation of dispersion and to keep the globulesof dispersed binder in suspension




Continue….

Bitumen content of emulsion ranges from 40 to 60% andthe remaining portion is water

Emulsifiers usually adopted are soaps, surface activeagents and colloidal powders (1.5 to 1%)

Penetration values of bitumen grades that are emulsifiedfor road construction are generally between 190-320

Manufactured emulsions stored in air tight drums

Used mainly in maintenance and patch works and also inwet weather conditions




Continue….

Breaking of Emulsion When applied on road, breaks down and the binder starts

binding the aggregates, though the full binding power developsslowly as and when the water evaporates.

First sign of breakdown is change in colour of film from chocolatebrown to black

Rapid-set grades: Emulsion which break rapidly on coming in

contact with aggregates

Medium-set grades: Which do not break spontaneously oncoming in contact with aggregates but break during mixing or byfine mineral dust

Slow-set grades: When special emulsifying agents are used tomake emulsion relatively stable




Aggregate

Aggregate is the major component of allmaterials used in road construction

It is used in granular bases and sub base,bituminous courses and in cement concretepavements




Types of aggregate

Most of the aggregates are prepared from natural rockand the properties of aggregate depend on properties

of rock:1. Igneous rocks

2. Sedimentary rocks

3. Metamorphic rock

Aggregates are specified based on:

1. Grain size: ascertained by sieving through squaresieves of successive decreasing size

2. Shape: gravel, angular, flaky, elongated etc




Continue….

Gradation: grading for different road making

purposes specified by like ASTM, BSI, ISI and IRC.

Texture: Coarse aggregates and fine aggregates

Hardness: Hard aggregates and soft aggregates

(Different specifications apply for each)Hard aggregates like, crushed stone are generally

used for wearing course of superior pavement types

Soft aggregates like, moorum, kankar, laterite, brick

aggregates and slag are generally used in

lower layers of low-cost/inferior road construction




Desirable properties of Aggregate

Strength:

The aggregate should be sufficiently strong to

withstand the stresses due to traffic wheel loadHardness:

Aggregate should have hard enough to resist the

wear due to abrasive action of traffic

Toughness:

Aggregate should have resistance to impact or toughness




Continue….

Durability:The aggregate used in pavement should

resistance to disintegration due to the actionof weather

Shape of aggregate:

Should not be flaky and elongated

Adhesion with Bitumen:Should have good affinity to bitumen

Quality Control Tests




Quality Control Tests

Soil

1. Gradation

2. Atterberg Limits and indices (LL, PL,PI, SL)3. Laboratory Compaction (MDD and OMC)

4. Field density test

5. CBR Test

6. Plate bearing test




Quality control tests

Aggregate

1. Sieve analysis

2. Aggregate crushing test

3. Aggregate impact test

4. Abrasion Test (LA abrasion test)

5. Shape test (FI, EI, Angularity no)

6. Soundness Test

7. Specific gravity and water absorption test

8. Stripping value test

Continue




Bitumen (Normal)1. Penetration2. Ductility

3. Softening point4. Specific gravity5. Loss on heating6. Flash & Fire point7. Viscosity

8. Solubility

Modified Bitumen (PMB, CRMB etc)

1. Elastic Recovery2. Separation Difference3. Tests on TFOT residue




Continue….

Cutback Bitumen

1. Viscosity test using specified orifice

2. Penetration test

3. Ductility test

4. Solubility test

5. Flash point test




Bituminous Emulsion

1. Residue on sieving: not more than 0.25% by wt. ofemulsion consists of particles greater than 0.15mmdiameter

2. Stability of mixing: To test if emulsion breaks downand coats the coarse aggregates with bitumen tooearly before mixing is complete

3. Stability of mixing: To assess the stability ofemulsions when the aggregate contains largeproportions of fines with cement

Continue….

Contin e




Continue….

4. Water Cement: To know the percentage

of water in the emulsion which depends on

the type of the emulsion

5. Sedimentation: Some sedimentation may

occur when a drum of emulsion is leftstanding before use

6. Viscosity: Should be Low enough to be sprayed

through jets or to coat aggregates in simple mixing

BIS C d f T ti P d




BIS Codes for Testing Procedures

Specification for industrial bitumenIS 702: 1988

Specification for preformed fillers for

expansion joint in pavements andstructures (non extruding and resilienttype): Part 1 Bitumen impregnated fiber

IS 1838: part1:

1983

Glossary of Terms Relating to Bitumenand Tar

IS 334: 2002

Specification for Cutback BitumenIS 217: 1988

Specification for paving bitumenIS 73: 1992

Title of the SpecificationSpecificationNo.

Bituminous Material

Continue




Continue……..

Methods of Test for Tars andBituminous Materials - Determinationof Breaking Point for Cationic BitumenEmulsion

IS 15173: 2002

Method for Determination of WaxContent in Bitumen - Specification

IS 10512: 2003

Methods for testing tar and bituminousmaterials: Determination of FRAASS

breaking point of bitumen

IS 9381 : 1979

Specification for distributors for hot tar

and bitumen

IS 2093 : 1974


Continue




Methods for Testing Tar andBituminous Material - Determination ofBreaking Point for Anionic Bitumen

Emulsion

IS 15174:2002

Polymer and Rubber Modified Bitumen- Specification

IS 15462:2004


Continue……..




Methods of test for aggregates for concretePart 4 Mechanical properties

IS 2386: Part4: 1963

Methods of test for aggregates for concretePart 3 Specific gravity, density, voids,

absorption and bulking

IS 2386: Part3: 1963

Methods of Test for Aggregates for

Concrete - Part I : Particle Size and Shape

IS 2386: Part

I: 1963

Specification for coarse and fineaggregates from natural sources forconcrete

IS 383: 1970


Aggregate Material

Continue




Methods of Test for Aggregates for Concrete- Part VIII : Petrographic Examination

IS 2386: Part8: 1963

Methods of Test for Aggregates for Concrete- Part VII : Alkali Aggregate Reactivity

IS 2386: Part7: 1963

Methods of test for aggregates for concrete :Part 6 Measuring mortar making propertiesof fine aggregates

IS 2386: Part6: 1963

Methods of Test for Aggregates for Concrete- Part V : Soundness

IS 2386: Part5: 1963


Continue……..

Continue




Schedule for Properties and Availability ofStones for Construction Purposes - Part II :

Maharashtra State - Section 3 : EngineeringProperties of Stone Aggregates

IS 7779: Part2: Section 3:

1979

Method of Test for Determination ofStripping Value of Road AggregatesIS 6241: 1971

Method of test for determining aggregateimpact value of soft coarse aggregates

IS 5640: 1970

Methods for Sampling of Aggregates for

Concrete

IS 2430: Part I:

1986


Continue……..

Continue




Specification for cylindrical metal

measures for use in tests ofaggregates and concrete

IS10079: 1982

Specification for machine for abrasiontesting of coarse aggregates

IS 10070: 1982


Continue……..




Thank You

L13-TVM_Pavement Materials & Desirable Propoties_27 & 28-09-06

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Transcript of L13-TVM_Pavement Materials & Desirable Propoties_27 & 28-09-06