Bitumen

BITUMENBITUMEN

PAVES THE WAYPAVES THE WAYPAVES THE WAYPAVES THE WAYPAVES THE WAYPAVES THE WAYPAVES THE WAYPAVES THE WAY

Types of BindersTypes of BindersTypes of BindersTypes of BindersTypes of BindersTypes of BindersTypes of BindersTypes of Binders

1. Tar

2. Natural Asphalt / Rock Asphalt / Lake Asphaltp

3. Bitumen

TarTarTarTarTarTarTarTar• COKE OVEN TAR

• Produced at temperatures above 1200OC during manufacturing of coke.

• High aromatic content.• Pitch content - 50 %.

• LOW AROMATIC TAR• Produced at temperatures 600OC to 700OC.• Less viscous.• Paraffinic in nature.• Pitch content - 35 %.

Natural Asphalt / Rock Asphalt / Natural Asphalt / Rock Asphalt / Natural Asphalt / Rock Asphalt / Natural Asphalt / Rock Asphalt / Lake AsphaltLake AsphaltLake AsphaltLake Asphalt

• Naturally occurring Bituminous binder.Bi d i i T i id d• Biggest deposits in Trinidad– 100 Acres,– 90 meter deep– 10 to 15 Million MT– Pen - 5 max

• Asphalt found in France, Italy & S it l d R k A h ltSwitzerland - Rock Asphalt.

BitumenBitumenBitumenBitumenBitumenBitumenBitumenBitumen• Conventional BitumenConventional Bitumen

Paving Grade BitumenIndustrial Grade BitumenIndustrial Grade Bitumen

• Cutback

• Bitumen Emulsions

• Modified Bitumen

M difi d Bit E l i• Modified Bitumen Emulsions

B I T U M E NB I T U M E NB I T U M E NB I T U M E NB I T U M E NB I T U M E NB I T U M E NB I T U M E N

COMPOSITIONCOMPOSITIONCOMPOSITIONCOMPOSITION

Elemental AnalysisElemental AnalysisElemental AnalysisElemental AnalysisElemental AnalysisElemental AnalysisElemental AnalysisElemental Analysis

Carbon 82 - 88 %Hydrogen 8 - 11 %Sulphur 0 - 6 %pOxygen 0 - 1.5 %Nitrogen 0 1 %Nitrogen 0 - 1 %

Chemical CompositionChemical CompositionChemical CompositionChemical CompositionChemical CompositionChemical CompositionChemical CompositionChemical Composition

BitBitBitumenBitumen

A h ltA h ltAsphaltenesAsphaltenes5 to 25% wt.

MaltenesMaltenes

SaturatesSaturates AromaticsAromatics ResinesResinesDecreases Penetration

SaturatesSaturates5 to 20% wt.

AromaticsAromatics40 to 65% wt.

ResinesResines10 to 20% wt.

Increases PenetrationReduces Shear Susceptibility

Increases Softening Point, reduces Penetration Index, p y e e a o de ,increases Viscosity

SpecificationsSpecificationsSpecificationsSpecificationsSpecifications Specifications andand

Specifications Specifications andandandand

T t M th dT t M th dandand

T t M th dT t M th dTest MethodsTest MethodsTest MethodsTest Methods

What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?What is expected from Bitumen?

• Ensure road behaves in a predictable way• Ensure road behaves in a predictable way• Bitumen performs the desired function on the road

Does not fail under predictable loads– Does not fail under predictable loads– Resists deterioration of road with time

Is able to withstand expected climatic conditions– Is able to withstand expected climatic conditions– Mix easily and form strong bond with a wide

variety of aggregatesvariety of aggregates– Is safe to handle– Modified Bitumen and Bitumen Emulsions should– Modified Bitumen and Bitumen Emulsions should

be a stable mixture in storage and handling

Penetration TestPenetration TestPenetration TestPenetration TestPenetration TestPenetration TestPenetration TestPenetration Test

• Arbitrary Empirical Number• Arbitrary Empirical Number• Depth of penetration of a

t d d i dl dstandard size needle under standard test conditions

• Very easy to perform at field level

• Helps in classification and traceabilityy

Softening Point TestSoftening Point TestSoftening Point TestSoftening Point TestSoftening Point TestSoftening Point TestSoftening Point TestSoftening Point Test• Arbitrary test to indicate y

the temperature at which bitumen is more of a liquid qand less of a solid

• Higher softening pointsHigher softening points indicate higher resistance to melting on roadto melting on road

• Higher resistance to melting indicates highermelting indicates higher rutting resistance

Ductility TestDuctility TestDuctility TestDuctility TestDuctility TestDuctility TestDuctility TestDuctility Test• Arbitrary empirical test to y p

measure the cohesive strengthg

• Cohesive strength is loosely related to theloosely related to the fatigue strength

• Testing temperatures• Testing temperatures may vary from country to country and from grade tocountry and from grade to grade also

RelationshipRelationshipRelationshipRelationshipRelationshipRelationshipBetweenBetween

RelationshipRelationshipBetweenBetweenBetween Between

PropertiesPropertiesBetween Between

PropertiesPropertiesPropertiesPropertiesPropertiesProperties

Penetration at

Softening Point – 800 Penetration

at Fraass Breaking Pt

– 1.25InterdependenciesInterdependenciesInterdependenciesInterdependencies

Viscosityat

Softening PointSoftening Point -1200 Pa s

(12000 poise) ( p )

Bitumen Test Data ChartBitumen Test Data ChartBitumen Test Data ChartBitumen Test Data Charttu e est ata C a ttu e est ata C a ttu e est ata C a ttu e est ata C a t

SelectionSelectionSelectionSelectionSelection Selection ofof

Selection Selection ofofofof

GradeGradeofof

GradeGradeG adeG adeG adeG ade

Choice of GradeChoice of GradeChoice of GradeChoice of GradeChoice of GradeChoice of GradeChoice of GradeChoice of Grade

• Choice of Bitumen is based on

Climatic Conditions - Maximum & Mi i t t & i f llMinimum temperature & rainfall.

I i f T ffi N b fIntensity of Traffic - Number of vehicles per day, Traffic speed & axle load of vehiclesaxle load of vehicles.

Applications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 GradeApplications of 30/40 Grade

• Suited for areas where diff. between min. & max. temp. < 25oC.

• Suited for traffic intensity > 1500 cv/ day• Used in metropolitan areas• Used in metropolitan areas.• Used in airport runways.

Applications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 GradeApplications of 60/70 Grade• More viscous grade.g• Higher softening point.• Suited for traffic intensity > 1500 cv/day• Suited for traffic intensity > 1500 cv/day.

– Can withstand heavier axle loads.– Better suited for highways, expressways &

urban roads. • Suited for areas where difference between min.

& max. temp. is > 25oC.p• Reduced stripping in presence of water.

Applications of 80/100 GradeApplications of 80/100 GradeApplications of 80/100 GradeApplications of 80/100 Grade

• Less viscous grade.g• Used in all climatic conditions.

S it d f t ffi l d < 1500 /d• Suited for traffic load < 1500 cv/day.• Better suited for high altitude/snow bound g

regions irrespective of traffic intensity.

HandlingHandlingHandling Handling

ofof

BitBitBitumenBitumen

Aging of BitumenAging of BitumenAging of BitumenAging of BitumenAging of BitumenAging of BitumenAging of BitumenAging of Bitumen

• Bitumen undergoes a process of• Bitumen undergoes a process of aging with time– Becomes harder and brittle

• Factors affecting aging of bitumenFactors affecting aging of bitumen– High Temperature

A il bilit f O– Availability of Oxygen– Exposure to UV radiation

Aging of BitumenAging of BitumenAging of BitumenAging of Bitumeng gg gg gg g

Optimal Viscosity for Mixing & CompactionOptimal Viscosity for Mixing & CompactionOptimal Viscosity for Mixing & CompactionOptimal Viscosity for Mixing & Compaction

N ll Bit h d Normally Bitumen hardens by one grade during by one grade during mixing and laying.m x ng and lay ng.

MODIFIED BITUMENMODIFIED BITUMENMODIFIED BITUMENMODIFIED BITUMENBinder ofBinder ofBinder of th f tBinder of th f tthe futurethe future

Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Why Modified Bitumen?Demands on Road increasing every yearg y y

Increasing Number of VehiclesIncreasing Axle Load gDesire to maintain higher serviceability level

Higher fatigue resistanceHigher resistance to weatheringBetter adhesionHigher stiffness modulusLesser cracking, ravelling, deformation & creep failurefailureReduce number of overlays

Reduction in vehicle operation costReduction in vehicle operation cost

Crumb Rubber ModifiedCrumb Rubber ModifiedCrumb Rubber ModifiedCrumb Rubber ModifiedCrumb Rubber Modified Crumb Rubber Modified BitumenBitumen

Crumb Rubber Modified Crumb Rubber Modified BitumenBitumen

BitumenBitumenBitumenBitumen++

Additives Additives

(Modifiers/Treated Crumb Rubber)(Modifiers/Treated Crumb Rubber)( )( )

Types of ModifiersTypes of ModifiersSynthetic Elastomers

SBS, SBR etc.

P l R bbPlastics

,

Polymers RubbersPlastics

Crumb RubberNatural Rubber(Latex)

ThermosetEpoxy Resins

(Latex)

Thermoplastic Chemically Plain

LDPE, EVA, EBA Treated

Selection CriteriaSelection CriteriaSelection CriteriaSelection CriteriaSelection CriteriaSelection CriteriaSelection CriteriaSelection Criteria

Atmospheric Temperature OCAtmospheric Temperature OCMinimum Maximum

<35 35 45 >45<35 35-45 >45<-10 CRMB50 CRMB 55 CRMB 55-10 to10 CRMB 50 CRMB 55 CRMB 60>10 CRMB 55 CRMB 55 CRMB 60

Methods of ClassificationMethods of ClassificationMethods of ClassificationMethods of ClassificationMethods of ClassificationMethods of ClassificationMethods of ClassificationMethods of Classification

Methods of ClassificationMethods of ClassificationMethods of ClassificationMethods of Classification

PenetrationPenetration Viscosity Viscosity of TFOTof TFOTViscosityViscosity PerformancePerformance

Penetration Based SystemPenetration Based SystemPenetration Based SystemPenetration Based SystemPenetration Based SystemPenetration Based SystemPenetration Based SystemPenetration Based System• More than 100 years oldMore than 100 years old• Has stood the test of time• Based on Penetration at 25 OC• Penetration 30 to 100 are suitable for roadPenetration 30 to 100 are suitable for road

constructionH d d it bl f h i t ffi l d• Harder grades suitable for heavier traffic loads

• Softer grades suitable for light traffic loadsSofter grades suitable for light traffic loads

Viscosity Based SystemViscosity Based SystemViscosity Based SystemViscosity Based SystemViscosity Based SystemViscosity Based SystemViscosity Based SystemViscosity Based System

• Viscosity is considered to be the primary propertyproperty

• Most tests over lap with that of Penetration based classification

• Classified as VG 10 20 30 and 40 basedClassified as VG 10, 20, 30 and 40 based on viscosity at 60OC

Viscosity of TFOT Residue Based Viscosity of TFOT Residue Based S tS t

Viscosity of TFOT Residue Based Viscosity of TFOT Residue Based S tS tSystemSystemSystemSystem

• Simulates aging of Bitumen• Viscosity ranging from 40 to 700 pascalViscosity ranging from 40 to 700 pascal

seconds at 60OC are suitable for road constructionconstruction

• Most tests overlap with that of Penetration based classification

• Higher viscosity for higher traffic and low• Higher viscosity for higher traffic and low viscosity for lower traffic

PERFORMANCE PERFORMANCE PERFORMANCE PERFORMANCE GRADE BITUMENGRADE BITUMENGRADE BITUMENGRADE BITUMEN

BITUMEN TODAYBITUMEN TODAYBITUMEN TODAYBITUMEN TODAY• Penetration/Viscosity based classification• 80/100, 60/70, 30/40• Penetration, Softening Point, Ductility, Viscosity

E i i l t t d t t d d t l di t• Empirical tests done at standard temp., loading, etc.• Ageing is not considered• No direct correlation with actual field conditionsNo direct correlation with actual field conditions • Seems to work somehow – Has stood the test of

timeN d t t i ffi i i C t ff ti• Need to cut inefficiencies – Cost effective

More direct correlation between bitumen andMore direct correlation between bitumen andMore direct correlation between bitumen and road performance is needed

More direct correlation between bitumen and road performance is needed

BITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROWBITUMEN TOMORROW• More direct correlation between road performance and

ti f bitproperties of bitumen• Properties desired

– Easier handling (mixing, coating, rolling) – Better rutting resistance– Higher fatigue life– Resistance to low temperature cracking

- New system of classification to be developed

- New tests to be developed

CLASSIFICATIONCLASSIFICATIONCLASSIFICATIONCLASSIFICATION

PG 58 22PG 58 22PG 58 -22PG 58 -22

Mi tPerformance Grade

Min. pavement design temp.

Average 7 day max. pavement design temp.pavement design temp.

MIXING AND LAYINGMIXING AND LAYINGMIXING AND LAYINGMIXING AND LAYING

• Tested in rotational viscometer

• Max viscosity of 3 Pa-s atMax. viscosity of 3 Pa s at 135oC

AGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMENAGEING OF BITUMEN

• During Construction• Early in Pavement’s life• Early in Pavement s life

– Post construction upto two years

• Late in pavement’s life

Rotating thin film oven test (RTFOT)

• Late in pavement s life– Seven plus years of life

RTFOT + Pressure Ageing V l (PAV)Vessel (PAV)

ROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TESTROTATING THIN FILM OVEN TEST

PRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSELPRESSURE AGEING VESSEL

RUTTINGRUTTINGRUTTINGRUTTINGRUTTINGRUTTINGRUTTINGRUTTING

• Due to melting of bitumen on the roadDue to melting of bitumen on the road• Always occurs at max. pavement temp.

T t t b d t d t t• Test to be conducted at max. pavement temp.

• Tested in Dynamic Shear Rheometer• G*/Sinδ min. 1 kPa, @ 10 rad/s for unaged , @ g

bitumen• G*/Sinδ min. 2.2 kPa, @ 10 rad/s forG /Sinδ min. 2.2 kPa, @ 10 rad/s for

RTFOT aged bitumen

DYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETERDYNAMIC SHEAR RHEOMETER

FATIGUEFATIGUEFATIGUEFATIGUE

• Due to repeated loading unloading• Due to repeated loading,unloading cycles

• Always occurs near the averageAlways occurs near the average pavement temp.

• Test to be conducted at average + 4OCTest to be conducted at average + 4 C pavement temp.

• Tested in Dynamic Shear RheometerTested in Dynamic Shear Rheometer• G*Sinδ max. 5000 kPa, @ 10 rad/s for

RTFOT + PAV aged bitumenRTFOT + PAV aged bitumen

LOW TEMP CRACKINGLOW TEMP CRACKINGLOW TEMP CRACKINGLOW TEMP CRACKING

• Due to loss of elasticity at very low temp• Due to loss of elasticity at very low temp.• Always occurs at lowest pavement temp.

T ti d t i t 10OC• Testing done at min. temp. + 10OC • Bending Beam Rheometer• Creep Stiffness of max. 300,000 kPa, m-

value min. 0.30• Direct Tension Test - For Modified

Bitumens• Failure strain min. 1%

BENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETERBENDING BEAM RHEOMETER

DIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTERDIRECT TENSILE TESTER

PERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATIONPERFORMANCE EVALUATION

GRADE BUMPINGGRADE BUMPINGGRADE BUMPINGGRADE BUMPING• Choice of grade depends on max. and min. pavement

temperature 20 mm below road surfacetemperature 20 mm below road surface.• Correction for Traffic speed

– > 90 km/h - No Correction– > 90 km/h - No Correction– < 90 km/h - Increase one high temp. grade

< 20 km/h Increase two high temp grade– < 20 km/h - Increase two high temp. grade • Correction for Traffic volume

< 10 million ESAL No Correction– < 10 million ESAL - No Correction– > 10 million ESAL - Increase one high temp. grade

> 30 million ESAL Increase two high temp grade– > 30 million ESAL - Increase two high temp. grade

Performance Vs TestsPerformance Vs TestsPerformance Vs TestsPerformance Vs TestsPerformance Vs TestsPerformance Vs TestsPerformance Vs TestsPerformance Vs Tests

LLRuttingRutting Fatigue Fatigue

CrackingCracking

Low Low Temperature Temperature

CrackingCracking

Mixing Mixing and and

LayingLaying

Ductility Fraass Breaking Point

Softening P i

Viscosity at

Fatigue Strength

Breaking Point

Creep Stiffness

Rate of change

Point

Viscosity

P t ti

y135OC

Softening Point,

Viscosity &

Rate of change of Creep

Failure Strain

Penetration

Complex Shear

Penetration after Aging

Shear Modulus

SafeSafeHandling PracticesHandling Practices

Health, Safety & Environmental Health, Safety & Environmental A tA t

Health, Safety & Environmental Health, Safety & Environmental A tA tAspectsAspectsAspectsAspects

1 Low order of potential hazard provided good1 Low order of potential hazard provided goodhandling practices are observed.

2 C t i P l li A ti H d b2 Contains Polycyclic Aromatic Hydrocarbons.PCAs with molecular wt. Of 200 to 4500 arebiologically active carcenogensbiologically active carcenogens.Concentration of these in Bitumen isextremely low.

3 Other than heat burns, hazards arenegligible. However it is prudent to avoidg g pprolonged & intimate skin contact.

Health, Safety & Environmental Health, Safety & Environmental Health, Safety & Environmental Health, Safety & Environmental , y, yAspects (contd.)Aspects (contd.)

, y, yAspects (contd.)Aspects (contd.)

4 In case of skin burns plunge the affected areaunder cold running water for 10 minutesunder cold running water for 10 minutes.

5 When bitumen is heated or mixed with5 When bitumen is heated or mixed withaggregate, fumes are emitted. The fumescontain particulate matter, Hydrocarboncontain particulate matter, Hydrocarbonvapours & very small amount of H2S.However, the concentration is rarely aboveHowever, the concentration is rarely abovepermissible limits.

Th k YTh k YTh k YTh k YThank YouThank YouThank YouThank You