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PAVES THE WAY. BITUMEN. Tar Natural Asphalt / Rock Asphalt / Lake Asphalt Bitumen. Types of Binders. Produced from Wood or Coal by destructive distillation process Coke Oven Tar Produced at temperatures above 1200 O C during manufacturing of coke. High aromatic content.

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types of binders
Tar

Natural Asphalt / Rock Asphalt / Lake Asphalt

Bitumen

Types of Binders
slide3
Produced from Wood or Coal by destructive distillation process

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 %.

Tar
natural asphalt rock asphalt lake asphalt
Natural Asphalt / Rock Asphalt / Lake Asphalt
  • Naturally occurring Bituminous binder.
  • Biggest deposits in Trinidad
    • 100 Acres,
    • 90 meter deep
    • 10 to 15 Million MT
    • Pen - 5 max
  • Asphalt found in France, Italy & Switzerland - Rock Asphalt.
bitumen
Bitumen
  • Conventional Bitumen
      • Paving Grade Bitumen
      • Industrial Grade Bitumen
  • Cutback
  • Bitumen Emulsions
  • Modified Bitumen
  • Modified Bitumen Emulsions
b i t u m e n

B I T U M E N

A VISCO - ELASTIC MATERIAL

the stiffness concept
In solids :

E = s

e

where, E = Elastic modulus

s =Stress

e =Strain

The Stiffness Concept
engineering properties of bitumen
Bitumen is a visco-elastic material & it’s deformation under stress is a function of both temperature & loading time

At higher temperature &/or longer loading time

Behave as viscous liquids

At low temperature &/or short loading time

Behave as elastic solids

The intermediate range of temperatures, more typical of the conditions in service, result in visco-elastic behaviour.

Engineering Properties of Bitumen
the stiffness concept1
In visco-elastic material :

St,T = s

et,T

Where, St,T = Stiffness modulus at specific time t & Temp. T.

s =Stress

et,T= Strain at specific time t & temp. T.

The Stiffness Concept
composition

COMPOSITION

B I T U M E N

elemental analysis
Carbon 82 - 88 %

Hydrogen 8 - 11 %

Sulphur 0 - 6 %

Oxygen 0 - 1.5 %

Nitrogen 0 - 1 %

Elemental Analysis
chemical composition
Chemical Composition

Increases Penetration

Decreases Penetration

Increases Softening Point, reduces Penetration Index, increases Viscosity

Reduces Shear Susceptibility

what is expected from bitumen
Ensure road behaves in a predictable way

Bitumen performs the desired function on the road

Does not fail under predictable loads

Resists deterioration of road with time

Is able to withstand expected climatic conditions

Mix easily and form strong bond with a wide variety of aggregates

Is safe to handle

Modified Bitumen and Bitumen Emulsions should be a stable mixture in storage and handling

What is expected from Bitumen?
what properties need to be tested
Hardness – Penetration

Withstand high temperatures – Softening Point

Withstand repetitive loading/unloading – Ductility

Withstand low temperatures – Fraass breaking point

Ease of mixing with aggregate – Viscosity at 135OC

Safety in handling - Flash point

Purity – Solubility in Trichloroethylene

Weight to volume conversion – Specific gravity

Deterioration of properties w.r.t. time and temperature – Thin Film Oven Test

What properties need to be tested?
slide17
Penetration

at

Softening Point

– 800

Penetration

at

Fraass Breaking Pt

– 1.25

Interdependencies

  • Viscosity
  • at
  • Softening Point
  • 1200 Pa s
  • (12000 poise)
choice of grade
Choice of Bitumen is based on

Climatic Conditions - Maximum & Minimum temperature & rainfall.

Intensity of Traffic - Number of vehicles per day, Traffic speed & axle load of vehicles.

Choice of Grade
applications of 80 100 grade
Less viscous grade.

Used in all climatic conditions.

Suited for traffic load < 1500 cv/day.

Better suited for high altitude/snow bound regions irrespective of traffic intensity.

Applications of 80/100 Grade
applications of 60 70 grade
More viscous grade.

Higher softening point.

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.

Reduced stripping in presence of water.

Applications of 60/70 Grade
applications 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 airport runways.

Applications of 30/40 Grade
hardening of bitumen
Bitumen hardens with time

Softening Point increases

Ductility decreases

Penetration decreases

Factors affecting hardening

High temperature

Surface area exposed to air

Exposure to UV radiation

Hardening of Bitumen
advantages
Bitumen

Advantages

advantages1
Smooth

Safe

Economical

Speed

Quiet

Environment friendly

Versatile

State of-the-art

Stage Construction

Resistant to de-icing material

Serviceability

Advantages
smooth
Better riding quality

Absence of joints

Estimated 15% increase in pavement life for 50% increase in smoothness

Less wear and tear to vehicle

Lesser fuel consumption

Enjoyable ride

Smooth
slide32
Better skid resistance over a longer period of time

Use of OGFC reduces Tyre Spray, Hydroplaning and Improves Visibility

Better contrast with pavement markings

Safe
economical
Low initial cost compared to PCC

Gap widens throughout pavement life

A well designed and constructed pavement

Can last for 25 to 34 years without reconstruction

Can serve for 15 year or more before distresses become sufficient to require rehabilitation

Economical
speed of construction
Newark Airport – 1,15,000MT in 15 days, 11,000MT in 24 hours

Pave during off peak hours and open to traffic as soon as it cools down

Reduces work zone accident

Can result in 80% reduction in user delay costs

24-hour closure will have 3 to 10 times more vehicles pass through the work zone

Speed of Construction
quiet pavements
Dense graded asphalt is quieter by 2 to 3 dB(A) compared to PCC

3 dB(A) corresponds to

Doubling the distance in the line of source

Reducing traffic volume by 50%

Reducing traffic speed by 25%

Open graded Friction Course

Reduces noise further

Costs 1/8th of noise barrier on side of the road

Aesthetically superior

Quiet Pavements
environment friendly
Used for water proofing of fish ponds without any problem

Very low level of leachable compounds

Most recycled product in the world

100% recyclable

Second highest - Aluminium cans – 60%

Can use waste material from other fields also like worn out PCC

Environment Friendly
state of the art
Road design, construction and maintenance methods are being overhauled

New tests being developed

New plants providing high quality materials

Pavers with laser controlled screeds for even smoother pavements

Better material transfer vehicles for uniformity and rollers with increased compactive effort.

The ultimate result of this new technology will be: smoother, more durable, longer lasting asphalt pavements

State-of-the-Art
stage construction
Bituminous pavements can be constructed in stages

Being made thicker and/or wider as the need arises

Each successive layer becomes an integral part of the pavement structure, increasing the load carrying capacity.

Stage Construction
de icing materials
Bituminous pavements are not harmed by de-icing chemicals

Also snow and ice melt quickly from bituminous pavements

De-icing Materials
serviceability
Bituminous pavements can easily maintain a high level of serviceability with minimal disruption to the traffic

Can be easily trenched, patched and quickly opened to traffic when underground utilities need to be repaired.

Serviceability
modified bitumen

MODIFIED BITUMEN

Binder of the future

why modified bitumen
Demands on Road increasing every year

Increasing Number of Vehicles

Increasing Axle Load

Desire to maintain higher serviceability level

Higher fatigue resistance

Higher resistance to weathering

Better adhesion

Higher stiffness modulus

Lesser cracking, ravelling, deformation & creep failure

Reduce number of overlays

Reduction in vehicle operation cost

Why Modified Bitumen?
crumb rubber modified bitumen
Bitumen

+

Additives (Modifiers/Treated Crumb Rubber)

Crumb Rubber Modified Bitumen
types of modifiers
THERMOPLASTIC ELASTOMERS

Styrene-butadiene-styrene(SBS)

Styrene-butadiene-rubber (SBR)

Styrene-isoprene-styrene (SIS)

Styrene-ethylene-butadiene-styrene (SEBS)

Ethylene-prppylene-diene terpolymer (EPDM)

Isobutene-isoprene copolymer (IIR)

Natural Rubber

Crumb Rubber

Polybutadiene (PBD)

Polyisoprene

THERMOPLASTIC POLYMERS

Ethylene vinyl acetate (EVA)

Ethylene methyl acrylate (EMA)

Ethylene butyl acrylate (EBA)

Atactic polypropylene (APP)

Polyethylene (PE)

Polypropylene (PP)

Polyvinyl chloride (PVC)

Polystyrene (PS)

THERMOSETTING POLYMERS

Epoxy resin

Polyurethane resin

Acrylic resin

Phenolic resin

CHEMICAL MODIFIERS

Organo-metallic compounds

Sulphur

Lignin

FIBRES

Cellulose

Alumino-magnesium silicate

Glass fibre

Asbestos

Polyester

Polypropylene

ADHESION IMPROVERS

Orgainc amines

Amides

ANTIOXIDANTS

Amines

Phenols

Organo-zinc/organo-lead compounds

NATURAL ASPHALTS

Trinidad lake Asphalt (TLA)

Gilsonite

Rock asphalt

FILLERS

Carbon black

Hydrated lime

Lime

Fly ash

Types of Modifiers
slide47
Types of Modifiers

Synthetic Elastomers

SBS, SBR etc.

Polymers

Plastics

Rubbers

Crumb Rubber

Natural Rubber

(Latex)

Thermoset

Epoxy Resins

Plain

Thermoplastic

LDPE, EVA, EBA

Chemically

Treated

selection criteria
Atmospheric Temperature OC

Minimum Maximum

<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

Selection Criteria
slide50
International Use of Crumb Rubber Modified Bitumen
  • CRMB is being used in USA from 1960
      • Currently Arizona , Florida , Texas and California using 2 million tons of Rubberized Bitumen.
  • CRMB is very popular in Australia for chip sealing wearing courses and structural layers .
  • Use of CRMB is increasing in developing countries of Latin America.
slide51
CRMB in use in USA, Canada, France , Germany and South Africa.

UK Environmentalist’s want use of CRMB to be encouraged on roads. Govts. especially are considering making the use mandatory.

Belgian Road Research Center is encouraging the use of CRMB on Freeways

South African companies are increasingly using Rubber Modified mixes

International Use of Crumb Rubber Modified Bitumen

new trends
Bitumen

New Trends

future trends in bituminous roads
ISO Certification of Roads

Road Safety Audit

Performance Based Specifications

Stone Mastic Asphalt

Perpetual Pavements

Foamed Bitumen

Polyphosphoric Acid Modified Bitumen

Sulphur Extended Bitumen Modifiers

Future Trends in Bituminous Roads
iso certification of roads
Growth in EN ISO 9000 certification in European countries

Voluntary activity driven by individual companies or by the national asphalt industry.

To obtain management and marketing tools.

In several countries certification is becoming a regulatory requirement, usually by mutual agreement between suppliers and clients.

Effective quality schedules can be produced only by joint action of supplier and client side of road sector.

If the positive aspects of certification are not taken into account in contract arrangements its introduction will increase the overall cost of asphalt roads

ISO Certification of Roads
road safety audit
Safety audit applied to

Fresh project proposals

Existing network of roads

Specific existing project

Auditors should be completely independent of the organization involved in development of project.

The audit team comprising of 4-5 people inspect the roads during daytime and also at night.

The team identifies aspects that the road controlling authority does well, as well as the aspects that could be improved.

Road Safety Audit
performance grade specifications
Existing Specifications

Most tests are empirical tests and are not directly related to performance on the road

Tests are conducted at one standard temp.

Performance under climatic condition prevailing throughout the year are not evaluated

Only short term ageing is evaluated, that too only in a few cases

Performance grade tests simulate the actual field conditions in a more realistic way

Performance Grade Specifications
stone mastic asphalt
Increasingly popular Worldwide in heavy traffic roads & airfields.

Even surface gives better riding comfort.

Texture gives good skid resistance & relatively low traffic noise.

Strong aggregate structure provided by the coarse aggregate particles gives excellent resistance to permanent deformation.

Rich mastic, which fills the voids, makes SMA highly durable.

Modified bitumen & Fibres can be used to further enhance the mechanical properties.

Allows thin layer application.

Stone Mastic Asphalt
perpetual pavements
Structure Lasts 50+ years

Bottom-Up Design and Construction

Indefinite Fatigue Life

Renewable Pavement Surface.

High Rutting Resistance

Tailored for Specific Application

Consistent, Smooth and Safe Driving Surface.

Environmentally Friendly

Avoids Costly Reconstruction

Perpetual Pavements
foamed bitumen
Mixture of Bitumen (98%), water (1%) and foaming agent (1%)

When hot bitumen (160 to 200OC) comes in contact with cold water (15 to 25OC)

Mixture expands more than 10 times

Forms a fine mist or foam

Foamed bitumen is sprayed on fine aggregate in mixing drums to get a strong flexible pavement material

Used for durable, fast and low cost rehabilitation of existing pavements

Foamed Bitumen
polyphosphoric acid modified bitumen
Lower stripping compared to other bitumens

Reduction in mixing and laying temperatures

Improves fracture strength and ductility

Very low dosage of modifier

Test tracks in the world are still under evaluation but preliminary results are very promising

Polyphosphoric Acid Modified Bitumen
sulphur extended asphalt modifier
Odourless pellets consisting of Sulphur, Plasticizers and additives

Is added to the hot mix

Melts and disperses easily

Acts as binder extender and asphalt mix modifier

Environmentally safe

Reduces Bitumen requirement by 30%

Mixing temperature is reduced by 10OC

Higher resistance to rutting, fatigue failure and low temperature cracking

Suitable for perpetual pavements

Sulphur Extended Asphalt Modifier
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