1. Bitumen Specifications

2. Agenda 1. What is Bitumen? 2. Modes of Failure of Pavement
3. Methods of Classification
4. Test Methods

3. What is Bitumen?

4. What is Bitumen?
Last residue obtained from fractional distillation of Crude Oil
Is black or dark brown in colour
Is a visco-elastic material
Does not have a distinct melting point
Gradually softens when heated
More solid at low temperatures and more liquid at high temperatures
Has adhesive properties
Has water proofing properties
Forms good bond with a variety of aggregates

5. What are Performance Parameters?
Mix and form a good bond with aggregate (at high temperature)
Not melt on the road at highest atmospheric temperature
Not crack at extreme low atmospheric temperature
Be able to withstand repeated cycles of loading and unloading
Be able to withstand repeated cycles of temperature change
Not be inflammable
Be free from impurities

6. What type of tests do we develop?
Tests should be simple
Tests should replicate the actual field conditions as accurately as possible
Rate of change of properties with time, temperature and load should be measurable or predictable

7. Modes of Failure

8. Rutting/ Permanent Deformation

9. Fatigue Cracking

10. Low Temperature Cracking

11. Low Temperature Cracking

12. Methods of Classification

13. Methods of Classification
Viscosity of TFOT
Performance
Penetration
Viscosity

14. Penetration Based System
More than 100 years old
Has stood the test of time
Based on Penetration at 25 OC
Penetration 30 to 100 are suitable for road construction
Harder grades suitable for heavier traffic loads
Softer grades suitable for light traffic loads

15. Viscosity Based System
Viscosity is considered to be the primary property
Most tests over lap with that of Penetration based classification
Classified as VG 10, 20, 30 and 40 based on viscosity at 60OC

16. Viscosity of TFOT Residue Based System
Simulates aging of Bitumen
Viscosity ranging from 40 to 700 pascal seconds at 60OC are suitable for road construction
Most tests overlap with that of Penetration based classification
Higher viscosity for higher traffic and low viscosity for lower traffic

17. Performance Based System
Radically different from Penetration & Viscosity based system
New set of tests developed for better simulation of field conditions
Long term & short term aging taken into consideration
Classification is based on the maximum and minimum pavement temperature that the Bitumen can withstand (PG )

18. Test methods

19. Penetration Test Arbitrary Empirical Number
Depth of penetration of a standard size needle under standard test conditions
Very easy to perform at field level
Helps in classification and traceability

20. Softening Point Test
Arbitrary test to indicate the temperature at which bitumen is more of a liquid and less of a solid
Higher softening points indicate higher resistance to melting on road
Higher resistance to melting indicates higher rutting resistance

21. Ductility Test
Arbitrary empirical test to measure the cohesive strength
Cohesive strength is loosely related to the fatigue strength
Testing temperatures may vary from country to country and from grade to grade also

22. Fraass Breaking Point Tests low temperature properties
This mode of failure likely to take place only when temperatures are less than 0OC

23. Viscosity Test
Viscosity at 135OC is a fair indicator of the coating ability of Bitumen
Viscosity at 65OC is a replacement for Softening Point test and is an indicator of the ability of Bitumen to resist rutting.

24. Thin Film Oven Test
This test simulates the process of aging of Bitumen during mixing and laying
Sample is kept in an oven at 163OC for 5 hours
TFOT aged bitumen can be tested for Penetration, Softening Point, Ductility, Viscosity, etc.

25. Other Tests Penetration ratio or penetration index Wax content
Specific gravity
Water content
Matter soluble in organic solvents
Flash Point

26. Performance Grade Tests

27. Mixing and Laying Tested in rotational viscometer
Max. viscosity of 3 Pa-s at 135oC

28. Aging of Bitumen During Construction Early in Pavement’s life
Post construction upto two years
Late in pavement’s life
Seven plus years of life
Rolling thin film oven test (RTFOT)
RTFOT + Pressure Ageing Vessel (PAV)

29. Rutting Due to melting of bitumen on the road
Always occurs at max. pavement temp.
Test to be conducted at max. pavement temp.
Tested in Dynamic Shear Rheometer
Complex Shear Modulus G*/Sind min rad/s for unaged bitumen
G*/Sind min rad/s for RTFOT aged bitumen

30. Fatigue Due to repeated loading,unloading cycles
Always occurs near the average pavement temp.
Test to be conducted at average + 4OC pavement temp.
Tested in Dynamic Shear Rheometer
Fatigue Strength G*Sind max rad/s for RTFOT + PAV aged bitumen

31. Low Temp. Cracking Due to loss of elasticity at very low temp.
Always occurs at lowest pavement temp.
Testing done at min. temp. + 10OC
Bending Beam Rheometer
Creep Stiffness of max. 300,000 kPa, Rate of Change of Creep with load (m-value) min. 0.30
Direct Tension Test - For Modified Bitumens
Failure strain min. 1%

32. Low Temperature Cracking
Performance Vs Tests
Low Temperature Cracking
Mixing and Laying
Fatigue Cracking
Rutting
Fraass Breaking Point
Creep Stiffness
Rate of change of Creep
Failure Strain
Softening Point
Viscosity
Penetration
Complex Shear Modulus
Ductility
Fatigue Strength
Softening Point, Viscosity &
Penetration after Aging
Viscosity at 135OC

33. Types of Binders Tar Natural Asphalt / Rock Asphalt / Lake Asphalt
Bitumen

34. Tar COKE OVEN TAR LOW AROMATIC 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 %.

35. 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 max
Asphalt found in France, Italy & Switzerland - Rock Asphalt.

36. Bitumen Cutback Bitumen Emulsions Modified Bitumen
Conventional Bitumen
Paving Grade Bitumen
Industrial Grade Bitumen
Cutback
Bitumen Emulsions
Modified Bitumen
Modified Bitumen Emulsions

37. B I T U M E N
A VISCO - ELASTIC MATERIAL

38. 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.

39. The Stiffness Concept In solids : E = s e where E = Elastic modulus
s = Stress
e = Strain

40. The Stiffness Concept 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.

41. B I T U M E N
COMPOSITION

42. Elemental Analysis Carbon 82 - 88 % Hydrogen 8 - 11 % Sulphur 0 - 6 %
Oxygen %
Nitrogen %

43. Chemical Composition Decreases Penetration Increases Penetration
Increases Softening Point, reduces Penetration Index, increases Viscosity
Reduces Shear Susceptibility

44. BITUMEN PRODUTION PROCESSES

46. Bitumen Production Process
Atmospheric Distillation
Vacuum Distillation
Air Blowing of Short Residue
Propane Deasphalting

47. Atmospheric Distillation
Only very heavy Crudes like Boscan Crudes can be processed
The atmospheric unit can be adjusted in such a manner that the residue of the atmospheric unit meets the bitumen specifications without any alteration and can be directly used as bitumen
Very little scope to control Bitumen properties

48. Vacuum Distillation Heavy Crudes like Arab Heavy can be processed
Vacuum Distillation Unit (Vacuum Tower Bottoms) may meet the specifications of paving grade bitumen without any further processing
Depending on origin of the crude, bitumen with penetration ranging form 35 to 300 can be produced directly from the Vacuum Distillation Unit
Still little scope for controlling the properties of Bitumen

49. Air Blowing of Short Residue
Relatively lighter Crudes can be used
The VTB is rectified by blowing hot air into it
The process is controlled by regulating the temperature, rate of blowing, duration of blowing and usage of catalyst
When hot air is blown into VTB the process of oxidation takes place resulting in increase in molecular weight. The increase in molecular weight is due increase in Asphaltenes and Resins accompanied by reduction in Aromatics and Saturates
Catalyst like Ferric Chloride, Phosphorus Pentoxide, Sulphuric Acid or Hydrochloric Acid can also be used to reduce the blowing time. However, the catalyst is consumed in the process of blowing and therefore strictly speaking it is not really catalytic reaction
Catalytic blowing results in bitumen with higher penetration for the same softening point

50. Propane Deasphalting
This process takes advantage of the complex internal solubility parameters of bitumen
In the Propane Deasphalting process Propane or mixture of Propane and Butane in liquid state is introduced at the bottom of the column
Under controlled conditions the Aromatics get dissolved in Propane and the resultant material left at the bottom is Propane Deasphalted Asphalt
This has very high concentration of Asphaltenes and Resins and confirms to specifications of harder grades of Bitumen
This can be blended with VTB to get a wide variety of bitumen

51. Specifications and Test Methods
Insert a map of your country.

52. 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
Insert a picture of one of the geographic features of your country.

53. 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

54. Relationship Between Properties

55. Interdependencies Penetration at Softening Point – 800 Penetration at
Fraass Breaking Pt
– 1.25
Interdependencies
Viscosity at
Softening Point
1200 Pa s
(12000 poise)

56. B I T U M E N
Properties

57. Relationship between Properties
Penetration
Softening Point
Penetration is approx. 800
Viscosity is 1200 Pa s
Fraass Breaking Point
Penetration is approx. 1.25
Viscosity

58. Bitumen Test Data Chart

59. Optimal Viscosity for mixing & compaction

60. Selection of
GRADE

61. 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.

62. 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.

63. 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.

64. 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.

65. Handling of
BITUMEN

66. Aging of Bitumen Bitumen undergoes a process of aging with time
Becomes harder and brittle
Factors affecting aging of bitumen
High Temperature
Availability of Oxygen
Exposure to UV radiation

67. Aging of Bitumen

68. Normally Bitumen hardens by one grade during mixing and laying.

69. Bitumen
Advantages

70. Advantages Versatile State of-the-art Stage Construction
Resistant to de-icing material
Serviceability
Smooth
Safe
Economical
Speed
Quiet
Environment friendly

71. 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

72. Safe Better skid resistance over a longer period of time
Use of OGFC reduces Tyre Spray, Hydroplaning and Improves Visibility
Better contrast with pavement markings

73. 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

74. 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

75. 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

76. 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

77. 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

78. 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.

79. De-icing Materials
Bituminous pavements are not harmed by de-icing chemicals
Also snow and ice melt quickly from bituminous pavements

80. 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.

81. Versatile

82. Beautiful

83. MODIFIED BITUMEN
Binder of the future

84. 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

85. Crumb Rubber Modified Bitumen+
Additives
(Modifiers/Treated Crumb Rubber)

86. 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

87. Types of Modifiers Polymers Plastics Rubbers Thermoset Thermoplastic
Synthetic Elastomers
SBS, SBR etc.
Polymers
Plastics
Rubbers
Crumb Rubber
Natural Rubber
(Latex)
Thermoset
Epoxy Resins
Plain
Thermoplastic
LDPE, EVA, EBA
Chemically
Treated

88. Selection Criteria Atmospheric Temperature OC <35 35-45 >45
Minimum Maximum
< >45
< CRMB50 CRMB 55 CRMB 55
-10 to CRMB CRMB CRMB 60
> CRMB CRMB CRMB 60

89. Conclusions
Quote:
“Based on the data analysis presented for the two pavements, an asphalt-rubber pavement would be more cost-effective than a conventional pavement with respect to agency costs as well as user costs. In addition, the good performance of the asphalt-rubber pavement would increase its service life, which in turn would have a substantial impact on life cycle cost analysis. Furthermore, if one or more rehabilitation is eliminated in a typical analysis period (35 years), it would also have a significant impact on user costs during the work zone periods.”
Unquote.

90. Bitumen
New Trends

91. 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

92. 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

93. 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.

94. 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.

95. 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

96. 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

97. 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

98. 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

99. Warm Mix Asphalt Helps in reduction of handling temperatures
Lower emission
Lower fuel cost
Some proprietary products available in international market
May have to review the aging of bitumen as handling temperatures will be lower
Research on at many places on Europe and USA.

100. 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

101. PERFORMANCE GRADE BITUMEN

102. More direct correlation between bitumen and road performance is needed
BITUMEN TODAY
Penetration/Viscosity based classification
80/100, 60/70, 30/40
Penetration, Softening Point, Ductility, Viscosity
Empirical tests done at standard temp., loading, etc.
Ageing is not considered
No direct correlation with actual field conditions
Seems to work somehow – Has stood the test of time
Need to cut inefficiencies – Cost effective
More direct correlation between bitumen and road performance is needed

103. - New system of classification to be developed
BITUMEN TOMORROW
More direct correlation between road performance and properties 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

107. PG 58 -22 CLASSIFICATION Min. pavement design temp. Performance Grade
Average 7 day max. pavement design temp.

108. MIXING AND LAYING Tested in rotational viscometer
Max. viscosity of 3 Pa-s at 135oC

109. AGEING OF BITUMEN During Construction Early in Pavement’s life
Post construction upto two years
Late in pavement’s life
Seven plus years of life
Rotating thin film oven test (RTFOT)
RTFOT + Pressure Ageing Vessel (PAV)

110. ROTATING THIN FILM OVEN TEST

111. PRESSURE AGEING VESSEL

112. RUTTING Due to melting of bitumen on the road
Always occurs at max. pavement temp.
Test to be conducted at max. pavement temp.
Tested in Dynamic Shear Rheometer
G*/Sind min rad/s for unaged bitumen
G*/Sind min rad/s for RTFOT aged bitumen

113. DYNAMIC SHEAR RHEOMETER

114. FATIGUE Due to repeated loading,unloading cycles
Always occurs near the average pavement temp.
Test to be conducted at average + 4OC pavement temp.
Tested in Dynamic Shear Rheometer
G*Sind max rad/s for RTFOT + PAV aged bitumen

115. LOW TEMP CRACKING Failure strain min. 1%
Due to loss of elasticity at very low temp.
Always occurs at lowest pavement temp.
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%

116. BENDING BEAM RHEOMETER

117. DIRECT TENSILE TESTER

118. PERFORMANCE EVALUATION

119. GRADE BUMPING
Choice of grade depends on max. and min. pavement temperature 20 mm below road surface.
Correction for Traffic speed
> 90 km/h No Correction
< 90 km/h Increase one high temp. grade
< 20 km/h Increase two high temp. grade
Correction for Traffic volume
< 10 million ESAL - No Correction
> 10 million ESAL - Increase one high temp. grade
> 30 million ESAL - Increase two high temp. grade

120. Safe Handling Practices

121. Health, Safety & Environmental Aspects
Low order of potential hazard provided good handling practices are observed.
Contains Polycyclic Aromatic Hydrocarbons. PCAs with molecular wt. Of 200 to 4500 are biologically active carcenogens. Concentration of these in Bitumen is extremely low.
Other than heat burns, hazards are negligible. However it is prudent to avoid prolonged & intimate skin contact.

122. Health, Safety & Environmental Aspects (contd.)
In case of skin burns plunge the affected area under cold running water for 10 minutes.
When bitumen is heated or mixed with aggregate, fumes are emitted. The fumes contain particulate matter, Hydrocarbon vapours & very small amount of H2S. However, the concentration is rarely above permissible limits.