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Bitumen Specifications

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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

45

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

104

105

106

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.


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