3Bitumen - HISTORY Used in Building and Paving since Ancient times. Oldest adhesive known to man.Used in 3500 B.C. as mortar for building stones and paving blocks in Mesopotamia.Used for water tightening of reservoirs, canals, bathing pools & embankments of rivers in Indus Valley.Used for Mummification in 300 B.C.Rock Asphalt used for flooring/sidewalks in France in 1800 A.D.First road surfacing with Bitumen done in New Jersey in 1870 A.D.From 1900 onwards Bitumen produced from Refineries being used extensively.
5Types of Binders TAR NATURAL ASPHALT / ROCK ASPHALT / LAKE ASPHALT BITUMEN
6Tar COKE OVEN TAR LOW AROMATIC TAR Produced at temperatures above 1200OC during manufacturing of coke.High aromatic content.Pitch content - 50 %.LOW AROMATIC TARProduced at temperatures 600OC to 700OC.Less viscous.Paraffinic in nature.Pitch content - 35 %.
7Natural Asphalt / Rock Asphalt / Lake Asphalt Naturally occurring Bituminous binder.Biggest deposits in Trinidad100 Acres,90 meter deep10 to 15 Million MTPen maxAsphalt found in France, Italy & Switzerland - Rock Asphalt.
10Production Process Fractional distillation Process Crude Oil heated to 300 – 350OC is fed into atmospheric distillation column.Lighter fractions like Naphtha, Kerosene, Diesel separated at different heightsHeaviest fractions at bottom column are called long residue.Long residue heated to OC fed into distillation column at reduced pressure.Residue at bottom of column called short residue used as feedstock for Bitumen.Hot air is blown into short residue to make Bitumen.
12BitumenA viscous liquid or a solid, consisting essentially of Hydrocarbons and their derivatives, which is soluble in Trichloroethylene and is substantially non-volatile and softens gradually when heated. It is Black or Brown in colour and posses water proofing & adhesive properties. It is obtained by refining processes from Crude Petroleum.
15Elemental Analysis Elemental composition depends on origin of crude processes used in refineryElemental compositionExtremely complex with the number of molecules with different chemical structures being very largeNot feasible to attempt a complete analysisElemental composition provides little information of the types of molecular structure
18Properties of Bitumen Characteristics 80/100 60/70 30/40 Specific gravity at 27OCSoftening Point OC to to to 65Penetration at 25OC, to to to 40100gm, 5 secs., 1/10 mmDuctility at 27OC, in cm min
19SIGNIFICANCE OF TESTS Penetration Test Indicates consistence Softening PointIndicates melting temperatureLoss on heating / thin film oven testHardening on roadDuctility TestAffinity for aggregatesSolubility in TrichloroetheleneIndicates purity of Bitumen
20PenetrationTravel in dmm of a specified needle under 100 g wt. for 5 secs into Bitumen at 25OCDenotes consistency
21Softening Point3.5 g steel ball placed on Bitumen sample in Brass ringBath temp. raised at 5OC per minute
22DUCTILITYIndicates the extent to which a sample can be stretched before breaking.Length in cm. at breaking point is ductility
23FLASH POINTUsed to measure temperature to which a sample bitumen may be safely heatedThe flash point is the temperature reached when the vapour causes an instantaneous flash
25Storage & HandlingBitumen tanks should have low surface to volume ratio.p r2 1Exposed surface =pr2h hProduct should be recirculated, however, return lines should enter the tank below Bitumen surface.Bitumen should always be handled at lowest possible temperature, consistent with efficient use.In case of reheating, heating should be done intermittently to prevent high localised temperatures. Prolonged direct flame heating may cause cracking of Bitumen.
26Recommended Handling Temperatures Characteristics / /70 30/40Min. Pumping Temp.27OCMixing/Coating Temp. OC 150 to to to 175Laying Temp.OC to to to 160Spraying Temp.OCMax. Safe Hdlng. Temp. OC
27Normally Bitumen hardens by one grade during mixing and laying.
29Selection Criteria 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.
30Applications 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.
31Applications 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.
32Applications of 30/40 Grade Suited for areas where diff. between min. & max. temp. < 25oC.Suited for traffic intensity > 1500 cv/ dayUsed in metropolitan areas.Used in airport runways.
39Smooth Better riding quality Absence of joints Estimated 15% increase in pavement life for 50% increase in smoothnessLess wear and tear to vehicleLesser fuel consumptionEnjoyable ride
40Safe Better skid resistance over a longer period of time Use of OGFC reduces Tyre Spray, Hydroplaning and Improves VisibilityBetter contrast with pavement markings
41Economical Low initial cost compared to PCC Gap widens throughout pavement lifeA well designed and constructed pavementCan last for 25 to 34 years without reconstructionCan serve for 15 year or more before distresses become sufficient to require rehabilitation
42Speed of ConstructionNewark Airport – 1,15,000MT in 15 days, 11,000MT in 24 hoursPave during off peak hours and open to traffic as soon as it cools downReduces work zone accidentCan result in 80% reduction in user delay costs24-hour closure will have 3 to 10 times more vehicles pass through the work zone
43Quiet PavementsDense graded asphalt is quieter by 2 to 3 dB(A) compared to PCC3 dB(A) corresponds toDoubling the distance in the line of sourceReducing traffic volume by 50%Reducing traffic speed by 25%Open graded Friction CourseReduces noise furtherCosts 1/8th of noise barrier on side of the roadAesthetically superior
44Environment FriendlyUsed for water proofing of fish ponds without any problemVery low level of leachable compoundsMost recycled product in the world100% recyclableSecond highest - Aluminium cans – 60%Can use waste material from other fields also like worn out PCC
46State-of-the-ArtRoad design, construction and maintenance methods are being overhauledNew tests being developedNew plants providing high quality materialsPavers with laser controlled screeds for even smoother pavementsBetter 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
47Stage Construction Bituminous pavements can be constructed in stages Being made thicker and/or wider as the need arisesEach successive layer becomes an integral part of the pavement structure, increasing the load carrying capacity.
48De-icing MaterialsBituminous pavements are not harmed by de-icing chemicalsAlso snow and ice melt quickly from bituminous pavements
49ServiceabilityBituminous pavements can easily maintain a high level of serviceability with minimal disruption to the trafficCan be easily trenched, patched and quickly opened to traffic when underground utilities need to be repaired.
52Engineering Properties of Bitumen Bitumen is a visco-elastic material & it’s deformation under stress is a function of both temperature & loading timeAt higher temperature &/or longer loading timeBehave as viscous liquidsAt low temperature &/or short loading timeBehave as elastic solidsThe intermediate range of temperatures, more typical of the conditions in service, result in visco-elastic behaviour.
53The Stiffness Concept In solids : E = s e where E = Elastic modulus s = Stresse = Strain
54The Stiffness Concept In visco-elastic material : St,T = s et,T Where St,T = Stiffness modulus at specific time t & Temp. T.s = Stresset,T = Strain at specific time t & temp. T.
56Why Modified Bitumen? Demands on Road increasing every year Increasing Number of VehiclesIncreasing Axle LoadDesire to maintain higher serviceability levelHigher fatigue resistanceHigher resistance to weatheringBetter adhesionHigher stiffness modulusLesser cracking, ravelling, deformation & creep failureReduce number of overlaysReduction in vehicle operation cost
57Why Modified Bitumen? Another view point 2.75 million vehicles generate discarded tyres30, ,000 tyres are disposed every day1,00,000 –1,20,000 tyres will be available by 2021Use of CRMB in maintenance of roads can consume 3500 Kg/km non-biodegradable waste rubber
59Advantages of CRMB Higher resistance to deformations/ wear & tear Resistance to reflective crackingReduced expense on frequent overlaysLower susceptibility to temp. variationHigher resistance to deformation at high temperatureBetter Age Resistance PropertiesHigher Fatigue Life of MixesBetter Adhesion PropertiesReduced Noise
62Grades of CRMB GRADES HP GRADES CRMB 50 HP MB(CR) 50 Meets IRC:SP:
63Tests on CRMB Penetration Softening Point Elastic Recovery Thin Film Oven Test
64Test and Trials with CRMB Central Road Research Institute, New Delhi.Highway Research Station, Chennai.Gujarat Engineering Research Institute, Vadodara.Indian Institute of Technology, Kharagpur.Municipal Corporation of Delhi.Research Station, P.W (R&B) Dept., Hyderabad., Andhra Pradesh.
65INTERNATIONAL USAGE OF CRUMB RUBBER MODIFIED BITUMEN
66International Use of Crumb Rubber Modified Bitumen CRMB is being used in USA from 1960Currently 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 increasing in developing countries of Latin America.
67International Use of Crumb Rubber Modified Bitumen 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 encouraging the use of CRMB on FreewaysSouth African companies are increasingly using Rubber Modified mixes
6825 YEAR ANALYSIS BY DEPARTMENT OF TRANSPORT, ARIZONA
69ConclusionsTotal thickness of conventional pavement was 21 inches Vs. 13 ½ inches for a rubberized pavement, the cost saving in initial construction was approx. 42%Roughness value of conventional pavement was poorer by 27% initially but due to higher deterioration the gap increased to 50% by end of 11 yearsIn span of 11 years 50% less money was spent on maintenance cost on rubberized pavement in comparison to conventional pavementThe benefit to the user by way of savings in VOC was also seen and estimated that it is significantly less on rubberized pavement in comparison to conventional pavement
70ConclusionsQuote:“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.
72Recommended Handling Temperatures Stage of WorkViscosity, PoiseTemp. Range, OCBinder at Mixing< 2165 – 185Mix at Mixing Plant< 4Mix at Laying Site< 5Rolling at Site10 – 1,000
73HANDLING OF CRMB CRMB should ideally be used in hot condition. When supplied in drums, it shall be agitated properly in melted condition for minutes before use.Mixing & rolling temperature should be approx. 10OC higher than conventional temperature.
75Future Trends in Bituminous Roads ISO Certification of RoadsRoad Safety AuditPerformance Based SpecificationsStone Mastic AsphaltPerpetual PavementsFoamed BitumenPolyphosphoric Acid Modified BitumenSulphur Extended Bitumen Modifiers
76ISO Certification of Roads Growth in EN ISO 9000 certification in European countriesVoluntary 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
77Road Safety Audit Fresh project proposals Existing network of roads Safety audit applied toFresh project proposalsExisting network of roadsSpecific existing projectAuditors 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.
78Road Safety Audits (Contd.) The team selects aspects and features that were observed on a number of audited roads.The teams’ recommendations focus on policies and procedures and not on correcting the identified deficiencies.The team ranks each recommendation on a four point subjective scale.The draft report in a standard format is reported to the authority for their commentsA formal final report is submittedDatabase is developed for all road safety audits
79Performance Grade Specifications Existing SpecificationsMost tests are empirical tests and are not directly related to performance on the roadTests are conducted at one standard temp.Performance under climatic condition prevailing throughout the year are not evaluatedOnly short term ageing is evaluated, that too only in a few casesPerformance grade tests simulate the actual field conditions in a more realistic way
80Stone Mastic AsphaltIncreasingly 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.
81Stone Mastic Asphalt (Contd.) The aggregate grading is similar to that of Porous Asphalt, but with the voids filled with mortar.The process of designing Stone Mastic Asphalt mix involves adjusting grading to accommodate required binder and void content rather than the more familiar process of adjusting the binder content to suit the aggregate grading.Cost effective despite high quality aggregate & higher binder content.Extremely low maintenance.Longer life.
82Perpetual Pavements Structure Lasts 50+ years Bottom-Up Design and ConstructionIndefinite Fatigue LifeRenewable Pavement Surface.High Rutting ResistanceTailored for Specific ApplicationConsistent, Smooth and Safe Driving Surface.Environmentally FriendlyAvoids Costly Reconstruction
83Perpetual Pavements Designed and build to last at least 50 years Will result in reduced maintenance cost and traffic disruptionsBuild bottom-up with strong foundation and structural stabilityHigher fatigue resistance in lower layersHigher rutting resistance in upper layersDrainage is an important consideration in the design of pavement structuresThe change in foundation properties with the different seasons must be adequately accounted forSpecial soil conditions such as frost heave and expansive behavior need to be included in the site investigation and design, depending upon the local situation and standard practiceThe selection of materials and mix design for the HMA layers is dependent upon the needs for the individual layers with respect to the overall performance of the pavementAggregate interlock is an important component to mix stability.
84Perpetual PavementsThe use of crushed, hard aggregate particles and an aggregate structure evaluation will help to guarantee particle-to-particle contact.use of polymers and fibers can enhance the high-temperature performance of asphalt binders.It is important to achieve the proper density during construction. An air void content higher than about six percent may result in consolidation and rutting early in the pavement’s life.The material in the top HMA layer may be either a SMA, OGFC or Superpave mix, depending upon the needs of a specific area. In any case, as distresses dictate the need for a new pavement surface, the old surface may be milled up and replaced with a minimum of traffic disruption and cost.This underscores the principles of the Perpetual Pavement: Design: build it for the traffic, soil and climate, and the only cost thereafter should be associated with periodic overlays.There are a number of initiatives by various countries and states to formalize the concept of Perpetual Pavements.In Europe, particularly England and France, the idea of high-modulus pavements has gained acceptance. These are thick asphalt pavements placed over one or more layers of granular material.Illinois is engaged in developing a long-life asphalt pavement design procedure. Participants have included the Illinois DOT, the HMA industry and the University of Illinois.The Michigan Asphalt Pavement Association has developed a Perpetual Pavement design procedure.Wisconsin is in the process of researching Perpetual Pavements at a number of test sites.Texas is using Perpetual Pavements along the heavily traveled I-35 corridor.Kentucky has used the Perpetual Pavement concept to design portions of interstate pavements.Other efforts are proceeding in Virginia and Ohio.What makes the Perpetual Pavement perpetual is that, while the surface will need periodic replacement, the bulk of the pavement structure will remain intact.
85Foamed BitumenMixture 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 timesForms a fine mist or foamFoamed bitumen is sprayed on fine aggregate in mixing drums to get a strong flexible pavement materialUsed for durable, fast and low cost rehabilitation of existing pavements
86Polyphosphoric Acid Modified Bitumen Lower stripping compared to other bitumensReduction in mixing and laying temperaturesImproves fracture strength and ductilityVery low dosage of modifierTest tracks in the world are still under evaluation but preliminary results are very promising
87Sulphur Extended Asphalt Modifier Odourless pellets consisting of Sulphur, Plasticizers and additivesIs added to the hot mixMelts and disperses easilyActs as binder extender and asphalt mix modifierEnvironmentally safeReduces Bitumen requirement by 30%Mixing temperature is reduced by 10OCHigher resistance to rutting, fatigue failure and low temperature crackingSuitable for perpetual pavements
89More direct correlation between bitumen and road performance is needed BITUMEN TODAYPenetration/Viscosity based classification80/100, 60/70, 30/40Penetration, Softening Point, Ductility, ViscosityEmpirical tests done at standard temp., loading, etc.Ageing is not consideredNo direct correlation with actual field conditionsSeems to work somehow – Has stood the test of timeNeed to cut inefficiencies – Cost effectiveMore direct correlation between bitumen and road performance is needed
90BITUMEN TOMORROW - New system of classification to be developed More direct correlation between road performance and properties of bitumenProperties desiredEasier handling (mixing, coating, rolling)Better rutting resistanceHigher fatigue lifeResistance to low temperature cracking- New system of classification to be developed- New tests to be developed
94CLASSIFICATION PG 58 -22 Min. pavement design temp. Performance Grade Average 7 day max. pavement design temp.
95MIXING AND LAYING Tested in rotational viscometer Max. viscosity of 3 Pa-s at 135oC
96AGEING OF BITUMEN During Construction Early in Pavement’s life Post construction upto two yearsLate in pavement’s lifeSeven plus years of lifeRotating thin film oven test (RTFOT)RTFOT + Pressure Ageing Vessel (PAV)
99RUTTING 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 RheometerG*/Sind min rad/s for unaged bitumenG*/Sind min rad/s for RTFOT aged bitumen
101FATIGUE 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 RheometerG*Sind max rad/s for RTFOT + PAV aged bitumen
102LOW 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. + 10OCBending Beam RheometerCreep Stiffness of max. 300,000 kPa, m-value min. 0.30Direct Tension Test - For Modified BitumensFailure strain min. 1%
106GRADE BUMPINGChoice 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. gradeCorrection for Traffic volume< 10 million ESAL - No Correction> 10 million ESAL - Increase one high temp. grade> 30 million ESAL - Increase two high temp. grade
109Bitumen Quality Depends on quality of input crude and process adopted Operates on set parameters with minimal human interventionEach batch tested for critical parameters
110Drum Quality Fabricated as per IS 3575-1977 Type B Quality of steel as per IS – 0.63mmQuality of drum fabricationEnsure zero defectsEnsure min. wastage of steelDouble sealingStrengthening corrugations – 5+1mmQuality of Painting – 2 coats of Bituminous paintTestingEach drum is tested at 0.25 kgf/cm2 pressure
111Drum Filling Highest quantity per drum – 161.8kg Lesser steel consumption per MT.Filling at reduced temp. – 110OCLess spillageMore qty. can be filledProper dimension of lids 175 mmDelayed sealing of lidsCoefficient of expansion – /oCBitumen cools downReduced temp. variations after sealingLess stress on drum surface & joints
112Storage Storage & handling different from Lube drums Vertical storage Pyramid styleStorage on firm surfaceAsphaltedConcretedWBMFirms dry soilAvoid Black cotton soilStacks of 500 or 1000 with passage between stacksSingle layer/Double layer/Triple layer depending upon the surface
113Handling Different from Lube drums Always transport drums in vertical position onlyWhile unloading drums are vertically lowered onto the tyresWhere ever possible fork lift can be usedWhile rolling the surface should be free of pebblesWhere ever possible wooden pellets to be used for unloading and storing
115Health, 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.
116Health, 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.
117No Wonder “The smart choice is HP Bitumen” Thank You!