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Rutting resistance of filler modified bituminous concrete surfaces 2
 

Rutting resistance of filler modified bituminous concrete surfaces 2

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    Rutting resistance of filler modified bituminous concrete surfaces 2 Rutting resistance of filler modified bituminous concrete surfaces 2 Document Transcript

    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME250RUTTING RESISTANCE OF FILLER MODIFIED BITUMINOUSCONCRETE SURFACESDr. K.V.Krishna Reddy1Professor & Principal, Chilkur Balaji Institute of Technology, Hyderabad-75, AP, IndiaABSTRACTIn the present study, an attempt is made to study the improvement in rut resistance ofthe conventional bituminous concrete by modification with fillers like fly ash, lime andcrumb rubber. The study includes evaluation of the conventional and modified bituminoussurface courses in the laboratory and with the Medium Scale Accelerated Pavement RutTester on a test track. The results found were encouraging with crumb rubber providing themaximum benefit.Key Words: Accelerated Pavement Testing, Rutting resistance, Filler modified bituminousconcrete.1. INTRODUCTIONIn recent years, highways have experienced an increase in the severity and extent ofpermanent deformation (rutting) in hot mix asphalt pavements. The increased rutting hasbeen attributed to increase in axle loads and traffic volumes. Conventional flexible pavementshave water bound macadam being used as the base course and granular material in thesubbase, both of which are load distributing layers. They have good material properties andsufficient strength to transfer the loads coming from the top layers and need no replacementor additives except for strict quality control during construction, leaving the top surfacecourse for modification for desired performance.In the present study, an attempt is made to evaluate the rutting resistance of theflexible pavements by improving the stiffness of the surface courses sufficiently to sustain thehigh stress states. The study includes evaluation of optimal quantities of fillers for bituminousconcrete layer and conduct laboratory wheel tracking test along with field tests on the testtrack built for the purpose to evaluate the life benefit due surface modifications in variouscombinations using a Medium Scale Accelerated Pavement Rut Tester (Krishna Reddy.K.V,2007) to evaluate the rutting resistance.INTERNATIONAL JOURNAL OF CIVIL ENGINEERING ANDTECHNOLOGY (IJCIET)ISSN 0976 – 6308 (Print)ISSN 0976 – 6316(Online)Volume 4, Issue 2, March - April (2013), pp. 250-257© IAEME: www.iaeme.com/ijciet.aspJournal Impact Factor (2013): 5.3277 (Calculated by GISI)www.jifactor.comIJCIET© IAEME
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME2512. RESEARCH METHODOLOGY2.1 Laboratory testing80/100-penetration grade bitumen has been considered as basic material for thesurface course. Aggregates with grade II specifications as per MORTH (Ministry of RoadTransport and Highways) specification have been collected from local quarry. Basic materialproperties have been determined as per codal provisions.Laboratory tests, namely abrasion, attrition, impact value, shape and crushing value havebeen conducted on the aggregate and the properties of the same are reported in Table 1. Testson bitumen, namely penetration, ductility, softening point, specific gravity and flash& firepoint test have been conducted and the findings are as per Table 2.Table 1 Properties of aggregate used for surface courseProperty Value Property ValueSpecific gravityCA 2.79FA 2.76Abrasion value 24%Impact value 15% Attrition value 21%Crushing value 20%Shape test(EI+FI)13%Table 2 Properties of bitumen used for modificationProperty Value Property ValueSpecific gravity 1.04 Ductility 100+ cmPenetration(in 0.1mm)84.65Flash pointFire point2700C3150CSoftening point 470C Viscosity 130 SecFly ash is procured from Ramagundam super thermal power plant, Hydrated lime ofspecific gravity 2.35 is procured locally. The filler is introduced as filler by replacing thefiner fraction (<75micron) in the aggregate in terms of % by weight of aggregate. Crumbrubber obtained by grinding scrap pneumatic motor vehicle / truck tires is procured locally.Wet process of mixing crumb rubber was adopted, where in the crumb is added to theconventional bituminous binder by weight of bitumen before incorporating the same into thefinal mix. Crumb rubber is added to bitumen after heating the conventional 80/100-bitumento a temperature of 1630C.Marshall Mix design using conventional materials was conducted on three sampleseach. The optimum bitumen content for conventional bituminous concrete mix is found to4.3% for grade-II aggregates. Further, optimum filler content in case of lime, fly ash andcrumb rubber were evaluated by adding them at the optimum bitumen content obtained forthe conventional bitumen The mix design values for conventional and modified mixes are asgiven in Table 3.
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME252Table 3. Properties of conventional and modified bituminous mixesS.NoMix / PropertyConventionalmixCrumbmodifiedmixFly ashmodifiedmixLimemodifiedmix1 Optimum Bitumen /filler content4.3% (Bitumen) 11.8% 2.30% 2.80%2 MSV (Kg) 1300 24051505 26503 Air voids (%) 3.875 3.425 4.5 4.054 Flow value (mm) 2.375 3.750 3.38 3.55 Bulk density (g/cc) 2.520 2.470 2.43 2.4462.2 Equipment usedLaboratory wheel tracking test is used in the laboratory to evaluate the ruttingresistance of the conventional and filler modified bituminous concrete samples. The mediumscale accelerated pavement rut tester (MAPRT) is used to conduct field tests operating on acircular track. This equipment can be used to evaluate the performance of the pavements interms of rut depth. The lab and field equipments used are as shown in the Fig. 1(a) and (b).Fig.1 (a) Laboratory wheel-tracking test Fig.1 (b) Medium scale accelerated rut tester
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME2532.3 Test Track Layout and DesignA test track of the flexible pavement was considered to study the performance and lifebenefit of stabilization in four combinations as depicted in the pavement lay out shown inFig.2. The design of the test track was done to ensure that the stresses reach the subgrade.FPAVE program was used to determine the stresses reaching the subgrade. Since, the wheelconsidered distributes load over a circular area of radius 2.82cm, to ensure that the stressesreach the subgrade and facilitate the testing of subgrade and surface in combination, apavement with 40mm thick bituminous concrete, 75mm of WBM base course and 100 mm ofsubbase course was prepared. This pavement system is similar to the full-scale pavements interms of stresses reaching the subgrade under full-scale wheel loads.3. DATA ANALYSISThe results obtained are plotted with number of wheel load repetitions on x -axis andrut depth on y-axis as shown in the Fig.3 for laboratory testing and Fig 4 for test track testingusing medium scale pavement rut tester.Fig.2 Test track Layout1.2m 1.2m3.6mSection 42m2mArm of the acceleratedtesting facilitySection 5 Section 6Section 1 Section 2 Section 3Subbase + Base21 & 3 4 & 6 5Crumb modified bituminoussurfaceGravel subgradeConventional Bituminous surfaceFly ash modified bituminoussurfaceLime modified bituminoussurface
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME2540.00 50000.00 100000.00 150000.00 200000.00 250000.00 300000.00No. of revolutions0.002000.004000.00Rutdepthin0.01mmgraph Type Model predicted R-square1 Conventional surface Y = 0.0129763 * X + 69.3329 0.9993332 Flyash modified surface Y = 0.0106765 * X + -28.1223 0.9995914 Crumb Modified Surface Y = 0.00789102 * X + 24.6849 0.9996473 Lime Modified Surface Y = 0.011543 * X + -57.2172 0.9998311234Fig 3. Figure showing rut life of the bituminous mixes in terms of wheel load repetitions inlab0.00 40000.00 80000.00 120000.00 160000.00 200000.00 240000.00No of repetitions0.001000.002000.003000.00Rutdepthin0.01mmGraph Type of pavment Equation R-sqr4 Crumb modified surface log(Y) = 0.588003 * log(X) + 0.725106 0.9715631 Conventional surface log(Y) = 0.396119 * log(X) + 3.16338 0.9968532 Flyash modified surface log(Y) = 0.468024 * log(X) + 2.27849 0.9793713 Lime modified Surface log(Y) = 0.516154 * log(X) + 1.65014 0.98683612 3 4Fig 4. Figure showing rut life of the bituminous mixes in terms of wheel load repetitionswith MAPRT4. RESULTSThe plots are interpreted and the results are tabulated in the tables 4 and 5. Table 4depicts the no of wheel load repetitions sustained by the conventional and filler modifiedbituminous concrete materials under the laboratory wheel tracking test on laboratory samplesand under the medium scale accelerated pavement rut tester on the test track. Table 5 presentsthe rut life benefit of the filler modified bituminous concrete materials in comparison to theconventional bituminous concrete material.
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME255Table 2 Rut Life of pavement in terms of repetitions of wheel loadS. NoType ofBituminousSurfaceNo of repetitions at a rut depth of 25.4mmWheel tracking testMedium Scale AcceleratedPavement Rut Tester1 Conventional 190000 1320002 Flyash modified 225000 1520273 Lime modified 240000 1600004 Crumb modified 322000 208000Table 3 Rut Life benefit of pavements with fillers compared toConventional pavementS. NoType ofBituminousSurfaceLife Benefit RatioWheel tracking testMedium Scale AcceleratedPavement Rut Tester1 Fly ash modified 18.42% 15.1%2 Lime modified 26.30% 21.2%3 Crumb modified 69.47% 57.5%5. ACKNOWLEDGEMENTAt the outset the author would thank the Head, CED and TE division, and otherprofessors at NIT Warangal for their valuable guidance and encouragement duringexperimentation.6. CONCLUSION1) 11.8% crumb addition by weight of bitumen through wet process to 80/100 bitumen andgrade II aggregates gave optimum mix design values for bituminous concrete with aMarshall Stability value or 2405kg and 3.42% Air voids.2) 2.3% Flyash replacement by weight of aggregate has resulted in optimum mix designvalues for bituminous concrete with a Marshall Stability value of 1505kg and 4.5% Airvoids3) 2.8% Hydraulic lime replacement by weight of aggregate has resulted in optimum mixdesign values for bituminous concrete with a Marshall Stability value of 2650kg and4.05% Air voids4) Medium Scale Accelerated Pavement Rut Testing represent an ideal case for pavementtesting unlike laboratory wheel tracking tests, where in the pavement moves under astandard wheel. The laboratory results are conservative than the field results by 50% andhence laboratory results does not depict the actual rut life when done on individualsamples to evaluate the rut resistance.
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME2565) The average rut life improvement of crumb modified bituminous surface is 57%compared to conventional bituminous concrete6) The average rut life improvement of Lime modified bituminous surface is 21% comparedto conventional bituminous concrete7) The average rut life improvement of Crumb modified bituminous surface is 57%compared to conventional bituminous concreteREFERENCES1. Aschenbrener, T., R. Terrel, and R. Zamora. (1994), “Comparison of the HamburgWheel-Tracking Device and the Environmental Conditioning System to Pavements ofknown Stripping Performance” Rep.No.CDOT-DTD-R-94-1, Colorado Department ofTransportation, Denver, CO.2. Aschenbrener, T. (1994), “Comparison of Test Results from Laboratory and FieldCompacted Samples - Final Report” Rep. No. CDOT-DTD-R-94-3, ColoradoDepartment of Transportation, Denver, CO3. Aschenbrener, T. (1995), “Evaluation of the Hamburg Wheel-Tracking Device toPredict Moisture Damage in Hot-Mix Asphalt” TRR- 1492, TRB, Washington, DC, pp.193-201.4. Albritton, G.E., and Gatlin, G.R. (1996), “Construction and Testing of crumb RubberModified Hot Mix Asphalt Pavement”, Rep. No. FHWA/MS-DOT-RD-96-115,Washington D.C.5. Carl W. Lubold, Jr. (2001), “Are u in a Rut?”, Pro. Moving forward, The PennsylvaniaLocal Road Program, Pennsylvania, Vol. 19, No.2, pp4-5.6. Cockrell, C. F. and Leonard, J. W., (1970), “Characterization and Utilization Studies ofLimestone Modified Flyash”, Coal Research Bureau, Vol. 60.7. Collins, R. J., and Ciesielski, S. K. (1992), “Highway Construction use of wastes andBy-products” Utilization of Waste Materials in Civil Engineering Construction,Published by ASCE, New York, pp.140-1528. Durga Prasad, K. (2002), “A study of lime and fly ash on the performance ofbituminous concrete mix”, Mtech thesis, NITW.9. FPAVE, “Software program for Analysis and Design of Flexible Pavements”,Transportation Engineering Section, Civil Engineering Department, IIT, Kharagpur.10. Izzo, R.P., and Tahmoressi, M. (1999), “Use of the Hamburg Wheel Tracking Device forEvaluating Moisture Susceptibility of Hot-Mix Asphalt”, TRR-1681, TRB, pp 76-85.11. Jorgenson, L. (2003), “Tires make the road - asphalt rubber pavement construction”,Public Works Journal, Vol. 134, No. 1, pp 30-31.12. MORT&H - 2001: Specifications for Roads and Bridge works, Ministry of RoadTransportation and Highways.13. Krishna Reddy,KV, 2007, “Medium Scale Accelerated Pavement Rut Tester”, IndianHighways, Indian Roads Congress, New Delhi, Vol 35, No.12, PP 23-3014. Metcalf, J. B. (1996), “Application of Full-Scale Accelerated Pavement Testing”,NCHRP Synthesis of Highway Practice, Rep. No. 235, National Research Council, TRB,Washington D.C.15. Quintus Von, H.L. (2001), “Hot-Mix Asphalt Layer Thickness Design for Longer-LifeBituminous Pavements”, Transportation Research Circular, No. 503.
    • International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME25716. Romero, P., and Stuart, K. (1998), “Evaluating Accelerated Rut Testers”, Public RoadsJournal, Vol. 62, No. 1, pp 50-54.17. Volle (2000), “The Performance of Rubberised Asphalt Pavements in Illinois”, Rep. No.FHWA/IL/PRR-136, Washington D.C.18. Williams, R.C., and Prowell, B.D. (1999), “Comparison of Laboratory Wheel-TrackingTest Results with WesTrack Performance” TRR-1681, TRB, pp 121-128.19. Yoder, EJ and Witczac, M.W (1975), “Principles of Pavement Design”, 2ndEdition, JohnWiley & Sons.20. Ravin M. Tailor, Prof. M. D. Desai and Prof. N. C. Shah, “Performance Observations forGeotextile Reinforced Flexible Pavement on Swelling Subgrade: A Case of Surat,India”, International Journal of Civil Engineering & Technology (IJCIET), Volume 3,Issue 2, 2012, pp. 347 - 352, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.21. Brijesh Kumar and Nitish Puri, “Stabilization of Weak Pavement Subgradesusing Cement Kiln Dust”, International Journal of Civil Engineering & Technology(IJCIET), Volume 4, Issue 1, 2013, pp. 26 - 37, ISSN Print: 0976 – 6308, ISSN Online:0976 – 6316.