Maturity period and curing as important quality control parameters

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Maturity period and curing as important quality control parameters

  1. 1. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME393MATURITY PERIOD AND CURING AS IMPORTANT QUALITYCONTROL PARAMETERS FOR LIME STABILIZED CLAYSUBGRADESDr. K.V.Krishna Reddy1, Mr.K.P.Reddy21Professor & Principal, Chilkur Balaji Institute of Technology, Hyderabad-75, AP, India2Maintenance Engineer, Vasavi College of Engineering, Hyderabad-75, AP, IndiaABSTRACTWith rapid industrialization and the need for rural road development, it has becomeimperative to use poor subgrades for road formation. Poor subgrades, especially clayey soilsneed stabilization for effective performance. Though undesirable, most of the times insituconditions does not go in hand with the strict quality control measures with regard to thedelay in compaction (maturity period) and curing in road formation works.The object of the present study is to determine the effect of delayed compaction onCalifornia bearing strength and curing period on the California bearing strength (CBR) andunconfined compressive strength (UCC) of clay-lime mixes. The results highlight theimportance of the maturity period and curing as important quality control parameters.Key Words: Maturity Period, Delay in compaction, Curing of lime stabilized subgrades,Lime stabilization.1. INTRODUCTIONRural Road Connectivity is not only a key component of Rural Development bypromoting access to economic and social services and thereby generating increasedagricultural incomes and productive employment opportunities in India, It is well known thateven where connectivity has been provided, the roads constructed are of such quality (due topoor construction or maintenance techniques) that they cannot always be categorized as All-weather roads. In the process of connecting various parts of the country, it has becomenecessary to use all the types of subgrades for highway formation and clayey soils are noexception.INTERNATIONAL JOURNAL OF CIVIL ENGINEERING ANDTECHNOLOGY (IJCIET)ISSN 0976 – 6308 (Print)ISSN 0976 – 6316(Online)Volume 4, Issue 2, March - April (2013), pp. 393-401© IAEME: www.iaeme.com/ijciet.aspJournal Impact Factor (2013): 5.3277 (Calculated by GISI)www.jifactor.comIJCIET© IAEME
  2. 2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME394Clayey subgrades stabilized with lime, cement or chemicals have come to stay as astandard engineering material for high way construction. During recent years, there has beenan extensive use or lime for the stabilization or clayey soils, which have many advantagesover the other types of stabilization, however due to minor negligence in parameters likematurity period and curing of the stabilized mixes a lot of strength loss occurs which isirreparable and need a lot of maintenance after construction2. LITERATURE REVIEWDumblet observed that the delay in wet mixing and subsequent compaction has littlesignificance. Mitchell working with an organic expansive clay mixed with 4 percent dolomitehydrated lime gathered that a delay of 24 hours between wet mixing and compaction canresult in loss in maximum dry density and a loss the compressive strength.To investigate the effect of elapsed time between mixing and compaction of a dunesand and montmorillonitic clay with flyash and a high Calcium hydrated lime, Davidson,inferred that a delay of 24 hours had negligible effect on the density and strength in case ofdune sand, but in case of clay, the delay in mixing and compaction caused appreciabledecrease in dry density and strength or the mixes.An evaluation of the effect of delay between mixing was investigated upon by cockaet al. Samples of soil mixed with lime and cement were compacted at different delay periods.Results indicated that the dry density or the samples showed a slight decrease irrespective ofthe addition of lime to the soil. Strength values also showed a decrease, though the decreasewas minimized by the addition or lime.Fly ash is one of the most plentiful and versatile of the industrial by-products (Collins,1992). It is classified into two classes based on the chemical composition of the flyash. Class‘F’ flyash is produced from burning anthracite and bituminous coals and contains smallamount of lime (CaO). (Cockrell, 1970; Chu and Kao 1993) This flyash has siliceous andaluminous material (pozzolans), which itself possesses little or no cementitious value but inthe presence of moisture, chemically reacts with lime at ordinary temperature to formcementitious compounds. Class ‘C’ flyash is produced from lignite and sub-bituminous coalsand usually contain significant amount of lime along with pozzolanic materials. Thepozzolanic reactivity of the flyash is not represented by any chemical or physical property ofthe flyash. Cementious calcium silicate and calcium aluminosilicate hydrates are formedwhen flyash reacts with water and lime, (Hausmann, 1990). Fly ash produced in thecombustion of sub bituminous coals exhibits self-cementing characteristics that can beadapted to a wide range of stabilisation applications. Ash treatment can effectively reduce theswell potential of fat clay soils and increase subgrade support capacity of pavementsubgrades. Ash hydration occurs rapidly and must be addressed by the constructionprocedures to obtain maximum potential benefit from the ash treatment. This can be accom-plished by limiting the delay between incorporation of the ash and final compaction to lessthan 2 hours. Hydration chemistry can differ significantly between specific sources anddesign mixes must be based on the specific ash to be used. Compressive strengths of ashtreated materials are dependent upon moisture content at time of compaction and strictmoisture control is required during construction (Katti, 1970; Churchill, 1999; Ferguson,1993 and Thomas, 2002). An optimum content of 15% of flyash and lime in ratio of 1:4could be used to obtain best stabilizing effect on alluvial soil (Ghosh, 1973). Addition of lime
  3. 3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME395to the soil-flyash mixture results in increased friction angle, cohesive intercept, and averagemodulus (Consoli, 2001).3. RESEARCH METHODOLOGYThe percentage of lime to be added to low plastic clay soils for stabilization has beenvaried from 0 to 4 % as literature review shows that the same has no effect beyond 4%. Theoptimum moisture content and maximum dry density of the soil and the soil lime mixes isdetermined to find the OMC and MDD values at which the samples have to be compacted forstrength tests, namely California bearing Ratio (CBR) and Unconfined compressive strength(UCC) of the clay and clay lime mixes.Delay in compaction is studied on California bearing ratio of clay lime mixes at 0, 2and 4% of lime at respective OMC and MDD for compaction after maturity period of 30minutes, 12 hours, 24 hours and 48 hours respectively.The California bearing ratio is determined for all the clay lime mixes with varying thecuring period on maturity of 30 minutes and after 7days, 28 days and 40 days followed by 4day soaking in all the cases.Unconfined compressive test of the clay lime mixes is done with varying curingperiods of 7 days, 28 days and 40 days. Results have been analyzed to determine the effect ofdelay in compaction and curing period.4. DATA ANALYSISThe experimental results are tabulated from the plots drawn for the respectivelaboratory experiments. Table I shows the properties of clay and lime used forexperimentation. Table 2 represent the optimum moisture content and maximum dry densityof the clay lime mixes at various percentages of lime. Table 3 represent the effect of delayedcompaction on optimum moisture content, maximum dry density and the California bearingratio value (CBR) of the clay lime mixes. Table 4 and 5 depict the effect of curing on theCBR value and unconfined compression strength (UCC) of the clay lime mixes respectively.Table 1 Properties of clay and lime used for experimentationS. No. Property Value1 Grain Size Distribution1.18mm75 micron%99832 Atterberg LimitsLiquid Limit (%)Plastic Limit (%)Plasticity Index2918113 Compaction propertiesOptimum moisture content (%)Maximum Dry Density (g/cc)14.61.844 Soaked CBR (%) 6.0S.No.Property Clay1 Calcium hydroxide95%2 Chloride 0.01%3 Sulphate 0.2%4Aluminium Ironand insolublematter1.0%5 Arsonic 0.0004%6 Lead 0.001%
  4. 4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME396Table 2 Compaction test resultsS.no Mix OMC (%) MDD( g/cc)1 Clay +0% lime 14.6 1.842 Clay +1% lime 14.7 1.853 Clay +2% lime 15.0 1.884 Clay +3% lime 15.0 1.885 Clay +4% lime 15.2 1.91Table 3 Properties for delay in compaction on clay -lime mixesClay +0% limeS.no Property On Maturity 12 hours 24hours 48 hours1 OMC(%) 14.6 13.6 12.8 12.02 MDD (g/cc) 1.84 1.82 1.78 1.723 CBR (%) 6 5.2 4.8 4Clay +1% limeS.no Property On Maturity 12 hours 24hours 48 hours1 OMC(%) 14.7 13.9 13.4 12.62 MDD (g/cc) 1.85 1.83 1.76 1.733 CBR (%) 6.5 5.7 4.5 4.2Clay +2% limeS.no Property On Maturity 12 hours 24hours 48 hours1 OMC (%) 14.8 14.6 14.2 14.02 MDD(g/cc) 1.86 1.84 1.78 1.743 CBR (%) 15 12 11 11Clay +3% limeS.no Property On Maturity 12 hours 24hours 48 hours1 OMC (%) 15.0 14.6 14.4 14.12 MDD(g/cc) 1.88 1.86 1.79 1.733 CBR (%) 15.6 13 11.1 10.8Clay +4% limeS.no Property On Maturity 12 hours 24hours 48 hours1 OMC (%) 15.2 14.8 14.6 14.22 MDD (g/cc) 1.91 1.87 1.84 1.783 CBR (%) 20 18 17 16
  5. 5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME397Table 4 CBR values on clay- lime mixes soil with curing and soakingS.no Mix CBR4 DsoakingCBR7Dcuring &4D soakingCBR28D curing &4D soakingCBR40D curing &4D soaking1 Clay +1%lime12% 25% 30% 32%2 Clay +2%lime15% 30% 32% 35%3 Clay +3%lime18% 31% 34% 38%4 Clay +4%lime20% 27% 36% 40%Table 5 UCC values on clay- lime mixes depicting effect of curingS.no Mix UCC7D Curing(Kg/cm2)UCC28D Curing(Kg/cm2)UCC40DCuring(Kg/cm2)1 Clay +0% lime 1.3 - -2 Clay +1% lime 2 3.8 3.93 Clay +2% lime 4 5.2 64 Clay +3% lime 4.1 5.15 6.35 Clay +4% lime 3.8 6 85. RESULTSThe results and plots thereof are interpreted to observe the effect of delay in compactionon CBR of the clay lime mixes and that of curing on UCC and CBR strength of clay limemixes. The same are depicted vide plots 1 to 3. Plot 1 shows the effect of delay incompaction on the clay lime mixes and Plots 2 and 3 show the effect of curing on CBRand UCC of the clay lime mixes respectively
  6. 6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME3980.00 10.00 20.00 30.00 40.00 50.00No of hours of dealy in Compaction4.008.0012.0016.0020.00CaliforniaBearingRatio%Clay + 0% LimeClay + 1% LimeClay + 2% LimeClay + 3% LimeClay + 4% Lime.Plot 1 Effect of Delay in compaction on CBR of clay –lime Mixes0.00 10.00 20.00 30.00 40.00No of Days of Curing10.0020.0030.0040.00CaliforniaBearingRatio%0 Days Curing + 4 Day Soaking7Days Curing + 4 Day Soaking28 Days Curing + 4 Day Soaking40 Days Curing + 4 Day SoakingPlot 2 Effect of curing period on CBR of clay –lime Mixes
  7. 7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME3990.00 10.00 20.00 30.00 40.00No. of Days of Curing2.004.006.008.00UuconfinedCompressiveStrengthkg/sqcmClay + 1% LimeClay + 2% LimeClay + 3% LimeClay + 4% LimePlot 3 Effect of curing period on UCC of clay –lime Mixes6. ACKNOWLEDGEMENTAt the outset the authors would thank the Head, CED at Vasavi Engineering Collegeand Head Transportation Division and professors at JNTUH for their valuable guidance andencouragement during experimentation.7. CONCLUSION1. The OMC and MDD values decreased with delay in compaction. The decrease wassignificant with OMC decreasing from 15.2% to 14.2% and MDD decreasing from 1.91g/cc to 1.78 g/cc. for 4% lime mixed clay soil.2. The CBR values decreased from 20% to 16% as the delay in compaction increased to 48hours for 4% lime mixed clay soil. This has a lot of effect on the strength of thesubgrades.3. The CBR and UCC values increased significantly for 7 day cured and 28 day curedsamples. Curing up to 7 days showed increase in the CBR and UCC values, whichincreased till 28 day strength and further the effect was insignificant.4. The CBR strength achieved with 2% of lime was almost achieved with 1% lime mixedclay soil with 7 days curing.5. UCC value with 2% lime mixing with no curing is found to be 4 kg/cm2and the same for1% lime mixed soils with 7 days curing is found to be 3.8 kg/cm26. Clay- Lime mixes should be compacted immediately after maturity of 30 minutes. Thereshould not be any delay in compaction after mixing clay with lime and water. Delay incompaction leads to substantial decrease in the CBR values.7. It is recommended that all the clay lime mixes should be cured at least for 7 days and fora maximum of 28 days.
  8. 8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME4008 REFERENCES1. Bhasin N.K., Dhawan, P.K., and Mehta, H.S. (1978), “Lime requirement in soilstabilisation”, Road Research Papers, Rep. no.149, CRRI, India.2. Bhasin, N.K., Dhawan, P.K., Mishra, A.K., Ashwin Kumar and Lal, N.B. (1983), “Astudy on The Distribution of Stabilizer Content using different Mixing Techniques inStabilized Soil Road Constructions”, Indian Roads Congress Journal.3. Blight, G.E., and Wet, J.A. (1995), “Acceleration of Heave of Structures on ExpansiveClay”, Proc. Symposium on Moisture Equilibria and Moisture Changes in the SoilsBeneath Covered Areas, Butterworths, Australia, Vol.1, pp.89-92.4. Bulman, J.N. (1972), “Soil Stabilisation in Africa”, Rep.No.476, TRRL, UK.5. Chopra, S.K., Reshi, S.S., and Garg, S.K. (1964), “ Use of Fly Ash as a Pozzolana”,Proc. Symposium on Pozzolan, their survey, Manufacture and Utilization, CRRI, India,p.18.6. Chu, S. C., and Kao, H. S. (1993), “A Study of Engineering Properties of a ClayModified by Flyash and Slag”, Flyash for Soil Improvement Geotechnical SpecialPublication, Vol. 36, pp 89-99.7. Chu, T.Y. (1955), “Soil Stabilisation with Lime Fly Ash mixture, Preliminary studieswith Silty and Clayey Soils”, HRB, No.108, p.102.8. Churchill, E.V., and Amirkhanian, S.N. (1999), “Coal Ash Utilization in AsphaltConcrete Mixtures”, Journal of Materials in Civil Engineering Vol. 11, pp. 295-301.9. Cockrell, C. F. and Leonard, J. W., (1970), “Characterization and Utilization Studies ofLimestone Modified Flyash”, Coal Research Bureau, Vol. 60.10. Consoli, N.C., Prietto, P.D.M., Carraro, J.A.H., and Heineck, K.S. (2001), “Behaviourof Compacted Soil-Fly Ash-Carbide Lime Mixtures”, Journal of Geotechnical andGeoenvironmental Engineering, Vol. 127, No. 9, pp 774-782.11. Cokca, E. (2001), “Use of Class C Fly Ashes for the Stabilisation of an ExpansiveSoil”, Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No.7, pp568-573.12. Consoli, N.C., Prietto, P.D.M., Carraro, J.A.H., and Heineck, K.S. (2001), “Behaviourof Compacted Soil-Fly Ash-Carbide Lime Mixtures”, Journal of Geotechnical andGeoenvironmental Engineering, Vol. 127, No. 9, pp 774-782.13. 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.140-15214. Croft, J.B. (1967), “The Influence of Soil Mineralogical Composition on CementStabilisation”, Geotechnique, London, England, Vol. 17.15. Davidson, L.K., Demirel, T., and Handy, R.L. (1965), “Soil Pulverization and LimeMigration in Soil-Lime Stabilisation”, Highway Research Record, No.92, pp 103-125.16. Deshpande, M.D., Pandya, P.C., Shall, J.D., and Vanjara, S.Y. (1990), “PerformanceStudy of Road Section Constructed with Local Expansive Clay Stabilized with Lime asSub Base Material”, Indian Highways, Vol. 18, No.6, pp 29-38.17. Ferguson, G. (1993), “Use of self-cementing fly ash as a soil stabilizing agent” Proc.Geotechnical special publication, No. 36, ASCE, New York.18. FHWA, (1995), “Fly ash Facts for the Highway Engineers” FHNA – SA – 44 – 081,December 1995, pp. 70.
  9. 9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME40119. Frydman, S., Ravina, I., and Ehrenreich, T, (1977), “Stabilisation of Heavy Clay withPotassium Chloride”, Journal of Geotechnical Engineering, South East AsianGeotechnical Society, Vol.8, pp 95-108.20. Ghosh, R.K., Chadda, L.R., Pant, C.S., and Sharma, R.K. (1973), “Stabilisation ofAlluvial Soils with both Lime and F1yash”, Journal of Indian Roads Congress.21. Hausmann, M. R. (1990), “Engineering Principles of Ground Modification”, Mc. GrawHill Publishing Co., New York.22. Holtz, W.G and Gibbs, H.J (1956), “Engineering Properties of Expansive Clays”,Transactions of ASCE, Vol. 121, pp 641-647.23. IRC 37 - 2001: Guidelines for Design of Flexible Pavements.24. IRC : SP : 53 - 2002: Guidelines on Use of Polymer and Rubber Modified Bitumen inRoad Construction.25. IS 2720 (part 16) - 1979, “Methods of Test for Soils; Laboratory Determination ofCBR”, Bureau of Indian Standards, New Delhi.26. Katti, R.K. (1970), “Use of Fly Ash in Road Construction” Get together and FieldDemonstration on the Use of Fly Ash in Civil Engineering Works, Madras, India.27. Mitchell, J. X., and Radd, L. (1973), “Control of Volume Changes in Expansive EarthMaterials”, Proc. Workshop on Expansive Clays and Shales in Highway Design andConstruction, Federal Highway Administration, Washington, D.C., pp 200-257.28. Thomas, Z. (2002), “Engineering Properties of Soil- Fly Ash Subgrade Mixtures”, Proc.Transportation Scholars Conference, Iowa State University.29. P.A. Ganeshwaran, Suji and S. Deepashri, “Evaluation of Mechanical Properties ofSelf Compacting Concrete with Manufactured Sand and Fly Ash”, International Journalof Civil Engineering & Technology (IJCIET), Volume 3, Issue 2, 2012, pp. 60 - 69,ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.30. Thulaseedharan V and Narayanan S.P, “The Effect of Soil Improvement on Foundation& Super Structure Design”, International Journal of Civil Engineering & Technology(IJCIET), Volume 4, Issue 2, 2013, pp. 258 - 269, ISSN Print: 0976 – 6308,ISSN Online: 0976 – 6316.31. P.S.Joanna, Jessy Rooby, Angeline Prabhavathy, R.Preetha and C.Sivathanu Pillai,“Behaviour of Reinforced Concrete Beams with 50 Percentage Fly Ash”, InternationalJournal of Civil Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013,pp. 36 - 48, ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.

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