ENGINEERMANUAL EM1110-3-137Apri l 1984ENGINEERING AND DESIGNSoil Stabilization for Pavements Mobilization ConstructionDEPARTMENT OF THE ARMYCORPS OF ENGINEERSOFFICE OF THE CHIEF OF ENGINEERSDAEN-ECE-G EngineerManual No.1110-3-137 DEPARTMENTOFTHEARMY U.S.ArmyCorpsofEngineers Washington,D.C.20314 EngineeringandDesign SOILSTABILIZATIONFORPAVEMENTS MobilizationConstruction EM1110-3-137 \9April1984 1.Purpose.Thismanualprovidesguidanceforthedesignandimprovementof thestructuralqualityandworkabilityofsoilsusedforbasecourses,subbase courses,selectmaterials,andsubgradesforpavementsconstructionforU.S. Armymobilizationfacilities. 2.Applicability.Thismanualisapplicabletoallfieldoperating activitieshavingmobilizationconstructionresponsibilities. 3.Discussion.Criteriaandstandardspresentedhereinapplytopavement construct1onconsideredcrucialtoamobilizationeffort.Theserequirements maybealteredwhennecessarytosatisfyspecialconditionsonthebasisof goodengineeringpracticeconsistentwiththenatureoftheconstruction. Designandconstructionofmobilizationfacilitiesmustbecompletedwithin lAOdaysfromthedatenoticetoproceedisgivenwiththeprojectedlife expectancyoffiveyears.Hence,rapidconstructionofafacilityshouldbe reflectedinitsdesign.Time-consumingmethodsandprocedures,normally preferredoverquickermethodsforbetterquality,shouldbede-emphasized. Lessergradematerialsshouldbesubstitutedforhighergradematerialswhen thelessergradematerialswouldprovidesatisfactoryserviceandwhenuseof highergradematerialswouldextendconstructiontime.Workitemsnot immediatelynecessaryfortheadequatefunctioningofthefacilityshouldbe deferreduntilsuchtimeastheycanbecompletedwithoutdelayingthe mobilizationeffort. FORTHECOMMANDER: / I.d"j 7/'j/- t:f:.t..u-r.. IPAUL.CorpsofEngineers ChiefofStaff EngineerManual No.1110-3-137 DEPARTMENTOFTHEARMY U.S.ArmyCorpsofEngineers Washington,DC20314 EngineeringandDesign SOILSTABILIZATIONFORPAVEMENTS MobilizationConstruction EM1110-3-137 9April1984 ParagraphPage CHAPTER1. CHAPTER2. CHAPTER3. CHAPTER4. CHAPTER5. CHAPTER6 .. GENERAL Purposeandscope ......... Definitions ...................... . Methodsofstabilization ........ PURPOSEOFSTABILIZATION Usesofstabilization ...... Selectionofstabilizeradditive . Useofstabilizedsoils1nfrost areas . ......................... . STABILIZATIONWITHPORTLANDCEMENT Stabilizationapproaches ..... Cementcontentformodification ofsoils ....................... . Cementcontentforcement-stabilizedsoil ...... STABILIZATIONWITHLIME Stabilizationapproaches ...... Limecontentforlime-modified soils .......................... . Limecontentforlime-stabilized soils .......................... . Limeandotheradditives ........ 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 4-1 4-2 4-3 4-4 STABILIZATIONWITHLIME-CEMENT-FLYASH(LCF) Reactionwithsoils ............ Suitablematerials ............ LCFcontent ............. STABILIZATIONWITHBITUMEN Typesofbituminous-stabilized soils .......................... . i 5-1 5-2 5-3' 6-1 1-1 1-1 1-1 2-1 2-2 2-5 3-1 3-1 3-2 4-1 4-1 4-1 4-4 5-1 5-1 5-1 6-1 EM1110-3-137 9Apr84 APPENDIXA. APPENDIXB. Table2-1. 2-2. 3-1. 3-2. 3-3. 3-4. 3-5. 6-1. 6-2. 6-3. Paragraph Soilgradation .. Typesofbitumen ................. . Mixdesign ....................... . PHTESTTODETERMINELIMEREQUIREMENTS FORLIMESTABILIZATION REFERENCES LISTOFTABLES Minimumunconfinedcompressive 6-2 6-3 6-4 strengthsforcement,lime,and combinedlime-cement-flyashstabilized soils. Guideforselectingastabilizing additive. Gradationrequirements. Estimatedcementrequirementsfor varioussoiltypes. Averagecementrequirementsforgranular andsandysoils. Averagecementrequirementsforsiltyand clayeysoils. Durabilityrequirements. Recommendedgradationsforbituminous-stabilizedsubgradematerials. Recommendedgradationsforbituminous-stabilizedbaseandsubbasematerials. Emulsifiedasphaltrequirements. 1.1 6-1 6-1 6-4 A-1 B-1 CHAPTER1 GENERAL EM1110-3-137 9Apr84 1-1.Purposeandscope.Thismanualpresentscriteriaforimproving thestructuralqualityandworkabilityofsoilsusedforbasecourses, subbasecourses,selectmaterials,andsubgradesforpavements.Itis applicabletoallelementsresponsibleforArmypavementconstruction atmobilizationfacilities. 1-2.Definitions.Thefollowingdefinitionsareapplicabletothis manual. a.Soils.Theterm"soils"referstonaturallyoccurringmaterials thatareusedfortheconstructionofallexceptthesurfacelayersof pavementsandthataresubjecttoclassificationteststoprovidea generalconceptoftheirengineeringcharacteristics.Alsoincluded arethematerialsnormallyusedforbasecourses,subbasecourses, selectmateriallayers,andsubgrades.Thesoilclassificationsystem tobeusedinevaluatingthesecharacteristicsisdescribedin MIL-STD-619. b.Stabilization.Stabilizationistheprocessofblendingand mixingmaterialswithasoiltoimprovethepertinentpropertiesofthe soil.Theprocessmayincludetheblendingofsoilstoachievea desiredgradationorthemixingofcommerciallyavailableadditives thatmayalterthegradation,changecertainproperties,oractasa binderforcementationofthesoil. c.Modification.Modificationreferstothestabilizationprocess thatresultsinimprovementinsomepropertyofthesoilbutdoesnot bydesignresultinasignificantincreaseinsoilstrengthand durability. d.Additive.Additivereferstoamanufacturedcommercialproduct that,whenaddedtothesoilintheproperquantities,willimprovethe qualityofthesoillayer.Thismanualisrestrictedtotheuseof portlandcement,lime,lime-cement-flyash,andbitumen,aloneorin combination,asadditivestostabilizesoils. 1-3.Methodsofstabilization.Thetwogeneralmethodsof stabilizationpresentedaremechanicalandadditive.Theeffectiveness ofstabilizationisdependentupontheabilitytoobtainuniformityin blendingthevariousmaterials.Mixinginastationaryortraveling plantispreferred;however,othermeansofmixing,suchasscarifiers, plows,disks,graders,androtarymixers,havebeensatisfactory. a.Mechanicalstabilization.Mechanicalstabilizationis accomplishedbymixingorblendingsoilsoftwoormoregradationsto obtainamaterialmeetingtherequiredspecification.Thesoil 1-1 EM1110-3-137 9Apr84 blendingmaytakeplaceattheconstructionsite,atacentralplant, orataborrowarea.Theblendedmaterialisthenspreadandcompacted torequireddensitiesbyconventionalmeans. b.Additivestabilization.Twotypesofadditivestabilizationare chemicalandbituminous.Chemicalstabilizationisachievedbythe additionofproperpercentagesofcement,lime,flyash,or combinationsofthesematerialstothesoil.Bituminousstabilization isachievedbytheadditionofproperpercentagesofbituminous materialtothesoil.Theselectionanddeterminationofthe percentageofadditivetobeaddedisdependentuponthesoil classificationandthedegreeofimprovementinsoilqualitydesired. Generally,smalleramountsofadditivesarerequiredwhenitissimply desiredtoaltersoilproperties,suchasgradation,workability,and plasticity,thanwhenitisdesiredtoimprovethestrengthand durabilitysufficientlytopermitathicknessreductiondesign.After theadditivehasbeenmixedwiththesoil,spreadingandcompa,tionare achievedbyconventionalmeans. 1-2 CHAPTER2 PURPOSEOFSTABILIZATION EM1110-3-137 9Apr84 2-1.Usesofstabilization.Pavementdesignisbasedonthepremise thatspecifiedlevelsofqualitywillbeachievedforeachsoillayer inthepavementsystem.Eachlayermustresistshearingwithinthe layer,avoidexcessiveelasticdeflectionsthatwouldresultinfatigue crackingwithinthelayerorinoverlyinglayers,andpreventexcessive permanentdeformationthroughdensification.Asthequalityofasoil layerisincreased,theabilityofthatlayertodistributetheload overagreaterareaisgenerallyincreasedenoughtopermitareduction ~ therequiredthicknessofthesoilandsurfacelayers. a.Improvequality.Themostcommonsoilqualityimprovements throughstabilizationincludebettersoilgradation,reductionof plasticityindexorswellingpotential,andincreasesindurabilityand instrength.Itisalsocommontostabilizeasoilbyanadditivein ordertoprovideanall-weatherworkingplatformforconstruction operations.Thesetypesofsoilqualityimprovementarereferredtoas soilmodifications. b.Reducethickness.Thetensilestrengthandstiffnessofasoil layercanbeimprovedthroughtheuseofadditivesandtherebypermita reductioninthethicknessofthestabilizedlayerandoverlyinglayers withinthepavementsystem.Beforeastabilizedlayercanbeusedto reducetherequiredthicknessinthedesignofapavementsystem,the stabilizedmaterialmustmeetthedurabilityrequirementsgivenin paragraph2-2onvarioustypesofadditivestabilizationandthe minimumstrengthrequirementsshownintable2-1. Table2-1.MinimumUnconfinedCompressiveStrengths forCement,Lime,andCombinedLime-Cement-FlyAsh StabilizedSoils Stabilized SoilLayer Basecourse Subbasecourse, selectmaterial orsubgrade MinimumUnconfinedCompressiveStrength,psia FlexiblePavementRigidPavement 750 500 250 200 aunconfinedcompressivestrengthdeterminedat7daysforcement stabilizationand7or28daysforlimeorlime-cement-flyash stabilization(Seechapter4) 2-1 EM1110-3-137 9Apr84 2-2.Selectionofstabilizeradditive.Intheselectionofa stabilizeradditive,thefactorsthatmustbeconsideredarethetype ofsoiltobestabilized,thepurposeforwhichthestabilizedlayer willbeused,thetypeofsoilqualityimprovementdesired,the requiredstrengthanddurabilityofthestabilizedlayer,andcostand environmentalconditions. a.Thesoilgradationtriangleinfigure2-1isbaseduponthe pulverizationcharacteristicsofthesoilthat,whencombinedwith certainrestrictionsrelativetoliquidlimit(LL)plasticityindex (PI),andsoilgradationcontainedintable2-2,provideguidancefor theselectionoftheadditivebestsuitedforstabilization.Figure 2-1isenteredwiththepercentageofgravel(percentmaterialretained onNo.4sieve),sand(percentmaterialpassingNo.4sieveand retainedontheNo.200sieve),andfines(percentmaterialpassingthe No.200sieve)todeterminetheareainwhichthesoilgradationfalls. Thearea(1A,2C,3,etc.)indicatedattheintersectionofthethree materialpercentagesisusedtoentertable2-2toselectthetypeof stabilizingadditiveconsideringthevariousrestrictionsandremarks. Forexample,asoilhavingaPIof15andcontaining67percentgravel, 26percentsand,and7percentfinesfallsinArea2Boffigure2-1. Table2-2indicatesthatcement,lime,lime-cement-flyash,orbitumen couldbeconsidered.However,thePIof15eliminatesbitumen,andthe factthatonly33percentofthematerialpassestheNo.4sieve indicatesthatlime.oracombinationoflime-cement-flyashwillbethe betteradditiveforstabilization. b.Thenextconsiderationintheselectionofanadditivewillbe theuseofthestabilizedlayer.Ifitisonlydesiredtomodifythe propertiesofthesoil(i.e.,lowerthePIandincreasepercentfines) sothatitwouldqualifyasasubbaseorbasecoursematerial,limemay wellbethebestadditive.If,however,highstrengthsandgood durabilityarerequiredtoeffectareductioninpavementthickness, theuseofalime-cementorlime-cement-flyashcombinationmaybethe bestadditive.Actually,thebestadditivecanonlybedeterminedby studiesasoutlinedlaterintnismanual.Thesuccessofadditive stabilizationdepends,toalargeextent,uponattainingcompleteand uniformdistributionoftheadditiveinthesoil.Thisstepismost criticalwhenusingbitumensorportlandcementasadditives.These materialsworkwellincoarse-grainedsoilsthatpulverizemoreeasily. Generally,asthepercentfinesandthePIincrease,pulverization becomesmoredifficult,anditishardertoobtainuniformdistribution ofthestabilizingadditive.Forthesetypesofsoils,preprocessing orpretreatmentwithotheradditivesmaybenecessary.Forexample, fine-grainedsoilsmaybepretreatedwithlimetoaidintheir pulverization,makingmixingofabitumenorcementadditivemore successful. 2-2 LEGEND EM1110-3-137 9Apr84 ---Boundariesbetweenmajorsoilgroups. Boundarieswithinamajorsoilgroup. PERCE NTBYWEIGHT,FINES (MATERIALPASSINGNO.200SIEVE) u.s.ArmyCorpsofEngineers FIGURE2-1.GRADATIONTRIANGLEFORAIDINSELECTING ACOMMERCIALSTABILIZINGAGENT 2-3 EM1110-3-137 9Apr84 Table GuideforSelectingaStabilizingAdditive Soils AreaClass.a 1ASWorSP 1BSW-SMor SP-SMor sw-scor SP-SC 1CSMorSC orSM-SC 2A 2B 2C 3 GWorGP GW-GMor or GW-GCor GP-GC GMorGC orGM-GC CHorCL orMHor MLorOH orOLor ML-CL Typeof Stabilizing AdditiveRecommended (1)Bituminous (2)PortlandCement (3)Lime-Cement-Fly (1)Bituminous (2)PortlandCement (3)Lime (4)Lime-Cement-Fly (1)Bituminous (2)PortlandCement (3)Lime Ash Ash (4)Lime-Cement-FlyAsh (1)Bituminous (2)PortlandCement (3)Lime-Cement-FlyAsh (1)Bituminous (2)PortlandCement (3)Lime (4)Lime-Cement-FlyAsh (1)Bituminous (2)PortlandCement (3)Lime (4)Lime-Cement-FlyAsh (1)PortlandCement (2)Lime Restriction onPercent RestrictiononLLPassing andPIofSoilNo.200Sieve a Remarks PInottoexceed25 PInottoexceed10 PInottoexceed30 PInotlessthan12 PInottoexceed25 PInottoexceed10Nottoexceed 30percentby weight ----b PInotlessthan12 PInottoexceed25 Well-gradedmaterialonly Materialshouldcontainatleast 45percentbyweightofmaterial passingNo.4sieve PInottoexceed25 PInottoexceed10Well-gradedmaterialonly PInottoexceed30 Materialshouldcontainatleast 45percentbyweightofmaterial passingNo.4sieve PInotlessthan12 PInottoexceed25 PInottoexceed10NottoexceedWell-gradedmaterialonly 30percentby weight ---bMaterialshouldcontainatleast 45percentbyweightofmaterial passingNo.4sieve PInotlessthan12 PInottoexceed25 LLlessthan40andOrganicandstronglyacidsoils PIlessthan20fallingwithinthisareaarenot susceptibletostabilizationby ordinarymeans PInotlessthan12 aSoilclassificationcorrespondstoMIL-STD-619.Restrictiononliquidlimit(LL)andplasticityindex(PI) inaccordancewithMethod103inMIL-STD-621. bPI 20 +50- percentpassingNo.200sieve 4 u.s.ArmyCorpsofEngineers 2-4 2-3.Useofstabilizedsoilsinfrostareas. EM1110-3-137 9Apr84 a.Additives.Bitumens,portlandcement,lime,andcombinationsof lime,portlandcement,andflyash(LCF)arethemostcommonadditives foruseinstabilizedsoils. b.Limitationsofuse.Infrostareas,stabilizedsoilusually willbeusedonlyinalayerorlayerscomprisingoneoftheupper elementsofapavementsystemanddirectlybeneaththepavement surfacinglayer,wheretheaddedcostofstabilizationiscompensated forbyitsstructuraladvantageineffectingareductioninthe requiredthicknessofthepavementsystem.Treatmentwithalower degreeofchemicalstabilizationshouldbeusedinfrostareasonly withcautionandafterintensivetests,becauseweaklycemented materialusuallyhaslesscapacitytoendurerepeatedfreezingand thawingthanfirmlycementedmaterial.Apossibleexceptionistheuse ofalowlevelofstabilizationtoimproveasoilthatwillbe encapsulatedwithinanimperviousenvelopeaspartofa membrane-encapsulated-soil-layerpavementsystem.Asoilthatis unsuitableforencapsulationduetoexcessivemoisturemigrationand thawweakeningmaybemadesuitableforsuchusebymoderateamountsof astabilizingadditive.Materialsthataremodifiedbysmallamounts ofachemicaladditivetoimprovecertainpropertiesofthesoil withoutsignificantcementationalsoshouldbetestedtoascertainthat thedesiredimprovementisdurablethroughrepeatedfreeze-thawcycles. Theimprovementshouldnotbeachievedattheexpenseofmakingthe soilmoresusceptibletoicesegregation.Additionaldiscussionson theuseofstabilizedsoilinseasonalfrostareasarepresentedinEM 1110-3-138. c.Constructioncutoffdates.Formaterialsstabilizedwith cement,lime,orLCFwhosestrengthincreaseswithtimeofcuring,it isessentialthatthestabilizedlayerbeconstructedsufficiently earlyintheseasontoallowthedevelopmentofadequatestrength beforethefirstfreezingcyclebegins.Therateofstrengthgainis substantiallyloweratSOdegreesF.thanat70or80degreesF. Chemicalreactionswillnotoccurrapidlyfor(1)lime-stabilizedsoils whenthesoiltemperatureislessthan60degreesF.andisnot expectedtoincreasefor1month,or(2)cement-stabilizedsoilswhen thesoiltemperatureislessthan40degreesF.andisnotexpectedto increasefor1month.Infrostareas,itisnotalwayssufficientto protectthemixturefromfreezingduringa7-daycuringperiodas requiredbytheapplicableguidespecifications,andaconstruction cutoffdatewellinadvanceoftheonsetoffreezingconditionsmaybe essential. 2-5 CHAPTER3 STABILIZATIONWITHPORTLANDCEMENT EM1110-3-137 9 Apr84 3-1.Stabilizationapproaches.Portlandcementcanbeusedeitherto modifyandimprovethequalityofthesoilortotransformthesoil intoacementedmass,whichsignificantlyincreasesitsstrengthand durability.Theamountofcementadditivewilldependuponwhetherthe soilistobemodifiedorstabilized. 3-2.Cementcontentformodificationofsoils. a.Modificationofquality.Theamountofcementrequiredto improvethequalityofthesoilthroughmodificationisdeterminedby thetrial-and-errorapproach.IfitisdesiredtoreducethePIofthe soil,successivesamplesofsoil-cementmixturesmustbepreparedat differenttreatmentlevelsandthePIofeachmixturedetermined.The RefereeTestofASTMD423andASTMD424procedureswillbeusedto determinethePIofthesoil-cementmixture.Theminimumcement contentthatyieldsthedesiredPIisselected,butsinceitwas determinedbasedupontheminus40fractionofthematerial,thisvalue mustbeadjustedtofindthedesigncementcontentbasedupontotal sampleweightexpressedasthefollowingequation: A =100Bc where: A = designcementcontent,percenttotalweightofsoil B= percentpassingNo.40sievesize,expressedasadecimal c= percentcementrequiredtoobtainthedesiredPIofminus 40material,expressedasadecimal. b.Modificationofgradation.Iftheobjectiveofmodificationis toimprovethegradationofgranularsoilthroughtheadditionof fines,theparticle-sizeanalysis,usingtheASTMD422procedure, shouldbeconductedonsamplesatvarioustreatmentlevelstodetermine theminimumacceptablecementcontent.Thedeterminationofcement contenttoreducetheswellpotentialoffine-grainedplasticsoilscan beaccomplishedbymoldingseveralsamplesatvariouscementcontents andsoakingthespecimensalongwithuntreatedspecimensfor4days. Thelowestcementcontentthateliminatestheswellpotentialor reducestheswellcharacteristicstotheminimumbecomesthedesign cementcontent.Proceduresformeasuringswellcharacteristicsof soilsarefoundinMIL-STD-621,Method101.Thecementcontent determinedtoaccomplishsoilmodificationshouldbecheckedtosee whetheritprovidesanunconfinedcompressivestrengthgreatenoughto qualifyforareducedthicknessdesigninaccordancewithcriteria establishedforsoilstabilization. 3-1 EM1110-3-137 9Apr84 c.Modificationforfrostareas.Cement-modifiedsoilalsomaybe usedinfrostareas,butinadditiontotheproceduresformixture designdescribedin3-2.a.and3-2.b.above,curedspecimensshouldbe subjectedtothefreeze-thawcyclesprescribedbyASTMD560(but omittingwire-brushing)orotherapplicablefreeze-thawprocedures, followedbyfrost-susceptibilitydeterminationsinstandardlaboratory freezingtests.Forcement-modifiedsoilusedinthebasecourse,the frostsusceptibility,determinedafterfreeze-thawcycling,shouldmeet therequirementssetforthforthebasecourse,Ifcement-modified soilisusedasthesubgrade,itsfrostsusceptibility,determined afterfreeze-thawcycling,shouldbeusedasthebasisofthepavement thicknessdesignifthereducedsubgradestrengthdesignmethodis applied(EM1110-3-138).Formobilization,theuseofASTMD560may bealteredto6cyclesof6hoursoffreeze/wet- 6hourthaw/dry. Percentagesofstabilizerselectedforusemaybebasedonlocal performancehistoryinlieuofthesetests. 3-3.Cementcontentforcement-stabilizedsoil.Thefollowing procedureisrecommendedfordeterminingthedesigncementcontentfor cement-stabilizedsoils. a.Step1.Determinetheclassificationandgradationofthe untreatedsoilfollowingproceduresinMIL-STD-619andASTMD422, respectively.Thesoilmustmeetthegradationrequirementsshown1n table3-1beforeitcanbeusedinareducedthicknessdesign. Table3-1.GradationRequirements TypeSieve CourseSize -----Base2-inch 1-1/2-inch l-inch 3/4-inch 1/2-inch No.4 No.10 No.30 No.40 No.200 Subbase3-inch No.4 No.10 No.100 No.200 3-2 Percent Passing 100 70-100 45-100 30-90 20-70 15-60 5-40 0-20 100 0-25 EM1110-3-137 9Apr84 b.Step2.Selectanestimatedcementcontentfromtable3-2using thesoilclassification. Table3-2.EstimatedCementRequirementsforVariousSoilTypes SoilClassificationa GW-SW GP,SW-SM,SW-SC, SW-GM,SW-GC GM,SM,GC,SC, SP-SM,SP-SC,GP-GM GP-GC,SM-SC,GM-GC SP,CL,ML,ML-CL MH,OH CH InitialEstimatedCementRequirement PercentDryWeight 5 6 7 10 11 10 aSoilclassificationcorrespondstoMIL-STD-619. c.Step3.Usingtheestimatedcementcontent,determinethe moisture-densityrelationsofthesoil-cementmixture.Theprocedure containedinASTMD558willbeusedtopreparethesoil-cementmixture andtomakethenecessarycalculations;however,theapparatusand proceduresoutlinedinMIL-STD-621,Method100,CompactionEffort DesignationCE-55willbeusedtocompactthesoil-cementmixture. d.Step4.Usingtheuntreatedsoilgradationcharacteristics, cementcontent,andmaximumdrydensitydeterminedinSteps1,2,and 3,respectively,verifytheestimatedcementcontentusingtable3-3or table3-4andfigure3-1dependinguponsoilclassification.Ifthe estimatedcementcontentfromStep2variesbymorethanplusorminus 2percentfromthevalueintable3-3ortable3-4,conductadditional moisture-densitytests,varyingthecementcontent,untilthevalue fromtable3-3ortable3-4iswithinplusorminus2percentofthat usedforthemoisture-densitytest.Themoisture-densitytestwillbe performedasoutlinedinStep3. e.Step5.Preparesamplesofthesoil-cementmixturefor unconfinedcompressionanddurabilitytestsatthedrydensityandat thecementcontentdeterminedinStep4andatcementcontents2 3-3 Table3-3.AverageCementRequirementsforGranularandSandySoils ~ t ;J>:s: Material "dl-' li...... MaterialSmaller ...... 000 RetainedonThanCementContent,PercentbyWeight .f:::.l CN No.4Sieve0.05mmMaximumDryDensity,pcf(TreatedMaterial) I ...... percentpercent116-120121-126127-131132-137138-142143ormore CN "'-l 0-191098765 0-1420-39987755 40-5011109865 0-191098655 15-2920-39987665 40-5012109876 0-191087655 30-4520-391198765 40-50121110986 w I Note:Basecoursegoesto70percentretainedontheNo.4sieve. u.s.ArmyCorpsofEngineers Table3-4.AverageCementRequirementsforSiltyandClayeySoils Material Between 0.05 andCementContent,PercentbyWeight Group0.005mmMaximumDryDensity,J2Cf(TreatedMaterial) Index apercent99-104105-109ll0-ll5116-120121-126127-131132ormore 0-191211108877 0-320-391211109887 40-591312119988 60ormore 0-191312ll9877 3-720-391312ll10988 40-59141312101098 60ormore151412111099 .....;0-191413 I 1110988

7-ll20-3915141110999 40-591614121110109 60ormore17151311101010 0-19151413121199 ll- 1520-39161513121 l1010 40-59l7161412121110 60ormore18161413121111 0-1917161413121110 15-2020-3918171514u1111 40-5919181514141212 m 60ormore2019161514u12 3: ............aT a kenfromfigure3-1 '.0-0 )>I '":)(.N ..... .;::A..:""n::r: .., :-::5-- ::.:1:'3 '"iI ....:)0(.N EM1110-3-137 9Apr84 ORLESS 12 II 10 8 7 PERCENTPASSINGNO.200 15202530354045 ., )( 6

2 655!54!535 .1:1 )( "' Q z 75 ORMOREPERCENTPASSINGNO.200ORLESS NOTE:GroupIndex= Indexa+Indexb. REPRINTEDFROMSOIL-CEMENTLABORATORYHANDBOOK(EB052.06S) WITHPERMISSIONOFTHEPORTLANDCEMENTASSOCIATION, SKOKIE,ILLINOIS. FIGURE3-1.CHARTSFORCALCULATINGGROUPINDEXVALUES 3-6 EM1110-3-137 9Apr84 percentaboveand2percentbelowthatdeterminedinStep4.The samplesshouldbepreparedinaccordancewithASTMD1632exceptthat whenmorethan35percentofthematerialisretainedontheNo.4 sieve,a4-inch-diameterby8-inch-highmoldshouldbeusedtoprepare thespecimens.Curethespecimensfor7daysinahumidroombefore testing.Testthreespecimensusingtheunconfinedcompressiontestin accordancewithASTMD1633,andsubjectthreespecimenstodurability tests,eitherwet-dry(ASTMD559)testsforpavementslocatedin nonfrostareasorfreeze-thaw(ASTMD560)testsforpavementslocated infrostareas(EM1110-3-138).Formobilization,theuseofASTM D560maybealteredto6cyclesof6hoursoffreeze/wet- 6hour thaw/dry.Percentagesofstabilizerselectedforusemaybebasedon localperformancehistoryinlieuofthesetests. f.Step6.Comparetheresultsoftheunconfinedcompressive strengthanddurabilitytestswiththerequirementsshownintables2-1 and3-5.Thelowestcementcontent,whichmeetstherequired unconfinedcompressivestrengthrequirementanddemonstratesthe requireddurability,isthedesigncementcontent.Ifthemixture shouldmeetthedurabilityrequirementsbutnotthestrength requirements,themixtureisconsideredtobeamodifiedsoil. TypeofSoil Stabilizeda Table3-5. Granular,PIlessthan10 Granular,PIgreaterthan10 Silt Clays DurabilityRequirements MaximumAllowableWeightLossAfter12 Wet-Dryor6Freeze-ThawCycles PercentofInitialSpecimenWeight 11 8 8 6 aRefertoMIL-STD-619andMIL-STD-621. 3-7 CHAPTER4 STABILIZATIONWITHLIME EM1110-3-137 9Apr84 4-1.Stabilizationapproaches.Limecanbeusedeithertomodifysome ofthephysicalpropertiesandtherebyimprovethequalityofasoilor totransformthesoilintoastabilizedmass,whichincreasesits strengthanddurability.Theamountoflimewilldependupon whetherthesoilistobemodifiedorstabilized.Thelimetobeused maybeeitherhydratedorquicklime,althoughthepreponderanceof stabilizationisaccomplishedusinghydratedlime,sincequicklimeis highlycausticanddangeroustouse.Thedesignlimecontents determinedfromthecriteriapresentedhereinareforhydratedlime. Asaguide,thelimecontentsdeterminedhereinforhydratedlime shouldbereducedby25percenttodetermineadesigncontentfor quicklime. 4-2.Limecontentforlime-modifiedsoils.Theamountoflime requiredtoimprovethequalityofasoilisdeterminedthroughthe sametrial-and-errorprocessusedforcement-modifiedsoils. 4-3.Limecontentforlime-stabilizedsoils. a.Strengthrequirements.Totakeadvantageofthethickness reductioncriteria,thelime-stabilizedsoilmustmeettheunconfined compressivestrengthsshownintable2-1aswellasthedurability requirementsintable3-5. b.Procedures.Whenlimeisaddedtoasoil,acombinationof reactionsbeginstotakeplaceimmediatelyandisnearlycomplete withinanhour,althoughsubstantialstrengthgainisnotreflectedfor sometime.Thesereactionsresultinachangeinboththechemical compositionandphysicalproperties.Mostlime,whenplacedinawater solution,hasapHofabout12.4.Therefore,thepHisagood indicatorofthedesirablelimecontentofasoil-limemixture.The reactionthattakesplacewhenlimeisintroducedtoasoilgenerally causesasignificantchangeintheplasticityofthesoil;therefore, thechangesintheplasticandliquidlimitsalsobecomeanindicator ofthedesiredlimecontent.Twomethodsarepresentedforthe determinationoftheinitialdesignlimecontent. (1)Step1.Thepreferredmethodistoprepareseveralmixtures atdifferentlimetreatmentlevelsanddeterminethepHofeachmixture after1hour.Thelowestlimecontentproducingthe pHofthe soil-limemixtureistheinitialdesignlimecontent.Proceduresfor conductingapHtestonlime-soilmixturesarepresentedinappendixA. Infrostareas,specimensmustbesubjectedtothefreeze-thawtestas discussedinStep2below.Analternatemethodofdeterminingan initialdesignlimecontentisbytheuseoffigure4-1.Specific valuesrequiredtousefigure4-1arethePIandthepercentof 4-1 EM1110-3:..137 9Apr84 :::;: c 0::: Ct:... c ______ WE-:z