Designation:D1883−14StandardTestMethodforCaliforniaBearingRatio(CBR)ofLaboratory-CompactedSoils1ThisstandardisissuedunderthefixeddesignationD1883;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1ThistestmethodcoversthedeterminationoftheCali-forniaBearingRatio(CBR)ofpavementsubgrade,subbase,andbasecoursematerialsfromlaboratorycompactedspeci-mens.Thetestmethodisprimarilyintendedfor,butnotlimitedto,evaluatingthestrengthofmaterialshavingmaximumparticlesizelessthan3⁄4in.(19mm).1.2Whenmaterialshavingamaximumparticlesizegreaterthan3⁄4in.(19mm)aretobetested,thistestmethodprovidesformodifyingthegradationofthematerialsothatthematerialusedfortestsallpassesthe3⁄4-in.(19-mm)sievewhilethetotalgravel(3in.(75mm)toplusNo.4(4.75mm))fractionremainsthesame.WhiletraditionallythismethodofspecimenpreparationhasbeenusedtoavoidtheerrorinherentintestingmaterialscontaininglargeparticlesintheCBRtestapparatus,themodifiedmaterialmayhavesignificantlydifferentstrengthpropertiesthantheoriginalmaterial.However,alargeexperi-encedatabasehasbeendevelopedusingthistestmethodformaterialsforwhichthegradationhasbeenmodified,andsatisfactorydesignmethodsareinusebasedontheresultsoftestsusingthisprocedure.1.3PastpracticehasshownthatCBRresultsforthosematerialshavingsubstantialpercentagesofparticlesretainedontheNo.4(4.75mm)sievearemorevariablethanforfinermaterials.Consequently,moretrialsmayberequiredforthesematerialstoestablishareliableCBR.1.4ThistestmethodprovidesforthedeterminationoftheCBRofamaterialatoptimumwatercontentorarangeofwatercontentfromaspecifiedcompactiontestandaspecifieddryunitweight.ThedryunitweightisusuallygivenasapercentageofmaximumdryunitweightdeterminedbyTestMethodsD698orD1557.1.5Theclientrequestingthe...
