Designation:D6572−13´1StandardTestMethodsforDeterminingDispersiveCharacteristicsofClayeySoilsbytheCrumbTest1ThisstandardisissuedunderthefixeddesignationD6572;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—EditorialcorrectionsmadethroughoutinFebruary2014.1.Scope*1.1Twotestmethodsareprovidedtogiveaqualitativeindicationofthenaturaldispersivecharacteristicsofclayeysoils:MethodAandMethodB.1.1.1MethodA—ProcedureforNaturalSoilCrumbsde-scribedin10.2.1.1.2MethodB—ProcedureforRemoldedSoilCrumbsdescribedin10.3.1.2Thecrumbtest,whileagood,quickindicationofdispersivesoil,shouldusuallyberuninconjunctionwithapinholetestandadoublehydrometertest,TestMethodsD4647andD4221,respectively.1.3Thecrumbtesthassomelimitationsinitsusefulnessasanindicatorofdispersivesoil.Adispersivesoilmaysometimesgiveanon-dispersivereactioninthecrumbtest.Soilscontain-ingkaolinitewithknownfielddispersionproblems,haveshownnon-dispersivereactionsinthecrumbtest(1).2However,ifthecrumbtestindicatesdispersion,thesoilisprobablydispersive.1.4Thesetestmethodsarenotapplicableforsoilswith12%orlessoftheparticlespassing0.005mmandhavingaplasticityindexlessthanorequalto8,asdeterminedbyTestMethodD4318.1.5Oven-driedsoilshouldnotbeusedtopreparecrumbtestspecimens,asirreversiblechangescouldoccurtothesoilpore-waterphysicochemicalpropertiesresponsiblefordisper-sion(2).NOTE1—Insomecases,theresultsofthepinhole,crumb,anddouble-hydrometertestmethodsmaydisagree.Thecrumbtestisabetterindicatorofdispersivesoilsthanofnon-dispersivesoils(3).1.6AllobservedandcalculatedvaluesshallconformtotheguidelinesforsignificantdigitsandroundingestablishedinPracticeD6026.1.6.1Theproceduresusedtospecifyhowdataarecollected/recordedorcalculatedinthisstandardareregardedastheindustrystandard.Inaddition,theyarerepresentativeofthesignificantd...
