Designation:D4254−16StandardTestMethodsforMinimumIndexDensityandUnitWeightofSoilsandCalculationofRelativeDensity1ThisstandardisissuedunderthefixeddesignationD4254;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thesetestmethodscoverthedeterminationoftheminimum-indexdrydensity/unitweightofcohesionless,free-drainingsoils.Theadjective“dry”beforedensityorunitweightisomittedinthetitleandremainingportionsofthisstandardstobebeconsistentwiththeapplicabledefinitionsgiveninSection3onTerminology.1.2SystemofUnits:1.2.1Thetestingapparatusdescribedinthisstandardhasbeendevelopedandmanufacturedusingvaluesinthegravi-metricorinch-poundsystem.Therefore,testapparatusdimen-sionsandmassgivenininch-poundunitsareregardedasthestandard.1.2.2Itiscommonpracticeintheengineeringprofessiontoconcurrentlyusepoundstorepresentbothaunitofmass(lbm)andaunitofforce(lbf).Thisimplicitlycombinestwoseparatesystemsofunits;thatis,theabsolutesystemandthegravita-tionalsystem.Itisscientificallyundesirabletocombinetheuseoftwoseparatesetsofinch-poundunitswithinasinglestandard.Thistestmethodhasbeenwrittenusingthegravita-tionalsystemofunitswhendealingwiththeinch-poundsystem.Inthissystem,thepound(lbf)representsaunitofforce(weight).However,balancesorscalesmeasuremass;andweightmustbecalculated.Intheinch-poundsystem,itiscommontoassumethat1lbfisequalto1lbm.Whilereportingdensityisnotregardedasnonconformancewiththisstandard,unitweightsshouldbecalculatedandreportedsincetheresultsmaybeusedtodetermineforceorstress.1.2.3Thetermsdensityandunitweightareoftenusedinterchangeably.Densityismassperunitvolume,whereasunitweightisforceperunitvolume.Inthisstandard,densityisgivenonlyinSIunits.Afterthedensityhasbeendetermined,theunitweightiscalcula...
