Designation:D8237−21StandardTestMethodforDeterminingFatigueFailureofAsphalt-AggregateMixtureswiththeFour-PointBeamFatigueDevice1ThisstandardisissuedunderthefixeddesignationD8237;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodprovidesaprocedurefordeterminingafatiguecurvethatisdevelopedusingthreeormorestrainlevels.Theresultingdatacanbeusedinthefatiguemodelsformechanistic-empiricalpavementdesign(thatis,PavementME).Failurepointsaredeterminedforestimatingthefatiguelifeof380mmlongby50mmthickby63mminbreadth(width)asphaltmixturebeam(rectangularprism)specimenssawedfromlaboratoryorfield-compactedasphaltmixture,whicharesubjectedtorepeatedflexuralbending.1.2Thelargestnominalmaximumaggregatesize(NMAS)recommendedforbeams50mmthickis19mm.BeamsmadewithanNMASgreaterthan19mmmightsignificantlyinter-ferewiththematerialresponse,therebyaffectingtherepeat-abilityofthetest.1.3Thetextofthisstandardreferencesnotesandfootnoteswhichprovideexplanatorymaterial.Thesenotesandfootnotes(excludingthoseintablesandfigures)shallnotbeconsideredasrequirementsofthestandard.1.4Units—ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard,withtheexceptionofdegrees(°)whereangleisspecifiedinaccordancewithIEEE/ASTMSI10.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.6Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoT...
