Designation:D7228−06a(Reapproved2015)StandardTestMethodforPredictionofAsphalt-BoundPavementLayerTemperatures1ThisstandardisissuedunderthefixeddesignationD7228;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversameansofpredictingtempera-tureswithintheasphalt-boundlayer(s)ofaflexiblepavementsection.1.2Deflectiontestingcommonlyinvolvesthemeasurementofpavementsurfacetemperatures.ThisstandardisbasedontemperaturerelationshipsdevelopedaspartoftheFederalHighwayAdministration(FHWA)LongTermPavementPer-formance(LTPP)SeasonalMonitoringProgram.2.ReferencedDocuments2.1ASTMStandards:2D4694TestMethodforDeflectionswithaFalling-Weight-TypeImpulseLoadDeviceD4695GuideforGeneralPavementDeflectionMeasure-mentsD4602GuideforNondestructiveTestingofPavementsUs-ingCyclic-LoadingDynamicDeflectionEquipmentD5858GuideforCalculatingInSituEquivalentElasticModuliofPavementMaterialsUsingLayeredElasticTheory2.2AASHTOStandards:3T256-00StandardMethodofTestforPavementDeflectionMeasurementsT317-02StandardMethodofTestforPredictionofAsphalt-BoundPavementLayerTemperatures2.3FederalHighwayAdministration:4FHWA-RD-98-085,TemperaturePredictionsandAdjust-mentFactorsforAsphaltPavements,June2000LTPPGuidetoAsphaltTemperaturePredictionandCorrec-tion,OnlineTemperaturePredictionandCorrectionGuide—TOC,November20023.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1BELLS—anacronymbasedontheinitialsofthefourdevelopersofthemethod:Baltzer,Ertman-Larsen,Lukanen,andStubstad.3.1.2depth—thedistancebelowthesurfaceofthetoplayerofasphalt.3.1.31-dayairtemperature—theaverageoftheminimumandmaximumairtemperaturesatthelocationoftestingduringthepreviouscomplete24-hourday.4.SummaryofTestMethod4.1InputDataElements:4.1.1IRTemperature—Theexposedsurfacetemperatureofanasphaltpavementismeasure...
