Designation:D4751−21aStandardTestMethodsforDeterminingApparentOpeningSizeofaGeotextile1ThisstandardisissuedunderthefixeddesignationD4751;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thesetestmethodscoverthedeterminationoftheapparentopeningsize(AOS)ofageotextileeitherbydry-sievingglassbeadsthroughageotextile(MethodsA1andA2)orbyusingacapillaryporometer(MethodB).1.2MethodBwillnotbeusedinlieuofMethodAunlessthepre-qualificationprocedurespecifiedinthisstandardisfollowed.1.3ThesetestmethodsshowthevaluesinbothSIunitsandinch-poundunits.SIunitsisthetechnicallycorrectnameforthesystemofmetricunitsknownastheInternationalSystemofUnits.Inch-poundunitsisthetechnicallycorrectnameforthecustomaryunitsusedintheUnitedStates.Thevaluesininch-poundunitsareprovidedforinformationonly.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregulatorylimitationspriortouse.1.5Thisinternationalstandardwasdevelopedinaccor-dancewithinternationallyrecognizedprinciplesonstandard-izationestablishedintheDecisiononPrinciplesfortheDevelopmentofInternationalStandards,GuidesandRecom-mendationsissuedbytheWorldTradeOrganizationTechnicalBarrierstoTrade(TBT)Committee.2.ReferencedDocuments2.1ASTMStandards:2D1331TestMethodsforSurfaceandInterfacialTensionofSolutionsofPaints,Solvents,SolutionsofSurface-ActiveAgents,andRelatedMaterialsD1776/D1776MPracticeforConditioningandTestingTex-tilesD4354PracticeforSamplingofGeosyntheticsandRolledErosionControlProducts(RECPs)forTestingD4439TerminologyforGeosyntheticsD6767TestMethodforPoreSizeCharacteristicsofGeotex-ti...
