Designation:D7864/D7864M−15StandardTestMethodforDeterminingtheApertureStabilityModulusofGeogrids1ThisstandardisissuedunderthefixeddesignationD7864/D7864M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoverstheprocedureformeasuringthe“ApertureStabilityModulus”ofageogrid.(Theterms“SecantApertureStabilityModulus,”“TorsionalRigidityModulus,”“In-planeShearModulus,”and“TorsionalStiffnessModulus”havebeenusedintheliteraturetodescribethissameproperty.)1.2Thistestmethodisintendedtodeterminethein-planestabilityofageogridbyclampingacenternodeandmeasuringthestiffnessoveranareaofthegeogrid.Thistestmethodisapplicableforvarioustypesofgeogrid.1.3Thistestmethodisintendedtoprovidecharacteristicpropertiesfordesign.Thetestmethodwasdevelopedforpavementandsubgradeimprovementcalibrateddesignmeth-odsrequiringinputofaperturestabilitymodulus.1.4ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D4439TerminologyforGeosyntheticsD4354PracticeforSamplingofGeosyntheticsandRolledErosionControlProducts(RECPs)forTesting2.2FHWADocument:3FHWAGeosyntheticDesignandConstructionGuidelines(2008)3.Terminology3.1Definitions:3.1.1Fordefinitionsofgeneraltermsusedinthistestmethod,refertoTerminologyD4439.3.1.2geogrid,n—ageosyntheticformedbyaregularnet-workofintegrallyconnectedelement...
