ASTM_D_4751_-_21a.pdf

Designation:D475121aStandard Test Methods forDetermining Apparent Opening Size of a Geotextile1This standard is issued under the fixed designation D4751;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 These test methods cover the determination of theapparent opening size(AOS)of a geotextile either by dry-sieving glass beads through a geotextile(Methods A1 and A2)or by using a capillary porometer(Method B).1.2 Method B will not be used in lieu of Method A unlessthe pre-qualification procedure specified in this standard isfollowed.1.3 These test methods show the values in both SI units andinch-pound units.SI units is the technically correct name forthe system of metric units known as the International System ofUnits.Inch-pound units is the technically correct name for thecustomary units used in the United States.The values ininch-pound units are provided for information only.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1331 Test Methods for Surface and Interfacial Tension ofSolutions of Paints,Solvents,Solutions of Surface-ActiveAgents,and Related MaterialsD1776/D1776M Practice for Conditioning and Testing Tex-tilesD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for TestingD4439 Terminology for GeosyntheticsD6767 Test Method for Pore Size Characteristics of Geotex-tiles by Capillary Flow TestE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 DefinitionsFor general geosynthetics terms used inthis standard,refer to Terminology D4439.3.2 Definitions:3.2.1 apparent opening size(AOS),O95,nfor a geotextile,a property that indicates the approximate largest particle thatwould effectively pass through the geotextile.3.2.1.1 DiscussionWhile the same“O95”symbol is usedin Test Methods A1 and B for defining the AOS of a geotextileas well as in Test Method D6767 for determining the pore sizeof geotextiles by capillary flow,they are not necessarilyequivalent.The O95 values are defined in terms of theirrespective test methods.Therefore,theAOS version of the O95value that is determined with Method B may not be identical tothe O95 value determined per Test Method D6767.4.Summary of Test Methods4.1 Glass Bead Dry-Sieving,Method A1A geotextilespecimen is placed in a sieve frame,and sized glass beads areplaced on the geotextile surface.The geotextile and frame areshaken laterally so that the jarring motion will induce the beadsto pass through the test specimen.The procedure is repeated onthe same specimen with various size glass beads until a beadsize with more than 5%passing and a bead size with less than5%passing are tested and its apparent opening size has beendetermined.This method is considered the referee method inthe case of inter-laboratory disputes involving both MethodsA2 and B.4.2 Method A2This procedure is strictly intended as a“Pass/Fail”test for manufacturing QC testing.The test is1These test methods are under the jurisdiction of ASTM Committee D35 onGeosynthetics and are the direct responsibility of Subcommittee D35.03 onPermeability and Filtration.Current edition approved Sept.1,2021.Published September 2021.Originallyapproved in 1993.Last previous edition approved in 2021 as D4751 21.DOI:10.1520/D4751-21A.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1performed identically to that of Method A1,except it isperformed us