1、Designation:D7748/D7748M14(Reapproved 2021)Standard Test Method forFlexural Rigidity of Geogrids,Geotextiles,and RelatedProducts1This standard is issued under the fixed designation D7748/D7748M;the number immediately following the designation indicates theyear of original adoption or,in the case of
2、revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the measurement of stiffnessproperties of geogrids,geotextiles,and geogrid-geo
3、textilecomposites,all of which are referred to as geosynthetics withinthis test method.Bending length is measured and flexuralrigidity is calculated through use of the cantilever test proce-dure.1.1.1 This test method employs the principle of cantileverbending of the geosynthetic under its own mass.
4、1.2 This test method applies to geogrids,geotextiles,andgeogrid-geotextile composites.1.3 This test method is for manufacturing quality controlpurposes only,to ensure uniformity and consistency of flexuralrigidity for a specific product from roll to roll and lot to lot.1.4 The values stated in eithe
5、r SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system are not necessarily exact equivalents;therefore,toensure conformance with the standard,each system shall beused independently of the other,and values from the twosystems shall not be combined.1.5
6、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.1.6 This
7、 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(TB
8、T)Committee.2.Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776/D1776M Practice for Conditioning and Testing Tex-tilesD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for TestingD4439 Terminology for GeosyntheticsE177 Practice for
9、 Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 For common definitions of terms in this test method,refer to Terminology D123 and Terminology D4439.3.2 Definitions of Terms Specif
10、ic to This Standard:3.2.1 bending length,na measure of the interaction be-tween geosynthetic weight and geosynthetic stiffness as shownby the way in which a geosynthetic bends under its ownweight.3.2.1.1 DiscussionBending length reflects the stiffness ofa geosynthetic when bent in one plane under th
11、e force ofgravity.4.Summary of Test Method4.1 A specimen is slid at a specified rate in a directionparallel to its long dimension,until its leading edge projectsfrom the edge of a horizontal surface.The length of theoverhang is measured when the tip of the specimen is de-pressed under its own mass t
12、o the point where the line joiningthe top to the edge of the platform makes a 0.724 radians41.5 angle with the horizontal.From this measured length,the bending length and flexural rigidity are calculated.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the dir
13、ect responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved Sept.1,2021.Published September 2021.Originallyapproved in 2012.Last previous edition approved in 2014 as D7748/D7748M 14.DOI:10.1520/D7748_D7748M-14R21.2For referenced ASTM standards,visit the ASTM website,
14、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 interna
15、tional 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)Committe
16、e.15.Significance and Use5.1 This test method is considered satisfactory for manufac-turing quality control testing of a specific geosynthetic;however,caution is advised since information about between-laboratory precision is incomplete.Comparative tests as di-rected in 5.1.1 may be advisable.5.1.1 In case of a dispute arising from differences inreported test results when using this test method for acceptancetesting of commercial shipments,the purchaser and the sup-plier should conduct comparati