ASTM_D_6768_-_D_6768M_-_20.pdf

Designation:D6768/D6768M20Standard Test Method forTensile Strength of Geosynthetic Clay Liners1This standard is issued under the fixed designation D6768/D6768M;the number immediately following the designation indicates theyear of original adoption or,in the case of 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 establishes the procedures for themeasurement of tensile strength of a geosynthetic clay liner(GCL).This test method is strictly an index test method to beused to verify the tensile strength of GCLs.Results from thistest method should not be considered as an indication of actualor long-term performance of the geosynthetic(s)in fieldapplications.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in nonconformancewith the standard.1.3 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.1.4 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:2D76/D76M Specification for Tensile Testing Machines forTextilesD123 Terminology Relating to TextilesD4439 Terminology for GeosyntheticsD5889/D5889M Practice for Quality Control of Geosyn-thetic Clay LinersD6072/D6072M Practice for Obtaining Samples of Geosyn-thetic Clay Liners3.Terminology3.1 Definitions:3.1.1 geosynthetic clay liner,na manufactured hydraulicbarrier consisting of clay bonded to a layer or layers ofgeosynthetic material(s).D44393.2 For terminology of other terms used in this test method,refer to Terminologies D123 and D4439.4.Summary of Test Method4.1 A 100-mm 4-in.wide specimen is gripped across itsentire width in the clamps of a constant rate of extension(CRE)type tensile testing machine operated at a prescribed rate ofextension,applying a longitudinal force to the specimen untilthe specimen ruptures.5.Significance and Use5.1 This test method may be used for the acceptance testingof commercial shipments of GCLs,but caution is advised sinceinformation about between-laboratory precision is incomplete.Comparative tests as directed in 5.1.1 may be advisable.5.1.1 In cases of a dispute arising from differences inreported test results when using this test method for acceptanceof shipments,the purchaser and the supplier should conductcomparative tests to determine if there is a statistical bias.Thetwo parties should take a group of test samples that are ashomogeneous as possible and which are from the lot ofmaterial in question.5.2 Some modification of clamping techniques may benecessary for a given GCL,depending upon its structure.Specimen clamping may be modified as required at thediscretion of the individual laboratory,provided a representa-tive tensile strength is obtained.In any event,the proceduredescribed in Section 10 of this test method for obtaining tensilestrength must be maintained.5.3 This test method is applicable for testing GCLs asreceived.It is used with a constant rate of extension typetension apparatus.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosyn-thetic Clay Liners.Current edition approved May 1,2020.Published May 2020.Originallyapproved in 2002.Last previous edition approved in 2019 as D6768/D6768M 19.DOI:10.1520/D6768_D6768M-20.2For 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.6.Atmospheric Conditions6.1 Atmospheric Conditions:6.1.1 The atmospheric conditions of the laboratory deter-mining tensile strength of geosynthetic clay liners shall be:relative humidity between 50 to 70%and a temperature of 216 2 C 70 6 4 F.7.Appar