ASTM_D_6768_-_D_6768M_-_04_2015e2.pdf

Designation:D6768/D6768M04(Reapproved 2015)2Standard 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.1NOTEUnits information was corrected editorially in February 2015.2NOTEFootnote 1 was corrected editorially in July 2015.1.Scope1.1 The test method establishes the procedures for themeasurement of tensile strength of 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 non-conformancewith the standard.1.3 This standard may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D76/D76M Specification for Tensile Testing Machines forTextilesD123 Terminology Relating to TextilesD2905 Practice for Statements on Number of Specimens forTextiles(Withdrawn 2008)3D4439 Terminology for GeosyntheticsD5889 Practice for Quality Control of Geosynthetic ClayLinersD6072/D6072M Practice for Obtaining Samples of Geosyn-thetic Clay Liners3.Terminology3.1 geosynthetic,na product manufactured wholly or inpart from polymeric material used with soil,rock,earth,orother geotechnical engineering related material as an integralpart of a project,structure,or system.D44393.2 geosynthetic clay liner,na manufactured hydraulicbarrier consisting of clay bonded to a layer or layers ofgeosynthetic material(s).3.3 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 providing a representa-tive tensile strength is obtained.In any event,the procedure1This 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 Jan.15,2015.Published February 2015.Originallyapproved in 2002.Last previous edition approved in 2009 as D676804(2009).DOI:10.1520/D6768_D6768M-04R15E02.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 described 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.6.Apparatus6.1 Tensile Testing Machine,a constant rate of extension(CRE)type of testing machine described in SpecificationD76/D76M shall be used with a minimum precision measuringcapability of 0.1 N/m 5.71 10-4lbf/in.6.2 Clamps,the clamps shall be a minimum 25 by 100 mm1 by 4 in.and with appropriate clamping power to preventslip