1、Designation: D6768/D6768M 18Standard 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 rev
2、ision. 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 The test method establishes the procedures for themeasurement of tensile strength of a geosynthetic clay liner(GCL). This test
3、 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 units
4、are 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 al
5、l 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 i
6、n 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
7、.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. T
8、erminology3.1 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 consis
9、ting of clay bonded to a layer or layers ofgeosynthetic material(s). D44393.3 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
10、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 si
11、nceinformation 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 conductco
12、mparative 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 struct
13、ure.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 ap
14、plicable 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 Jun
15、e 1, 2018. Published June 2018. Originallyapproved in 2002. Last previous edition approved in 2015 as D6768/D6768M 04(2015)2. DOI: 10.1520/D6768_D6768M-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
16、Standards 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 princ
17、iples 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.16. Apparatus6.1 Tensile Testing MachineA constant rate of extension(CRE) ty
18、pe of testing machine described in SpecificationD76/D76M shall be used with a minimum precision measuringcapability of 0.1 N/m 5.71 104lbf/in.6.2 ClampsThe clamps shall be a minimum 25 by100 mm 1 by 4 in. and with appropriate clamping power toprevent slipping or crushing (damage).6.3 Die or Template
19、, 100 by 200 mm (61 mm) 4 by 8 in.(60.04 in.).6.4 MiscellaneousKnives, razor, etc., as required.7. Sampling and Test Specimens7.1 Lot SampleFor the lot sample, take rolls of GCLs asdirected in an applicable material specification, PracticeD5889/D5889M, or as agreed upon between the purchaser andthe
20、supplier.7.2 Laboratory SampleFor the laboratory sample, sampleshall be taken in accordance with Practice D6072/D6072M.The sample received at the testing laboratory should be insatisfactory condition and representative of the product manu-factured or delivered to a site, or both.7.3 Test SpecimensA
21、minimum of five test specimensshall be taken in the machine direction from each swatch in thelaboratory sample. Take specimens from the laboratory sample,with those for the measurement of the machine direction tensileproperties from different positions across the GCL width. Nospecimens shall be take
22、n within 10 cm 4 in. of the selvage oredge of the GCL.7.4 The size of the die or template for cutting specimens is100 by 200 mm (minimum) 4 by 8 in.7.5 The loss of clay during the specimen cutting processshould have no bearing on the results of the test.8. Conditioning8.1 The test specimen shall be
23、tested as received.9. Procedure9.1 Obtain SpecimensUsing the die, or template and razor,and other necessary apparatus, carefully cut from the labora-tory sample five (5) test specimens. The five specimens shouldbe randomly selected from locations on the sample, but shouldbe distributed across the sa
24、mple. All specimens should be cutparallel to the machine direction.9.2 Machine Setup ConditionsAdjust the distance be-tween the clamps at the start of the test to 100 6 3mm460.1 in. Set the CRE at 300 mm/min 12 in./min.9.3 Insertion of Specimen in ClampsMount the specimencentrally in the clamps. The
25、 specimen must be visuallyobserved 25 mm 1 in. extended past the clamp. The specimenlength in the machine direction must be parallel to the directionof application of force.9.4 Measurement of Tensile StrengthStart the tensile test-ing machine.9.4.1 Continue testing the specimen until complete ruptur
26、eand record the maximum tensile force of the GCL.NOTE 1In some instances, it may be required to determine elongation.In these cases, the user shall indicate the criteria at which elongation isrequired.9.4.2 Readings of force and time shall be taken at aminimum rate of 20 readings per second.9.4.3 If
27、 a specimen slips in the jaws, or if for any reasonattributable to faulty operation the results fall significantlybelow the average for the set of specimens, discard the resultsand test another specimen. Continue until the required numberof readings has been taken.10. Calculation10.1 Tensile Strengt
28、hCalculate the tensile strength as readdirectly from the test instrument expressed in N/m lbf/in. ofwidth, using the following equation:fn5f11f211f5!5 5fnWswhere:fn= average recorded peak tensile strength for specimen, Nlbf, = tensile strength of the GCL, N/m lbf/in., andWs= specified specimen width
29、, m in.11. Report11.1 Report the following information on tensile strength ofGCLs:11.1.1 All specimen values and average peak tensilestrength/unit width to the nearest 0.1 N/m lbf/in.11.1.2 If requested, the standard deviation, coefficient ofvariation, or both.11.1.3 Sample identification (for examp
30、le, sample number,roll number, or other traceable identifier).11.1.4 Type of GCL tested.11.1.5 Type of testing machine and upper limit of load.11.1.6 Full-scale force range used for testing.11.1.7 A statement of any departure from the suggestedtesting procedures so that the results can be evaluated
31、and used.11.1.8 Note any cause or need for testing additional speci-mens due to rupture of the geotextile(s) during test, damage tospecimen from the grips, etc.11.2 Identification of testing agency, person performing thetest, date of test, and client or project identification.11.3 Verification that
32、the rupture of the GCL occurred.12. Precision and Bias12.1 Interlaboratory Test ProgramAn interlaboratorystudy of the test method was run in 2002/2003. Four differentgeosynthetic clay liner samples were distributed to ten labora-tories. Three sets of test results were generated for each sampleby eac
33、h of the laboratories.12.2 Test ResultsThe precision information is given inTable 1. The results are presented for the average of thecoefficient of variation, CV %, for the four samples.D6768/D6768M 18212.3 BiasThe procedure in Test Method D6768/D6768Mfor measuring the tensile strength of the geosyn
34、thetic clay linerhas no bias because the value of the tensile strength of ageosynthetic clay liner is defined only in the terms of this testmethod.13. Keywords13.1 clay; geosynthetic; geosynthetic clay liner; tensilestrengthASTM International takes no position respecting the validity of any patent r
35、ights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at a
36、ny time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments
37、will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by
38、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail);
39、 or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1 Test ResultsStatisticILSAverageWithin-laboratory repeatability limit, CVSr, % 4Between-laboratory reproducibility limit, CVSR, % 895 % confidence limit within-laboratory repeatability, CVr, % 1095 % confidence limit between-laboratory repeatability, CVr, % 23D6768/D6768M 183
