1、Designation: D6768/D6768M 04 (Reapproved 2015)1Standard 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, t
2、he 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 editorially corrected in February 2015.1. Scope1.1 The test method establishes the procedure
3、s 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
4、) 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
5、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 a
6、nd 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
7、(Withdrawn 2008)3D4439 Terminology for GeosyntheticsD5889 Practice for Quality Control of Geosynthetic ClayLinersD6072/D6072M Practice for Obtaining Samples of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, ro
8、ck, 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
9、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
10、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 advisabl
11、e.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 a
12、re 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-
13、tive tensile strength is obtained. In any event, the proceduredescribed in Section 10 of this test method for obtaining tensilestrength must be maintained.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.04 on Geos
14、yn-thetic Clay Liners.Current edition approved Nov. 1, 2009. Published February 2015. Originallyapproved in 2002. Last previous edition approved in 2009 as D676804 (2009).DOI: 10.1520/D6768_D6768M-04R15E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、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
16、Conshohocken, PA 19428-2959. United States15.3 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 SpecificationD
17、76/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 preventslipping or crushing (damage).6.3 Die or Template, 100 by 200 mm (61 mm) 4 by 8 in.(60.04 in.).
18、6.4 Miscellaneous, knives, 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, or as agreed upon between the purchaser and thesupplier.7.2 Laboratory SampleFor the laboratory sam
19、ple, 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 minimum of five test specimensshall be taken in the
20、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 taken within 10 cm 4 in. of the selvage oredge of the GC
21、L.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 tested as received.9. Procedure9.1 Obtain SpecimensU
22、sing 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 sample. All specimens should be cutparallel to the mac
23、hine direction.9.2 Machine Set-Up 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 specimen must be visuallyobserved 25 mm 1 in. exte
24、nd 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 ruptureand record the maximum tensile force of the GCL.9.4.
25、2 Readings of force and time shall be taken at aminimum rate of 20 readings per second.9.4.3 If 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. C
26、ontinue until the required numberof readings has been taken.10. Calculation10.1 Tensile StrengthCalculate 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
27、for specimen, Nlbf, = tensile strength of the GCL, N/m lbf/in., andWs= specified specimen width, 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, t
28、he standard deviation, coefficient ofvariation, or both.11.1.3 Sample identification (for example, sample no., rollno., 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
29、 any departure from the suggestedtesting procedures so that the results can be evaluated 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 perfo
30、rming thetest, date of test and client or project identification.11.3 Verification that 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 distribut
31、ed to ten labora-tories. Three sets of test results were generated for each sampleby each 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 04 (2015)1212.
32、3 BiasThe procedure in Test Method D6768/D6768 formeasuring the tensile strength of the geosynthetic clay liner hasno bias because the value of the tensile strength of a geosyn-thetic clay liner is defined only in the terms of this test method.13. Keywords13.1 clay; geosynthetic; geosynthetic clay l
33、iner; tensilestrengthASTM International takes no position respecting the validity of any patent rights 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 infringemen
34、t of such rights, are entirely their own responsibility.This standard is subject to revision at any 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 f
35、or additional standardsand should be addressed to ASTM International Headquarters. Your comments 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 know
36、n to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by 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
37、 at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); 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 repeatibility, CVr, % 1095 % confidence limit between laboratory repeatibility, CVr, % 23D6768/D6768M 04 (2015)13
