1、Designation: D 6768 04Standard Test Method forTensile Strength of Geosynthetic Clay Liners1This standard is issued under the fixed designation D 6768; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 Geosynthetic Clay Liner(GCL). This test method is st
3、rictly 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 in SI units are to be regarded as the standard.Values in p
4、ound units are in parentheses for information.1.3 This standard may involve hazardous materials, opera-tions, 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 appropri
5、ate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 76 Specification for Tensile Testing Machines for TextilesD 123 Terminology Relating to TextilesD 2905 Practice for Statements on Number of Specimensfo
6、r TextilesD 4439 Terminology for GeosyntheticsD 5889 Practice for Quality Control of Geosynthetic ClayLinersD 6072 Guide for Obtaining Samples of Geosynthetic ClayLiners3. Terminology3.1 geosynthetic, na product manufactured wholly or inpart from polymeric material used with soil, rock, earth, oroth
7、er geotechnical engineering related material as an integralpart of a project, structure, or system. D 44393.2 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 metho
8、d,refer to Terminologies D 123 and D 4439.4. 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 spec
9、imen 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
10、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 ashomoge
11、neous 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 tensil
12、e 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.6. Apparatus6.1 Tensile T
13、esting Machine, a constant rate of extension(CRE) type of testing machine described in Specification D 76shall be used with a minimum precision measuring capabilityof 0.1 N/m (5.71 3 10-4lbf/in.).1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct resp
14、onsibility of Subcommittee D35.04 on Geosyn-thetic Clay Liners.Current edition approved June 1, 2004. Published June 2004. Originallyapproved in 2002. Last previous edition approved in 2003 as D 6768032For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
15、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Clamps, the clamps shall be a minimum 25
16、by 100 mm(1 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 8in.(60.04 in.).6.4 Miscellaneous, knives, razor, etc, as required.7. Sampling and Test Specimens7.1 Lot SampleFor the lot sample, take rolls of GCLs asd
17、irected in an applicable material specification, PracticeD 5889, or as agreed upon between the purchaser and thesupplier.7.2 Laboratory SampleFor the laboratory sample, sampleshall be taken in accordance with Guide D 6072. The samplereceived at the testing laboratory should be in satisfactoryconditi
18、on and representative of the product manufactured ordelivered to a site, or both.7.3 Test SpecimensA 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
19、 direction tensileproperties from different positions across the GCL width. Nospecimens shall be taken 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 cutti
20、ng 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 SpecimensUsing the die, or template andrazor, and other necessary apparatus, carefully cut from thelaboratory sample five (5) test specimens. The five s
21、pecimensshould be randomly selected from locations on the sample, butshould be distributed across the sample. All specimens shouldbe cut parallel to the machine direction.9.2 Machine Set-Up ConditionsAdjust the distance be-tween the clamps at the start of the test to 100 6 3mm(460.1 in.). Set the CR
22、E 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.) extend past the clamp. The specimenlength in the machine direction must be parallel to the directionof application of force.9.4 Measurement o
23、f 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.9.4.2 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 a
24、ny 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 StrengthCalculate the tensile strength as readdir
25、ectly from the test instrument expressed in N/m (lbf/in.) ofwidth, using the following equation:afn5af11af21 . 1af5!5a5afnWswhere:afn= average recorded peak tensile strength for specimen,N (lbf),a = tensile strength of the GCL, N/m (lbf/in.), andWs= specified specimen width, m (in.).11. Report11.1 R
26、eport 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 example, sample no., roll
27、no., 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 and used.11.1.8 Note any c
28、ause 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 the rupture of the GCL occu
29、rred.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 each of the laboratories.12.2
30、Test ResultsThe precision information is given inTable 1. The results are presented for the average of thecoefficient of variation, CV%, for the four samples.12.3 BiasThe procedure in Test Method D 6768 for mea-suring the tensile strength of the geosynthetic clay liner has nobias because the value o
31、f the tensile strength of a geosyntheticclay liner is defined only in the terms of this test method.TABLE 1 Test ResultsStatistic ILS AverageWithin laboratory repeatability limit, CVSr, % 4Between laboratory reproducibility limit, CVSR, % 895% confidence limit within laboratory repeatibility, CVr, %
32、 1095% confidence limit between laboratory repeatibility, CVr, % 23D676804213. Keywords13.1 clay; geosynthetic; geosynthetic clay liner; tensilestrengthASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Us
33、ers 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 any time by the responsible technical committee and must be reviewed ever
34、y 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 will receive careful consideration at a meeting of theresponsible techni
35、cal 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 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); or through the ASTM website(www.astm.org).D6768043
