ASTM D6768-02

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 6768 – 02
Standard Test Method for
Tensile Strength of Geosynthetic Clay Liners
This standard is issued under the fixed designation D 6768; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope barrier consisting of clay bonded to a layer or layers of
geosynthetic material(s).
1.1 The test method establishes the procedures for the
3.3 For terminology of other terms used in this test method,
measurement of tensile strength of Geosynthetic Clay Liner
refer to Terminologies D 123 and D 4439.
(GCL). This test method is strictly an index test method to be
used to verify the tensile strength of GCLs. Results from this
4. Summary of Test Method
test method should not be considered as an indication of actual
4.1 A 4-in. wide specimen is gripped across its entire width
or long-term performance of the geosynthetic(s) in field
in the clamps of a constant rate of extension (CRE) type tensile
applications.
testing machine operated at a prescribed rate of extension,
1.2 The values in SI units are to be regarded as the standard.
applying a longitudinal force to the specimen until the speci-
Values in pound units are in parentheses for information.
men ruptures.
1.3 This standard may involve hazardous materials, opera-
tions, and equipment. This standard does not purport to
5. Significance and Use
address all of the safety concerns, if any, associated with its
5.1 GCL Test Method Dxxxx for the determination of the
use. It is the responsibility of the user of this standard to
tensile strength of GCLs may be used for the acceptance testing
establish appropriate safety and health practices and deter-
of commercial shipments of GCLs but caution is advised since
mine the applicability of regulatory limitations prior to use.
information about between-laboratory precision is incomplete.
2. Referenced Documents Comparative tests as directed in 5.1.1 may be advisable.
5.1.1 In cases of a dispute arising from differences in
2.1 ASTM Standards:
reported test results when using this test method for acceptance
D 76 Specification for Tensile Testing Machines for Tex-
2 of shipments, the purchaser and the supplier should conduct
tiles
2 comparative tests to determine if there is a statistical bias. The
D 123 Terminology Relating to Textiles
two parties should take a group of test samples that are as
D 2905 Practice for Statements on Number of Specimens
homogeneous as possible and which are from the lot of
for Textiles
3 material in question.
D 4439 Terminology for Geosynthetics
5.2 Some modification of clamping techniques may be
D 4595 Test Method for Tensile Properties of Geotextiles
3 necessary for a given GCL depending upon its structure.
by Wide-Width Strip Method
Specimen clamping may be modified as required at the
D 5889 Practice for Quality Control of Geosynthetic Clay
3 discretion of the individual laboratory providing a representa-
Liners
tive tensile strength is obtained. In any event, the procedure
D 6072 Guide for Obtaining Samples of Geosynthetic Clay
3 described in Section 10 of this test method for obtaining tensile
Liners
strength must be maintained.
3. Terminology 5.3 This test method is applicable for testing GCLs as
received. It is used with a constant rate of extension type
3.1 geosynthetic, n—a product manufactured wholly or in
tension apparatus.
part from polymeric material used with soil, rock, earth, or
other geotechnical engineering related material as an integral
6. Apparatus
part of a project, structure, or system. D 4439
6.1 Tensile Testing Machine, a constant rate of extension
3.2 geosynthetic clay liner, n—a manufactured hydraulic
(CRE) type of testing machine described in Specification D 76
shall be used with a minimum precision measuring capability
-4
This test method is under the jurisdiction of ASTM Committee D35 on of 0.1 N/m (5.71 3 10 lbf/in.).
Geosynthetics and is the direct responsibility of Subcommittee D35.04 on Geosyn-
6.2 Clamps, the clamps shall be a minimum 25 by 100 mm
thetic Clay Liners.
(1 by 4 in.) and with appropriate clamping power to prevent
Current edition approved Feb. 10, 2002. Published April 2002.
slipping or crushing (damage).
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 04.09.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 6768
6.3 Die or Template, 100 by 200 mm (61 mm) (4 by 8 in.). below the average for the set of specimens, discard the results
6.4 Miscellaneous, knives, razor, spatulas, scoops, quarter- and test another specimen. Continue until the required number
ing cloth, sample splitters, etc, as required. of readings has been taken.
10. Calculation
7. Sampling and Test Specimens
10.1 Tensile Strength—Calculate the tensile strength as read
7.1 Lot Sample—For the lot sample, take rolls of GCLs as
directly from the test instrument expressed in N/m (lbf/in
...