ASTM D6637/D6637M-15(2023)
(Test Method)Standard Test Method for Determining Tensile Properties of Geogrids by the Single or Multi-Rib Tensile Method
Standard Test Method for Determining Tensile Properties of Geogrids by the Single or Multi-Rib Tensile Method
SIGNIFICANCE AND USE
5.1 The determination of the tensile force-elongation values of geogrids provides index property values. This test method shall be used for quality control and acceptance testing of commercial shipments of geogrids.
5.2 In cases of dispute arising from differences in reported test results when using this test method for acceptance testing of commercial shipments, the purchaser and supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test for unpaired data and an acceptable probability level chosen by the two parties before the testing began. If a bias is found, either its cause must be found and corrected or the purchaser and supplier must agree to interpret future test results in light of the known bias.
5.3 All geogrids can be tested by any of these methods. Some modification of techniques may be necessary for a given geogrid depending upon its physical makeup. Special adaptations may be necessary with strong geogrids, multiple layered geogrids, or geogrids that tend to slip in the clamps or those which tend to be damaged by the clamps.
SCOPE
1.1 This test method covers the determination of the tensile strength properties of geogrids by subjecting strips of varying width to tensile loading.
1.2 Three alternative procedures are provided to determine the tensile strength, as follows:
1.2.1 Method A—Testing a single geogrid rib in tension (N or lbf).
1.2.2 Method B—Testing multiple geogrid ribs in tension (kN/m or lbf/ft).
1.2.3 Method C—Testing multiple layers of multiple geogrid ribs in tension (kN/m or lbf/ft).
1.3 This test method is intended for quality control and conformance testing of geogrids.
1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6637/D6637M − 15 (Reapproved 2023)
Standard Test Method for
Determining Tensile Properties of Geogrids by the Single or
Multi-Rib Tensile Method
This standard is issued under the fixed designation D6637/D6637M; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of the tensile
D76/D76M Specification for Tensile Testing Machines for
strength properties of geogrids by subjecting strips of varying
Textiles
width to tensile loading.
D123 Terminology Relating to Textiles
1.2 Three alternative procedures are provided to determine
D4354 Practice for Sampling of Geosynthetics and Rolled
the tensile strength, as follows:
Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
1.2.1 Method A—Testing a single geogrid rib in tension (N
D5262 Test Method for Determining the Unconfined Ten-
or lbf).
sion Creep and Creep Rupture Behavior of Planar Geo-
1.2.2 Method B—Testing multiple geogrid ribs in tension
synthetics Used for Reinforcement Purposes
(kN/m or lbf/ft).
1.2.3 Method C—Testing multiple layers of multiple
3. Terminology
geogrid ribs in tension (kN/m or lbf/ft).
3.1 Definitions:
1.3 This test method is intended for quality control and 3.1.1 atmosphere for testing geosynthetics, n—air main-
tained at a relative humidity of 50 to 70 % and a temperature
conformance testing of geogrids.
of 21 6 2 °C [70 6 4 °F].
1.4 The values stated in either SI units or inch-pound units
3.1.2 breaking force, (F), n—the force at failure.
are to be regarded separately as standard. The values stated in
3.1.3 corresponding force, n—synonym for force at speci-
each system are not necessarily exact equivalents; therefore, to
fied elongation.
ensure conformance with the standard, each system shall be
used independently of the other, and values from the two 3.1.4 force at specified elongation, FASE, n—a force asso-
ciated with a specific elongation on the force-elongation curve
systems shall not be combined.
(synonym for corresponding force).
1.5 This standard does not purport to address all of the
3.1.5 force-elongation curve, n—in a tensile test, a graphical
safety concerns, if any, associated with its use. It is the
representation of the relationship between the magnitude of an
responsibility of the user of this standard to establish appro-
externally applied force and the change in length of the
priate safety, health, and environmental practices and deter-
specimen in the direction of the applied force (synonym for
mine the applicability of regulatory limitations prior to use.
stress-strain curve).
1.6 This international standard was developed in accor-
3.1.6 geogrid, n—a geosynthetic formed by a regular net-
dance with internationally recognized principles on standard-
work of integrally connected elements with apertures greater
ization established in the Decision on Principles for the
than 6.35 mm [ ⁄4 in.] to allow interlocking with surrounding
Development of International Standards, Guides and Recom-
soil, rock, earth, and other surrounding materials to primarily
mendations issued by the World Trade Organization Technical
function as reinforcement. D5262
Barriers to Trade (TBT) Committee.
3.1.7 geosynthetic, n—a product manufactured from poly-
meric material used with soil, rock, earth, or other geotechnical
This test method is under the jurisdiction of ASTM Committee D35 on
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
cal Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 15, 2023. Published November 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2001. Last previous edition approved in 2015 as D6637/D6637M – 15. Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D6637_D6637M-15R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6637/D6637M − 15 (2023)
engineering related material as an integral part of a man-made shall be used for quality control and acceptance testing of
project, structure, or system. commercial shipments of geogrids.
3.1.8 index test, n—a test procedure which may contain
5.2 In cases of dispute arising from differences in reported
known bias, but which may be used to establish an order for a
test results when using this test method for acceptance testing
set of specimens with respect to the property of interest.
of commercial shipments, the purchaser and supplier should
conduct comparative tests to determine if there is a statistical
3.1.9 integral, adj—in geosynthetics, forming a necessary
bias between their laboratories. Competent statistical assis-
part of the whole; a constituent.
tance is recommended for the investigation of bias. As a
3.1.10 junction, n—the point where geogrid ribs are inter-
minimum, the two parties should take a group of test speci-
connected to provide structure and dimensional stability.
mens which are as homogeneous as possible and which are
3.1.11 rib, n—for geogrids, the continuous elements of a
from a lot of material of the type in question. The test
geogrid which are interconnected to a node or junction.
specimens should then be randomly assigned in equal numbers
3.1.12 rupture, n—for geogrids, the breaking or tearing
to each laboratory for testing. The average results from the two
apart of ribs.
laboratories should be compared using Student’s t-test for
unpaired data and an acceptable probability level chosen by the
3.1.13 tensile, adj—capable of tensions, or relating to ten-
two parties before the testing began. If a bias is found, either its
sion of a material.
cause must be found and corrected or the purchaser and
3.1.14 tensile strength, (α ), n—for geogrids the maximum
f
supplier must agree to interpret future test results in light of the
resistance to deformation developed for a specific material
known bias.
when subjected to tension by an external force. Tensile strength
of geogrids is the characteristic of a sample as distinct from a
5.3 All geogrids can be tested by any of these methods.
specimen and is expressed in force per unit width.
Some modification of techniques may be necessary for a given
geogrid depending upon its physical makeup. Special adapta-
3.1.15 tensile test, n—for geosynthetics, a test in which a
tions may be necessary with strong geogrids, multiple layered
material is stretched uniaxially to determine the force-
geogrids, or geogrids that tend to slip in the clamps or those
elongation characteristics, the breaking force, or the breaking
which tend to be damaged by the clamps.
elongation.
3.1.16 tension, n—the force that produces a specified elon-
6. Apparatus
gation.
6.1 Testing Clamps—The clamps shall be sufficiently wide
3.2 For definitions of other terms used in this test method,
to grip the entire width of the specimen (as determined by the
refer to Terminologies D123 and D4439.
test method) and with appropriate clamping power to prevent
4. Summary of Test Method
slipping or crushing (damage). For a given product, the same
clamps shall be used in testing Methods A, B, and C prior to
4.1 Method A—In this method, a single representative rib
making any comparison between results.
specimen of a geogrid is clamped and placed under a tensile
6.1.1 Size of Jaw Faces—Each clamp shall have jaw faces
force using a constant rate of extension testing machine. The
measuring wider than the width of the specimen.
tensile force required to fail (rupture) the specimen is recorded.
The ultimate single rib tensile strength (N or lbf) is then
6.2 Tensile Testing Machine—A testing machine of the
determined based on the average of six single rib tensile tests.
constant rate of extension type as described in Specification
4.2 Method B—A relatively wide specimen is gripped across D76/D76M shall be used. The machine shall be equipped with
a device for recording the tensile force and the amount of
its entire width in the clamps of a constant rate of extension
type tensile testing machine operated at a prescribed rate of separation of the grips. Both of these measuring systems shall
be accurate to 61.0 % and, preferably, shall be external to the
extension, applying a uniaxial load to the specimen until the
specimen ruptures. Tensile strength (kN/m or lbf/ft), testing machine. The rate of separation shall be uniform and
capable of adjustment within the range of the test.
elongation, and secant modulus of the test specimen can be
calculated from machine scales, dials, recording charts, or an
6.3 Distilled Water and Nonionic Wetting Agent, shall be
interfaced computer.
used for wet specimens only.
4.3 Method C—A relatively wide, multiple layered speci-
6.4 Extensometer—When required by the method, a device
men is gripped across its entire width in the clamps of a
capable of measuring the distance between two reference
constant rate of extension type tensile testing machine operated
points on the specimen without any damage to the specimen or
at a prescribed rate of extension, applying a uniaxial load to the
slippage, care being taken to ensure that the measurement
specimen until the specimen ruptures. Tensile strength (kN/m
represents the true movement of the reference points. Ex-
or lbf/ft), elongation, and secant modulus of the test specimen
amples of extensometers include mechanical, optical, infrared,
can be calculated from machine scales, dials recording charts,
or electrical devices.
or an interfaced computer.
7. Sampling
5. Significance and Use
5.1 The determination of the tensile force-elongation values 7.1 Lot Sample—Divide the product into lots and take the
of geogrids provides index property values. This test method lot sample as directed in Practice D4354.
D6637/D6637M − 15 (2023)
7.2 Laboratory Sample—For the laboratory sample, take a
full roll-width swatch long enough in the machine direction
from each roll in the lot sample to ensure that the requirements
in 8.1 can be met. The sample may be taken from the end
portion of a roll provided there is no evidence it is distorted or
different from other portions of the roll.
8. Test Specimen
FIG. 2 Specimen Dimensions for Method A
8.1 The specimens shall consist of at least three (3) junc-
tions or 300 mm [12 in.] in length, in order to establish a
minimum specimen length in the direction of the test. The
direction of the test shall be defined as either the machine
direction (MD), cross-machine direction (CMD), or a nominal
skewed angle referenced from the machine direction according
to Fig. 1, where MD and CMD are defined as 0° and 90°,
respectively. All specimens should be free of surface defects,
etc., not typical of the laboratory sample. Take no specimens
nearer the selvage edge along the geogrid than ⁄10 the width of
the sample.
FIG. 3 Specimen Dimensions for Methods B and C
NOTE 1—If a comparison of one geogrid to another is to be made, the
length of each specimen shall be the same (as similar as possibly) and
agreed upon by all parties.
8.2 Preparation:
(two apertures) or 300 mm [12 in.] long in the direction of the
8.2.1 Method A—Prepare each finished specimen, as shown
testing, with the length dimension being designated and accu-
in Fig. 2, to contain at least one intersecting rib (or set of ribs)
rately cut parallel to the direction for which the tensile strength
crossing the test direction with at least three junctions (two
is being measured. This must be repeated for each layer of
apertures) in the direction of the testing, with the length
geogrid included in the test.
dimension being designated and accurately cut parallel to the
8.2.4 Within Test Methods A, B, and C, the outermost ribs
direction for which the tensile strength is being measured. See
are commonly cut prior to testing to permit extra width of
Note 2.
material in the clamps to minimize slippage within the clamps.
NOTE 2—In some applications, it may be necessary to perform tensile
If this procedure causes nonuniform distribution of load to the
tests in more than one direction (for example, both the machine and the
gauge length area of the specimen, the same width of material
cross-machine direction). When testing a geogrid with ribs oriented in
shall be included in the clamps as will be tested in the gauge
more than one direction, in all cases, the nominal rib direction of the
length area. In either case, the test results shall be based on the
tensile test specimen(s) should be clearly noted per Fig. 1.
unit of width associated with the number of intact ribs.
8.2.2 Method B—Prepare each finished specimen, as shown
in Fig. 3, to be a minimum of 200 mm wide and contain five 8.3 Number of Test Specimens:
ribs in the cross-test direction wide by at least three junctions 8.3.1 Unless otherwise agreed upon as when provided in an
(two apertures) or 300 mm [12 in.] long in the direction of the applicable material specification, take a number of test speci-
testing, with the length dimension being designated and accu- mens per swatch in the laboratory sample such that the user
rately cut parallel to the direction for which the tensile strength may expect at the 95 % probability level that the test result is
is being measured. no more than 5 % above the true average for each swatch in the
8.2.3 Method C—Prepare each finished specimen, as shown laboratory sample for each required direction, see Note 2.
in Fig. 3, to be a minimum of 200 mm wide and contain five 8.3.2 Reliable Estimate of v—When there is a reliable
ribs in the cross-test direction wide by at least three junctions estimate of v based upon extensive past records for similar
FIG. 1 Specimen Orientation and Test Direction
D6637/D6637M − 15 (2023)
materials tested in the user’s laboratory as directed in the least one clamp should be supported by a free swivel or
method, calculate the required number of specimens using Eq universal joint which will allow the clamp to rotate in the plane
1, as follows: of the geogrid. Select the force range of the testing machine so
2 the break occurs between 10 and 90 % of full-scale force. The
n 5 tv/A (1)
~ !
test shal
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.