ASTM D7556-10(2019)
(Test Method)Standard Test Methods for Determining Small-Strain Tensile Properties of Geogrids and Geotextiles by In-Air Cyclic Tension Tests
Standard Test Methods for Determining Small-Strain Tensile Properties of Geogrids and Geotextiles by In-Air Cyclic Tension Tests
SIGNIFICANCE AND USE
5.1 Test Methods A, B, and C provide a means of evaluating the tensile modulus of geogrids and geotextiles for applications involving small-strain cyclic loading. The test methods allow for the determination of cyclic tensile modulus at different levels of prescribed or permanent strain, thereby accounting for possible changes in cyclic tensile modulus with increasing permanent strain in the material. These test methods shall be used for research testing and to define properties for use in specific design methods.
5.2 In cases of dispute arising from differences in reported test results when using these test methods 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 shall be found and corrected or the purchaser and supplier shall agree to interpret future test results in light of the known bias.
5.3 All geogrids can be tested by Test Method A or B. 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.
5.4 Most geotextiles can be tested by Test Method C. Some modification of clamping techniques may be necessary for a given geotextile depen...
SCOPE
1.1 These test methods cover the determination of small-strain tensile properties of geogrids and geotextiles by subjecting wide-width specimens to cyclic tensile loading.
1.2 These test methods (A, B, and C) allow for the determination of small-strain cyclic tensile modulus by the measurement of cyclic tensile load and elongation.
1.3 This test method is intended to provide properties for design. The test method was developed for mechanistic-empirical pavement design methods requiring input of the reinforcement tensile modulus. The use of cyclic modulus from this test method for other applications involving cyclic loading should be evaluated on a case-by-case basis.
1.4 Three test methods (A, B, and C) are provided to determine small-strain cyclic tensile modulus on geogrids and geotextiles.
1.4.1 Test Method A—Testing a relatively wide specimen of geogrid in cyclic tension in kN/m (lbf/ft).
1.4.2 Test Method B—Testing multiple layers of a relatively wide specimen of geogrid in cyclic tension in kN/m (lbf/ft).
1.4.3 Test Method C—Testing a relatively wide specimen of geotextile in cyclic tension in kN/m (lbf/ft).
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard.
1.6 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.
1.7 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: D7556 − 10 (Reapproved 2019)
Standard Test Methods for
Determining Small-Strain Tensile Properties of Geogrids and
Geotextiles by In-Air Cyclic Tension Tests
This standard is issued under the fixed designation D7556; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 These test methods cover the determination of small-
strain tensile properties of geogrids and geotextiles by subject-
2. Referenced Documents
ing wide-width specimens to cyclic tensile loading.
2.1 ASTM Standards:
1.2 These test methods (A, B, and C) allow for the deter-
D76/D76M Specification for Tensile Testing Machines for
mination of small-strain cyclic tensile modulus by the mea-
Textiles
surement of cyclic tensile load and elongation.
D123 Terminology Relating to Textiles
1.3 This test method is intended to provide properties for D579/D579M Specification for Greige Woven Glass Fabrics
D4354 Practice for Sampling of Geosynthetics and Rolled
design. The test method was developed for mechanistic-
empirical pavement design methods requiring input of the Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
reinforcementtensilemodulus.Theuseofcyclicmodulusfrom
this test method for other applications involving cyclic loading
3. Terminology
should be evaluated on a case-by-case basis.
3.1 Definitions:
1.4 Three test methods (A, B, and C) are provided to
3.1.1 atmosphere for testing geosynthetics, n—air main-
determine small-strain cyclic tensile modulus on geogrids and
tained at a relative humidity of 50 to 70 % and a temperature
geotextiles.
of 21 6 2 °C (70 6 4 °F).
1.4.1 Test Method A—Testing a relatively wide specimen of
3.1.2 corresponding force, n—synonym for force at speci-
geogrid in cyclic tension in kN/m (lbf/ft).
fied elongation.
1.4.2 Test Method B—Testing multiple layers of a relatively
wide specimen of geogrid in cyclic tension in kN/m (lbf/ft).
3.1.3 force at specified elongation (FASE), n—force associ-
1.4.3 Test Method C—Testing a relatively wide specimen of
ated with a specific elongation on the force-elongation curve.
geotextile in cyclic tension in kN/m (lbf/ft).
(Synonym for corresponding force.)
1.5 The values stated in SI units are to be regarded as
3.1.4 force-elongation curve, n—in a tensile test, graphical
standard. The values given in parentheses are provided for
representation of the relationship between the magnitude of an
information only and are not considered standard.
externally applied force and the change in length of the
specimen in the direction of the applied force. (Synonym for
1.6 This standard does not purport to address all of the
stress-strain curve.)
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.5 geogrid, n—geosynthetic formed by a regular network
priate safety, health, and environmental practices and deter-
of integrally connected elements with apertures greater than
mine the applicability of regulatory limitations prior to use. 6.35 mm ( ⁄4 in.) to allow interlocking with surrounding soil,
1.7 This international standard was developed in accor-
rock, earth, and other surrounding materials to primarily
dance with internationally recognized principles on standard- function as reinforcement.
ization established in the Decision on Principles for the
3.1.6 geosynthetic, n—product manufactured from poly-
Development of International Standards, Guides and Recom-
meric material used with soil, rock, earth, or other geotechnical
engineering-related material as an integral part of a man-made
project, structure, or system.
These test methods are under the jurisdiction of ASTM Committee D35 on
Geosynthetics and are the direct responsibility of Subcommittee D35.01 on
Mechanical Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2019. Published April 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2010. Last previous edition approved in 2010 as D7556 – 10. Standards volume information, refer to the standard’s Document Summary page on
DOI:10.520/D7556-10R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7556 − 10 (2019)
3.1.7 geotextile, n—any permeable textile material used permanent axial strain. Tensile modulus in kN/m (lbf/ft) of the
with foundation, soil, rock, earth, or any other geotechnical testspecimencanbecalculatedateachlevelofprescribedaxial
engineering-related material, as an integral part of a man-made strain from the last cycles of load from machine scales, dials,
project, structure, or system. recording charts, or an interfaced computer.
3.1.8 integral, adj—in geosynthetics, forming a necessary
5. Significance and Use
part of the whole; a constituent.
5.1 Test MethodsA, B, and C provide a means of evaluating
3.1.9 junction, n—point where geogrid ribs are intercon-
the tensile modulus of geogrids and geotextiles for applications
nected to provide structure and dimensional stability.
involving small-strain cyclic loading. The test methods allow
3.1.10 rib, n—for geogrids, continuous elements of a
for the determination of cyclic tensile modulus at different
geogrid which are either in the machine or cross-machine
levelsofprescribedorpermanentstrain,therebyaccountingfor
direction as manufactured.
possible changes in cyclic tensile modulus with increasing
3.1.11 tensile, adj—capable of tensions, or relating to ten- permanent strain in the material. These test methods shall be
sion of a material. used for research testing and to define properties for use in
specific design methods.
3.1.12 tensile strength, (α ), n—for geogrids, maximum
f
resistance to deformation developed for a specific material
5.2 In cases of dispute arising from differences in reported
whensubjectedtotensionbyanexternalforce.Tensilestrength
test results when using these test methods for acceptance
of geogrids is the characteristic of a sample as distinct from a
testing of commercial shipments, the purchaser and supplier
specimen and is expressed in force per unit width.
should conduct comparative tests to determine if there is a
statistical bias between their laboratories. Competent statistical
3.1.13 tensile test, n—for geosynthetics, test in which a
assistance is recommended for the investigation of bias. As a
material is stretched uniaxially to determine the force elonga-
minimum, the two parties should take a group of test speci-
tion characteristics, the breaking force, or the breaking elon-
mens which are as homogeneous as possible and which are
gation.
from a lot of material of the type in question. The test
3.1.14 tension, n—force that produces a specified elonga-
specimens should then be randomly assigned in equal numbers
tion.
to each laboratory for testing.The average results from the two
3.2 Fordefinitionsofothertermsusedinthesetestmethods,
laboratories should be compared using Student’s t-test for
refer to Terminologies D123 and D4439.
unpaireddataandanacceptableprobabilitylevelchosenbythe
twopartiesbeforethetestingbegan.Ifabiasisfound,eitherits
4. Summary of Test Method
cause shall be found and corrected or the purchaser and
4.1 Test Method A—In this test method, a relatively wide
supplier shall agree to interpret future test results in light of the
geogrid specimen is gripped across its entire width in the
known bias.
clamps of a constant rate of extension type tensile testing
5.3 All geogrids can be tested byTest MethodAor B. Some
machine operated at a prescribed rate of extension, applying a
modification of techniques may be necessary for a given
uniaxial cyclic load to the specimen over specified limits of
geogrid depending upon its physical makeup. Special adapta-
cyclic axial strain and centered around six successively greater
tions may be necessary with strong geogrids, multiple-layered
levels of prescribed or permanent axial strain. Tensile modulus
geogrids, or geogrids that tend to slip in the clamps or those
in kN/m (lbf/ft) of the test specimen can be calculated at each
which tend to be damaged by the clamps.
levelofprescribedaxialstrainfromthelastcyclesofloadfrom
5.4 Most geotextiles can be tested by Test Method C. Some
machine scales, dials, recording charts, or an interfaced com-
modification of clamping techniques may be necessary for a
puter.
given geotextile depending upon its structure. Special clamp-
4.2 Test Method B—A relatively wide, multiple-layered
ing adaptations may be necessary with strong geotextiles or
geogrid specimen is gripped across its entire width in the
geotextiles made from glass fibers to prevent them from
clamps of a constant rate of extension type tensile testing
slipping in the clamps or being damaged as a result of being
machine operated at a prescribed rate of extension, applying a
gripped in the clamps.
uniaxial cyclic load to the specimen over specified limits of
5.5 These test methods are applicable for testing geotextiles
cyclic axial strain and centered around six successively greater
levels of prescribed or permanent axial strain. Tensile modulus either dry or wet. It is used with a constant rate of extension
type tension apparatus.
in kN/m (lbf/ft) of the test specimen can be calculated at each
levelofprescribedaxialstrainfromthelastcyclesofloadfrom
5.6 These test methods may not be suited for geogrids and
machine scales, dials, recording charts, or an interfaced com-
geotextiles that exhibit strengths approximately 100 kN/m
puter.
(600 lbf⁄in.) due to clamping and equipment limitations. In
those cases, 100-mm (4-in.) width specimens may be substi-
4.3 Test Method C—Arelativelywidegeotextilespecimenis
gripped across its entire width in the clamps of a constant rate tuted for 200-mm (8-in.) width specimens.
of extension type tensile testing machine operated at a pre-
6. Apparatus
scribed rate of extension, applying a uniaxial cyclic load to the
specimen over specified limits of cyclic axial strain and 6.1 Testing Clamps—The clamps shall be sufficiently wide
centered around six successively greater levels of prescribed or to grip the entire width of the specimen and with appropriate
D7556 − 10 (2019)
clamping power to prevent slipping or crushing (damage). 8.2.2 Test Method B—Prepare each finished specimen to be
Fixed clamps shall be used. a minimum of 200 mm (8 in.) wide and contain five ribs in the
6.1.1 Size of Jaw Faces—Each clamp shall have jaw faces cross-testdirectionbyatleastthreejunctions(twoapertures)or
measuring wider than the width of the specimen.
300 mm (12 in.) long in the direction of testing, with the length
dimension being designated and accurately cut parallel to the
6.2 Tensile Testing Machine—A testing machine of the
direction for which the tensile strength is being measured.This
constant rate of extension type as described in Specification
shall be repeated for each layer of geogrid included in the test.
D76/D76M shall be used.The testing machine shall be capable
of applying cyclic loads between specified limits of deforma- 8.2.3 Test Method C—Prepare each finished specimen to be
a minimum of 200 mm (8 in.) wide (excluding fringe when
tion as specified in 10.4 and 10.6. The machine shall be
equipped with a device for recording the tensile force and the applicable;see8.2.5)byatleast200mm(8in.)long(see8.2.5)
amount of separation of the grips. Both of these measuring with the length dimension being designated and accurately
systems shall be accurate to 61.0 % and, preferably, shall be
parallel to the direction for which the tensile modulus is being
external to the testing machine. The rate of separation shall be
measured. Centrally, draw two lines running the full width of
uniform and capable of adjustment within the range of the test.
the specimen, accurately perpendicular to the length dimension
A stroke of approximately 100 to 150 mm (4 to 6 in.) and a
and separated by 100 mm (4 in.) to designate the gauge area.
load rating of approximately 50 kN (11 kips) is recommended
8.2.4 For some woven geotextiles, it may be necessary to
for these types of tests.
cut each specimen 210 mm (8.5 in.) wide and then remove an
6.3 Distilled Water and Nonionic Wetting Agent—Used for equal number of yarns from each side to obtain the 200-mm
wet specimens only. (8-in.) finished dimension. This helps maintain specimen
integrity during the test.
6.4 Extensometer—When required by the test method, a
8.2.5 For geotextiles where specimen integrity is not
device capable of measuring the distance between two refer-
affected, the specimens may be initially cut to the finished
ence points on the specimen without any damage to the
width.
specimen or slippage, care being taken to ensure that the
measurement represents the true movement of the reference
8.2.6 When the wet tensile modulus of the geotextile is
points. Examples of extensometers include mechanical,
required in addition to the dry tensile modulus, cut each test
optical, infrared, or electrical devices.
specimen at least twice as long as is required for a standard test
(see Note 2). Number each specimen and then cut it crosswise
7. Sampling
into two parts: one for determining the conditioned tensile
modulusandtheotherfordeterminingthewettensilemodulus.
7.1 Lot Sample—Divide the product into lots, and take the
Each portion shall bear the specimen number. In this manner,
lot sample as directed in Practice D4354.
each paired break is performed on test specimens containing
7.2 Laboratory Sample—For the laboratory sample, take a
the same yarns.
full roll-width swatch long enough in the machine direction
from each roll in the lot sample to ensure that the requirements
NOTE 2—For geotextiles which shrink excessively when wet, cut the
in 8.1 can be met. The sample may be taken from the end test specimens for obtaining wet tensile strength longer in dimension than
that for dry tensile strength.
portion of a roll, provided there is no evidence it is distorted or
different from other portions of the roll.
8.3 Number of Test Specimens:
8.3.1 Unless otherwise agreed upon as when provided in an
8. Test Specimen
applicable material specification,
...
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