ASTM D4885-01(2023)
(Test Method)Standard Test Method for Determining Performance Strength of Geomembranes by the Wide Strip Tensile Method
Standard Test Method for Determining Performance Strength of Geomembranes by the Wide Strip Tensile Method
SIGNIFICANCE AND USE
5.1 This test method is a performance test intended as a design aid used to determine the ability of geomembranes to withstand the stresses and strains imposed under design conditions. This test method assists the design engineer in comparing several candidate geomembranes under specific test conditions.
5.2 As a performance test, this method is not intended for routine acceptance testing of commercial shipments of geomembranes. Other more easily performed test methods, such as Test Methods D751 or Test Method D882, can be used for routine acceptance testing of geomembranes. This test method will be used relatively infrequently and to establish performance characteristics of geomembrane materials.
5.2.1 There is no known correlation between this test method and index test methods, such as Test Methods D751.
5.3 All geomembranes can be tested by this method. Some modification of techniques may be necessary for a given geomembrane depending upon its physical makeup. Special adaptations may be necessary with strong geomembranes or geomembranes with extremely slick surfaces, to prevent them from slipping in the clamps or being damaged by the clamps.
SCOPE
1.1 This test method covers the determination of the performance strength of synthetic geomembranes by subjecting wide strips of material to tensile loading.
1.2 This test method covers the measurement of tensile strength and elongation of geomembranes and includes directions for calculating initial modulus, offset modulus, secant modulus, and breaking toughness.
1.3 The basic distinctions between this test method and other methods measuring tensile strength of geomembranes are the width of the specimens tested and the speed of applied force. The greater width of the specimens specified in this test method minimizes the contraction edge effect (necking) which occurs in many geosynthetics and provides a closer relationship to actual material behavior in service. The slower speed of applied strain also provides a closer relationship to actual material behavior in service.
1.4 As a performance test, this method will be used relatively infrequently, and to test large lots of material. This test method is not intended for routine quality control testing of geomembranes.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
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: D4885 − 01 (Reapproved 2023)
Standard Test Method for
Determining Performance Strength of Geomembranes by
the Wide Strip Tensile Method
This standard is issued under the fixed designation D4885; 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
1.1 This test method covers the determination of the perfor- 2.1 ASTM Standards:
mance strength of synthetic geomembranes by subjecting wide D76/D76M Specification for Tensile Testing Machines for
strips of material to tensile loading. Textiles
D123 Terminology Relating to Textiles
1.2 This test method covers the measurement of tensile
D751 Test Methods for Coated Fabrics
strength and elongation of geomembranes and includes direc-
D882 Test Method for Tensile Properties of Thin Plastic
tions for calculating initial modulus, offset modulus, secant
Sheeting
modulus, and breaking toughness.
D1593 Specification for Nonrigid Vinyl Chloride Plastic
1.3 The basic distinctions between this test method and
Film and Sheeting
other methods measuring tensile strength of geomembranes are
D1909 Standard Tables of Commercial Moisture Regains
the width of the specimens tested and the speed of applied
and Commercial Allowances for Textile Fibers
force. The greater width of the specimens specified in this test
D4354 Practice for Sampling of Geosynthetics and Rolled
method minimizes the contraction edge effect (necking) which
Erosion Control Products (RECPs) for Testing
occurs in many geosynthetics and provides a closer relation-
D4439 Terminology for Geosynthetics
ship to actual material behavior in service. The slower speed of
applied strain also provides a closer relationship to actual
3. Terminology
material behavior in service.
3.1 Definitions:
1.4 As a performance test, this method will be used rela-
3.1.1 atmosphere for testing geomembranes, n—air main-
tively infrequently, and to test large lots of material. This test tained at a relative humidity of 50 to 70 % and a temperature
method is not intended for routine quality control testing of
of 21 6 2 °C (70 6 4 °F).
geomembranes.
3.1.1.1 Discussion—Within the range of 50 to 70 % relative
humidity, moisture content is not expected to affect the tensile
1.5 The values stated in SI units are to be regarded as
properties of geomembrane materials. In addition, geotextile
standard. The values given in parentheses are for information
standard test methods restrict the range of relative humidity to
only.
65 6 5 %, while geomembrane standard test methods restrict
1.6 This standard does not purport to address all of the
the range of relative humidity to 55 6 5 %. The restricted
safety concerns, if any, associated with its use. It is the
range in this test method is made broader to reduce the need for
responsibility of the user of this standard to establish appro-
testing laboratories to change laboratory conditions, and con-
priate safety, health, and environmental practices and deter-
sidering the lack of expected effect of moisture on geomem-
mine the applicability of regulatory limitations prior to use.
branes. The user should consult Table D1909 to resolve
1.7 This international standard was developed in accor-
questions regarding moisture regains of textile fibers, espe-
dance with internationally recognized principles on standard-
cially if the user is testing a new or unknown material.
ization established in the Decision on Principles for the
3.1.2 breaking force, (F), J, n—the force at failure.
Development of International Standards, Guides and Recom-
−1 −2
mendations issued by the World Trade Organization Technical 3.1.3 breaking toughness, T, (FL ), Jm , n—for
Barriers to Trade (TBT) Committee. geosynthetics, the actual work per unit volume of a material
corresponding to the breaking force.
This test method is under the jurisdiction of ASTM Committee D35 on
Geosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomem-
branes. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2023. Published May 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1988. Last previous edition approved in 2018 as D4885 – 01 (2018). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D4885-01R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4885 − 01 (2023)
−1 −1
3.1.3.1 Discussion—Breaking toughness is proportional to 3.1.13 offset modulus, J , (FL ), Nm , n—for
o
the area under the force-elongation curve from the origin to the geosynthetics, the ratio of the change in force per unit width to
breaking point (see also, work-to-break). Breaking toughness is the change in elongation below an arbitrary offset point at
calculated from work-to-break and width of a specimen. In which there is a proportional relationship between force and
geomembranes, breaking toughness is often expressed as force elongation, and above the inflection point on the force-
per unit width of material in inch-pound values. In other elongation curve.
materials, breaking toughness is often expressed as work per
3.1.14 performance test, n—a test which simulates in the
unit mass of material.
laboratory as closely as practicable selected conditions expe-
rienced in the field and which can be used in design. (Synonym
3.1.4 corresponding force, n—synonym for force at speci-
for design test.)
fied elongation.
−1 −1
3.1.15 secant modulus, J , (FL ), Nm , n—for
sec
3.1.5 elastic limit, n—in mechanics, the stress intensity at
geosynthetics, the ratio of change in force per unit width to the
which stress and deformation of a material subjected to an
change in elongation between two points on a force-elongation
increasing force cease to be proportional; the limit of stress
curve.
within which a material will return to its original size and shape
when the force is removed, and hence, not a permanent set. 3.1.16 tensile, adj—capable of tensions, or relating to ten-
sion of a material.
3.1.6 failure, n—an arbitrary point beyond which a material
−1 −1
3.1.17 tensile modulus, J, (FL ), Nm , n—for
ceases to be functionally capable of its intended use.
geosynthetics, the ratio of the change in tensile force per unit
3.1.6.1 Discussion—In wide strip tensile testing of
width to a corresponding change in elongation.
geosynthetics, failure occurs either at the rupture point or at the
yield point in the force-elongation curve, whichever occurs 3.1.18 tensile strength, n—the maximum resistance to de-
first. For reinforced geomembranes, failure occurs at rupture of
formation developed by a specific material when subjected to
the reinforcing fabric. For nonreinforced geomembranes that tension by an external force.
exhibit a yield point, such as polyethylene materials, failure
3.1.19 tensile test, n—for geosynthetics, a test in which a
occurs at the yield point. Even though the geomembrane
material is stretched uniaxially to determine the force-
continues to elongate, the force-elongation relationship has
elongation characteristics, the breaking force, or the breaking
been irreversibly altered. For nonreinforced geomembranes
elongation.
that do not exhibit a yield point, such as plasticized PVC
3.1.20 tension, n—the force that produces a specified elon-
materials, failure occurs at rupture of the geomembrane.
gation.
3.1.7 force at specified elongation, FASE, n—a force asso-
3.1.21 wide strip tensile test, n—for geosynthetics, a tensile
ciated with a specific elongation on the force-elongation curve.
test in which the entire width of a 200-mm (8.0-in.) wide
(Synonym for corresponding force.)
specimen is gripped in the clamps and the gauge length is
3.1.8 force-elongation curve, n—in a tensile test, a graphical
100 mm (4.0 in.).
representation of the relationship between the magnitude of an
3.1.22 work-to-break, W, (LF), J, n—in tensile testing, the
externally applied force and the change in length of the
total energy required to rupture a specimen.
specimen in the direction of the applied force. (Synonym for
3.1.22.1 Discussion—For geomembranes, work-to-break is
stress-strain curve.)
proportional to the area under the force-elongation curve from
the origin to the breaking point.
3.1.9 geomembrane, n—an essentially impermeable geosyn-
thetic used with foundation soil, rock, earth, or any other
3.1.23 yield point, n—in geosynthetics, the point on the
geotechnical engineering-related material as an integral part of
force-elongation curve at which the first derivative equals zero
a manmade project, structure, or system.
(the first maximum).
3.1.9.1 Discussion—Other names under which geomem-
3.1.24 For definitions of other terms used in this test
branes are recognized include: flexible membrane liners
method, refer to Terminologies D123 and D4439.
(FMLs), liners, and membranes.
4. Summary of Test Method
3.1.10 index test, n—a test procedure which may contain a
known bias, but which may be used to establish an order for a 4.1 A relatively wide specimen is gripped across its entire
set of specimens with respect to the property of interest. width in the clamps of a constant rate of extension type tensile
testing machine operated at a prescribed rate of extension,
3.1.11 inflection point, n—the first point of the force-
applying a uniaxial load to the specimen until the specimen
elongation curve at which the second derivative equals zero.
ruptures. Tensile strength, elongation, initial and secant
3.1.11.1 Discussion—The inflection point occurs at the first
modulus, and breaking toughness of the test specimen can be
point on the force-elongation curve at which the curve ceases
calculated from machine scales, dials, recording charts, or an
to curve upward and begins to curve downward (or vice versa).
interfaced computer.
−1 −1
3.1.12 initial tensile modulus, J , (FL ), Nm , n—for
i
5. Significance and Use
geosynthetics, the ratio of the change in force per unit width to
the change in elongation of the initial portion of a force- 5.1 This test method is a performance test intended as a
elongation curve. design aid used to determine the ability of geomembranes to
D4885 − 01 (2023)
withstand the stresses and strains imposed under design con- cross-machine direction. Take the specimens from a diagonal
ditions. This test method assists the design engineer in com- on the swatch, with no specimen nearer the edge of the
paring several candidate geomembranes under specific test geomembrane than one-tenth of the width of the geomem-
conditions. brane. Cut each specimen 200 mm (8.0 in.) wide by at least
200 mm (8.0 in.) long, with the length precisely aligned with
5.2 As a performance test, this method is not intended for
the direction in which the specimen is to be tested. The
routine acceptance testing of commercial shipments of
specimens must be long enough to extend completely through
geomembranes. Other more easily performed test methods,
both clamps of the testing machine. Draw two parallel lines
such as Test Methods D751 or Test Method D882, can be used
near the center of each specimen length that: (1) are separated
for routine acceptance testing of geomembranes. This test
by 100 mm (4.0 in.); (2) extend the full width of the specimen;
method will be used relatively infrequently and to establish
and (3) are exactly perpendicular to the length of the specimen.
performance characteristics of geomembrane materials.
Exercise the utmost care in selecting, cutting, and preparing
5.2.1 There is no known correlation between this test
specimens to avoid nicks, tears, scratches, folds, or other
method and index test methods, such as Test Methods D751.
imperfections that are likely to cause premature failure.
5.3 All geomembranes can be tested by this method. Some
modification of techniques may be necessary for a given
8. Conditioning
geomembrane depending upon its physical makeup. Special
8.1 Expose the specimens to the standard atmosphere for
adaptations may be necessary with strong geomembranes or
testing geomembranes for a period long enough to allow the
geomembranes with extremely slick surfaces, to prevent them
geomembrane to reach equilibrium with the standard atmo-
from slipping in the clamps or being damaged by the clamps.
sphere. Consider the specimen to be at moisture equilibrium
6. Apparatus when the change in mass of the specimen in successive
weighings made at intervals of not less than 2 h does not
6.1 Clamps—A gripping system that minimizes (with the
exceed 0.1 % of the mass of the specimen. Consider the
goal of eliminating) slippage, damage to the specimen, and
specimen to be at temperature equilibrium after 1 h of exposure
uneven stress distribution. The gripping system shall extend to
3 to the standard atmosphere for testing.
or beyond the outer edge of the specimen to be tested.
6.2 Specimen Cutter—An appropriate cutting device which
9. Procedure
does not create irregularities or imperfections in the edge of the
9.1 Test adequately conditioned specimens. Conduct tests at
specimen. For wide strip specimens, a jig may not be necessary
a temperature of 21 6 2 °C (70 6 4 °F) and at a relative
provided that the actual cut dimensions of the specimen can be
humidity of 50 to 70 %. The engineer may specify additional
measured accurately to the nearest 1.0 mm (0.04 in.), and that
temperatures based upon expected service conditions for the
the width of the specimen is constant to within 1.0 mm
installation.
(0.04 in.).
9.2 Measure for the specimen’s thickness at the four corners
6.3 Tensile Testing Machine—A testing machine of the
of the specimen. Select specimens used in this procedure so
constant rate of extension type as described in Specification
that thickness is uniform to within 5 %. Measure thickness
D76/D76M shall be used. The machine shall be equipped with
using either Specification D1593 for nonreinforced geomem-
a device for recording the tensile force and the amount of
branes or Test Methods D751 for reinforced geomembranes.
separation of the grips. Both of these measuring systems shall
be accurate to 62 % and, preferably, shall be external to the
9.3 Position the grips of the testing apparatus to a separation
testing machine. The rate of separation shall b
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