ASTM D4885-01(2018)

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

• Status: Historical
• Publication Date: 30-Apr-2018
• ICS: 59.080.70 - Geotextiles
• Technical Committee: D35 - Geosynthetics
• Drafting Committee: D35.10 - Geomembranes

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4885 − 01 (Reapproved 2018)
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
geosynthetics, the actual work per unit volume of a material
Barriers to Trade (TBT) Committee.
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, 2018. Published May 2018. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1988. Last previous edition approved in 2011 as D4885 – 01 (2011). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D4885-01R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4885 − 01 (2018)
−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
3.1.5 elastic limit, n—in mechanics, the stress intensity at sec
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 (2018)
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 be uniform and
of 100 6 3 mm (4 6 0.1 in.). At least one clamp should be
capable of adjustment within the range of the test.
suppor
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4885 − 01 (Reapproved 2011) D4885 − 01 (Reapproved 2018)
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
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 safety, health, and healthenvironmental 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.
2. Referenced Documents
2.1 ASTM Standards:
D76D76/D76M Specification for Tensile Testing Machines for Textiles
D123 Terminology Relating to Textiles
D751 Test Methods for Coated Fabrics
D882 Test Method for Tensile Properties of Thin Plastic Sheeting
D1593 Specification for Nonrigid Vinyl Chloride Plastic Film and Sheeting
D1909 Standard Tables of Commercial Moisture Regains and Commercial Allowances for Textile Fibers
D4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
3. Terminology
3.1 Definitions:
3.1.1 atmosphere for testing geomembranes, n—air maintained at a relative humidity of 50 to 70 % and a temperature of 21 6
2°C2 °C (70 6 4°F).4 °F).
This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.
Current edition approved June 1, 2011May 1, 2018. Published July 2011May 2018. Originally approved in 1988. Last previous edition approved in 20062011 as
D4885 – 06.D4885 – 01 (2011). DOI: 10.1520/D4885-01R11.10.1520/D4885-01R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4885 − 01 (2018)
3.1.1.1 Discussion—
Within the range of 50 to 70 % relative humidity, moisture content is not expected to affect the tensile properties of geomembrane
materials. In addition, geotextile standard test methods restrict the range of relative humidity to 65 6 5 %, while geomembrane
standard test methods restrict the range of relative humidity to 55 6 5 %. The restricted range in this test method is made broader
to reduce the need for testing laboratories to change laboratory conditions, and considering the lack of expected effect of moisture
on geomembranes. The user should consult Table D1909 to resolve questions regarding moisture regains of textile fibers, especially
if the user is testing a new or unknown material.
3.1.2 breaking force, (F), J, n—the force at failure.
−1 −2
3.1.3 breaking toughness, T, (FL ), Jm , n—for geosynthetics, the actual work per unit volume of a material corresponding
to the breaking force.
3.1.3.1 Discussion—
Breaking toughness is proportional to the area under the force-elongation curve from the origin to the breaking point (see also,
work-to-break).work-to-break). Breaking toughness is calculated from work-to-break and width of a specimen. In geomembranes,
breaking toughness is often expressed as force per unit width of material in inch-pound values. In other materials, breaking
toughness is often expressed as work per unit mass of material.
3.1.4 corresponding force, n—synonym for force at specified elongation.
3.1.5 elastic limit, n—in mechanics, the stress intensity at which stress and deformation of a material subjected to an increasing
force cease to be proportional; the limit of stress within which a material will return to its original size and shape when the force
is removed, and hence, not a permanent set.
3.1.6 failure, n—an arbitrary point beyond which a material ceases to be functionally capable of its intended use.
3.1.6.1 Discussion—
In wide strip tensile testing of geosynthetics, failure occurs either at the rupture point or at the yield point in the force-elongation
curve, whichever occurs first. For reinforced geomembranes, failure occurs at rupture of the reinforcing fabric. For nonreinforced
geomembranes whichthat exhibit a yield point, such as polyethylene materials, failure occurs at the yield point. Even though the
geomembrane continues to elongate, the force-elongation relationship has been irreversibly altered. For nonreinforced
geomembranes whichthat do not exhibit a yield point, such as plasticized PVC materials, failure occurs at rupture of the
geomembrane.
3.1.7 force at specified elongation, FASE, n—a force associated with a specific elongation on the force-elongation curve.
(Synonym for corresponding force.)force.)
3.1.8 force-elongation curve, n—in a tensile test, a graphical representation of the relationship between the magnitude of an
externally applied force and the change in length of the specimen in the direction of the applied force. (Synonym for stress-strain
curve.)curve.)
3.1.9 geomembrane, n—Anan essentially impermeable geosynthetic used with foundation soil, rock, earth, or any other
geotechnical engineering related engineering-related material as an integral part of a man-mademanmade project, structure, or
system.
3.1.9.1 Discussion—
Other names under which geomembranes are recognized include: flexible membrane liners (fml’s),(FMLs), liners, and membranes.
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 set
of specimens with respect to the property of interest.
3.1.11 inflection point, n—the first point of the force-elongation curve at which the second derivative equals zero.
3.1.11.1 Discussion—
The inflection point occurs at the first point on the force-elongation curve at which the curve ceases to curve upward and begins
to curve downward (or vice versa).
−1 −1
3.1.12 initial tensile modulus, J , (FL (FL ), Nm Nm , n—for geosynthetics, the ratio of the change in force per unit width to
i
the change in elongation of the initial portion of a force-elongation curve.
D4885 − 01 (2018)
−1 −1
3.1.13 offset modulus, J , (FL (FL ), Nm Nm , n—for geosynthetics, the ratio of the change in force per unit width to the
o
change in elongation below an arbitrary offset point at which there is a proportional relationship between force and elongation, and
above the inflection point on the force-elongation curve.
3.1.14 performance test, n—a test which simulates in the laboratory as closely as practicable selected conditions experienced
in the field and which can be used in design. (Synonym for design test.)test.)
−1 −1
3.1.15 secant modulus, J , (FL (FL ), Nm Nm , n—for geosynthetics, the ratio of change in force per unit width to the
sec
change in elongation between two points on a force-elongation curve.
3.1.16 tensile, adj—capable of tensions, or relating to tension of a material.
−1 −1
3.1.17 tensile modulus, J, (FL ), Nm , n—for geosynthetics, the ratio of the change in tensile force per unit width to a
corresponding change in elongation.
3.1.18 tensile strength, n—the maximum resistance to deformation developed by a specific material when subjected to tension
by an external force.
3.1.19 tensile test, n—for geosynthetics, a test in which a material is stretched uniaxially to determine the force-elongation
characteristics, the breaking force, or the breaking elongation.
3.1.20 tension, n—the force that produces a specified elongation.
3.1.21 wide strip tensile test, n—for geosynthetics, a tensile test in which the entire width of a 200 mm (8.0 in.) 200-mm (8.0-in.)
wide specimen is gripped in the clamps and the gauge length is 100 mm (4.0 in.).
3.1.22 work-to-break, W, (LF), J, n—in tensile testing, the total energy required to rupture a specimen.
3.1.22.1 Discussion—
For geomembranes, work-to-break is proportional to the area under the force-elongation curve from the origin to the breaking
point.
3.1.23 yield point, n—in geosynthetics, the point on the force-elongation curve at which the first derivative equals zero (the first
maximum).
3.1.24 For definitions of other terms used in this test method, refer to Terminologies D123 and D4439.
4. Summary of Test Method
4.1 A relatively wide specimen is gripped across its entire width in the clamps of a constant rate of extension type tensile testing
machine operated at a prescribed rate of extension, applying a uniaxial load to the specimen until the specimen ruptures. Tensile
strength, elongation, initial and secant modulus, and breaking toughness of the test specimen can be calculated from machine
scales, dials, recording charts, or an interfaced computer.
5. 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,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 make-up.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.
6. Apparatus
6.1 Clamps—A gripping system that minimizes (with the goal of eliminating) slippage, damage to the specimen, and uneven
stress distribution. The gripping system shall extend to or beyond the outer edge of the specimen to be tested.
6.2 Specimen Cutter—An appropriate cutting device which does not create irregularities or imperfections in the edge of the
specimen. For wide strip specimens, a jig may not be necessary provided that the actual cut dimensions of the specimen can be
measured accurately to the nearest 1.0 mm (0.04 in.), and that the width of the specimen is constant to within 1.0 mm (0.04 in.).
Examples of clamping and extensometer systems which have been successfully used are shown in Appendix X2Appendixes. and Appendix X3.
D4885 − 01 (2018)
6.3 Tensile Testing Machine—A testing machine of the constant rate of extension type as described in Specification
D76D76/D76M shall be used. The machine shall be equipped with a device for recording the tensile force and the amount of
separation of the grips. Both of these measuring systems shall be accurate to 62 % and, preferably, shall be external to the testing
machine. The rate of separation shall be uniform and capable of adjustment within the range of the test.
7. Sampling
7.1 Lot Sample—Divide the product into lots and take the lot sample as directed in Practice D4354.
7.2 Laboratory Sample—For the laboratory sample, take a full-width swatch approximately 1 m (40 in.) long in the machine
direction from each roll in the lot sample. 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.
7.3 Test Specimens—Take a total of twelve specimens from each swatch in the laboratory sample, with six specimens for tests
in the machine direction and six specimens for tests in the cross-machine direction. Take the specimens from a diagonal on the
swatch, with no specimen nearer the edge of the geomembrane than 1/10one-tenth of the width of the geomembrane. Cut each
specimen 200 mm (8.0 in.) wide by at least 200 mm 200 mm (8.0 in.) long, with the length precisely aligned with the direction
in which the specimen is to be tested. The specimens must be long enough to extend completely through both clamps of the testing
machine. Draw two parallel lines near the center of each specimen length that (1)that: (1) are separated by 100 mm (4.0
in.),(4.0 in.); (2 (2) ) extend the full width of the specimen,specimen; and (3)(3) are exactly perpendicular to the length of the
specimen. Exercise the utmost care in selecting, cutting, and preparing
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