ASTM D5323-19
(Practice)Standard Practice for Determination of 2 % Secant Modulus for Polyethylene Geomembranes
Standard Practice for Determination of 2 % Secant Modulus for Polyethylene Geomembranes
SIGNIFICANCE AND USE
4.1 Where to draw the tangent to determine the modulus of elasticity is often unclear when performing tensile tests with polyethylene geomembranes. This problem results in a wide variation in test results and, therefore, makes this property unreliable for comparisons.
4.2 A secant modulus based on 2 % strain can be useful when making comparisons between materials, in quality control, and in comparing the same sample after being subjected to a nonstandard environment.
4.3 Secant modulus is an approximation of modulus of elasticity and generally results in a lower value than that for the modulus of elasticity.
4.4 Although the technique for measuring 2 % secant modulus is described here, other percent secant moduli can be measured by this practice.
SCOPE
1.1 This practice presents a technique for calculating the 2 % secant modulus for polyethylene geomembranes between 0.5 and 5 mm (20 and 200 mil) using Test Method D638.
1.2 This practice will facilitate modulus comparisons of similar materials by standardizing the method for deriving the points on the stress-strain curve from which the calculations are performed.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 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.
1.5 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.
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Designation: D5323 − 19
Standard Practice for
Determination of 2 % Secant Modulus for Polyethylene
1
Geomembranes
This standard is issued under the fixed designation D5323; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
−2
3.2.1 modulus of elasticity, MPa (FL ), n—the ratio of
1.1 This practice presents a technique for calculating the
stress(nominal)tocorrespondingstrainbelowtheproportional
2% secant modulus for polyethylene geomembranes between
limit of a material, expressed in force per unit area, such as
0.5 and 5 mm (20 and 200 mil) using Test Method D638.
megapascals (pounds-force per square inch).
1.2 This practice will facilitate modulus comparisons of
3.2.1.1 Discussion—The stress-strain relations of many
similar materials by standardizing the method for deriving the
plastics do not conform to Hooke’s law throughout the elastic
points on the stress-strain curve from which the calculations
range, but rather deviate therefrom even at strains well below
are performed.
the elastic limit. For such materials, the slope of the tangent to
1.3 The values stated in SI units are to be regarded as
the stress-strain curve at a low strain is usually taken as the
standard. The values given in parentheses are for information
modulus of elasticity (or elastic modulus). Since the existence
only.
ofatrueproportionallimitinpolyethyleneisquestionable,and
1.4 This standard does not purport to address all of the
with the impracticality of measuring it reliably, the use of
safety concerns, if any, associated with its use. It is the
secant modulus for comparative evaluations is preferred.
responsibility of the user of this standard to establish appro-
3.2.2 secant modulus, n—the ratio of stress (nominal) to
priate safety, health, and environmental practices and deter-
corresponding strain at any specified point on the stress-strain
mine the applicability of regulatory limitations prior to use.
curve.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.2.2.1 Discussion—The measurement units for secant
ization established in the Decision on Principles for the
modulus may change, depending on the standard used. For the
Development of International Standards, Guides and Recom-
purposes of this practice, the measurement units shall be force
−2
mendations issued by the World Trade Organization Technical
per unit area (FL ), such as megapascals (pounds-force per
Barriers to Trade (TBT) Committee.
square inch).
2. Referenced Documents
4. Significance and Use
2
2.1 ASTM Standards:
4.1 Where to draw the tangent to determine the modulus of
D638Test Method for Tensile Properties of Plastics
elasticity is often unclear when performing tensile tests with
D883Terminology Relating to Plastics
polyethylene geomembranes. This problem results in a wide
D4439Terminology for Geosynthetics
variation in test results and, therefore, makes this property
unreliable for comparisons.
3. Terminology
3.1 Definitions—See Terminologies D883 and D4439 for 4.2 A secant modulus based on 2% strain can be useful
general definitions. when making comparisons between materials, in quality
control, and in comparing the same sample after being sub-
jected to a nonstandard environment.
1
This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-
4.3 Secant modulus is an approximation of modulus of
thetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.
Current edition approved Jan. 15, 2019. Published February 2019. Originally
elasticityandgenerallyresultsinalowervaluethanthatforthe
approved in 1992. Last previous edition approved in 2018 as D5323–92 (2018).
modulus of elasticity.
DOI: 10.1520/D5323-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.4 Althoughthetechniqueformeasuring2%secantmodu-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
lus is described here, other percent secant moduli can be
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. measured by this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D5323 − 19
5. Procedure stress
2% secantmodulus 5 (1)
strain
5.1 Follow the test procedure described in Test Method
D638.
where:
5.1.1 A crosshead speed of 50 mm/min (2 in./min) is
stress = force/area (at 2% strain),
recommended for determining secant mod
...
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: D5323 − 92 (Reapproved 2018) D5323 − 19
Standard Practice for
Determination of 2 % Secant Modulus for Polyethylene
1
Geomembranes
This standard is issued under the fixed designation D5323; 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 practice presents a technique for calculating the 2 % secant modulus for polyethylene geomembranes between 0.5 and
5 mm (20 and 200 mil) using Test Method D638.
1.2 This practice will facilitate modulus comparisons of similar materials by standardizing the method for deriving the points
on the stress-strain curve from which the calculations are performed.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 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.
1.5 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
2.1 ASTM Standards:
D638 Test Method for Tensile Properties of Plastics
D883 Terminology Relating to Plastics
D4439 Terminology for Geosynthetics
3. Terminology
3.1 Definitions—See Terminologies D883 and D4439 for general definitions.
3.2 Definitions:Definitions of Terms Specific to This Standard:
−2
3.2.1 modulus of elasticity, MPa (FL ), n—the ratio of stress (nominal) to corresponding strain below the proportional limit
of a material, expressed in force per unit area, such as megapascals (pounds-force per square inch).
3.2.1.1 Discussion—
The stress-strain relations of many plastics do not conform to Hooke’s law throughout the elastic range, but rather deviate
therefrom even at strains well below the elastic limit. For such materials, the slope of the tangent to the stress-strain curve at a low
strain is usually taken as the modulus of elasticity (or elastic modulus). Since the existence of a true proportional limit in
polyethylene is questionable, and with the impracticality of measuring it reliably, the use of secant modulus for comparative
evaluations is preferred.
3.2.2 secant modulus, n—the ratio of stress (nominal) to corresponding strain at any specified point on the stress-strain curve.
3.2.2.1 Discussion—
1
This practice is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.
Current edition approved July 1, 2018Jan. 15, 2019. Published July 2018February 2019. Originally approved in 1992. Last previous edition approved in 20112018 as
D5323 – 92 (2011).(2018). DOI: 10.1520/D5323-92R18.10.1520/D5323-19.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. 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
1
---------------------- Page: 1 ----------------------
D5323 − 19
The measurement units for secant modulus may change, depending on the standard used. For the purposes of this practice, the
−2
measurement units shall be force per unit area (FL ), such as megapascals (pounds-force per square inch).
4. Significance and Use
4.1 Where to draw the tangent to determine the modulus of elasticity is often unclear when performing tensile tests with
polyethylene geomembranes. This problem results in a wide variation in test results and, therefore, makes this property unreliable
for comparisons.
4.2 A secant modulus based on 2 % strain can be useful when making comparisons between materials, in quality control, and
in comparing the same sample after being subjected to a nonstandard environment.
4.3 Secant modulus is an approximation of modulus of elasticity and generally results in a lower value than that for the modulu
...
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