ASTM D5323-19a

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 D6693/D6693M.  
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.

General Information

• Status: Historical
• Publication Date: 31-Jan-2019
• 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D5323 − 19a
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 3. Terminology
1.1 This practice presents a technique for calculating the
3.1 Definitions—See Terminologies D883 and D4439 for
2 % secant modulus for polyethylene geomembranes between
general definitions.
0.5 and 5 mm (20 and 200 mil) using Test Method D6693/
3.2 Definitions of Terms Specific to This Standard:
D6693M.
−2
3.2.1 modulus of elasticity, MPa (FL ), n—the ratio of
1.2 This practice will facilitate modulus comparisons of
stress (nominal) to corresponding strain below the proportional
similar materials by standardizing the method for deriving the
limit of a material, expressed in force per unit area, such as
points on the stress-strain curve from which the calculations
megapascals (pounds-force per square inch).
are performed.
3.2.1.1 Discussion—The stress-strain relations of many
1.3 The values stated in SI units are to be regarded as plastics do not conform to Hooke’s law throughout the elastic
standard. The values given in parentheses are for information
range, but rather deviate therefrom even at strains well below
only.
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
1.4 This standard does not purport to address all of the
modulus of elasticity (or elastic modulus). Since the existence
safety concerns, if any, associated with its use. It is the
of a true proportional limit in polyethylene is questionable, and
responsibility of the user of this standard to establish appro-
with the impracticality of measuring it reliably, the use of
priate safety, health, and environmental practices and deter-
secant modulus for comparative evaluations is preferred.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
3.2.2 secant modulus, n—the ratio of stress (nominal) to
dance with internationally recognized principles on standard-
corresponding strain at any specified point on the stress-strain
ization established in the Decision on Principles for the
curve.
Development of International Standards, Guides and Recom-
3.2.2.1 Discussion—The measurement units for secant
mendations issued by the World Trade Organization Technical
modulus may change, depending on the standard used. For the
Barriers to Trade (TBT) Committee.
purposes of this practice, the measurement units shall be force
−2
per unit area (FL ), such as megapascals (pounds-force per
2. Referenced Documents
square inch).
2
2.1 ASTM Standards:
D883 Terminology Relating to Plastics 4. Significance and Use
D4439 Terminology for Geosynthetics
4.1 Where to draw the tangent to determine the modulus of
D6693/D6693M Test Method for Determining Tensile Prop-
elasticity is often unclear when performing tensile tests with
erties of Nonreinforced Polyethylene and Nonreinforced
polyethylene geomembranes. This problem results in a wide
Flexible Polypropylene Geomembranes
variation in test results and, therefore, makes this property
unreliable for comparisons.
4.2 A secant modulus based on 2 % strain can be useful
1
This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-
when making comparisons between materials, in quality
thetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.
Current edition approved Feb. 1, 2019. Published February 2019. Originally
control, and in comparing the same sample after being sub-
approved in 1992. Last previous edition approved in 2019 as D5323 – 19. DOI:
jected to a nonstandard environment.
10.1520/D5323-19A.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
4.3 Secant modulus is an approximation of modulus of
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
elasticity and generally results in a lower value than that for the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. modulus of elasticity.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D5323 − 19a
4.4 Although the technique for measuring 2 % secant modu- 6.1.1 Calculate the 2 % secant modulus as follows and as
lus is described here, other percent secant moduli can be shown in Annex A2:
measured by this practice.
stress
2 % secant
...

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 − 19 D5323 − 19a
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 D638D6693/D6693M.
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
D6693/D6693M Test Method for Determining Tensile Properties of Nonreinforced Polyethylene and Nonreinforced Flexible
Polypropylene Geomembranes
3. Terminology
3.1 Definitions—See Terminologies D883 and D4439 for general definitions.
3.2 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.
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 Jan. 15, 2019Feb. 1, 2019. Published February 2019. Originally approved in 1992. Last previous edition approved in 20182019 as D5323 – 92
(2018).D5323 – 19. DOI: 10.1520/D5323-19.10.1520/D5323-19A.
2
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
1

---------------------- Page: 1 ----------------------
D5323 − 19a
3.2.2.1 Discussion—
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 S
...