ASTM D5323-19a(2023)
(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 mm and 5 mm (20 mil 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
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: D5323 − 19a (Reapproved 2023)
Standard Practice for
Determination of 2 % Secant Modulus for Polyethylene
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 mm and 5 mm (20 mil and 200 mil) using Test Method
3.2 Definitions of Terms Specific to This Standard:
D6693/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).
2.1 ASTM Standards:
4. Significance and Use
D883 Terminology Relating to Plastics
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
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 May 1, 2023. Published May 2023. Originally
control, and in comparing the same sample after being sub-
approved in 1992. Last previous edition approved in 2019 as D5323 – 19a. DOI:
jected to a nonstandard environment.
10.1520/D5323-19AR23.
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 service@astm.org. 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.
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D5323 − 19a (2023)
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 modulus 5 (1)
strain
5. Procedure
where:
5.1 Follow the test procedure described in Test Method
D669
...
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