ASTM D5994/D5994M-10(2021)
(Test Method)Standard Test Method for Measuring Core Thickness of Textured Geomembranes
Standard Test Method for Measuring Core Thickness of Textured Geomembranes
SIGNIFICANCE AND USE
5.1 Thickness is one of the basic index properties used to control and track the quality of many geomembranes. Additionally, many mechanical properties (for example, tensile yield strength, puncture strength, etc.) can be related to core thickness. Core thickness values may also be required in calculation of some parameters such as diffusion coefficients or tensile stresses.
5.2 The measured core thickness of geomembranes may vary considerably depending on the pressure applied to the specimen during measurement. To reduce variation in measurements and the chance of unrealistically low values due to excessively high pressures, a specific gauge point geometry and applied force are prescribed in this test method.
5.3 The test method is applicable to all commonly available textured geomembranes that are deployed as manufactured geomembrane sheets.
SCOPE
1.1 This test method covers a procedure to measure the core thickness of textured geomembranes.
1.2 This test method does not provide thickness values for geomembranes under variable normal stresses.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
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: D5994/D5994M − 10 (Reapproved 2021)
Standard Test Method for
Measuring Core Thickness of Textured Geomembranes
This standard is issued under the fixed designation D5994/D5994M; 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 tainty of Test Results of a Test Method Using Control
Chart Techniques
1.1 This test method covers a procedure to measure the core
thickness of textured geomembranes.
3. Terminology
1.2 This test method does not provide thickness values for
3.1 For definitions of other terms relating to geomembranes
geomembranes under variable normal stresses.
used in this test method, refer to Terminology D4439.
1.3 The values stated in either SI units or inch-pound units
3.2 Definitions:
are to be regarded separately as standard. The values stated in
3.2.1 core thickness, n—the average thickness of a textured
each system are not necessarily exact equivalents; therefore, to
geomembrane as measured using this particular test method.
ensure conformance with the standard, each system shall be
3.2.2 geomembrane, n—anessentiallyimpermeablegeosyn-
used independently of the other, and values from the two
thetic composed of one or more synthetic sheets. D4439
systems shall not be combined.
3.2.3 pressure, n—the force or load per unit area.
1.4 This standard does not purport to address all of the
3.2.4 textured geomembrane, n—a geomembrane having
safety concerns, if any, associated with its use. It is the
one or both surfaces intentionally manufactured with projec-
responsibility of the user of this standard to establish appro-
tions or indentations, most commonly for the purpose of
priate safety, health, and environmental practices and deter-
providing increased shear strength against adjacent materials.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
3.2.5 thickness, n—the perpendicular distance between one
dance with internationally recognized principles on standard-
surface and its opposite.
ization established in the Decision on Principles for the
3.2.6 thickness gauge points, n—the tips of a thickness
Development of International Standards, Guides and Recom-
gauge which contact the upper and lower geomembrane
mendations issued by the World Trade Organization Technical
surfaces, and between which the thickness is measured.
Barriers to Trade (TBT) Committee.
4. Summary of Test Method
2. Referenced Documents
4.1 The core thickness of a textured geomembrane is
2.1 ASTM Standards:
calculated as the average value of measurements taken on
D4354 Practice for Sampling of Geosynthetics and Rolled
replicate specimens of the sample under investigation. The
Erosion Control Products (RECPs) for Testing
thicknessofeachspecimenismeasuredataspecificlocationas
D4439 Terminology for Geosynthetics
thedistancebetweentwogaugepoints.Theopposingthickness
E177 Practice for Use of the Terms Precision and Bias in
gauge points are manufactured to a defined geometry, with a
ASTM Test Methods
specified force of 0.56 6 0.05 N [2.0 6 0.2 oz] applied along
E691 Practice for Conducting an Interlaboratory Study to
their axis.
Determine the Precision of a Test Method
E2554 Practice for Estimating and Monitoring the Uncer-
5. Significance and Use
5.1 Thickness is one of the basic index properties used to
control and track the quality of many geomembranes.
This test method is under the jurisdiction of ASTM Committee D35 on
Additionally, many mechanical properties (for example, tensile
GeosyntheticsandisthedirectresponsibilityofSubcommitteeD35.10onGeomem-
branes.
yield strength, puncture strength, etc.) can be related to core
Current edition approved July 1, 2021. Published July 2021. Originally approved
thickness. Core thickness values may also be required in
ɛ1
in 1996. Last previous edition approved in 2015 as D5994/D5994M – 10 (2015) .
calculation of some parameters such as diffusion coefficients or
DOI: 10.1520/D5994_D5994M-10R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or tensile stresses.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.2 The measured core thickness of geomembranes may
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. vary considerably depending on the pressure applied to the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5994/D5994M − 10 (2021)
specimenduringmeasurement.Toreducevariationinmeasure- met. Exclude the inner and outer wraps of the roll or any
ments and the chance of unrealistically low values due to material not representative of the sample (see Note 1).
excessively high pressures, a specific gauge point geometry
7.2 Remove test specimens from the sample in a randomly
and applied force are prescribed in this test method.
distributed pattern across the width. The thickness readings
5.3 The test method is applicable to all commonly available
must include measurements within 15 cm [6 in.] of both edges
textured geomembranes that are deployed as manufactured of the geomembrane roll.
geomembrane sheets.
7.3 Test Specimens—From each unit in the sample, remove
the specimens so that the edge of the specimen will extend
6. Apparatus
beyond the edge of the gauge points by 10 mm [0.4 in.] in all
6.1 Thickness Gauge—The thickness gauge shall be of the
directions. It is recommended to use circular test specimens of
dead-weight type capable of measuring to an accuracy of at
approximately 75 mm [3 in.] diameter.
least 60.01 mm [0.0004 in.].The gauge shall be constructed to
7.4 Number of Specimens—Unless otherwise agreed upon,
permit application of a specific force of 0.56 6 0.05 N [2.0 6
as when provided in an applicable material specification, take
0.2 oz]. The gauge shall have a base point (or anvil) and a
a number of test specimens per sample such that the user may
free-movingpresserpointwhoseaxesarealignedtoeachother.
expect, at the 95 % probability level, that the test result is not
NOTE 1—The geomembrane specimen being measured should be
more than 5 % of the average above or below the true average
maintained perpendicular to the axes of the opposing gauge points. An
of the sample. Determine the number of specimens per sample
underlying support system may be necessary to support large test
as follows:
specimens.
7.4.1 Reliable Estimate of v—When there is a reliable
6.2 Thickness Gauge Points—The gauge points shall be
estimate of v based upon extensive sample records for similar
made of hardened steel. The points shall be tapered at an angle
materials tested in the user’s laboratory as directed in the
of 60 6 2° to the horizontal with the tip rounded to a radius of
method, calculate the required number of specimens as fol-
0.8 6 0.1 mm [0.031 6 0.004 in.]. Fig. 1 shows the critical
lows:
dimensions.
n 5 tv/A (1)
~ !
NOTE 2—The gauge and points can be calibrated using standard
thickness blocks. Frequent use and rough use of the gauge can dull the
where:
gauge points and cause misalignment, both of which will cause incorrect
n = number of test specimens (rounded upward to a whole
readings. These problems can be detected by frequent calibration.
number),
t = the value of Student’s “t” for one-sided limits (seeTable
7. Sampling
1 in Practice D4354), a 95 % probability level, and the
7.1 Sample—For the sample, take a full-width sample of
degrees of freedom associated with the estimate of v,
sufficient length so that the requirements of 7.2 – 7.4.2 can be
FIG. 1 Dead-Weight Thickness Measurement Device for Textured Geomembranes
D5994/D5994M − 10 (2021)
11.1.7 Report
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