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ASTM D5994-10(R2021) pdf free download

ASTM D5994-10(R2021) pdf free download.Standard Test Method for Measuring Core Thickness of Textured Geomembranes
1. 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 For definitions of other terms relating to geomembranes used in this test method, refer to Terminology D4439. 3.2 Definitions: 3.2.1 core thickness, n—the average thickness of a textured geomembrane as measured using this particular test method. 3.2.2 geomembrane, n—an essentially impermeable geosyn- thetic composed of one or more synthetic sheets. D4439 3.2.3 pressure, n—the force or load per unit area. 3.2.4 textured geomembrane, n—a geomembrane having one or both surfaces intentionally manufactured with projec- tions or indentations, most commonly for the purpose of providing increased shear strength against adjacent materials. 3.2.5 thickness, n—the perpendicular distance between one surface and its opposite. 3.2.6 thickness gauge points, n—the tips of a thickness gauge which contact the upper and lower geomembrane surfaces, and between which the thickness is measured.
4. Summary of Test Method
4.1 The core thickness of a textured geomembrane is calculated as the average value of measurements taken on replicate specimens of the sample under investigation. The thickness ofeach specimen is measured at a specific location as the distance between two gauge points. The opposing thickness gauge points are manufactured to a defined geometry, with a specified force of 0.56 6 0.05 N [2.0 6 0.2 oz] applied along their axis.
5. 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 ofsome 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 measure- ments 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.
6. Apparatus
6.1 Thickness Gauge—The thickness gauge shall be of the dead-weight type capable of measuring to an accuracy of at least 60.01 mm [0.0004 in.]. The gauge shall be constructed to permit application of a specific force of 0.56 6 0.05 N [2.0 6 0.2 oz]. The gauge shall have a base point (or anvil) and a free-moving presser point whose axes are aligned to each other. N OTE 1—The geomembrane specimen being measured should be maintained perpendicular to the axes of the opposing gauge points. An underlying support system may be necessary to support large test specimens. 6.2 Thickness Gauge Points—The gauge points shall be made of hardened steel. The points shall be tapered at an angle of 60 6 2° to the horizontal with the tip rounded to a radius of 0.8 6 0.1 mm [0.031 6 0.004 in.]. Fig. 1 shows the critical dimensions. N OTE 2—The gauge and points can be calibrated using standard thickness blocks. Frequent use and rough use of the gauge can dull the gauge points and cause misalignment, both of which will cause incorrect readings. These problems can be detected by frequent calibration.

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