This test method is designed to produce tensile property data for the control and specification of nonreinforced polyethylene and flexible nonreinforced polypropylene geomembranes. These data are also useful for qualitative characterization and for research and development. It may be necessary to modify this procedure for use in testing certain materials as recommended by the material specifications. Therefore, it is advisable to refer to that material''s specification before using this test method. Table 1 in Classification D4000 lists the ASTM materials standards that currently exist.
Tensile properties may vary with specimen preparation, test speed, and environment of testing. Consequently, where precise comparative results are desired, these factors must be carefully monitored and controlled.
It is realized that a material cannot be tested without also testing the method of preparation of that material. Hence, when comparative tests of materials are desired, the care must be exercised to ensure that all samples are prepared in exactly the same way, unless the test is to include the effects of sample preparation. Similarly, for referee purposes or comparisons within any given series of specimens, care must be taken to secure the maximum degree of uniformity in details of preparation, treatment, and handling.
Note 28212;Tensile properties may provide useful data for plastics engineering design purposes. However, because of the high degree of sensitivity exhibited by many plastics to rate of straining and environmental conditions, data obtained by this test method cannot be considered valid for applications involving load-time scales or environments widely different from those of this test method. In cases of such dissimilarity, no reliable estimation of the limit of usefulness can be made for most plastics. This sensitivity to rate of straining and environment necessitates testing over a broad load-time scale and range of environmental conditions if tensile properties are to suffice for engineering design purposes.
1.1 This test method covers the determination of the tensile properties of nonreinforced geomembranes in the form of standard dumbbell-shaped test specimens when tested under defined conditions of pretreatment, temperature, and machine speed.
1.2 This test method can be used for testing materials thickness between 0.25 mm (0.010 in.) and 6.3 mm (0.25 in.).
Note 18212;This test method is not intended to cover precise physical procedures. The constant rate of crosshead movement of this test lacks accuracy from a theoretical standpoint. A wide difference may exist between the rate of crosshead movement and the rate of strain of the specimen indicating that the testing speeds specified may disguise important effects or characteristics of these materials in the plastic state. Further, it is realized that variations in the thicknesses of test specimens, as permitted by this test method, produce variations in the surface-volume ratios of such specimens, and that these variations may influence the test results. Hence, where directly comparable results are desired, all samples should be of equal thickness. Special additional tests should be used where more precise physical data are needed.
1.3 Test data obtained by this test method are relevant and may be appropriate for use in engineering design with consideration of test conditions as compared with in-service conditions.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated wit......
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