【国外标准】 Standard Test Method for Evaluation of Stress Crack Resistance of Polyolefin Geomembranes Using Notched Constant Tensile Load Test

5.1 This test method does not purport to interpret the resulting response curve. Such interpretation is left to the parties involved in the commissioning and reporting of the test results.5.2 This test method is intended as an index test and may be used for grading polyolefin geomembrane sheets in regard to their stress-cracking sensitivity.5.2.1 Conditions that can affect stress cracking include: level of loading, test temperature and environment, microstructure, polymer additive package, processing history, and thermal history.5.3 The test method is applicable to smooth, homogeneous polyolefin geomembranes where the two sides are parallel to permit application of the stress on a well-defined surface delimited by the surface of the geomembrane on one side, and the bottom of the notch on the other side.5.4 The test is applicable to textured geomembranes when prepared as described in 8.3.2.5.5 The test may be applicable to multi-component geomembranes (such as white, conductive, or other non-homogeneous sheets) or limited to the evaluation of the base polymer when prepared as described in 8.3.3.5.6 The test is not applicable to bituminous, EPDM, plasticized PVC, and other non-polyolefin geomembranes, as these materials are not susceptible to slow crack growth.5.7 This test method may not be applied to polyolefin geomembranes that do not exhibit a well-defined yield point, such as some VLDPE and LLDPE.1.1 This test method is used to develop test data from which the susceptibility of polyolefin geomembrane sheet material to stress cracking under a constant tensile load condition and an accelerated environmental condition can be evaluated.1.2 This test method measures the failure time associated with a given test specimen at a specified tensile load level. Results from a series of such tests utilizing a range of load levels can be used to construct a stress-time plot on a log-log axis.1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are provided 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.