ASTM D5970/D5970M-16 (R2021) pdf free download.Standard Test Method for Deterioration of Geotextiles from Outdoor Exposure.
1.1 This test method covers evaluating the deterioration in tensile strength and strain after outdoor exposure.
1.2 The deterioration is assessed as a reduction in strength and strain at failure from the unexposed geotextile.
1.3 The specific location of the light and weather exposure is made on the basis of a site-specific decision between the parties involved.
1.4 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.
3. Terminology
3.1 For definitions of terms related to geosynthetics, refer to Terminology D4439.
3.2 For definitions of terms related to weathering, refer to Terminology G113.
3.3 Defin itiO?1S.
3.3.1 ultra violet degradation—the photoche mical change induced by exposure to ultraviolet radiation that results in deterioration of the performance characteristics of the poiymerle structure.
3.3.2 weathering degradation—the change induced by cxposure to outdoor conditions that results in deterioration of the performance characteristics of the polymeric structure.
4. Summary of Test Method
4.1 Geotextile coupons are attached to a test frame oriented
450 from the horizontal and facing the equator at a designated
location for exposure times of 1. 2. 4, 8. 12, and 18 months. Exposure shall begin so as to ensure that material is exposed during the maximum intensity of ultraviolet light of the year. Unless otherwise specified, the test should be initiated in May in the northern hemisphere. and in November in the southern hemisphere.
4.1.1 Unexposed coupons, or ‘file specimens’ according to Terminology Gl 13, shall be retained for testing.
4.2 After each exposure time, the appropriate coupons are brought into a laboratory for strength determination. The results of these tests are compared to the strength determined for the unexposed coupons. The user may he interested in exposure times other than specified in this test method. These times should be noted in reporting the results.
4.3 The results are presented in the form of various plots.
4.4 Additional recommendations may be found in Practice G7/G7M and Terminology G113.
5. Significance and Use
5.1 Outdoor exposure tests at one location may not be applicable to a project site at another location.ASTM D5970/D5970M pdf download.