ASTM D4533-11 pdf free.Standard Test Method for Trapezoid Tearing Strength of Geotextiles.
1.Bring the specimens to moisture equilibrium in the atmosphere for testing geotextiles (3.1). Equilibrium is considered to have been reached when the increase in mass of the specimen, in successive weighings made at intervals of not less than 2 h, does not exceed 0.1 % of the mass of the specimen.In general practice, the industry approaches equilibrium from the “as received” side.
It is recognized that in practice, geotextile materials are frequently not weighed to determine when moisture equi librium has been reached. While such a method cannot be accepted in cases of dispute, it may be sufficient in routine testing to expase the material to the standard atmosphere for testing for a reasonable period of time before the specimens are tested. A time of at least 24 h has been found aceptable in most cases. However, certain fibers may exhibit slow moisture equi lization rates from the“as received” wet side. When this is known, a preconditioning cycle, as described in Practice D1776, may be agreed
upon by the contractunal parties for routine testing.
2. This test method may be used for acceptance testing of commercial shipments; however, caution is advised since information about between-laboratory precision is incomplete.Comparative tests as directed in 53.1 may be advisable.
2.1 In case of a dispute arising from diferences in reported test results when using this test method for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the type in question. Test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the twolaboratories should be compared using the appropriate Student’s t-test and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results in the light of the known bias.
2.2 Most geotextile fabrics can be tested by this test method.Some modifcation of clamping techniques may be necessary for a given fabric, depending upon its structure. Special adaptation may be necessary with strong fabrics, or fabrics made from glass fibers, to prevent them from slipping in the clamps or being damaged as a result of being gripped in the clamps.ASTM D4533 pdf download.