ASTM D7361-07

Use of the SIM decreases the time required for creep to occur and the obtaining of the associated data.

The statements set forth in Section 1.5 are very important in the context of significance and use, as well as scope of the standard.

Creep test data are used to calculate the creep modulus of materials as a function of time. These data are then used to predict the long-term creep deformation expected of geosynthetics used in drainage applications.

Note 1—Currently, SIM testing has focused mainly geonets made from high density polyethylene. Additional testing on other materials is ongoing.

R+H testing is done to establish the range of creep strains experienced in the brief period of very rapid response following the peak of the load ramp.

1.1 This test method covers accelerated testing for compressive creep properties using the Stepped Isothermal Method (SIM).

1.2 The test method is focused on geosynthetic drainage materials such as HDPE geonet specimens.

1.3    The SIM tests are laterally unconfined tests based on time-temperature superposition procedures.

1.4 Ramp and Hold (R+H) tests may be completed in conjunction with SIM tests. They are designed to provide additional estimates of the initial rapid compressive creep strain levels appropriate for the SIM results.

1.5 This method can be used to establish the sustained load compressive creep characteristics of a geosynthetic that demonstrates a relationship between time-dependent behavior and temperature. Results of this method are to be used to augment results of compressive creep tests performed at 20 ± 1°C and may not be used as the sole basis for determination of long term compressive creep behavior of geosynthetic material.

1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.7 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 and health practices and determine the applicability of regulatory limitations prior to use.