A theoretical framework to analyse the behaviour of polymer geosynthetic reinforcement in temperature-accelerated creep tests

A non-linear three-component model has been developed that can predict the strength and deformation of polymer geosynthetic reinforcement when subjected to arbitrary histories of strain, strain rate and temperature as encountered in the laboratory and in the field. An existing model framework assuming the elasto-viscoplastic property of material was modified to account for the effects of changes in ambient temperature on the load-strain relation. Tensile load-strain-time relations for typical geosynthetic reinforcement properties were obtained by direct simulations of long-term sustained loading ( SL) tests at a fixed temperature as well as simulations of monotonic loading and sustained loading at different elevated temperatures in time-temperature superposition ( TTS) and stepped isothermal method ( SIM) tests. The procedures to obtain the master creep strain and modulus curves from the results of these three types of numerical analysis are presented and compared. Creep rupture curves constructed from the master curves obtained by direct simulations of long-term SL tests as well as the numerical TTS and SIM tests are compared. The creep rupture curves obtained by the three methods are similar for shorter creep rupture times, but they become different with an increase in the creep rupture time. The reasons for the difference are discussed. It is argued that the theoretical framework of the model is relevant and useful for analysing and interpreting results from TTS and SIM tests in a consistent manner.