Geosynthetics initial creep behavior parameters as a function of the load level applied in ramp and hold tests

Abstract

Long-term analysis of geosynthetics is mandatory in the design phase. Once the performance of creep-rupture tests is too time-consuming, adopting temperature to accelerate the geosynthetics creep behavior is an attractive solution. The ASTM D 6992 provides guidelines to perform accelerated creep rupture tests in geosynthetics and recommends adopting ramp and hold tests to help assess the initial creep rupture behavior. Thus, this paper aims to assess the initial creep behavior of two geogrids and two non-woven geotextiles. A universal testing machine was used to perform ramp and hold tests. The specimens were loaded (at a similar load condition to the ones adopted in the accelerated creep rupture tests) to load levels ranging between 10% and 90 % of the geosynthetic ultimate tensile strength. Each load level was maintained for 3,600s and 10,800s for geogrids and non-woven geotextiles, in this order. Three specimens were tested for each load level and a best-fit equation was used to obtain the initial creep train rate and the initial axial strain of the mean curve obtained. The results revealed a higher development of creep strains for the non-woven geotextile than the geogrids. The effects of the non-woven geotextile mass per unit area, and the polymer type of the geogrids were pointed out. The results help to identify and compare the initial axial strain of these geosynthetics after the performance of the accelerated creep rupture tests.