Use of Temperature to Accelerate Cyclic Residual Strain of a Polypropylene Geogrid

Abstract

Presently, geosynthetic-reinforced soil (GRS) structures are widely used in geotechnical engineering works, due to their high performance and cost-effectiveness. However, when compared with other types of reinforcing materials such as metal strips, polymer geogrids are more deformable, especially when subjected to cyclic loadings. Generally, the geogrid’s tensile strain consists of the part that is recoverable upon unloading and the part that is irreversible even after a full unloading.   The latter part is known as the residual strain. This research aims to investigate the use of temperature to accelerate cyclic residual strain of a polypropylene (PP) geogrid. A tensile loading test series was performed with different loading and temperature histories as follows: i) Monotonic loading (ML) under different but constant temperature (CT) (ML-CT) at 30, 35, 40, 45 and 50 ^oC ; ii) Cyclic loading (CL) test with stepped increased temperature (SIT) (CL-SIT) from 30 -> 35 -> 40 -> 45 -> 50 ^oC ;and iii) Cyclic loading test (CL-CT). From the results, it is found that the cyclic residual strain from CL-SIT test can be used to predict the cyclic residual strain of the tested PP geogrid.