Repeated load triaxial tests of WickGrid™ stabilized base materials

Abstract

In road construction, geogrids are frequently used to stabilize the base course through their lateral confinement applied to the base materials. Wicking fabrics are also used to improve road performance by installing them at the road base and subgrade interface to remove water from the road and reduce the build-up of pore water pressure while providing a separate function to mitigate the weak subgrade intrusion into the base course. However, the combined use of these two materials on the road has not been reported. This study aims to investigate the effectiveness of using an innovative geosynthetic composite called WickGrid™ in stabilizing the base materials. WickGrid™ is made by high stiffness biaxial polypropylene (PP) geogrid, heat bonded to a continuous filament nonwoven geotextile having wicking properties. To achieve the objectives, repeated load triaxial tests were conducted on sand materials to evaluate the improvement of the base materials in accordance with the AASHTO T 307-99(2021). The specimens were stabilized with WickGrid™ placed at the mid-height of the specimens. Meanwhile, unstabilized specimens and specimens stabilized with biaxial geogrids were also tested for comparison. The outcomes of these tests would allow for quantifying the beneficial effects of WickGrid™ on the improvement of road bases.