Evaluation of Multi-shape Geogrids for Base Stabilization in Flexible Pavements

Abstract

A full-scale test section was constructed to evaluate the performance of newly-developed multi- shape geogrids for base course stabilization in flexible pavements. The test section included one unstabilized test item and three geogrid stabilized test items. The geogrids were manufactured from either monolithic or coextruded polymer sheets that were punched and oriented to form hexagonal, trapezoidal, and triangular aperture shapes. The geogrids had the same aperture geometry, but had a different rib aspect ratio with the coextruded geogrids having “compressible caps” to improve geogrid/aggregate interaction. The test section was instrumented with earth pressure cells, asphalt strain gauges, and geogrid strain gauges to compare the influence of geogrid inclusion on measured response. Test traffic was applied with a dual-tandem truck gear mounted on a heavy vehicle simulator under controlled climatic conditions. Deformation measurements and falling weight deflectometer data were collected at discrete traffic intervals. Instrumentation response data showed that the geogrid inclusion altered the stress/strain distribution through the pavement layers indicating the effects on the mechanistic responses. The deformation data indicated that the geogrids reduced initial shakedown in the pavement section, and were effective in improving rutting performance.