30 Oct 2025

Full-Scale Evaluation of Multi-Axial, Multi-Aperture Shape Geogrids in Flexible Pavement Applications

Abstract: The US Army Engineer Research and Development Center (ERDC) con-structed a full-scale pavement test section to evaluate the performance of three recently developed multi-axial, multi-aperture shape geogrids, referred to as HX5.5, NX750, and NX-Dev, in asphalt-surfaced highway applications. The test section consisted of a 4.2 in. thick and a 3.8 in. thick hot-mix asphalt layer placed over a 6 in. thick and 4 in. thick crushed aggregate layer, respectively. Underlying the crushed aggregate layer was a 2 ft thick clay subgrade that had a 6% California Bearing Ratio. Simulated truck traffic was applied using ERDC’s heavy vehicle simulator–transportation with a dual-wheel tandem axle truck gear. Rutting performance and instrumentation response data were monitored at multiple traffic intervals. Observed rutting in the geogrid test items was approximately one-third of that in the unstabilized item, in which was a meaningful performance improvement. Instrumentation response data indicated that the geogrid inclusion pro-vided a stiffening effect that altered the anticipated pavement response. An analytical investigation showed that traditional layered elastic analysis techniques did not adequately describe the pavement response with geogrid inclusion. A robust model that included material nonlinearity and a geogrid interface model provided a closer approximation to the measured subsurface response.