Full-Scale Evaluation of Geosynthetic-Reinforced Hot Mix Asphalt

Abstract

This study aims to evaluate the potential of using geosynthetics to reinforce flexible pavements and improve their resistance to reflective cracking. To achieve the goals, three full-scale test strips (control, geogrid, and geotextile) were constructed at Rowan University, each being 30 ft long by 15 ft wide. The pavement structure of each test strip included two hot mix asphalt (HMA) layers with a total thickness of 3.0 in., and five intentional cracks (with widths of 0.2 in.) were introduced to the first HMA layer. After sealing the cracks and applying the tack coat layer, the geosynthetic interlayer was added, and the top HMA layer was constructed. Asphalt strain gauges and thermocouples were embedded in each section to measure critical strains. All sections were also loaded using a heavy vehicle simulator (HVS) with dual-tire configurations while the temperature around the test strips was maintained at 50°F. In addition, each test strip’s deflection and rutting were measured before and after HVS loading using a heavy weight deflectometer and a laser profiler, respectively. The HVS loading results found that the geogrid-reinforced test strip had a better strain response than the geotextile-reinforced layer, and the geotextile-reinforced layer showed slightly higher bonding (lower delamination). It is noted that the results of this study are in line with a former laboratory study with respect to crack reflection and delamination. Rut profiler data recorded a 25% reduction in rut depth for reinforced sections compared to the control. Moreover, the geosynthetic interlayer was able to mitigate reflective cracking propagation. Both interlayers improved fatigue performance.