Failure mechanisms of geogrid-reinforced asphalt pavements: A viscoelastic 3D FEM analysis

Abstract

The increasing traffic volume, axle loads, and tire contact pressures significantly impact asphalt pavement performance, often accelerating early-stage failures like rutting and cracking before the expected service life is reached. To improve the sustainability and resilience of pavements, new materials and technologies have been integrated into pavement design and construction. One such technology is geosynthetics, which have been widely implemented to improve pavement performance. The objective of this research is to evaluate the impact of placing different geogrids within the asphalt layer on mitigating or preventing rutting and fatigue cracking (both bottom-up and top-down) in pavements. To achieve this, viscoelastic analyses of reinforced and unreinforced pavements were conducted under non-uniform tire–pavement contact stresses (including wide-base and dual-tire configurations) using a three-dimensional (3D) finite-element (FE) model. The critical responses associated with the primary failure mechanisms at medium to high temperatures were then computed and compared. The results indicate that placing high modulus geogrids, especially at the bottom or one-third of the asphalt concrete layer, significantly enhances pavement performance at elevated temperatures. Geogrid reinforcement, particularly geogrid type one (GEO1), reduced vertical compressive strain by 28.1 % and shear strain by 48.4 % at 50°C, effectively mitigating rutting. Additionally, strategic geogrid placement reduced transverse strains by up to 42 %, alleviating top-down cracking (TDC). This research highlights the importance of geogrid type, AC layer thickness, and vehicle speed in optimizing pavement resistance to deformation and cracking.