Full-scale accelerated testing of geogrid-reinforced inverted pavements

Decades of research has been dedicated to investigating inverted pavement as an alternative to traditional flexible pavement structures. While previous studies have largely focused on the stress dependency of the unbound aggregate base (UAB) layer using numerical simulations, there is limited research on the construction and use of geogrid reinforcement in inverted pavement. This study presents a comprehensive evaluation of full-scale inverted pavements, specifically assessing the impact of geogrid reinforcement on rutting performance. The results indicate that adding geogrid to the UAB layer improves rutting resistance, with optimal results achieved when the geogrid is placed in the upper third of the layer. On the other hand, when the geogrid was positioned in the bottom two-thirds of the layer, it led to inferior rutting performance compared to the inverted pavement where geogrid reinforcement was placed in the upper one-third of the UAB layer. Numerical simulations validate the field test results, demonstrating that higher tensile strains in the upper third location enhance aggregate interlocking and stiffness due to the geogrid's enhanced constraining capacity and reinforcement. Conversely, lower tensile strains in the bottom two-thirds location limit geogrid constraints, leading to increased rutting and surface deformation.