Behaviours of Geogrid-Reinforced Asphalt Pavement over a Localized Void under Cyclic Loading

A set of large-scale physical model tests were performed to investigate the performance of unreinforced and glass fibre geogrid-reinforced asphalt pavement under the development of a void in the subgrade. Traffic loadings were simulated with repeated sinusoidal loadings of different amplitudes. The formation of the void was simulated using a novel displacement control device between loading cycles. The accumulative permanent deformation of the asphalt pavement, the composite resilient modulus and dissipated energy were presented and analysed. It was found that the inclusion of geogrid greatly improved the fatigue life of asphalt pavement, and the stronger the geogrid, the greater the improvement if a void was formed below the asphalt layer. After forming the void, the composite moduli of the pavements increased compared with that during the first cyclic loading stage (without the void) and seemed to be not much affected by the geogrid type. The effect of cyclic loading level on the composite modulus was not significant. The inclusion of geogrid in asphalt had a limited effect on the dissipated energy in the pavements with and without voids. The dissipated energy increased with the cyclic loading amplitude.