Evaluation of Asphalt Pavement Internal Distresses Using Three-Dimensional Ground-Penetrating Radar

The coupling effect of traffic loads and environmental factors causes damage to the different structural layers within the asphalt pavement, such as transverse cracks, longitudinal cracks, and loose materials. These internal distresses will gradually extend to the road surface, thereby accelerating the deterioration of the asphalt pavement structural performance. Three-dimensional ground penetrating radar (3D-GPR) has 21 pairs of antenna channels, capable of detecting the structural condition of asphalt pavement nondestructively, quickly, and efficiently. The multi-dimensional radar images (longitudinal, horizontal, and cross sections) allow to visualize the internal distresses of the pavement structure. In this paper, 3D-GPR was used to investigate asphalt pavement internal distresses in Guangzhou South China Expressway. The distresses at the asphalt course–base interface, base–subbase interface, and subbase–subgrade interface were evaluated and statistically analyzed. Three-dimensional distress ratio (DR_3d) and pavement internal condition index (PICI_3d) were proposed to assess the internal distress condition of asphalt pavement. The results reveal that DR_3d can better reflect the distress condition of the whole pavement structure when compared with the traditional two-dimensional distress ratio (DR_2d).