We present the GPR results dealing with flexible road pavements located on cut and fill sections with retaining wall. The aim is to evaluate the road damage (particularly the ramified cracks) taking into consideration also other parameters (cut and fill section height and traffic load). The GPR evaluation was carried out on 20 sites selected in the secondary urban road network of L’Aquila, a medium-size urban area representative of the Abruzzi Region (Central Italy). Stress induced by traffic load generally affects a road section thickness of about 1.0 m from the ground; so a monostatic GPR antenna, with a nominal frequency of 2000 MHz, was used given that its maximum inspection depth corresponds to 1.0 m from the ground. The 2000 MHz antenna has also a quite high-resolution when inspecting road damage. The GPR acquisition was carried out in damaged and adjoining undamaged road sites, to compare the GPR data of the two areas. GPR data analysis was based on the sweep-rectified power approach to evaluate the radar signal attenuation curve vs. depth, which permitted us to single out different road types of damage and to discuss the factors which caused them.

Damaged road pavement; Georadar; Monitoring and Inspection