Road inspection using full-wave inversion of far-field ground-penetrating radar data

Inspecting how robustly and safely the roads are built in order to develop better methods for both design and quality control of materials is an important task in road engineering. In this research we studied the potential of full-wave model of Lambot et al. 2004 for far-field ground-penetrating radar (GPR) configuration in order to retrieve the physical and electromagnetic properties of the road, including both asphalt and subbase layers. Two different GPR systems, namely, stepped frequency GPR and impulse GPR systems were used to collect data along a 50 m long transect. Accurate positioning was performed using a dGPS and a survey wheel. Both GPR data sets were processed using GPR full-wave inversion in the time domain focusing on the asphalt and subbase reflections. Comparison of the results from both GPR systems showed a good agreement between them. In addition, results showed that a compacted zone on the road leads to a compaction feature influenced the retrieved road parameters. The proposed radar data processing method demonstrated a strong potential of the GPR full-wave model to be used for quantitative road inspection