Combined GPR and ultrasonic tomography measurements for the evaluation of a new concrete pavement

Ground Penetrating Radar and Ultrasonic Tomography are two nondestructive techniques that are particularly well suited for the inspection of concrete pavements using electromagnetic and ultrasonic sound waves, respectively. In this study, both methods were used for the evaluation of a newly laid concrete pavement. The positions of the dowels in the transverse joints and the thickness of the pavement were surveyed. Results showed that GPR was more efficient for dowel positioning, while both devices could be used for thickness estimation. With both methods the precision was higher when calibration spots were available (mean relative error smaller than 2%), but the errors remained limited (<6%) when appropriate nondestructive methods were used for speed estimation.