Development of ground-penetrating radar equipment for detecting pavement condition for preventive maintenance

A ground penetrating radar (GPR) system was developed to locate potential maintenance problems in highway pavements. The system identifies sections of pavement with conditions such as voids that could be effectively treated with maintenance measures. It is described how GPR has the potential to detect 4 defects in pavements: stripping in an asphalt layer; moisture in base layer; voids or loss of support under rigid pavements; and overlay delamination. Two generations of prototype systems were developed which produced a GPR that could acquire radar signals with higher resolution than previously possible and interpret the data by automatic signal-processing techniques. The report describes the results of tests on the second generation protoype and the correlation between the radar results and ground truth. Recommendations are presented for further testing and development together with recommendations for incorporating a GPR system into typical pavement maintenance and rehablitation operations.