Non-destructive testing technologies: Application of the ground penetrating radar (GPR) to perpetual pavements

In this study, the application of the Ground Penetrating Radar (GPR) as a nondestructive testing (NDT) tool was investigated for evaluating perpetual pavements. In total, eight in-service Texas perpetual pavement sections were evaluated and are discussed in this paper. Based on this study, the GPR was found to be an ideal NDT tool for structurally evaluating perpetual pavements. Concerns were raised in this paper about the uniformity and permeability of the 1-inch Stone Filled HMA layer, which is the main structural layer in the Texas perpetual pavement structure. The results obtained indicated that the GPR has great potential for determining pavement layer thickness, assessing compaction uniformity, locating areas of moisture retention, and identifying low density areas in the upper asphalt layers. Additionally, TTI's GPR system has the advantage of rapidly and continuously collecting pavement data up to a depth of 610 mm, together with integrated video images, over any desired highway length while travelling at a speed of about 113 kin/hr. Overall, the GPR was found to be a highly beneficial and effective NDT tool for forensic and structural evaluation of perpetual pavement structures. Based on the findings of this study and subsequent validation of the GPR results through coring, the Texas DOT has modified its recommendations for future perpetual pavement designs. © 2009 Lavoisier, Paris.