An overview of GPR applications for evaluation of pavement thickness and cracking

Pavement asset management requires accurate and rapid measurement of asphalt layer thickness for reliable backcalculation of modulus values of pavement layers from nondestructive deflection tests. Also needed are measurements of layer delamination, surface cracking, and other distresses. Top-down cracking in the longitudinal wheel path of thick asphalt highway pavement is a major distress problem. The objective of this paper is to evaluate several nondestructive testing technologies that can be operated at highway speed to assess asphalt thickness and surface cracking depth. This paper presents key findings of an extensive literature review of GPR equipment and data interpretation methodologies. The study supports that nondestructive GPR technology has evolved over the last three decades to measure pavement layer thickness and delamination accurately, which is more cost-effective than extracting cores. The study did not find a field technology that can operate at highway speeds for mapping pavement surface cracking and its penetration depth. However, GPR remote sensing has the potential to map the penetration depth of top-down cracking from the surface through asphalt layer thickness.