Structural Assessment of Pavements Using a Coreless GPR Approach

The reliability of the estimated pavement moduli for structural assessment depends on the accuracy of layers thickness. In this paper, the thickness of the bituminous layer was estimated using a coreless Ground Penetrating Radar (GPR) approach: the Common Mid-Point method with Air-Coupled antennas (CMP-AC), by combining multiple GPR offset configurations. For each survey line, the thicknesses are estimated through a GPR testing campaign consisting of three passages with distinct antennas offsets. A dedicated processing methodology was implemented. The results obtained are promising as allow for detecting the changes between the designed and the estimated bituminous layer thickness. This methodology does not interfere with traffic flow, nor requires pavement coring. A case study of a flexible pavement is presented herein, in which load tests performed with Falling Weight Deflectometer (FWD) were combined with GPR to assess the bearing capacity of the pavement. The structural models obtained initially using the design thickness were adjusted based on the CMP-AC approach leading to more realistic values for layer moduli.