Ground Penetrating Radar applied to asphaltic pavements – a study in a controlled site

The major challenges in road infrastructure studies are related to the evaluation of the road pavement quality in a practical, non-destructive, and low-cost way. Information about the thickness of the layers is fundamental to pavement repairing. In this study, the applicability of the ground penetrating radar (GPR) method in the delimitation of the pavement layer is tested at the Shallow Geophysical Test Site Applied to Engineering of Universidade Estadual de Goiás (UEG). The ground penetrating radar presents satisfactory results, identifying the top and bottom of the first five layers by the 270, 400, and 900 MHz antennas. The 2 GHz antenna was able to only delimit the top and bottom of the Hot Rolled Asphalt (HRA). The geomembrane with geotextile set and the concrete layer were not identified in the radargrams. The resolution of each antenna is 9.8 cm for 270 MHz; 6.0 cm for 400 MHz; 2.9 for 900 MHz; and 1.6 cm for 1600 MHz. Concerning layer thickness estimates, the antennas had an efficiency percentage of 83 % (270 and 1600 MHz), 83.29 % (400 MHz), and 84.40 % (900 MHz). Layer thickness estimates obtained by GPR antennas were compared with true thickness using a paired t-test (α= 0.05). No significant differences in layer thickness were observed for the GPR antennas versus the actual pavement thickness.Keywords: GPR; geosynthetics; road investigation; shallow geophysical test site; non-destructive testing.