GPR was examined to measure void size under concrete pavement at 88 expressway using monostatic-mode antenna of 400MHz which allows relatively deep penetration. Support loss site was identified by comparing resultant radar traces with sound positions....
GPR was examined to measure void size under concrete pavement at 88 expressway using monostatic-mode antenna of 400MHz which allows relatively deep penetration. Support loss site was identified by comparing resultant radar traces with sound positions. Void detection for the same position as GPR tests was also performed by FWD based on AASHTO′s techniques as Variable Load Corner Deflection Analysis and Void Size Estimation Procedures. Closed-form backcalculation for FWD tests is adopted to evaluate the subsurface properties of concrete pavement. In this study, effects of base layer, slab size and temperature gradient within concrete slab are considered to modify the backcalculated values from closed-form equations which are based on conditions of infinite dimension, one layer and no curling or warping of concrete slab. Subgrade reaction and concrete elastic modulus backcalculated from measured deflections at Seohae expressway show considerable changes with large temperature gradient of concrete slab. Based on field testing, basic modification chart was obtained to adjust these variations.