Investigation of ground-penetrating radar defect detection capabilities, influence of moisture content, and optimal data collection orientation in condition assessments of concrete bridge decks

Abstract

Eighteen specimens with simulated bridge deck defects were tested in different moisture contents and directions using ground-penetrating radar (GPR). When analyzing reflection amplitudes from the top reinforcement mat, it was found that GPR could not effectively locate delaminations, vertical cracks, concrete deterioration, poorly-constructed concrete, and clay-filled voids. Nonetheless, GPR could detect chloride-induced corrosion and water-filled voids in the cover layer. Hypothesis testing revealed that an increase in moisture content generally causes an increase in variance and a decrease in mean of reflection amplitudes, and reinforcement intersections decrease the mean of data collected while oriented perpendicular to the bottom bar in the top reinforcement mat.