Innovative Method for Interpreting Ground-Penetrating Radar (GPR) Data from Concrete Bridge Decks

The deterioration of concrete bridge decks is one of the most problematic issue facing Departments of Transportation (DOTs) in North America. Among various bridge elements, concrete decks usually have the highest rate of deterioration and therefore need to be inspected regularly and carefully. Since important defects in concrete bridge decks such as delamination and rebar corrosion cannot be found by visual observation, nondestructive evaluation (NDE) technologies are being studied worldwide as an alternative method for inspection. In that context, this paper presents a new methodology developed for interpreting ground penetrating radar (GPR) of concrete bridge decks. This innovative method is based on the comparison of individual GPR signals (A-scans) those are taken at the same location but at two different points in time, using correlation analysis – a signal processing technique. The comparison results, indicated by the correlation coefficients are then employed to develop contour map and predict the location of deteriorated concrete. The method is validated based on the data collected from a concrete bridge deck in Quebec.