Detection of rebar corrosion in bridge deck by using GPR

Abstract

Ground Penetrating Radar based inspection technique is currently used for mapping bridge deck in order to monitor the health of this vital structure. Research over recent years in this field has focused on identification of rebar corrosion which is known to cause staged deficiencies by reducing bridge deck strength to critical levels. It is expected that using high-frequency antennas could improve discrimination of anomalies and enhance detection of small corrosion defects affecting bridge deck rebars. In this work, simulation of the input reflection coefficient of reinforced concrete bridge deck as modified by corrosion of a steel rebar is performed. The objective is to analyse the effect of the work frequency and corrosion layer thickness on the input reflection coefficient. Simulations have been carried out for various situations involving intact and corroded zones of a rebar buried in a reinforced concrete plate with the whole infrastructure overlaid by an asphalt layer. The obtained results have shown that the value of work frequency is very important and should be carefully selected.