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The Ground Penetrating Radar is a device which can be used for non-destructive inspection of civil engineering structures such as reinforced concrete buildings and bridges. Because of its ability to detect defects and provide reliable image of the substructure, it has attracted large interest from both practitioners and researchers in the field of health monitoring of vital structures. The objective of this work is to analyze detectability of defects in reinforced concrete structures by considering the presence of a defect which can attenuate GPR signals. Defects embedded in the structure can in fact cause significant changes in the intensity of the hyperbolic like reflection patterns generated by reinforcement bars. To assess this effect, a numerical simulation study of GPR data was conducted by using the GprMax software which is based on finite differences time domain method. The proposed approach has enabled to study the modification affecting the radargram due to the presence of a defect of finite size.

Bridge deck deterioration includes delamination, corrosion of rebars, vertical cracking and concrete degradation. Ground Penetrating Radar based inspection technique was used for mapping bridge deck in order to monitor the health of this vital structure. Beginning from the 1970‘s, research has focused on identification of bridge deck deterioration which causes severe deficiencies by reducing seriously strength. The main purpose of this work was to review the literature existing in the field of bridge deck diagnosis by means of Ground Penetrating Radar. This enabled to survey detailed evolution of this technique, to understand the effects of key intervening parameters and to determine the kind of material disorders that this device could be used for. Bridge deck condition assessment can then be performed more successfully, based on the huge progress experienced by this particular method of inspection.

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.