An Investigation on Application of the Electrical Resistivity Tomography Method to Concrete Structures

Reinforced concrete used for bridge decks and pillars, highways and other transportation facilities experience loss of integrity over time caused by poor initial quality, action of de-icing salts, temperature changes, fatigue and, above all, delamination caused by corrosion of reinforcement bars (rebars for brevity). Electrical resistivity is sensitive to those losses of integrity. Using 3D numerical modeling we first examine resistivity responses associated with those problems. In the case of rebars, differences occur if they are corroded or not and if cracking or delamination is taking place; resistivity anisotropy is also indicative of rebar distribution and concrete integrity. We also investigate the potential of imaging to recover the resistivity distribution. Finally, the technique is applied to the auscultation of two bridge decks in Montreal and compared with other geophysical and geotechnical data.