Corrosion monitoring of reinforced concrete
University of New Brunswick
A major concern for all owners and contractors dealing with reinforced concrete structures is corrosion. The University of New Brunswick's heating steam is carried in a system of underground tunnels and the corrosion of the steel reinforcing in the tunnel roof of the service tunnel was so severe that it had to be replaced after approximately 25 years. Monitoring the condition of the tunnels is part of the University's ongoing procedure for evaluating the condition of all the facilities. Basing the evaluation of the condition of the tunnels on visual appearance and physical measurements is not very effective. Measurement by half cell potential and linear polarization was found to give a much better measure of the condition of this type of structure. An approximation of the corrosion potential and rate of corrosion can be determined for a reinforced concrete structure with these techniques. To determine the nature of the corrosion process a scanning electron microscope proved to be effective in examining both the microchemical and microstructural features. It also allows evaluation of how effective the epoxy coating is in reducing corrosion of the reinforcing bars and extending the life of the structure.