METHODS FOR STUDYING CORROSION IN REINFORCED-CONCRETE

This Paper reviews available techniques for monitoring steel corrosion in reinforced concrete. Electrochemical techniques are by far the most suitable for this purpose, and meet most of the requirements. The responses of direct and alternating current corrosion monitoring methods for steel-concrete systems are compared under two extreme conditions, i.e. steel being corroded in the active state and in the passive state. Most practical situations will belong to one of these or be intermediate to them. Results of polarization resistance measurements (taken by applying a potential step, a current step and small-amplitude cyclovoltammetry), a coulostatic method and electrochemical impedance spectroscopy are reported. It is shown that metal polarization resistance in particular, and electrochemical methods in general, can provide fast and reliable information on the corrosion rate of steel in concrete, sufficiently accurate to distinguish between acceptable and unacceptable conditions in most scientific and technical applications.