Influence of Cover Porosity on Steel Corrosion in Cement-Based Materials

Abstract

A detailed investigation has been carried out to clarify the effect of porosity on steel corrosion in cement-based materials. Corrosion behaviours of steel were studied by means of corrosion potential, linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS), while the porosity of cover zone cement-based materials were investigated by evaporative water method (EWM) and mercury intrusion porosimetry (MIP). The results highlight that the corrosion parameters of steel are strongly related with porosity of cement-based materials. A linear relationship between porosity and corrosion rate of steel has been established which is in good agreement with the principle that the diffusion of chloride ions through porous cementitious materials may accelerate the anodic reaction of steel corrosion as well as oxygen diffusion for the cathodic reaction simultaneously.