Electrochemical behaviour of steel in mortar and in simulated pore solutions: Analogies and differences

On evaluating the corrosion resistance of concrete, it is frequent to perform electrochemical tests in the so called simulated pore solutions (SPS) to replace tests performed in concrete specimens. Besides, to study the effect of the chloride content in concrete, chloride ions are added to the SPS. However, it is not obvious whether the SPS simulate the electrochemical behaviour of steel in concrete. Another concern is related to the relationship between the chloride content in concrete and the chloride content of a SPS. To investigate this issue a comparison between the polarization curves of steel in mortar and in SPS was performed. It was found that the SPS is not fully representative of the corrosion behaviour of steel in mortar but it yields conservative results. The relationship between the chloride content in mortar and in SPS that yields similar behaviour is not straightforward but depends on the electrochemical parameter considered.