Various electro-chemical techniques for corrosion protection of reinforcing steel have been developed in the last few years. The advent of these techniques presents the possibility of lasting rehabilitation for concrete through tackling the causes instead of symptoms. One of these methods is the electro-chemical realkalisation (ECR) which provides a non-destructive means for remedying the effects of carbonation. ECR aims to re-establish the corrosion protective qualities of concrete by increasing the alkalinity of carbonated concrete to a suitably high pH level.
This paper aims to study the main mechanisms controlling the ECR processes and factors affecting such treatment. Subsequently, as a means of restoring passivation of steel embedded in carbonated concrete, a pre-conditioned carbonated hardened cement paste specimens at 65% and 100%RH were subjected to ECR using different current densities (0, 1 and 5 A/m2), electrolyte types (sodium carbonate, sodium phosphate, sodium hydroxide and lithium hydroxide) for different treatment periods (0, 7, 14 and 28 days). The influence of ECR on the chemistry of the pore solution of the surface and the steel/cement paste interface zones was also investigated