Durability aspects of electrochemical realkalisation treatment

Electrochemical realkalisation (ER) is a technique used for the repair of concrete suffering carbonation-induced corrosion of steel reinforcement. It aims at restoring high levels of pH through the application of a temporary cathodic current to steel, and subsequent production of alkalinity at the steel surface; a further mechanism of realkalisation relies on the ingress of an alkaline solution in the concrete through the surface in contact with the anode. ER does not require the replacement of carbonated concrete, if it is not damaged, and so it can be advantageous compared to conventional repair, that usually requires the removal of large amounts of mechanically sound concrete. Although ER was introduced in the 1980s and has been used since then for the repair of carbonated structures, there are still some aspects connected with its application that need further investigation. This paper presents the results of an experimental research aimed at investigating the durability of ER, considering both the realkalisation of carbonated mortar and the protection of reinforcement from corrosion.