Electrochemical Realkalization as a Conservation Technique for Reinforced Concrete

Abstract

Electrochemical realkalization (ER) is a repair technique aimed at restraining corrosion of steel in carbonated concrete. ER is based on the application of a current to restore concrete alkalinity—the favorable environment for the protection of steel from corrosion. The treatment lasts from few days to weeks; then, when the entire concrete cover is realkalized, the external anode that supplied the current is removed, leaving the surface unchanged. Moreover, ER does not require the replacement of carbonated concrete if it is not damaged, so it can be advantageous compared with the traditional repair, which usually requires the removal of large amounts of mechanically sound (although carbonated) concrete. Although ER treatment was introduced in the 1980s, debate continues on some aspects connected with its application. This study presents the preliminary results of a long-term experimental research aimed at investigating this technique. The results obtained allowed determining ER effects in terms both of realkalization of the initially carbonated material and of protection of reinforcement from corrosion.