Changes in Concrete Pore Size Distribution Due to Electrochemical Chloride Migration Trials

Abstract

Concrete structures suffering reinforcement corrosion are starting to be rehabilitated by means of electrochemical techniques, such as cathodic protection, chloride extraction, and realkalization that, in some cases, involve the application of relatively large electrical potentials or currents. The generalized movement of the ions dissolved in the aqueous phase of pores leads researchers to think that microstructure of concrete can be altered. In this study, results are presented on the changes in the pore size distribution after penetration of chlorides driven by an electrical field (migration) in comparison with natural diffusion penetration. Results indicate that the application of an electrochemical treatment to a structure induces an increase in total porosity, because of the solution of precipitated phases initially located in the smallest capillary pores that, after some time, evolve to be found in the range of 5 micro m to 0.05 micro m.