Corrosion and Sulfate Attack Mitigation in Concrete Using Electrokinetic Nanoparticle Treatment

This work demonstrates a new method to rehabilitate damaged concrete using electrokinetic insertion of pozzolanic nanoparticles. The intent was to use the electric field to simultaneously extract deleterious species while inserting nanoparticles as a means of inhibiting the return migration of these agents. Reinforced concrete deteriorates due to the chloride induced corrosion of the steel reinforcement. The hardened cement binder phase of concrete is susceptible to sulfate attack. In this study reinforced concrete specimens were exposed to sulfates and others to chlorides. The chlorides and sulfates were extracted concurrent with the initiation of electrokinetic nanoparticle (EN) treatment. EN treated specimens exhibited 30% decreases in porosity and 33 % increases in strength in the sulfate exposed specimens. Among the chloride exposed specimens EN treatment yielded significantly lower corrosion rates and 50-75 % reductions in porosity. It was observed that the level of porosity reduction appeared to correlate to the sizes of species transported. Analytical modeling and a computer simulation were used to understand the nature of porosity reductions achieved via electrokinetic nanoparticle transport in these systems.