Electrochemical Performance of Low-Carbon Steel in Alkaline Model Solutions Containing Hybrid Aggregates

Abstract

This work reports on the electrochemical performance of low-carbon steel electrodes in model alkaline solutions in the presence of 4.9.10-4 g/l hybrid aggregates i.e. cement extract, containing PDADMAC (poly (diallyl, dimethyl ammonium chloride) / PAA (Poly (acrylic acid)/ PDADMAC over a CaO core. The main objective was to determine if the addition of hybrid aggregates will lead to increased corrosion resistance of the steel surface layers, generally formed in the hereby investigated environmental medium. Further, it was expected that when chlorides are involved, as corrosion accelerating factor, the presence of hybrid aggregates will delay corrosion initiation and therefore lead to increased corrosion resistance. This investigation forms part of a novel approach to control steel corrosion in reinforced concrete, using self-healing mechanisms. The results from this study denote for indeed superior corrosion performance of steel in chloride-free and chloride containing alkaline solution, when hybrid aggregates are involved. The mechanisms are related to increased barrier effects of the formed layer and CaO release from the core of the aggregates.