Influence of Concrete Resistance on Electrochemical Chloride Extraction

Corrosion of embedded steel in reinforced concrete (RC) is a world-wide problem which leads to a reduction in structural performance and lifespan. Chloride attack, one of the leading causes of corrosion in reinforcing steel, may be a result of seawater, de-icing salts or contaminated addmixtures, brought on by ingress of chlorides into the concrete. Electrochemical Chloride Extraction (ECE) is a non-destructive treatment for contaminated RC structures, that due to uncertainty of treatment times and applied current densities, it is only 50% effective, is often diesel powered with detrimental environmental impacts and often very costly due to the long treatment times. To achieve a more efficient treatment system, a 15 week long experimental program investigated the electrical requirements of ECE. Embedded resistance sensors and thermistors were used to measure the resistance of the concrete during ECE and dust samples were taken to measure the reduction of chlorides. The reduction of embedded chlorides correlated with resistance measurements. The results of this experimental work will be used to design a photovoltaic (PV) system to power ECE.