STEEL CORROSION IN CONCRETES DETERIORATED BY CHLORIDES AND SULFATES - ELECTROCHEMICAL STUDY USING IMPEDANCE SPECTROMETRY AND STEPPING DOWN THE CURRENT METHOD

This investigation deals with reinforced concrete specimens which were previously placed in aggressive aqueous solutions containing chlorides or sulphates. So, the steel rebars were corroded. The object of this study is to characterize the steel surface condition by using two electrochemical methods. The first method is the electrochemical impedance spectrometry (EIS), and the second one is the "stepping down the current" method (SDC). The results of the EIS method are in agreement with results which were previously published by other authors. It means that the shape of the Nyquist diagrams and the electrochemical parameters calculated from these diagrams characterize the rusting conditions of the rebars. The parameters calculated from the SDC results by using the Randles equivalent circuit, are also able to characterize the rusting condition of the rebars.