NON CONTACTING CORROSION METHOD APPLIED TO THE STEEL CORROSION RATE DETERMINATION IN DIFFERENT SOLUTIONS AND REINFORCED CONCRETE SPECIMENS

All the current techniques used to measure the metallic corrosion require contact with the metal. Particularly, in the case of reinforcement corrosion, this signifies the need to reach the bar that is embedded in the concrete, which may consequently result in the disruption of the integrity of the real structures. In a recent paper it has been published the feasibility of using a new method for polarizing the reinforcement or any metal in an electrolyte, without the need of direct contact with it. The polarization was obtained through the induction of current from an external electrical field. The current runs through the electrolyte and the metal in parallel, depending on the electrode arrangement. The resulting Polarization Resistance calculated is termed as Inductive, R_p = R_pi. The Inductive is calculated by the model of resistances in parallel, which requires a separate measurement of the electrolyte ohmic resistance. In this study, an extension to different electrolytes of the feasibility of the method is presented. Solutions with several different resistivities and concrete specimens with and without chlorides have been used. The results indicate that electrolytes of low resistivity mask the measurement, and consequently, R_pi could not be calculated in the manner tried. In electrolytes with high resistivity, such as concrete, the feasibility is found to depend on the relative values of R_e and R_pi.
KEYWORDS: corrosion, rate measurement, non-metallic contact.