A STUDY OF MACRO-CELL AND MICRO-CELL CORROSION OF STEEL IN CONCRETE

Abstract

Tatsuo KAWAHIGASHI Koichi KOBAYASHI Toyoaki MIYAGAWA The use of non-destructive methods to evaluate the corrosion of reinforcing steel in concrete is one crucial tool for the maintenance of concrete structure. However, such methods are still in the examination stage, both with respect to methodology (type of non-destructive methods and implementation) and evaluation of measured values. Still, there is expectation that evaluation methods will soon be established. In this investigation, non-destructive methods such as measurements of half-cell potential, polarization resistance (AC impedance), and electric current are tested in a model experiment using different sized steel plates, leading to an understanding of changes in electrochemical response of the reinforcing steel. Macro-cell corrosion and micro-cell corrosion are then calculated from the experiment results using numerical methods. This study shows that it is possible to separate macro-cell corrosion from micro-cell corrosion, and that steel reinforcement corrosion can be estimated.