Electrochemical Behavior of Steel in Concrete Under Wet and Dry Condition with NaCl Solution

The corrosion of steel and environmental factors in concrete under the wet and dry condition were examined by using electrochemical impedance spectroscopy (EIS) and microelectrode sensors. The concentration of chloride ion (CL) was detected by Ag/AgCl microelectrode, and the pH was monitored by W/WO x one. The CL increased step by step according to the wet and dry condition. Besides, the cathodic current of the oxygen ( I O 2 ) was increased just after the immersion of concrete sample in wet process. These behaviors were thought to promote the corrosion of steel. From EIS, the rust was formed and destroyed on the surface of steel in concrete under the wet and dry condition. It was quantitatively demonstrated by monitoring that the corrosion of steel started when CL exceeded the threshold value in concrete under the wet and dry condition.