Experiments were performed to study the mechanism of corrosion of steel in carbonated concrete in cyclic wetting/drying exposure. It was found that the corrosion rate increased during wetting, followed by a decrease during drying. The increase and decrease of the corrosion rate can be explained by changes in electrochemically active steel area as a function of the moisture state of the mortar and its porosity. The corrosion rate achieved in the wet phase stabilizes during the first few wetting and drying cycles. The mechanism of the electrochemical process is discussed on the basis of theoretical considerations. It is concluded that the corrosion kinetics are under activation control. The availability of oxygen does not seem to be a limiting parameter for the corrosion process in cyclic wetting/drying exposure.

进行了实验，以研究循环湿润/干燥暴露下碳酸盐混凝土中钢的腐蚀机理。发现在润湿过程中腐蚀速率增加，而在干燥过程中腐蚀速率降低。腐蚀速率的增加和降低可以通过电化学活性钢的面积随灰浆的水分状态及其孔隙率的变化来解释。在最初的几个润湿和干燥周期中，在湿相中获得的腐蚀速率稳定。在理论考虑的基础上讨论了电化学过程的机理。结论是腐蚀动力学处于活化控制之下。对于循环润湿/干燥暴露中的腐蚀过程，氧气的可用性似乎并不是一个限制参数。