In Situ Detection on Electrochemical Chloride Removal of Reinforcement in Concrete by Combined pH/Cl- Probes
- 2014年第20卷 
采用恒电流法电化学除氯处理受氯离子污染的钢筋混凝土试样，并用pH/Cl-复合探针原位检测电化学除氯过程钢筋混凝土不同位置孔隙液的氯离子含量与pH值分布，同时用线性极化曲线和交流阻抗谱图等电化学技术考察钢筋的腐蚀性能，探讨电化学除氯过程的混凝土微环境和钢筋腐蚀速率. 研究结果表明：在电化学除氯过程，混凝土孔隙液的氯离子浓度逐降，而pH值在初期略有升高，随之其pH值略降；电化学除氯施加的阴极电流，使钢筋处于阴极极化状态而得到保护；除氯停止（即退极化）后钢筋的腐蚀电位明显正移，腐蚀电流降低，极化电阻升高，表明电化学除氯能改善钢筋的腐蚀环境，降低钢筋的腐蚀速率.In this work, the concrete samples polluted by chloride ion were electrochemically treated using galvanostatic technique, and the distributions of chloride ion concentration and pH value in the polluted concretes were in-situ monitored by embedding a combined pH/Cl- probe during the electrochemical chloride removal. The corrosion behaviors of reinforcing steel in the concrete were simultaneously studied by using linear polarization and electrochemical impedance spectroscopy techniques (EIS). The micro environment of the concrete and corrosion rate of steel were explored during the electrochemical chloride removal. It was indicated that the Cl- concentration in the concrete pore solution decreased with time, while the pH value around steel increased first in the early stage, and then decreased in a certain extent. The steel in the concrete was cathodically polarized and protected by the applied cathodic current. After the electrochemical chloride removal ceased (namely depolarization)，the corrosion potential of steel was obviously shifted to a positive direction，the corrosion current decreased, and the corrosion resistance increased. This illustrates that the electrochemical chloride removal is enable to improve the corrosive environment of steel in concrete and to decrease the corrosion rate.