关键词: pH/Cl^-复合探针, 电化学除氯, 钢筋混凝土, 腐蚀

Abstract: 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.

Key words: pH/Cl^- probe, electrochemical removal chloride, reinforced concrete, corrosion