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.
[1] Polder R B, van den Hondel H. Electrochemical realkalisation and chloride removal of concrete: State of the art, laboratory and field experience[M]. TNO Building and Construction Research, 1992.
[2] Hansson I, Hansson C M. Electrochemical extraction of chlorides from concrete part I—A qualitative model of the process[J]. Cement and Concrete Research, 1993, 23(5): 1141-1152.
[3] Orellan J, Escadeillas G, Arliguie G. Electrochemical chloride extraction: Efficiency and side effects[J]. Cement and Concrete Research, 2004, 34(2): 227-234.
[4] Garcés P, Sánchez de Rojas M, Climent M. Effect of the reinforcement bar arrangement on the efficiency of electrochemical chloride removal technique applied to reinforced concrete structures[J]. Corrosion Science, 2006, 48(3): 531-545.
[5] Swamy R N, McHugh S. Effectiveness and structural implications of electrochemical chloride extraction from reinforced concrete beams[J]. Cement & Concrete Composites, 2006, 28(8): 722-733.
[6] Yeih W, Chang J J, Hung C C. Selecting an adequate procedure for the electrochemical chloride removal[J]. Cement and Concrete Research, 2006, 36(3): 562-570.
[7] Siegwart M, Lyness J F, McFarland B J. Change of pore size in concrete due to electrochemical chloride extraction and possible implications for the migration of ions[J]. Cement and Concrete Research, 2003, 33(8): 1211-1221.
[8] Ismail M, Muhammad B. Electrochemical chloride extraction effect on blended cements[J]. Advances in Cement Research, 2011, 23(5): 241-248.
[9] Yao W, Zhao Z. Chloride transference during electrochemical chloride extraction process[J]. Science China-Technological Sciences, 2010, 53(6): 1466-1470.
[10] Andrade C, Diez J, Alaman A, et al. Mathematical modelling of electrochemical chloride extraction from concrete[J]. Cement and Concrete Research, 1995, 25(4): 727-740.
[11] Sa’id-Shawqi Q, Arya C, Vassie P. Numerical modeling of electrochemical chloride removal from concrete[J]. Cement and Concrete Research, 1998, 28(3): 391-400.
[12] Ihekwaba N, Hope B, Hansson C. Carbonation and electrochemical chloride extraction from concrete[J]. Cement and Concrete Research, 1996, 26(7): 1095-1107.
[13] Fajardo G, Escadeillas G, Arliguie G. Electrochemical chloride extraction (ECE) from steel-reinforced concrete specimens contaminated by “artificial” sea-water[J]. Corrosion Science, 2006, 48(1): 110-125.
[14] Hong D H. Corrosion and protection of reinforcement in concrete[M]. Beijing: China Railway Publishing House, 1998.
[15] Arya C, Sa'id-Shawqi Q, Vassie P. Factors influencing electrochemical removal of chloride from concrete[J]. Cement and Concrete Research, 1996, 26(6): 851-860.
[16] Ma K L, Xie Y Y, Long G C. Corrosion behavior and destructive mechanism of bridge concrete structyre under chloride salt environment[J]. Joural of Architecture and Cival Engineering, 2008, 25(3): 32-36.
[17] Jiang Z W, Yang K F, Pan W W. Study on effectiveness of electrochemical realkalization for carbonated concrete[J]. Joural of Building Materials, 2012, 15(1): 17-21.
[18] Dong S G, Lin C J, Hu R G, et al. Effective monitoring of corrosion in reinforcing steel in concrete constructions by a multifunctional sensor[J]. Electrochimica Acta, 2011, 56(4): 1881-1888.
[19] Analytical chemistry section of Hangzhou University. The hangbook of Analytical Chemistry, 2nd Section[M]. Beijing: Chemical Industry Press（化学工业出版社）, 1982.
[20] Guo Y X（郭育霞）, Gong J X（贡金鑫）. Study on electrochemical chloride extraction of reinforced concrete[J]. Joural of Taiyuan University of Technology（太原理工大学学报）, 2011, 42(6): 588-592.
[21] Gao X, Yang Y, Deng H. Electrochemical changes of pre-corroded steel reinforced concrete due to electrochemical chloride extraction[J]. International Journal of Electrochemical Science, 2011, 6(6): 1797-1809.
