电化学除氯和硅酸根电迁移法的联合修复研究.pdf

电化学除氟和硅酸根电迁移法的联合修复研究/单鸿猷等
电化学除氯和硅酸根电迁移法的联合修复研究
单鸿猷,徐金霞,蒋林华
(河海大学力学与材料学院,南京210098)
摘要为了抑制氯离子反向扩散造成钢筋二次腐蚀,进一步延长修复后混凝土结构的服役寿命,在电化学除
氣(ECR)基础上提出一种通过电驱动Si2进入孔隙,与孔隙中的Ca(OH)2反应生成CSH凝胶硬化混凝土/砂
浆,并同时去除混凝土/砂浆内氯离子的新型的联合修复方法。由对比试验,通过滴定氣离子,利用自腐蚀电位
(Eom)、腐蚀电流密度(Iom)和电化学阻抗谱法(EIS)研究了该方法的修复效果及其修复后的长期耐久性,此外,由压
汞法和热重分析探讨了该方法的徽观作用机制。结果表明:联合修复方法与电化学除氯具有相近的除氯效率;与电
化学除氯相比,联合修复方法能更有效延缓钢筋的二次腐蚀;随着初始氯离子含量的减少,联合修复方法廷缓钢筋二
次腐蚀的效果更为显著;联合修复方法对钢筋二次腐做的抑制源于其致密化作用,经联合修复后砂桨总孔隙率与有
害孔数量相比于修复前均有所下降
关键词电化学脱盐硅酸根致密化联合修复水泥砂浆
中图分类号:TU528.01文献标识码:ADOI:10.11896/.issn.1005-023X.2016.14.001
Remediation Method of Combining Electrochemical Chloride Removal
with Electro-migration of Silicate lon
SHAN Hongyou, XU Jinxia, JIANG Linhua
(College of Mechanics and Materials, Hohai University, Nanjing 210098)
Abstract For the aim of suppressing the reverse diffusion of chlorine ions and furter extending the service life
of concrete structures after remediation, a novel remediation method of combining electrochemical chloride removal
(ECR with clectro-migration of silicate ion has been developed. By a comparative experiment, the efficiency of chlo-
ride removal and corrosion properties of steel reinforcement in mortar specimens after remediation were investigated by
means of chloride potentiometric titration, corrosion potential(Em)and corrosion current density (I)determine
by electrochemical impendence spectroscopy(ETS). Besides, the mortar microstructure was characterized by mercury
intrusion porosimeter and thermogravimetric analysis. The results showed that the combined remediation had a similar
fficiency of chloride removal when compared with the electrochemical chloride removal method Moreover, the com
bined remediation method could effectively reduce the corrosion rate of steel reinforcement for the second time. with
the decrease of initial chloride content, the efficiency of reducing the corrosion rate of steel reinforcement for the se-
cond time would be improved after the combined remediation. The corrosion of steel reinforcement for the second
could be inhibited effectively after the combined remediation method, owing to densification by electro-migration reac
tion of silicate ion. After the combined remediation, the porosity and the harmful pore number were reduced
Key words electrochemical chloride removal, silicate ion, densification, combined remediation, cement mortar
0引言
也面临一个重要问题,即修复后钢筋混凝土结构的耐久性劣
化,尤其是环境介质中的氯离子反向扩散进入混凝土引发的
电化学除氯是目前能有效去除侵蚀性的氯离子,并从根混凝土内钢筋的二次腐蚀。一方面由于电化学除氯后钢筋
源上对混凝土中钢筋氯离子腐蚀进行修复的一种无损方法。混凝土结构仍处于严酷的氯盐环境下,环境介质中的氯离子
同现有其他修复技术进行比较,它具有高效、快速、低成本的不可避免会反向扩散侵入富含孔隙的混凝土2。另一方面
优势,因此受到国内外研究者的广泛关注,并得到一定的应因为电化学除氯并不能完全根除混凝土中侵蚀性的氯离子
用
(电化学脱盐的氯离子排除率仅有30%~75%,具体依赖于
即便如此,电化学除氯修复混凝土中钢筋氯离子腐蚀时初始氯离子含量、脱盐工艺参数与配筋量等)“,由反向扩
x国家自然科学基金面上项目(51278168;51478164;51278167)
单鸿猷:男,1991年生,博士生,主要从事混凝土结枃耐久性研究 E-mail: shanhongyou@ hhu.edu,cn徐金霞:通讯作者,男,
1972年生,博士,副教授,主要从事混疑土结构耐久性研究E-mail:xujinxial@hhu.edu.cn