混凝土中钢筋的腐蚀是一电化学过程,采用电化学方法评价钢筋的锈蚀情况具有测试速度快、灵敏度高、可连续跟踪、原位测量和非破坏性等优点,在实验室已成功地用于检测混凝土试样中钢筋的锈蚀状况和瞬时锈蚀速度,并已开始尝试用于现场监测及检测。在普通三电极电化学测量系统下,对于现场较大面积的钢筋混凝土结构,而采用较小面积的辅助电极(CE),由于二者面积的强烈不对称性,CE电力线势必不均匀的分布在钢筋表面,并且极化信号随着与CE距离的增加而减弱乃至消失,以致钢筋极化面积不能确定。本文从这一点出发,通过护环技术克服这一不足,即在普通三电极测量系统基础上添加一辅助电极护环电极(Guard Ring Electrode,简称GE),GE与CE均为环形并保持同心圆结构,GE的尺寸大于CE。该测量系统包含了CE极化电路和GE反馈极化电路,CE极化后,通过GE反馈极化电路补偿CE极化引起的RE2与RE3电位差变化值,使CE极化电力线主要分布在预定的CE下方钢筋表面积内。目前,该技术在国内试验研究很少,而国外较早的进行了研究,但是,它只是从混凝土表面进行了补偿测量,而对于不同的腐蚀体系,采用同样的补偿和极化面积,这是不合...
【英文摘要】
The electrochemistry method is applied to evaluate the corrosion of rebars in concrete for it is an electrochemical process. The method is employed successfully to detect the corrosion state and rate of rebars in test samples and has been used to monitor and detect the corrosion of steel in field recently. However, the three-electrode system is prone to result in non-uniform current distribution on the surface of rebars in detecting the corrosion rate of on-site large reinforced concrete because ...