Embeddable corrosion rate‐measuring sensor for assessing the corrosion risk of steel in concrete structures
Embeddable corrosion rate‐measuring sensor for assessing the corrosion risk of steel in concrete structures
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DOI：
10.1002/stc.262
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发表时间：
2009-06
影响因子：
5.4
通讯作者：
R. Vedalakshmi;H. Dolli;N. Palaniswamy
中科院分区：
文献类型：
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作者：
R. Vedalakshmi;H. Dolli;N. Palaniswamy
新建和修复的混凝土结构需要更精确地评估钢筋的腐蚀速率（CR），以确保防腐效果。为了评估腐蚀状态，已经开发了不同的传感器来降低未被检测到的腐蚀问题的风险。在建造新结构时，可嵌入的CR -测量传感器要么嵌入在靠近杆的地方，要么嵌入在旧结构的钻孔中，以便产生可靠的数据。通过与其他常规电极布置方式的比较，评价了嵌入式传感器预测腐蚀电流（Icorr）的准确性。在钢筋被动和主动两种工况下进行了Icorr评价。还研究了横杆的存在和覆盖对Icorr的影响。采用线性极化电阻（LPR）技术和电化学阻抗谱（EIS）技术测定了CR，并与失重法进行了比较。结果表明，利用电化学阻抗技术，所研制的嵌入式传感器能与重量法测得的CR非常接近。由于与理想线性曲线的偏差和混凝土中钢的界面电容较大，导致LPR法低估了钢筋的CR。在钢筋处于被动状态时，横杆的存在使主杆的Icorr增加了4倍，而在钢筋处于主动状态时则没有效果。嵌入式传感器虽然具有较小的对电极（CE），但在主动和被动状态下，极化钢筋的长度都是对电极长度的2倍。版权所有©2008 John Wiley & Sons， Ltd
New and rehabilitated concrete structures need assessment of corrosion rate (CR) of rebars more precisely to ensure efficiency of protection against corrosion. For assessing the corrosion status, different sensors have been developed to reduce the risk of undetected corrosion problems. An embeddable CR‐measuring sensor is embedded either closer to the rod during the construction of a new structure or in drilled holes in old structures so as to generate reliable data. In the present paper, the accuracy in predicting the corrosion current (Icorr) by embeddable sensor was assessed by comparing with other conventional electrode arrangements. Icorr was assessed under passive and active conditions of rebar. The presence of a cross bar and the effect of cover on Icorr were also studied. Using linear polarization resistance (LPR) technique and electrochemical impedance spectroscopic (EIS) technique, the CR was determined and compared with the weight‐loss method. Results concluded that by using electrochemical impedance technique, developed embeddable sensor is able to predict the CR very close to the CR determined from gravimetric method. The deviation from an ideal linear curve and the higher interfacial capacitance of steel in concrete caused the LPR method to underestimate the CR of rebar. The presence of the cross bar increases the Icorr of the main bar by 4 times in a passive state of the rebar and it has no effect if the rebar is in an active state. The embedded sensor, though having smaller counter electrode (CE), polarizes the rebar up to 2 times the length of CE under both active and passive states. Copyright © 2008 John Wiley & Sons, Ltd.