Theoretical analysis of the measurement of polarisation resistance in reinforced concrete
Theoretical analysis of the measurement of polarisation resistance in reinforced concrete
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DOI：
10.1016/s0958-9465(00)00040-8
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发表时间：
2000-12-01
影响因子：
10.5
通讯作者：
Song, GL
中科院分区：
文献类型：
--
作者：
Song, GL
基于Stern-Geary方程的极化电阻（R-p）技术是现场测量钢筋腐蚀速率最常用的方法之一。借助于“传感保护环”，这种电化学技术据称能够确定给定测量区域内的腐蚀速率（I-corr）。然而，该技术在应用中存在三个理论问题：（1）原始Stern-Geary方程适用于均匀腐蚀体系的腐蚀电位，而钢筋混凝土结构可能受到宏电池电偶效应或外加电流的非均匀腐蚀或强极化;（2）估计原始Stern-Geary方程中的参数B的值落在25-52 mV的范围内。这可能不适用于所有的钢筋混凝土结构的腐蚀情况;（3）当保护层混凝土太厚时，钢的极化表面区域理论上可能不总是被传感保护环完全限制。在一般条件下，推导出钢筋溶解速率与极化电阻测量值之间的一般关系。根据钢筋混凝土可能出现的各种腐蚀情况，分析了B值的取值范围。此外，不令人满意的限制传感器保护环上的厚盖混凝土被证明。(C)2000爱思唯尔科技有限公司版权所有。
Polarisation resistance (R-p) technique based on Stern-Geary equation is one of the most widely used methods of measuring corrosion rate of reinforcement in the field. With the aid of a "sensorised guard ring", this electrochemical technique is claimed to be able to determine corrosion rate (I-corr) within a given measuring area. However, there are three theoretical problems in the application of this technique: (1) the original Stern-Geary equation is applicable in a uniform corrosion system at its corrosion potential, whereas the reinforced concrete structure may be subjected to non-uniform corrosion or strong polarisation by macro-cell galvanic effects or imposed currents; (2) the value of the parameter B in the original Stern-Geary equation has been estimated to fall within the range 25-52 mV. This may not be suitable for all the corrosion cases of reinforced concrete structures; (3) The polarised surface area of steel may theoretically not always be fully confined by the sensorised guard ring when the cover concrete is too thick.This paper aims at discussing the theoretical problems. A general relationship between the dissolution rate of steel reinforcement and the measured polarisation resistance is deduced under general conditions. The range of B value is also analysed based on all the possible corrosion situations of reinforced concrete. Furthermore, unsatisfactory confinement by sensorised guard ring on a thick cover concrete is demonstrated. (C) 2000 Elsevier Science Ltd. All rights reserved.