Quantitative determination of corrosion status of rebar by electrochemical parameters

Abstract

In this paper, the relationship between electrochemical parameters and corrosion status of rebar was analyzed by measuring macro-current and potential difference of self-made anode ladder monitoring system under different environmental conditions.Laboratory tests show that the anode ladder monitoring system can better judge the corrosion status of steel bars and provide a basis for structural durability evaluation and remaining life prediction. Reinforced concrete is the most widely used building material in engineering. The durability of reinforced concrete structure gradually declines under the long-term action of unfavorable factors in using environment. At present, there are many "models" for predicting the durability life of concrete published in the world, and more researches are being carried out. The most studied "model" is the "model" related to corrosion, especially the relationship between reinforcement corrosion and concrete durability, is the most common and in-depth research. The problem of durability of reinforced concrete structures caused by corrosion of reinforcing bar has been paid more and more attention in engineering field. Early detection and diagnosis of reinforcement corrosion is an important prerequisite for durability evaluation, remaining service life prediction and maintenance scheme selection of reinforced concrete structures.The development of accurate and reliable on-site monitoring technology of reinforcement corrosion has become the focus of scholars at home and abroad. In order to monitor the corrosion of reinforcement in concrete, some electrochemical parameters need to be measured by sensors. These electrochemical parameters include: potential distribution, macrocurrent, concrete resistance, and so on. Among them, the measurement of macrocurrent is a relatively simple and easy method, which has been widely used in the measurement of reinforcement corrosion. Using this method, in recent years, many countries have developed anodic sensor systems for monitoring reinforcement corrosion, a typical non-destructive monitoring system for the embedded durability of TRAPEZOIDAL anode ladder concrete structure is developed by the Institute of Civil Engineering, Aachen University of Technology, Germany, the corrosion degree and depth of steel bar in concrete can be measured for a long time by embedding steel bar sensors with different depths in concrete, which has been put into engineering application in many countries. In this paper, a self-made multi-group anode ladder monitoring system is designed in the laboratory. The corrosion status of each anode steel bar and the change of electrochemical parameters are obtained by using the method of half-cell potential test in the environmental solution of different concentrations, the criterion of electrochemical parameters to determine the corrosion status of rebar was obtained.