System for Continuous Monitoring of the Corrosion Rate in Concrete Reinforcement based on Bimetallic Batch Sensors

Abstract—A preproduction model (prototype) of a system for continuous monitoring of the corrosion rate of steel reinforcement in reinforced concrete structures based on bimetallic batch sensors built in concrete down to the depth of coverage of the reinforcement has been developed. The proposed prototype of the system also included a portable computer, an analog–digital converter, an electronic time relay, and an ammeter with "zero" resistance. A long-term testing (for ~800 days) of the system with continuous data recording was successfully carried out in the laboratory. The optimal parameters of data collection (duration of one measurement, frequency of measurements) have been determined at different levels of sample contamination with chlorides and the current value at the sensor. It has been shown that the suggested device enables one to identify reliably an increase of the corrosion rate of steel under a layer of concrete as a result of its depassivation due to the penetration of chlorides from the environment. The ability of the sensor to record the current value of a galvanic pair modeling the process of reinforcement corrosion for a long time (both at high and low concentrations of chloride ions) has been demonstrated. The ways of improving the system aimed at reducing the cost, energy consumption, ensuring autonomous operation, and remote data transmission have been suggested. The prospects of application at the objects of industrial and civil construction and transport infrastructure have been discussed.