Sacrificial Elements for Corrosion Detection in Reinforced Concrete

A new class of wireless threshold sensors that use sacrificial elements to detect corrosion in concrete was developed at The University of Texas at Austin. The sensor is embedded in concrete, where it is exposed to the same environment affecting steel reinforcement. Corrosion of the sacrificial element (transducer) alters the sensor response, indicating corrosion activity. Hence, the reliability of the corrosion sensor depends on the selection of a sacrificial element that exhibits the same corrosion tendencies as the steel reinforcement being monitored. This study evaluates the corrosion performance of the sacrificial element in chloride-contaminated and carbonated concrete pore solutions. Cyclic potentiodynamic polarization tests were used to compare the performance of cold-rolled steel sacrificial elements and reinforcing bar samples under the same exposure conditions. The results demonstrate that the selected sacrificial elements exhibit the same electrochemical characteristics as steel reinforcement in different concrete environments. These sacrificial elements can be used for reliable early detection of corrosion activity in concrete.