ConcrEITS: An Electrical Impedance Interrogator for Concrete Damage Detection Using Self-Sensing Repairs

Abstract

Concrete infrastructure requires continuous monitoring to ensure any new damage or repair failures are detected promptly. A cost-effective combination of monitoring and maintenance would be highly beneficial in the rehabilitation of existing infrastructure. Alkali-activated materials have been used as concrete repairs and as sensing elements for temperature, moisture, and chlorides. However, damage detection using self-sensing repairs has yet to be demonstrated, and commercial interrogation solutions are expensive. Here, we present the design of a low-cost tomographic impedance interrogator, denoted the “ConcrEITS”, capable of crack detection and location in concrete using conductive repair patches. Results show that for pure material blocks ConcrEITS is capable of measuring 4-probe impedance with a root mean square error of ±5.4% when compared to a commercially available device. For tomographic measurements, ConcrEITS is able to detect and locate cracks in patches adhered to small concrete beam samples undergoing 4-point bending. In all six samples tested, crack locations were clearly identified by the contour images gained from tomographic reconstruction. Overall, this system shows promise as a cost-effective combined solution for monitoring and maintenance of concrete infrastructure. We believe further up-scaled testing should follow this research before implementing the technology in a field trial.

Strain Monitoring of Concrete Using Carbon Black-Based Smart Coatings

“…Cement-based sensing coatings, on the other hand, boast a simpler installation process and can operate with cost-effective electrical devices. Moreover, these coatings achieve a greater interaction with the substrate as well as higher flexibility in monitoring as they are capable of pivoting from strain-sensing [97] to damage-sensing and tomography applications [98]. Lastly, beyond their sensing capabilities, cementitious coatings can also serve as an effective retrofitting solution for structural or non-structural repairs [99].…”

Self-Sensing Rubber for Bridge Bearing Monitoring

“…Another approach for characterizing the electrical properties of the rubber compounds would be by assessing the electrical impedance, which can be achieved by applying an alternating current (ac) potential and then measuring the phase and amplitude ac voltage response current, which carries more information on the system. In particular, the impedance is a combination of the resistance and of the reactance, which measures the opposition of the system to changes in electric current [ 32 ].…”