Detection and Monitoring of Cracks in Reinforced Concrete Using an Elastic Sensing Skin

A sensing skin has been employed to detect and monitor cracks in reinforced concrete specimens. This sensing skin is constituted of a flexible electronic termed soft elastomeric (SEC) capacitor, which detects a change in strain through changes in capacitance. The SEC is a low cost and robust sensing technology that has previously been studied for the monitoring of fatigue cracks in steel bridges. The sensor is highly elastic and as such offers a unique capability to detect and monitor the growth of cracks in structural elements. In this study, an array of surface-deployed SECs was used to detect and locate bending-induced cracks. To validate the proposed approach, an experimental campaign was conducted using reinforced concrete beams. Three-point bending tests were conducted on two small-scale reinforced concrete beams. Different configurations of SEC arrays were used on the two specimens to assess the capacity and limitation of the proposed approach. Results show that the sensing skin was capable of detecting and localizing cracks that formed in both specimens. Additionally, the sensor is shown to offer a good signal-to-noise ratio and thus could represent a cost-effective alternative to current sensing technologies for the monitoring of cracks in concrete structures.