Experimental study of the in-situ fabrication of strain sensor with conductive adhesive to monitor the concrete structure

Conventional strain sensors typically had a limited detection area and the fragility of the sensor-concrete interface. This study proposed an in-situ sensor fabrication technique using conductive epoxy adhesive to fabricate strain sensors in the concrete. The performance of the strain sensors was systematically evaluated, resulting in the conductive adhesive strain sensor exhibiting excellent linearity, sensitivity, low zero drift, and minimal hysteresis. There was a positive impact on strain sensor linearity and sensitivity through the increase in the length of the conductive adhesive. The resistance change rate in the sensors accelerated with increasing temperature, establishing a functional relationship between resistance change rate and temperature. The sensors exhibited excellent linearity and sensitivity with strain, and all the fitted data points were within the 95 % confidence interval. Furthermore, the microscopic characterization revealed that the in-situ fabricated sensors exhibited excellent adhesion to the cement composite, demonstrating favorable working performance in the cement-based environment.