Coupling performance of the interface between sensor and concrete by the double shear method

The rupture of sensor packaging shells and debonding at the interface between the embedded sensors and the surrounding concrete are considered as the primary causes of signal interruption in the structural health monitoring of infrastructure. Ensuring the coupling performance between the embedded sensor and the surrounding concrete is crucial for the long-term structural health monitoring. To investigate the coupling performance of the interface between the sensor and the surrounding concrete, a new interface double shear test device is designed and manufactured. Factors considered in the study include the sensor packaging materials (304 stainless steel, glass fiber reinforced nylon), whether the interface is coated with epoxy adhesive sand or not, the coating density of epoxy adhesive sand, and the water-to-cement ratio of the matrix concrete (w/c ratio = 0.3, 0.4, 0.5). The load-slip curves, interfacial shear strength, and slip value at the peak load are systematically analyzed. A comparative analysis of the failure modes and failure morphology of specimens is also conducted. The shear bonding mechanism between the sensor and the matrix concrete is revealed, and an interfacial coupling model is established. The research findings can provide reference and guidance for optimizing the design of embedded sensor packaging, improving packaging processes, and enhancing interface coupling, thus achieving the long-term accurate monitoring of infrastructure.