Damage monitoring of concrete laminated interface using piezoelectric-based smart aggregate

To reduce the risk in the integrity and safety of concrete composite structures (CCS), a monitoring approach was developed by using piezoelectric-based smart aggregates (SAs) and an evaluation method with the damage extent (D-c) of crack was proposed based on the energy attenuation of stress wave. A two-phase monitoring approach was presented firstly, and then two experiments and a numerical simulation were carried out to validate the approach proposed. More specifically, a push-out experiment was conducted with the active sensing approach on the laminated interface, and the results show that with the increase of loading, the signal energy attenuation index (DI) increases continuously. At the phase of damage initiation, there exists an alternative impact by the crack length and crack depth, and almost no slippage appeared on concrete prisms; subsequently, the crack width holds the dominant position in the phase of crack evolution, and the slippage rises rapidly; lastly, the components of composite structures completely debond at the failure phase. In addition, based on a combination of artificial cracks experiment and numerical simulation analysis, the debonding and damage behavior of the laminated interface were figured out. A correlation equation of damage extent and energy attenuation index was derived. The results show that the proposed damage index can effectively detect the existence and severity of crack on the concrete laminated interface. This indicates that the approach proposed is applicable to monitor the occurrence and evolution of crack damage and predict crack extent on the laminated interface.