Meso-scale finite element analysis of FRP-to-concrete bond behavior

The interfacial behaviour between FRP and concrete is the key problem for the application of FRP to strengthen concrete structures. In this paper, a finite element (FE) model is presented for the debonding in FRP-concrete interface. In this model, concrete elements are connected with FRP elements directly without additional interface elements, so the debonding is modeled with fracture of concrete elements. Very small elements (0.25 mm to 0.5 mm in size, referred as meso-scale model) are used to simulate the crack propagation in the concrete layer adjacent to FRP. The effect of element size is considered in modeling the behavior of cracked concrete. Comparisons between the predictions of this model and test results are presented to demonstrate the capability and accuracy of this FE model. The debonding mechanism is also examined using results obtained with the FE model.