Numerical Modeling of the Interface Between Old Concrete and Fiber-Reinforced Concrete

Abstract

For decades, Griffith's failure theory was the most suitable theoretical framework to explain the behaviour of a brittle or quasi-brittle material in fracture. With the advance of computing and numerical modelling, this approach began to present weaknesses, especially from a practical point of view, which had to be overcome. This is how improvements and new models appeared, such as the cohesive zone model, which led to better results, easier computational implementation, as well as a more appropriate way of representing the behaviour of an interface between two materials. However, there are still aspects of this behaviour that are not fully understood, and the contribution of new experimental and numerical results is of great relevance. In this sense, this work consists of developing an algorithm and implementing a numerical model that allows to evaluate the behavior of the interface between an old concrete and concrete and a fiber-reinforced concrete reinforcement by means of beam test simulation, using the cohesive zone approach at the interface with an exponential traction-separation law, and implemented by means of interface finite elements derived from an augmented Lagrangian functional. Finally, the results are compared with experimental tests for the validation of the model.