Flexural fatigue of pre-cracked plastic fibre reinforced concrete: experimental study and numerical modeling

The objective of this paper is to analyse the mechanical behaviour of polypropylene fibre reinforced concrete subjected to load cycles and propose a model to predict the crack-opening increase and mechanical performance evolution over the cycles. Fatigue tests were performed in pre-cracked specimens with two fibre types and contents to assess the evolution of the crack-opening for prescribed numbers of load cycles. The residual flexural tensile strength was assessed before and after these tests to estimate the impact of the cycles in the remaining resistant capacity of the specimens. Results suggest that the mechanism of crack propagation is independent of the fibre type and content. The accumulated damage due to the cycles produces an offset in the quasi-static residual tensile strength curve. These findings underpin the proposal of a model to predict the evolution of the crack-opening and the remaining resistant capacity. An optimisation procedure is proposed to derive the model parameters using a limited number of initial load cycles.