ABSTRACT
Concrete cover spalling caused by reinforcement action is characterised by a pressure acting on the internal surface. The plasticity theory exhibits limitations when used for predicting the mechanical response during crack propagation since concrete exhibits tensile softening, which may be taken into account by implementation of so-called effectiveness factors. Therefore, this contribution proposes an analytical methodology with the goal of predicting post-peak softening until the concrete cover spalls. A continuum Finite Element model is used to analyse crack propagation, the kinematics of the system and the propagation of the principal tensile stress along the relevant cracks. Subsequently, an analytical model is developed, where cracks are explicitly considered following Bažant’s crack band theory, which propagate towards the surface. Stresses, strains and crack widths are defined according to the deformed state of the spalling concrete body. By expressing that the system should be in static equilibrium for all deformed states, the internally applied pressure is expressed as a function of the deformed state. Eventually, the pressure - displacement diagram is plotted and compared with experimental results from the literature. It is shown that the peak pressure can be reasonably well predicted and that it is possible to capture post-peak softening by applying simple methodologies. Further improvements are possible to be explored in future work.
