Chloride Penetration in Reinforced Concrete Beams under Combined Sustained Loading and Drying–Wetting Cycles

Abstract

In this paper, the spatial and time-variant chloride distribution in RC beams subjected to combined sustained flexural loads and cyclic drying–wetting action is studied. By means of the digital image correlation (DIC) technique, the distribution and evolution of load-induced damage and cracks in beam specimens during four-point bending are mapped and quantified using a damage factor. The influence of damage and cracks on the chloride resistance of beams is elucidated and a numerical model to reproduce the chloride penetration in precracked beams is proposed. The results show that the concrete in the pure bending zone of the beam has the highest rates of chloride ingress and reinforcement corrosion activity, followed by those in the support zone and combined shear-flexure zone. The regression analysis suggests that the apparent chloride diffusion coefficient of concrete increases exponentially, while the corrosion current density increases linearly, with the increasing magnitude of loads applied on the beams. The proposed model can reasonably predict the chloride profiles across the entire RC beams.