Effect of Different Pre-exposure Loading on Chloride Penetration in Reinforced Concrete Specimens

In this study, the effect of various pre-exposure loadings on chloride penetration in concrete beams, reinforced with both normal black and epoxy-coated bars, was experimentally investigated. In-service static and fatigue loads (around 30–35% of the designed loading capacity) were applied to the RC beams before they were exposed to a designed chloride wetting/drying cycles, simulating the seawater attacks at the tidal zone, for about 1 year. At the end of the simulated seawater exposure, the chloride profiles in the uncracked and cracked concrete cover were measured. Apparent chloride diffusion coefficients and surface chloride concentrations were then estimated on the basis of the measured chloride profiles. Results indicated that the differences in initial concrete compaction, load-induced micro-cracks and visible cracks are the main factors affecting the chloride penetration and diffusion coefficients. Fatigue load-induced cracks resulted in increase in chloride penetration in specimens compared with those in unloaded and static loaded specimens with similar initial compaction.