Effect of fly ash and sustained uniaxial compressive loading on chloride diffusion in concrete

For the structures exposed to marine environment, the corrosion of rebar is mainly controlled by the chloride diffusion process. Meanwhile, the presence of compressive stress generally disturbs the process. This investigation intends to inspect the chloride diffusion in fly ash concrete (FAC) under sustained uniaxial compressive loads using a new testing method. The results pointed out that when FA content was no more than 30%, the chloride ion concentration decreased with increasing of FA replacement, and the relationship presented no consequential modification with a deviation of compressive stress. When stress ratio (λσ) was less than 0.6, the chloride diffusivity (DCl) decreased with an increase in FA replacement. The increase of compressive stress resulted in a consequence that the chloride diffusivity decreased first and then increased, and the curve fitting results demonstrated that chloride diffusivity and stress ratio conformed to a quadratic parabola relationship in fly ash concrete. •A new testing method for examining the diffusion mechanism was proposed.•The effect of fly ash content on chloride diffusion was investigated.•The effect of different external loads on chloride diffusion in fly ash concrete was included.