Theoretical and experimental investigation of loading effects on chloride diffusion in saturated concrete

Abstract

In this paper, a comprehensive investigation regarding the loading effects on chloride diffusion in saturated concrete is reported. It involves both theoretical and experimental aspects, towards contributing to the service-life prediction of infrastructure under chloride attack. A revised chloride diffusion model is proposed based on the modified Fick's second law with an emphasis on the loading effects. In particular, this influence is quantified using a newly-introduced damage effect factor defined by tortuosity and constrictivity of damaged concrete. This model is capable of predicting the chloride profiles in concrete under different loading states, regardless of whether it is damaged or undamaged. Meanwhile, a series of experimental studies were extensively operated in order to analyze the influence of loading on chloride diffusion process. Two types of mixtures (i.e. ordinary concrete and ordinary concrete mixed with slag) were investigated for chloride diffusion tests under different natures (i.e. compressive and tensile loads) and magnitudes of loads. Totally four levels of loads were applied to further correlate the relation between chloride diffusivities and associated strain values. Finally, two groups of test data with different tensile strain were adopted to validate the theoretical model. It shows that the model is reasonable and the numerical result is adequately accurate.