Combined effect of water and sustained compressive loading on chloride penetration into concrete

Abstract

This paper presents the results of an experimental investigation on the water and chloride transport properties of unsaturated concrete under combined short-term sustained compressive loading and chloride attack. Aiming for the coupled effect of sustained compressive loading and chloride penetration, an improved test apparatus, which is compared with the traditional gravimetric measurement, was designed to real-timely and continuously measure the amount of water solution absorbed by the cylindrical hollow concrete specimen under sustained loading. A series of chloride transport experiments on water/chloride diffusivity and penetration profiles of chloride were conducted on the saturated, half-saturated and fully dried concrete respectively subjected to several compressive stress levels (ranging in 0–50% of the corresponding compression loading capacity). The experimental results showed that the saturation level and sustained compressive loadings have significant influences on water and chloride transport properties of the unsaturated concrete. The quantitative relationship between water/chloride diffusivity and compressive stress level was developed by fitting the obtained experimental data. Finally, on the basis of convection-diffusion equation, the prediction model of chloride transport in unsaturated concrete under sustained compressive loading was proposed and validated by the experimental results. The comparison of chloride profiles indicates that the numerical results were in good agreement with the experimental measurements.