Effect of External Loads on Chloride Transport in Concrete

Abstract

Although the ingress of chloride into concrete is normally controlled by absorption and diffusion mechanisms, external loads can affect this process by modifying the microstructure of concrete. To predict the chloride ingress into real structures under service conditions, the effects of external loads on the chloride transport should be considered. In this paper, the effects of compressive and flexural loads on chloride transport were studied. The experimental results indicated that the chloride concentration and apparent chloride diffusion coefficient Dapp decreased with the increase of the compressive stress, up to 55% of the compressive strength, and they increased with the increase of the flexural stress. On the basis of these results, a model for predicting the chloride diffusion process under different loading conditions is established by accounting for various parameters, such as stress level, water-cement ratio, curing time, temperature, concrete age, humidity, and chloride diffusion coefficient. The validation of the proposed model indicated good correlation between the predicted chloride diffusion coefficients and the experimental results.