Numerical and experimental research on the effect of rainfall on the transporting behavior of chloride ions in concrete.

• The humid environment with different rainfall times and rainfall intensity was simulated in the laboratory. • The surface chloride contents showed decreasing trends and were strongly affected by the rainfall parameters. • The convection zone depth and peak chloride ion concentration in chloride profiles was studied. • Numerical simulation of chloride transportation in the humid environment with rainfall was conducted. • A prediction model for chloride transportation under different rainfall parameters was proposed. Reinforced Concrete (RC) structures eroded by chloride ions will reduce the chloride ion concentration on the concrete surface under the effect of sustained rainfall dilution and erosion, and there will be rainfall convection areas and peak chloride ion contents. In this study, the influence of rainfall environment on the transporting behavior of chloride ions in concrete is studied through capillary absorption test and rainfall experiment. A numerical prediction model of chloride ion transporting behavior in concrete was established by COMSOL Multiphysics based on the rainfall tests. The chloride behavior is analyzed and studied. It is found that the numerical simulation results are in good agreement with the experimental results, and the predicted models of chloride ion diffusion under different rainfall conditions are obtained, and the transporting behavior of chloride ions can be effectively predicted. The results also show that with the increasing of rainfall intensity and rainfall time, the chloride ion contents on the concrete surface decreases obviously. When the rainfall time and rainfall intensity increase, the chloride ion contents of concrete decreases, and the binding capacity of chloride ions in the matrix weakens. This research provides some resulting information of RC structures in rainy marine areas. [ABSTRACT FROM AUTHOR]