Service life of RC seawall under chloride invasion: A theoretical model incorporating convection-diffusion effect

Abstract

This paper presents a theoretical approach, which comprises the chloride transportation model and cover cracking model, to predict the service life of RC seawall under chloride invasion. The chloride transportation model combined the Fick's second law and Darcy's law to model the convection-diffusion of chloride ions in the RC seawall. The governing equation for chloride migration in the RC seawall is solved with the separation of variables technique. The proposed model is validated by comparing with a corresponding finite difference solution and the experimental results. The mechanical model that represents the cracking of the concrete cover induced by the expansion pressure of the corrosion products is finally developed to predict the service life of the RC seawall under chloride invasion. Parametric studies are performed to illustrate the effects of convection-diffusion and other key variables on the chloride ions transportation and service life of the RC seawall. The results reveal that the convection effect substantially accelerates the chloride penetration process in the chloride gradient descent direction while inhibits the penetration in the opposite direction. The proposed analytical solution in conjunction with the mechanical model provides a theoretical approach for predicting the service life of RC seawall, which can be used to aid durability design of coastal structures.