Numerical Simulations of Chloride Transport in Concrete Considering Connectivity of Chloride Migration Channels in Unsaturated Pores

Abstract

This study aimed to develop a method for the reasonable prediction of chloride ingress into concrete under unsaturated conditions. To achieve this, the connectivity of both the pore networks and the water paths in hardened cement paste were investigated and modeled in the existing numerical analytical system. Previous measurement results for the continuous porosity in hardened cement paste were reorganized, and the relationship between the total porosity and continuous porosity was clarified and formulated as the pore connectivity. In addition, the connectivity of the liquid water in unsaturated pore structures was formulated referring to previous numerical studies, suggesting that the connectivity of the liquid water decreases at a lower degree of saturation. Furthermore, by calculating the chloride transport considering the pore connectivity and the liquid water connectivity under unsaturated conditions, the chloride penetration into unsaturated concrete, including an airborne chloride environment, could be reproduced more realistically than was previously possible.