Calculation of chloride ion diffusion in glass and polypropylene fiber-reinforced concrete

Abstract A numerical model was proposed to predict the diffusion of chloride ions into fiber-reinforced concrete. The permeability of fiber-reinforced concrete was calculated as function of total porosity, which considered the interfacial transition zone voids around aggregate and fibers as well as the connection between voids due to the addition of fibers. Based on Fick's second law, a diffusion model for chloride ions was established and solved by the finite difference method. The chloride ion diffusion tests of glass fiber, polypropylene fiber, and hybrid fiber-reinforced concrete was conducted, these experimental results and collected test data were used to validate the numerical model. Finally, the sensitivity of the numerical model was analyzed, and the results indicated that the four factors, including fiber diameter, volume fraction of fibers, aggregate diameter and volume fraction of aggregates, significantly influence the process of chloride diffusion in fiber-reinforced concrete.