Diffusion Resistance to Two Opposite-Side Chloride Ions of Concrete Based on the Diffusion Constant

Abstract

A new theoretical calculation method for the two opposite-side chloride diffusions was established, which is different from traditional diffusion calculations and the value-taking rule of error function. A new parameter, δ, a diffuse constant of the object being diffused, is proposed to reflect the internal diffusion characteristics of the object, and the concrete studied in this paper has a δ value between 2 and 3—closer to 3. By performing comparison experiments with a stronger effect of superposition and accumulation in concrete under two opposite-side chloride ion, diffusion can be found, which is consistent with the calculation results. In order to improve the resistance of concrete to two opposite-side chloride codiffusion, the concrete modified by nanosilica and nanotitania was designed in this study. Due to its excellent microstructure and porosity properties, the concrete modified by nanosilica at 1.5% and nanotitania at 0.5% cement weight showed an excellent resistance to the single-side chloride ion diffusion, and the same goes for two opposite-side diffusions.