Simulations on Sulfate Ion Diffusivity in Concrete Column under Random Excitations

Abstract

This paper presents a 2-D nonlinear and non-steady equation for the diffusion reaction of sulfate ion in concrete column subjected to couplings of random excitations and sulfate attack. Taking the diffusion reaction of sulfate ion in concrete column as an example, the time-variation behaviors of the ion concentration and its diffusion coefficients under white noise excitations are numerically analyzed. The results show that with the increasing of diffusion time, the sulfate ion concentration in the concrete column section has a gradual increase to reach a plateau in which the diffusion and reaction is in dynamical equilibrium state. Under random excitations, the sulfate ion concentrations in the column section increase with the excitation amplitudes, and the sulfate ion diffusion coefficients in concrete change randomly with the excitations and increase with its amplitudes. This work will provide a basis for analyzing the diffusion reaction behaviors of the corrosive medium in concrete structure and the damage evolution of concrete structure durability.