Analytical Model for Load Dependence of Chloride Penetration into Concrete

摘要

The concrete permeability at low deformation of the chlorine ion is closely related to the porosity of concrete. Under stress, the porosity of concrete will change; at the same time, the chloride ion diffusion coefficient will also change. In this study, at the microscale, concrete was simplified as solid phase (zero porosity) and pore (the sum of various scales pores) of two phase composite materials. Based on the theory of elasticity, an analytical model was developed, and the quantitative relationship between the current porosity of concrete and the diffusion coefficient of the chloride ion, as well as the external equivalent stress, were evaluated. The primary parameters in the analytical model were the solid phase elastic moduli and the solid phase Poisson's ratio, the initial porosity of the concrete and the external equivalent stress. The good agreement between the proposed model and the available test data illustrated the proposed model's reliability and accuracy. The proposed model showed that the chloride diffusion coefficient or current porosity of concrete at low deformation levels decreases with the increase in compressive stress and increases with the increase in tensile stress. However, the initial porosity of concrete was still the primary factor influencing the chloride ion diffusion.