ANALYSIS OF OLD STRUCTURES AND NUMERICAL MODEL FOR DEGRADATION OF CALCIUM ION LEACHING FROM CONCRETE

Abstract

This paper describes the evaluation of degradation by the calcium ion leaching from concrete. Numerical model to predict the degradation of calcium leaching is constructed by the chemical equilibrium of calcium, movement analysis of diffusion and advection, and the change of mechanical properties and porosity.
From the comparison of the results of numerical simulation and the results of investigation for thirty-year through one-hundred-year old actual structures, it was concluded that the developed model could satisfactorily express the fundamental degradation mechanisms. And it was found that the water to cement ratio and calcium ion concentration at the boundary had large effect on the degradation speed.