Numerical modeling of concrete carbonation under wide range of environmental conditions

Abstract

A new mathematical model for carbonation of concrete is proposed in this study. This model can cover many parameters affecting the carbonation rate of concrete. The input data for this model include chemical composition, physical properties and mineral characteristics of Portland cement and mineral admixtures, water/cement ratio, aggregate/cement ratio, maximum aggregate size, curing condition (period, temperature, relative humidity), preconditioning (period, temperature), CO2 concentration, exposure time and the ambient conditions. The output of this model is depth of carbonation after defined period of time. A new model for the prediction of degree of pozzolanic activity of mineral admixtures has been proposed and studied in this work. Also the effect of crack on increasing the rate of carbonation of concrete has been considered. To verify the effect of preconditioning and mineral admixtures on saturation degree and drying rate, an experimental work was done and by monitoring the total weight loss during drying-wetting process, the drying rate and final saturation degree of concrete with various mix proportions were studied. The pore structure of concrete with various mix proportions and in various conditions was also studied by using mercury intrusion porosimeter (MIP).