Mathematical Modeling of Transport Phenomena of Carbon Dioxide in Concrete Structures

Abstract

Concrete has a reputation as a “low tech” material, but it is actually very complex and worthy of study. It’s the most widely used construction material in the world. Carbonation process in concrete regularly involves a chemical reaction between carbon dioxide ( CO₂) and the products of cement hydration. By treating transport phenomena as a concrete carbonation process, this study presented a two-dimensional linear partial differential equation derived based on the principle of mass balance and convective-dispersive equation incorporating rate constant for zero-order production. We assume the diffusion coefficient of CO₂ in any direction of concrete is all the same. The analytical solution of the model is achieved by the eigenfunctions expansion technique. The results obtained are presented graphically and discussed. It is revealed that the relationships among CO₂ concentration, carbonation depth and time that can be used to state a carbonation transport phenomena in concrete structures are influenced by the diffusion coefficient.