A theoretical model of sulfuration depth of concrete based on SO2 reaction and mass balance

Industrial production emits a large amount of SO2, and the alkaline environment of pore solution of concrete is destroyed by the reaction of SO2 and Ca(OH)2. This process, called sulfuration of concrete, decreases the pore-solution pH and causes the damage of concrete cover and corrosion of rebar. In this paper, the sulfuration reaction process of concrete is presented, and the mass balance equations of SO2 and sulfurable substances are established. Some important parameters are discussed in the mathematical model. The formation rates, content and sulfuration rates of sulfurable substances, the consumption rate of SO2, as well as the porosity and pore saturation of concrete are analysed. A calculation method of SO2 diffusion coefficient is proposed. The initial conditions and boundary conditions of the model are determined, and the prediction model of sulfuration depth of concrete is obtained by using the dimensionless method. The accuracy of the model of concrete sulfuration depth is verified by comparing the calculated results and experimental results obtained from previous studies.