Reactive Transport Modeling of CO2 through Cementitious Materials under CO2 Geological Storage Conditions

摘要

We propose a modeling able to predict the behavior of water-saturated cement-based materials in contact with a CO2 saturated aqueous solution. The presence of CaCO3 and Ca(OH)2 is determined from the mass action laws related to each solid compound. An ideal solid solution model is employed to explain the continuous decalcification of the calcium silicate hydrates (C-S-H). The changes in porosity and microstructure induced by the precipitation-dissolution of the various solid compounds are also taken into account. Aqueous species are added and their concentration is determined by considering the reactions at equilibrium. The transport of these species is taken into account by considering the Nernst-Plank equation. The coupling between the transport equations and the chemical reactions is treated thanks to several mass balance equations written for each atom. The model is implemented within a finite-volume code. Some simulations illustrating some carbonation fronts and porosity profiles are presented and compared with experimental results taken from the literature.