Modeling of Ph Profile in Pore Water Based on Mass Transport and Chemical Equilibrium Theory

The authors present a computational system that can deal with pH fluctuations and the decomposition of cementitious materials exposed to various environmental actions. In order to evaluate the fall in pH due to carbon dioxide, material models are developed for the transport and equilibrium of carbon dioxide, ionization, ion equilibriums, and the carbonation reaction based on thermo-dynamic theory. The material properties of concrete are evaluated by considering the inter-relationships among hydration, moisture transport, and pore-structure development based on fundamental physical material models. The proposed system is able to reasonably predict the carbonation phenomena and pH profiles in concrete for arbitrary conditions.