ABSTRACT
In this study, a novel method is proposed by coupling chemical kinetics and chemical thermodynamics to model the accelerated leaching of cement pastes in the ammonium nitrate solution. The chemical reactions of a number of major cement hydrates can be evaluated. A simplified PoissonNernst-Planck (PNP) model is employed to model the ionic diffusion in a gradually degraded material, and the Sequential Non-Iterative Approach (SNIA) is utilized to separate the simultaneous diffusion-reaction process. The proposed method is applied to model three types of cement pastes. The estimations of leached depths from the proposed method comply with the square root-time relationship and also agree well with the reported experiments (Kamali et al., 2008). The proposed method is considered to be more applicable in general comparing to the well-known solid-liquid equilibrium curve.
