| Despite a substantial body of well-documented work in the literature, including diverse mathematical formulations as well as careful experimental assessments, there are yet many unresolved questions related to the hydration behavior of portland cement phases. For example, why does alite dissolution slow so abruptly seconds after contact with water? Is alite dissolution congruent? Why is the apparent rate of early hydration so insensitive to water to cement (water to C3S) ratio? What determines the length of the induction period? A robust modeling platform based on fundamental principles and through solution-phase kinetics is vital for testing various mechanistic hypotheses. The present study extends the recently introduced advanced continuumbased single particle model to include rigorous multi-ionic transport, non-linear equilibrium reaction kinetics and portlandite precipitation. The extended model also includes an Avramianbased representative volume, heterogeneous C-S-H nucleation and C3S surface coverage, and a two-step (densification) and growth process. Such a multi-constrained model is now not only able to capture the experimentally observed calorimetric hydration behavior, but also predicts the evolution of the corresponding pore solution chemistry. The model predictions are in good agreement with the available experimental results and predictions of other multi-physical modeling platforms. Finally, the single particle continuum model has PC-based run times measured in minutes, once again strongly emphasising the utility of the continuum-based approach as one tool among others for the elucidation of cement hydration processes. |
