Enhanced Model and Simulation of Hydration Process of Blast Furnace Slag in Blended Cement

A hydration model for cementitious materials was applied to slag blended cement. The original model was found to overestimate the hydration degree of slag, and the influence of the slag ratio on the hydration degree not to be well simulated either. The hydration mechanism of slag was investigated, considering the role of calcium hydroxide as activator and the Ca/Si ratio of C-S-H. It is assumed that for low Ca/Si ratio, the C-S-H inner product has a stronger resistance against ion diffusion and thus influences the hydration process significantly. Accordingly an enhanced model for slag hydration is proposed. Finally, the enhanced model is verified by both hydration degree and heat generation tests.