Synthesis of alite, belite and ferrite in both monophase and polyphase states and their hydration behavior

Understanding the synthesis process of Portland cement's various mineral phases and the phase interactions during hydration is highly critical for the design and optimization of cement-based materials. In this work, by using an optimized solid-state reaction method, three pure clinker phases (alite, belite and ferrite) and two polyphase phases (alite-belite and alite-ferrite-belite) of Portland cement were synthesized. The optimized method is featured with high-quality product yield, short burning time without regrinding or reburning. The factors that influence synthesis results, such as crystallinity/purity of the synthesized pure phases, were discussed based on X-ray powder diffraction (XRD) tests along with Rietveld refinement analysis with an external standard. The hydration behavior of the synthesized phases in monophase, polyphase as well as mixture states was investigated via isothermal calorimetry along with thermogravimetry and XRD. The results indicate that alite and belite have relatively little interactions during hydration, while the hydration rate of ferrite can be strongly inhibited in the presence of alite both in mixture and polyphase states.