Impact of Lime Saturation Factor on Alite-Ye'Elimite Cement Synthesis and Hydration

Alite(C₃S)-Ye'elimite(C₄A₃$) cement is a high cementitious material that incorporates a precise proportion of ye'elimite into the ordinary Portland cement. The synthesis and hydration behavior of Alite-Ye'elimite clinker with different lime saturation factors were investigated. The clinkers were synthesized using a secondary thermal treatment process, and their compositions were characterized. The hydrated pastes were analyzed for their hydration products, pore structure, mechanical strength, and microstructure. The clinkers and hydration products were characterized using XRD, TG-DSC, SEM, and MIP analysis. The results showed that the Alite-Ye'elimite cement clinker with a lime saturation factor (KH) of 0.93, prepared through secondary heat treatment, contained 64.88% C₃S and 2.06% C₄A₃$. At this composition, the Alite-Ye'elimite cement clinker demonstrated the highest 28-day strength. The addition of SO₃ to the clinkers decreased the content of tricalcium aluminate (C₃A) and the ratio of Alite/Belite (C₃S/C₂S), resulting in a preference for belite formation. The pore structure of the hydrated pastes was also investigated, revealing a distribution of pore sizes ranging from 0.01 to 10 μm, with two peaks on each differential distribution curve corresponding to micron and sub-micron pores. The pore volume decreased from 0.22 ± 0.03 to 0.15 ± 0.18 cm³ g^-1, and the main peak of pore distribution shifted towards smaller sizes with increasing hydration time.