Synthesis and calorimetric study of hydration behavior of sulfate-rich belite sulfoaluminate cements with different phase compositions

Sulfate-rich belite sulfoaluminate (BSA) cements with varied phase compositions were synthesized in this work. The presence of sulfate in the clinker is in the form of anhydrite in addition to calcium sulfoaluminate. The aim of this paper is to study the effect of mineral composition on cement properties. Experimental results indicate that the improvement of early-age strengths mainly depends on the hydration of ye'elimite. The increase of ferrite content promotes the compressive strength after 7 days of hardening, but has adverse effect on cement strength at early ages. The optimum content of ferrite is between 10 and 20% for BSA cement containing approximately 35% ye'elimite. Different amounts of natural gypsum were added to the synthetic sulfate-rich BSA clinkers and we found that anhydrite formed in BSA clinkers can replace natural gypsum to facilitate the hydration of ye'elimite.