Study on the system of calcined desulfurization gypsum - aluminate cement - slag powder cement

In this study, by adding a small amount of calcined desulfurization gypsum and aluminate cement into slag powder cement, the effects of calcined desulfurization gypsum and aluminate cement on the flowability, mechanical properties and volume stability of the composite cementitious system were studied. The results show that the mechanical properties and volume stability of the composite cementitious system can be improved by adding appropriate amount of calcined desulfurization gypsum and aluminate cement. For example, when the ratio of sulfur to aluminum is 0.5:1, the compressive strengths of calcined desulfurization gypsum-aluminate cement-slag powder cement composite cementitious system increases by 34% in 1 day, 8% in 180 days, the free expansion rates are less than 0.6%, and the expansion stresses are less than tensile strengths. The volumes are stable. The hydration products of the system mainly include AFt, Ca(OH)2 and C-S-H. During the hydration process, some of the calcined desulfurization gypsum will be converted into dihydrate desulfurization gypsum.