Effect of different types of gypsum in steel slag-cement systems
WU Binbin
HE Tingshu
MA Xiaodong
CHENG Fuan
DA Yongqi
GUO Keyu
HU Menglong
Abstract：To address the issues of low reactivity and low resource utilization efficiency of steel slag,while overcoming the high cost associated with traditional chemical activators,this study employs low-cost solid waste as an activator.It specifically in-vestigates the effects of three types of desulfurization gypsum(dihydrate gypsum,hemihydrate gypsum,and anhydrite)on the hydra-tion behavior of a steel slag-cement system.The investigation included tests of compressive strength,setting time,compatibility with admixtures,and rheological properties,supplemented by microstructural analysis using XRD and TG-DSC.The results demonstrate that all three gypsum types significantly enhance the compressive strength of the steel slag-cement system.The 28-day activity in-dices were 90%for dihydrate gypsum,89%for anhydrite,and 86%for hemihydrate gypsum.Furthermore,the gypsums extended the setting time,improved compatibility with the superplasticizer,and reduced the system's viscosity and thixotropy.The underlying mechanism involves the SO42-ions released by the dissolution of gypsum reacting with Al3+and Ca2+ions in the system to form et-tringite(AFt),which accelerates the hydration process and consequently improves the performance of the steel slag-cement system.
Keywords：gypsum typesteel slaghydration characteristicsrheological propertiesettringite
Publication Date：2025-11-25
Online Publishing Date：2025-12-15(First online date of this platform, not the publication date of the document)
Pages：7( 100-106 )