Study on the synergistic effect of calcium carbide residue -fly ash enhanced desulphurisation gypsum under high temperature maintenance condition

Abstract

The preparation of cementitious materials from bulk industrial solid waste is an effective way to replace cement. Based on the multi-component synergistic coupling effect, the influence law of different dosage of fly ash (FA) and calcium carbide residue (CCR) on the performance of flue-gas desulfurization gypsum (FGDG) slurry was investigated, and the hydration process of composite cementitious materials was discussed through the analysis of hydration products, micro morphology and pore structure by the characterisation methods such as XRD, FTIR, MIP and SEM-EDS. The results show that FA incorporation can improve the flow properties of the slurry, and under the action of CCR and FGDG, the alkalinity of the whole system rises, and the FA vitreous body undergoes dissolution corrosion, releasing reactive SiO2 and Al2O3, and forming C-S-H gel and AFt. In addition, some of the tiny FA particles fill up the pore spaces and microcracks, and the structure becomes denser, and all these effects together contribute to the development of the mechanical properties. This research is conducive to the application of new green cementitious materials and promotes the resourceful use of industrial solid waste.