Study on the influence mechanism of flue gas desulphurisation gypsum on solid waste-based geopolymer grouting materials

Solid waste-based geopolymer grouting materials were prepared using fly ash, calcium carbide slag, and flue gas desulphurisation gypsum as the main raw materials. The effect of desulphurisation gypsum dried at different temperatures on the performance of the solid waste-based geopolymer grouting materials was explored. The mechanical properties, phase composition, and microstructure of the grouting materials were determined using a universal testing machine, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The results show that flue gas desulphurisation gypsum dried at 120 °C generated more whiskers. The mechanical properties of the solid waste-based geopolymer grouting materials prepared by drying flue gas desulphurisation gypsum at 120 °C were significantly improved, and the compressive strength was increased by more than 11%, thereby promoting the hydration reaction of the system and generating over 3% of the hydration products.