Effect of GGBS on Mechanical Properties of Alkali-activated MSWIFA Vitrified Slags

Objective To prepare green and low-carbon alkali-activated cementitious materials and achieve the resource utilization of fly ash from waste incineration at the premise of environmental safety, Method the vitrified slag was used as the subject investigated, with Ground Granulated Blast Furnace Slag (GGBS) as the mineral admixture. Binding materials were prepared at the action of alkali activator, and the samples were tested for compressive strength. The reaction products were examined using XRD, SEM and other methods to analyze the reaction mechanism. The environmental safety was assessed through heavy metal leaching tests. Result Using sodium hydroxide as the alkaline activator, the compressive strength of the samples increased with the addition of mineral powder. The optimal alkali equivalence was 4%, and at a 30% GGBS mix, the 28 d compressive strength of the samples reached 56.34 MPa. The additon of GGBS facilitated the formation of flocculent C-S-H / C-A-S-H hydration products and AFm, which together formed a more stable spatial network structure. Additionally, the heavy metal leaching concentrations of the samples at various ages all met standard requirements. Conclusion Utilizing vitrified slag in the study of alkali-activated binding materials can achieve safe and effective utilization of MSWIFA.