Comprehensive evaluation of low-carbon cementitious materials prepared with industrial by-product calcium carbide residue (CCR) as alkali source.

The preparation of low-carbon cementitious materials through the synergistic coupling of multiple solid wastes has great potential for development, which can improve the problems of resource shortage and environmental pollution. In this paper, a new type of supersulfated cement was developed by using calcium carbide residue (CCR) as an alkaline activator. The effects of CCR content on the mechanical properties and hydration behaviors of the samples under steam curing conditions were discussed. The reaction process of the samples was analyzed by means of pH value, XRD and FTIR, TG and SEM-EDS, and the mechanism of CCR-flue gas desulfurization gypsum (FGDG) synergistic activation of ground granulated blast furnace slag (GGBS) was elucidated. The results show that the incorporation of CCR provides an alkaline environment, and the reactivity of GGBS is improved, which promotes the formation of more cementitious hydration products, and the microstructure is more compact, which has a greater contribution to the development of strength. In addition, the appropriate amount of CCR can reduce the Ca/(Si + Al) and (Ca + S)/(Si + Al) ratios and increase the degree of polymerization of C-(A)-S-H. The results of this study provide a green solution for the large-scale, high-value and resource utilization of industrial solid waste, which is of great significance for achieving carbon peak and carbon neutralization.