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The substantial accumulation of solid waste poses serious environmental risks and resource depletion concerns, calling for effective treatment strategies. In this study, a novel green and low-carbon cementitious material entirely composed of solid wastes, denoted as SR-GGBS-PG, was developed by using soda residue (SR) and phosphogypsum (PG) as synergistic activators for ground granulated blast furnace slag (GGBS). The SR/GGBS ratio and PG content were systematically investigated to evaluate the paste's fluidity, setting time, pH value, and compressive strength. The hydration mechanism was elucidated through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET) analysis. When the mass ratio of SR, GGBS, and PG was 10:81:9, the 28-day compressive strength reached 46.15 MPa. This performance was attributed to the synergistic activation by SR and PG, which promoted the dissolution of Si⁴⁺ and Al³ ⁺ from GGBS and facilitated the formation of substantial C-(A)-S-H gel and ettringite (AFt). The macroscopic properties, mineral composition, and hydration products were comprehensively analyzed, and the hydration mechanism was illustrated with a schematic diagram. This work provides a valuable strategy for the high-value utilization of multiple solid wastes to develop sustainable construction materials. • An all-solid-waste SR-GGBS-PG binder was innovatively developed. • The compressive strength achieved 46.15 MPa at the optimal ratio. • Abundant C-(A)-S-H and AFt were generated under synergistic activation. • The dense microstructure significantly improved the performance.
Jiang et al. (Mon,) studied this question.