• A 28-day compressive strength of 32.804 MPa was achieved using 50 wt% MMS, 40 wt% CFS, and 10 wt% MP.
• The alkali-activated system produces abundant C-S(A)-H gels and AFt phases that refine the pore structure and boost mechanical performance.
• A synergistic reaction between CFS-MP and MMS occurs in high-alkalinity environments, accelerating MMS hydrolysis.
• Controlling MMS dosage is critical to avoid incomplete depolymerization-repolymerization of active silica-aluminum wastes, which can reduce late strength.