This study utilizes polymers based on coal gangue and blast furnace slag to solidify engineering slurry with high silt content. Response surface methodology was employed to investigate the effects of polymer composition, alkali activator modulus, and coal gangue calcination temperature on the unconfined compressive strength of stabilized soil. Additionally, the study comprehensively characterized the thermal stability, pore structure, molecular bonds, mineral composition, and micro-morphology of the stabilized soils, and explored the mechanisms governing their strength development. The results demonstrate that the highest strength of stabilized soils is achieved with a slag to coal gangue ratio of 2.5:7.5, a water glass modulus of 1.2, and a coal gangue calcination temperature of 750 degrees C. Formation of calcium-aluminum-silicate-hydrate (C-A-S-H) and sodium-aluminum-silicate-hydrate (N-A-S-H) contributes significantly to the strength development. The presence of slag promotes early strength through C-A-S-H formation, while coal gangue facilitates N-A-S-H formation, supporting later-stage strength development by filling micropores. By applying alkali-activated calcined coal gangue-slag based cementitious materials to solidify engineering slurry, this research not only elucidates the mechanism of alkaliactivated calcined coal gangue-granulated blast furnace slag in slurry solidification but also promotes the utilization of industrial solid waste, providing new insights for environmental protection and resource recovery.

This paper investigated the improvement behaviors on dispersivity, water stability and mechanical properties of dispersive soil by calcined coal gangue (CCG) at 700 degrees C, and analyzed the modification mechanism. Dispersive soil specimens with different content of CCG (varying from 1 % to 10 %) were prepared and cured for 0-28 days. The dispersivity of the soil was determined by three different dispersivity determination tests. The tensile strength and compressive strength of the dispersive soil were determined by mechanical property tests. SEM, EDS, TG and XRD analytical methods were employed to reveal microstructure and mineral changes during modification. The results of the study show that the admixture of CCG and the prolongation of curing time contributed favorably to suppressing the dispersivity of the soil and enhancing the water stability, the compressive strength and tensile strength of the dispersive soil. With the increasing of CCG content and the prolongation of curing time, the dispersive soil gradually transforms into non-dispersive soil. Microstructural and mineral analysis indicate that CCG has pozzolanic activity, and the production of pozzolanic reaction products significantly increase the friction and cohesion among soil particles. The results show that the utilization of CCG as an admixture to improve the dispersive soil not only solves the disposal problem of waste gangue, but also optimizes the undesirable characteristics of the dispersive soil. And the modification effect of CCG on dispersive soil in practical engineering is confirmed by validation test.