Comparative Strength Development and Microstructural Characteristics of Individual Industrial Solid Waste Systems Treated with Sodium Silicate.

Bulk industrial solid wastes are promising materials for clay stabilization, but the independent performance of different waste types under identical conditions remains insufficiently understood. In this study, fly ash (FA), coal gangue (CG), and ground-granulated blast-furnace slag (GGBS) were independently incorporated into a low-liquid-limit clay matrix treated with sodium silicate. Waste dosages of 10%, 15%, and 20% and curing ages of 3, 7, and 28 days were investigated using unconfined compressive strength (UCS) tests. Representative 28-day specimens were further examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The three systems exhibited distinct dosage- and age-dependent UCS responses, and strength did not increase monotonically with waste dosage. At 15% dosage, the 28-day UCS values of the FA, CG, and GGBS systems were 0.26, 0.26, and 0.29 MPa, respectively. XRD showed broadly similar crystalline phase assemblages, while SEM revealed differences in particle morphology and local surface deposits. The results provide a controlled comparison of the independent performance of FA, CG, and GGBS in clay stabilization under the investigated conditions.