Effect of multi-source solid waste synergistic activation on strength evolution and micro-mechanism of dredged sludge stabilized with low-carbon curing agent

To enhance the strength of solidified waste sludge, this study builds upon traditional cement-based sludge solidification methods and the waste-to-waste treatment principle. Cement, slag and fly ash were selected as solidifies, with water glass serving as an activator. The objective is to determine the optimal raw material proportions for solidified sludge under composite activation. The strength and microstructure of the cured samples were investigated by unconfined compressive strength (UCS), X-ray diffraction (XRD) and thermogravimetric (TG) experiments. Taking the single-doped cement sample as the control group, the internal relationship between the amount of raw materials and the UCS of the sludge was explored, which provided a theoretical basis for optimizing the mix design of the sludge. The results demonstrate that when the ratio of cement: slag: fly ash is 15: 10: 5, the optimal dosage of water glass is 7%. Water glass provides a good alkaline environment for the composite system, which effectively promotes the hydration reaction and pozzolanic reaction of cement, slag and fly ash. The generated hydration products make the internal structure of solidified sludge more compact, thus significantly improving the strength of solidified sludge.