Utilizing Industrial Waste to Enhance Mechanical Strength and Cost-Effectiveness of Dredged Soil

The large-scale dredging activities in port areas generate substantial quantities of dredged soil, leading to land occupation and disposal challenges, while industrial wastes such as fly ash and desulfurization gypsum remain underutilized. In this study, industrial wastes were employed as a curing agent to stabilize dredged soil, aiming to achieve both mechanical performance improvement and cost-effective recycling. In total, 100 g of curing agent was added to 1 kg of sludge. The optimal strength-maximizing formulation comprised 4.5% activator 1 #, 4.5% fly ash, 4.5% mineral powder, and 0.5% desulfurization gypsum. It achieved an unconfined compressive strength of 0.794 MPa. For enhanced cost-effectiveness, a modified binder blend (1.88% activator 1 #, 4.5% fly ash, 4.5% mineral powder, and 0.5% desulfurization gypsum) delivered 0.63 MPa at 28 days, satisfying mechanical construction specifications. Results demonstrate that unconfined compressive strength increases with solid wastes; however, with the extension of solidification time, the unconfined compressive strength of dredged soil gradually slows down.