Experimental study on solidified dredged sediment with MgO and industrial waste residue.

• MgO-DG-SS was used instead of cement to solidify dredged sediment. • Microscopic mechanism model of MgO-DG-SS solidified sediment is proposed. • MgO-DG-SS can significantly improve the sediment strength. • MgO-DG-SS can effectively immobilize the heavy metals in sediment. To improve the engineering performance of dredged sediment, a solidification study using reactive MgO in combination with desulfurization gypsum (DG) and steel slag (SS) was carried out. The results indicated that the optimum contents of MgO, DG and SS in the solidified sediment were 7.62%, 11.31% and 5.80%, respectively. The encapsulation, cementation and filling of hydration products of MgO-DG-SS made the soil microstructure more stable, thus significantly improving the mechanical properties of sediment. Meanwhile, the MgO-DG-SS could effectively immobilize the heavy metals in sediment through chemical bonding and adsorption of hydration products. [ABSTRACT FROM AUTHOR]