Abstract: The river dredging projects will produce a large amount of silty and peaty dredged sludge every year, the traditional physical dehydration and landfill cannot permanently solve the characteristics of high silty peaty clay content and high compression rate, so the silty peaty dredged soils should be solidified. The currently widely used Portland cement has the disadvantage of large amounts of hydration and high heat release. To minimize the cost of solidifying dredged sludge and to reduce carbon emission, this paper adopts magnesium oxychloride cement combined with other additives derived from the solid waste material as the curing agent of dredged silty peaty soils from river channels. Based on the physical and mechanical properties of solidified soil, the effects of different amounts of composite magnesium oxychloride cement curing agent on the Atterberg limits and unconfined compressive strength of dredged sludge samples are explored. A reference group with and without naphthalene series C superplasticizer was set up. The results show that the addition of the curing agent can significantly reduce the water content of the silty peaty soils. With the increase of the curing agent, the liquid limit of the solidified samples gradually increases, the plastic limit gradually decreases, and the plastic index decreases. Moreover, the strength of the solidified silty peaty soils reaches 266kPa when the addition of the curing agent is 10%. However, it has a decreasing effect on the strength, but overall, the waterreducing agent can effectively improve the curing effect of magnesium cement solidified soil.

Key words: Dredged Sludge, Solidified Soil, Magnesium Oxychloride Cement, Physical and Mechanical Properties