Engineering Characteristics Research of Slag-Modified Dredged Sediment for Pipe Trench Backfill

Slag and dredged sediment are typical solid waste. In order to expand the utilization of resources, the dredged sediment was modified into early strength flowable soil by using slag and sulfoaluminate cement as curing agent, and it was used for backfilling in municipal pipe ditch engineering. The workability and mechanical properties of flowable soil with different water content and slag replacement ratio were studied after slag partly replaced sulfoaluminate cement. The results show that when the moisture content increases, the fluidity increases and the density decreases, and the change of slag replacement ratio has limited influence on the fluidity and density. The unconfined compressive strength of flowable soil increases with the increase of curing age, but decreases with the increase of moisture content and slag replacement ratio. When the slag replacement ratio is less than 42.9%, the strength can reach more than 100 kPa after curing for 1 day, and the drying-wetting cycle resistance of flowable soil decreases with the increase of slag replacement ratio. When the fluidity is greater than 200 mm, the filling rate of the flowable soil can reach more than 97%, which can be better used for engineering.