Dry-Wet Durability of Solidified Sludge under Capillary Immersion Mode

Using soda residue (SR)-ground granulated blast furnace slag (GGBS)-carbide slag (CS) and cement as solidifiers of sludge, the dry-wet durability of solidified sludge under capillary immersion and full immersion in seawater are conducted, and the influence laws and mechanisms of different immersion methods on the durability of solidified silt under seawater erosion environment are investigated. The results show that: SR-GGBS-CS solidified sludge shows better dry-wet durability than cement solidified sludge when cement dosage equals GGBS dosage. Generally, the samples in full immersion mode are damage severely, and show a high mass loss rate and low unconfined compressive strength. However, the strength of the sample in capillary immersion mode is lower than that in full immersion mode when the solidifier dosage and dry-wet cycles increase. The corrosive ions rising with the capillary water cause salt crystallization and the formation of Thaumasite, which deepens the inhomogeneity and damage for the samples under the coupling effects of multiple dry-wet cycles and seawater. Therefore, the adverse effect of capillary immersion on the dry-wet durability of solidified sludge gradually exceeds that of full immersion, and the zone above groundwater is the weakest.