Mechanical behavior and microstructure mechanism of artificially stabilized marine sediment under high water content

The calcium oxide (CaO) activated ground granulated blast-furnace slag (GGBS) is used as a low-carbon binder to stabilize the dredged marine sediment in this research. The purpose is to investigate the physicochemical, strength behaviors, and compressibility by unconfined compression and one-dimensional consolidation tests. The microstructural characteristics were examined using thermogravimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results demonstrated that with the increasing binder dosage, the volume shrinkage ratio and water content of the stabilized sediment decreased while the dry density, pH, and strength increased. The predicted strength equation was proposed under the given curing age and water-binder ratio. With increasing binder dosage, the vertical strain, declining rate of void ratio, creep deformation, pre-yield compressibility and secondary compression index decreased, while the yield stress increased. The microstructural analyses confirmed the existence of cementation products such as CSH, CAH/CASH, and AFt which improved the mechanical properties of sediment through the binding, and filling effects. This research provides a possibility for the reuse of industrial by-product slag and waste-dredged sediment in the application of subgrade fillers, and the CaO-GGBS binder could meet the design requirements content under the binder content was more than 5%.