Consolidation Behavior of Fly Ash-Based Geopolymer-Stabilized Dredged Mud

Abstract

Ports use soft dredged material for land reclamation to address land scarcity and environmental constraints. Land reclaimed with soft dredged material has the properties of high compressibility and slow consolidation that need to be improved. This laboratory study investigated the effect of a fly ash-based geopolymer binder on the consolidation behavior of soft dredged mud derived from the Port of Townsville, Queensland, Australia. For geopolymer synthesization, an alkali activator solution to aluminosilicate source material mix designs that is used in the geopolymer concrete industry was adopted. The dredged mud sediments were reconstituted at 4% water content dredged mud slurries of nontreated and geopolymer stabilized at 6, 12, and 18% by weight. A series of standard one-dimensional consolidation tests was conducted to study the consolidation and compressibility characteristics of the dredged mud sediments. Taylor’s square root of time curve-fitting method was used to estimate the coefficient of consolidation. The study found that the fly ash-based geopolymer stabilization improved the compressibility, permeability, and consolidation characteristics of the dredged mud sediments. The findings indicate the feasibility of stabilizing dredged mud while still in its slurry form.