Identifying water components in slurry after pressurised electro-osmotic dewatering

Throughout the dewatering process of construction slurry, geotechnical properties, including permeability and shear strength, vary with the moisture content of different water components in the slurry, such as capillary water and adsorptive water. This study used thermogravimetric analysis (TGA) and kinetic analysis to identify and quantify water components in the slurry following pressurised electro-osmotic dewatering (PEOD). To determine kinetic parameters and accurately quantify the slurry’s water components, TGA was performed on samples post-PEOD, with a heating rate of 9°C/min, across various moisture content (M_c) levels. The kinetic analysis categorised the water components into adsorptive and capillary water. The activation energy required to remove adsorptive water is significantly higher than that for capillary water. Moreover, the kinetics analysis indicates that while mechanical dewatering primarily removes capillary water, PEOD effectively eliminates most capillary water and a substantial portion of adsorptive water. Notably, after undergoing PEOD at 20 V, adsorptive water remains the predominant component, yet this condition achieves an enhanced dewatering effect, reducing the final moisture content from 120% to 32.6%. This study’s method and results offer a new perspective on determining and quantifying the slurry water component. They also provide valuable insights for soil improvement and broader applications in geotechnical engineering.