Upward Wetting Behavior of Unsaturated Xanthan Gum-Treated Sand

Abstract

Biopolymer-soil treatment shows high potential to be used in various geotechnical engineering practices. Previous studies show appropriate performance of biopolymer on soil strength improvement and hydraulic instability reduction. In this study, the capillary conductivity of biopolymer-treated soils is investigated via laboratory testing. A mini column (3.5 cm diameter and 10 cm height) approach was used. Xanthan gum-treated soils were compacted into the columns and dried before wetting. The columns were then partially wetted from the bottom to induce upward wetting via hydrophilic adsorption and capillarity. Depending on soil types, effects of xanthan gum hydrogel concentration on capillary conductivity of soils was different. Direct water flow via capillary rise is restricted, while diffusion through hydrogels seems to become the dominant path in sand. Meanwhile, xanthan gum concentration could decide an increase or decrease in capillary conductivity within clayey soil.