Soil consistency and interparticle characteristics of xanthan gum biopolymer-containing soils with pore-fluid variation

Abstract

Biopolymer-soil technology is currently recognized as an environmentally friendly soil improvement method for geotechnical engineering practices. However, concerns exist regarding biopolymer fine-soil applications because the performance of biopolymers is based on an electrical interaction with clay or a pore fluid. Thus, the effect of water content and pore-fluid chemistry on biopolymer behavior in soil must first be clarified in terms of biopolymer applications. In this study, the liquid limits of xanthan gum biopolymer-treated clay-sand mixtures (clayey silt, kaolinite, montmorillonite, and sand) were obtained using three chemically distinct pore fluids (deionized water, 2 mol/L NaCl brine, and kerosene). Xanthan gum has contrary effects to the soil consistency, where the liquid limit can decrease via xanthan gum-induced particle aggregation or increase due to xanthan gum hydrogel formation. The clay-mineral type governed the xanthan gum behavior in the deionized water, while the pore-fluid chemistry governed the xanthan gum behavior in the brine and the kerosene.