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

Ilhan Chang,Jooyoung Im,Gye-Chun Cho,Yeong-Man Kwon

doi:10.1139/cgj-2018-0254

Ilhan Chang, Jooyoung Im + Show 2 more

Open Access

https://doi.org/10.1139/cgj-2018-0254

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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.

Highlights

The use of exocultured biological materials, known as biopolymers, has been introduced to overcome the limitations of microbe endocultivation in soil in the form of a newly utilized environmentally-friendly construction material for geotechnical engineering applications (Chang et al 2016a; Latifi et al 2017).Recent studies have reported a promising biopolymer effect improving the strength and stability of soils (Chang et al 2016b; Ferruzzi et al 2000; Orts et al 2007)
Xanthan gum behavior variations according to the pore-fluid chemistry and clay mineral have not been analyzed in previous studies
Xanthan gum behavior was affected by the clay type

Summary

Introduction

The use of exocultured biological materials, known as biopolymers, has been introduced to overcome the limitations of microbe endocultivation in soil in the form of a newly utilized environmentally-friendly construction material for geotechnical engineering applications (Chang et al 2016a; Latifi et al 2017). Recent studies have reported a promising biopolymer effect improving the strength and stability of soils (Chang et al 2016b; Ferruzzi et al 2000; Orts et al 2007). Biopolymers synthesized from lignin, starch, and acrylamide can decrease the decomposition of plant residues (Awad et al 2012), or even promote vegetation growth in soils (Chang et al 2015d). Biopolymers can become an alternative earth construction binder in regions where ordinary cement is scarce and expensive, such as Africa (Chang et al 2015b)

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