Sustainability in Ground Improvement: The Case of Xanthan Gum Biopolymer

Sustainable soil stabilization solutions aim to maintain a perfect balance between infrastructure performance and the social, economic and ecological processes required to sustain human equity, diversity, and the functionality of natural systems. To this end, biopolymers, either chemically synthesized from biological matter or biosynthesized by living organisms, are exhibiting great promise as a financially competitive and green alternative for conventional calcium-based binders. Recent experimental studies have shown that soils stabilized by polysaccharide-type biopolymers, such as xanthan gum (XG), exhibit a variety of promising physical and mechanical treatments, including improved water-retention capacity, reduced compressibility and hydraulic conductivity, enhanced shear strength, and improved resistance against wind/water erosion. Despite these advancements, the existing literature reveals numerous inconsistencies, and a thorough understanding of the behaviour/properties of XG-treated soils under diverse loading and environmental conditions remains somewhat elusive. More importantly, there remains a notable gap in understanding how different factors affect the interactions between XG and various soil types throughout the processes of mixing, curing, and later environmental exposure. This book represents the first of its kind, offering a comprehensive, fundamental overview of the current state of XG usage for sustainable ground improvement, while also identifying future research directions towards addressing existing gaps in knowledge and application.