Effects of Xanthan gum biopolymer on soil strengthening

•We investigated the interaction between Xanthan gum biopolymer and soils.•Xanthan gum prefers fine particles which enhances strength via hydrogen bonding.•Xanthan gum–fine soil matrix acts as a cementation binder between coarse particles.•Soil composition is important for chemical bonding and mechanical friction.•The most effective concentration of Xanthan gum is 1–1.5% to the soil mass.

The general aim of soil treatment in construction engineering is to improve soil properties such as aggregate stability, strength, and erosion resistance. Conventional soil treatment materials have several shortcomings, especially from an environmental standpoint. As a result, a suitable eco-friendly replacement for conventional materials is required. Xanthan gum is a polysaccharide commonly used as a food additive and rheology modifier. It has been used as a soil improvement material in the present study and experimental tests were performed with different types of soils. The results show that the Xanthan gum fibers interact directly with the charged surfaces of clayey particles while forming Xanthan matrices that resemble a hard plastic between uncharged particles. Consequently, the strengthening effect of Xanthan gum was shown to have the greatest efficiency with well graded soils with fine particles. Through experiments with varying concentrations of Xanthan gum, it was found that the strengthening effect leveled off at higher concentrations. The strengthening effect was also shown to be greatly dependent on the hydration level of the soils. Overall, the strengthening effect of Xanthan gum is shown to be dependent on four factors: type of soil, hydration level (e.g., moisture content), Xanthan gum content, and mixing method.