Compaction Characteristics of Biopolymer-Amended Nonplastic Soils

The use of environmentally friendly materials such as biopolymers has been gaining traction in geotechnical and construction communities as a possible way to stabilize and augment poorly graded soils, improving both compaction characteristics and engineering properties. This laboratory study investigates the impacts of practical and optimum mixtures of commercially available Xanthan gum biopolymer on the compaction characteristics of a range of different nonplastic soils. Control and treated samples are compared across a combination of parameters (mixture ratios, water content, and compactive effort) using standard soil testing methods to determine the impact on density and optimum moisture content. Results demonstrate that increasing concentrations of Xanthan gum had an assorted effect on all of the soils tested depending on available void space. Most soils did not display an observed improvement to compaction, the notable exception being those containing a high percentage of fines. These findings suggest a strong link between the void space of a soil and the hydrogel properties of the biopolymer that need to be taken into consideration when determining the suitability of its use for a given application.