Filler-Stabilized Xanthan Gum for Soil Improvement

摘要

This paper presents the preliminary results for the use of filler-stabilized biopolymers to enhance the mechanical properties of sands. Biopolymers include natural polymers produced by micro-organisms or artificially manufactured fully degradable polymers. Several studies in the literature have reported the successful use of biopolymers (e.g. xanthan gum, agar gum, guar gum) as additives for soil improvements. However, concerns were also raised about the strength dependency of these improved soils on moisture content as well as the expected increase in the swelling potential of these soils. In this study, xanthan gum was first stabilized using bentonite clay as a filler to strength the resulting gel, which was then mixed with a clean sand. The results of triaxial consolidated-undrained tests on the clean sand, sand treated with un-stabilized xanthan gum, and sand treated with xanthan gum stabilized with two percentages of bentonite clay are presented. Also, the results of free swelling tests on sand samples treated with un-stabilized xanthan gum, and xanthan gum stabilized with different fillers are reported. While more experiments are needed, the main conclusion of this study is that stabilizing biopolymers with a small percentage of a filler-such as clays-will provide a viable ecofriendly bioinspired soil improvement technique. This could also help providing the nutrition needed for microbially induced calcite precipitation (MICP) without compromising the soil strength.