Multi-functional Performance of Biopolymers and Biocement in Stabilisation of Soil for Road Bases

Abstract

To achieve the sustainability goals, Australia must dramatically reduce use of cement for stabilisation of soil used in road bases. Bio-based binders for soil stabilization are potential alternatives. Biocementation through Microbially Induced Calcite Precipitation (MICP) is well researched. Some research on biopolymeric stabilization is also available. This paper explores the synergistic effect of combined biopolymer and biocement for the stabilization of sandy soil and road bases. The soil has been stabilised using both biopolymer xanthan gum and MICP. The synergy between biopolymer and MICP has been evaluated by giving a few samples a combined treatment. The performance has been evaluated by compressive strength tests, micrographic analysis and water absorption. Although biopolymer treatment improved the compressive strength it degraded significantly in presence of water. Relatively high water absorption of xanthan gum could be mitigated by MICP. The study demonstrates that MICP surface coating is a sustainable solution to overcome this limitation of biopolymer. Likewise, the addition of biopolymers reduces the release of ammonia from MICP. The present study unravels the potential of a composite bio-treatment for stabilisation of road bases.