Sustainable biopolymer stabilized earthen: Utilization of chitosan biopolymer on mechanical, durability, and microstructural properties

Abstract

Earthen construction materials are of great importance in terms of having natural and sustainable properties. Bio-stabilization of earthen construction is defined as the products or biological processes used to improve earthen construction properties. Earthen constructions are usually stabilized with stabilizers such as cement and calcium-based binders, but biopolymers may provide green alternatives. The main purpose of this study is to investigate the mechanical properties, durability, microstructure, and sustainability of earthen constructions stabilized with chitosan biopolymer. To achieve this, 0.5 to 3 wt% of dry soil mass chitosan was added to a base soil at 0.5 wt% increments. After the curing process was completed,the mechanical properties of the mixtures were investigated. Durability performance of stabilized soil with optimum chitosan content was measured and underpinned with microstructure. The findings indicate that the optimum mechanical and durability properties can be achieved in soils mixed with 2.5 wt% chitosan biopolymer content and 28 days of curing. Compared to control samples with 8% cement, the average compressive strength and average flexural strength were 27% and 11% higher, respectively, for soils stabilized with 2.5 wt% chitosan additives. The findings provide evidence of the benefits of chitosan biopolymer as a stabilizer for the engineering of earthen construction materials.