Biopolymer treated Korean residual soil

Abstract

Soil is a natural material consisting variable minerals that differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics. Biological aspects and considerations of soil behavior is an important topic for geotechnical engineering problems. The strengthened and stabilized behavior of organic soil is induced by biological by-products such as biopolymers. Korean residual soil (commonly known as Hwangtoh) is a common and environment-friendly material due to its high absorbency, self-purification, and far infrared ray radiation characteristics. However, its low strength and high drying shrinkage problems have restricted its broader usage and development. This dissertation centers on the treatment and strengthening behavior of Korean residual soil in relation to environment-friendly biopolymers. Biopolymers are polymers produced by living organisms. Biopolymers are generally applied in medical, food, cosmetic, medicine fields and so on, according to their various beneficial properties. Recently, applications in the geotechnical field have been increasing; these applications are related to soil erosion control, aggregate stabilization, and drilling aspects. This study introduces typical biopolymers, such as $\beta$-1,3/1,6-glucan, Xanthan gum, Chitosan, and Gellan gum, that can be used to treat Korean residual soil with the aim of improving engineering properties. The inter-particle behavior and strengthening mechanism of $\beta$-1,3/1,6-glucan depends on the adsorption and tensile characteristics of $\beta$-1,3/1,6-glucan fibers. Under saturated conditions, free-floating polymers attach to Hwangtoh particles, increasing the shear modulus of the soil. The hydrophilic characteristic of $\beta$-1,3/1,6-glucan fibers alter the geotechnical behavior of Hwangtoh. During drying, polymer fibers tend to adsorb Hwangtoh particles, and vice versa. The adsorption process dominates until all Hwangtoh particles are primarily...