Effect of locust bean gum biopolymer on mechanical properties of organic soil

Abstract

In recent years, biopolymers have been widely used in soil, but few concentration on the application of biopolymers in the organic soil. In this work, the potential using locust bean gum for improving the physical characteristics of the organic soil has been fully evaluated, while the Atterberg limit test, unconfined compressive strength test, and unconsolidated undrained shear test were conducted. In addition, the mineral composition and micro-mechanisms have been analyzed by X-ray diffraction tests, Fourier transform infrared spectra tests, and scanning electron microscopy tests. And we found that locust bean gum could increase the liquid limit and plastic limit of the organic soil, and enchance the compressive strength and shear strength. The increase in soil cohesion with locust bean gum content was more pronounced than the increase in internal friction angle. And as the curing time progresses, locust bean gum gradually transformed from a hydrogel state to a high tensile strength biofilm or flocculent gel matrix, which enhanced the bonding force between soil particles, thus increasing the strength of the specimens, which can be validated by the scanning electron microscopy observations, in which the porosity of soil was significantly reduced. We believed that this work could provide an ecological, economical and practical insight dealing with the engineering project constructions in the organic soil area.