Using Biopolymers to Stabilize Collapsible Soil by Using Wet Mix Method

This study is concerned with stabilizing collapsible soil with eco-friendly materials. The additives used in this study are classified as types of biopolymers. Biopolymers have been utilized nowadays in many fields as alternatives to unfriendly materials. This study investigates the potential of using biopolymers to stabilize the collapsible soil which was collected from New Borg-Alarab City, Egypt. Gelatin, sodium alginate, and xanthan gum were added to the soil in contents of 0.5, 1, 2, 3, and 4% to investigate to what extent the biopolymer content affected the soil's characteristics. The soil was mixed with biopolymers using the wet mixing technique. The compaction characteristics, shear strength parameters, and collapse index have been evaluated for the soil before and after treatment. Moreover, the microstructure of the untreated and treated soils was examined by carrying out scanning electron microscopy (SEM) and X-ray diffraction (XRD) tests. The effect of biopolymers on the soil characteristics was obvious, as the biopolymers improved the shear strength and decreased the collapse index. When 4% gelatin, sodium alginate, and xanthan gum were mixed with the soil, its unsoaked shear strength increased by 79%, 275%, and 313%, respectively. While, the soaked shear strength increased by 232%, 285%, and 327%, respectively. The results showed that a 4% concentration of gelatin, sodium alginate, and xanthan gum greatly decreased the collapse index by 85%, 93%, and 98%, respectively. Additionally, the interaction between the biopolymers and the fine-grained particles is obvious in the SEM and XRD results.