This study aims to investigate the possibility of using biopolymer (environmental friendly material) to enhance the mechanical behaviors of collapsible soil. Two types of biopolymers were (xanthan gum and guar gum) used in this study due to their stable behaviors under severe conditions and their availability with reasonable prices. The experimental program focused on three major soil properties, i.e. compaction characterizations, collapsible potential and shear parameters. These three properties are essential in process of soil improvement. Different biopolymer concentrations were used in this study and the experimental program was performed at two curing periods (soon after mixing the soil with the biopolymer and after one week curing time). Shear parameters were measured for the treated specimens under both soaked and unsoaked conditions, while a collapsible potential test was performed under different mixing conditions (wet mix and dry mix). A numerical model was built to predict the behavior of the treated collapsible soil after and before water immersing. The results indicated that the ability of both xanthan gum and guar gum can be used as improvement materials for collapsible soil treatment. The collapsible potential has been reduced from 9% to 1% after mixing the soil with 2% biopolymer concentration in the wet case. After one week curing, the cohesion has been increased from 8.5 kPa to 105 kPa by increasing the xanthan gum concentration from zero to 2%, leading to an overall improvement in soil shear strength. It also proves that the guar gum is superior to the xanthan gum. The shear strength of soil can be increased by about 30% when using the guar gum in comparison with the xanthan gum at the same conditions; however, the collapsible potential of soil material will be reduced by about 20%

This investigation is aiming to evaluate the effectiveness of biopolymer material in the suppression of wind erosion. Four different types of biopolymer (xanthan gum, guar gum, carrageenan and modified starches) were used in this study in three different concentrations (0.25, 0.50 and 0.75%). The effectiveness of the biopolymer on reducing soil erosion was measured from the mass loss of the specimens after being exposed to air device to simulate wind speeds similar to field conditions. Shear strength and liquid limits for treated specimens were measured and used to predict the loss of soil mass. Also, the effect of durability of biopolymer was studied through cycles of wet and dry. A neural network model was successfully used to predict the soil loss mass under different concentrations and cycles. The study verified the ability of biopolymer to reduce wind erosion; however, the erosion resistance varies according to the type of biopolymer used and its concentration. Although the effectiveness of biopolymer may be affected after different wet and dry cycles, the erosion resistance for soil treated with guar gum or modified starches is still noticeable even after the fifth cycle. Moreover, 0.5% biopolymer concentration is a sufficient percentage, as almost all specimens treated with this percentage can resist the wet/dry cycles till the fifth cycle.