The world today is more oriented towards sustainable and environmental-friendly solutions in every field of science, technology, and engineering. Therefore, novel sustainable and eco-friendly approaches for soil improvement have also emerged. One of the effective, promising, and green solutions is the utilization of biopolymers. However, even though the biopolymers proved to be effective in enhancing the soil-mechanical properties, it is still unknown how they behave under real environmental conditions, such as fluctuating temperatures, moisture, plants, microorganisms, to name a few. The main research aim is to investigate the durability of biopolymer-improved soil on the cyclic processes of wetting and drying. Two types of biopolymers (Xanthan Gum and Guar Gum), and two types of soils (clean sand and silty sand) were investigated in this study. The results indicated that some biopolymer-amended specimens kept more than 70% of their original mass during wetting-drying cycles. During the compressive strength analysis, some biopolymer-treated specimens kept up to 45% of their initial strength during seven wetting-drying cycles. Furthermore, this study showed that certain damaged soil-biopolymer bonds could be restored with proper treatment. Repeating the process of wetting and drying can reactivate the bonding properties of biopolymers, which amends the broken bonds in soil. The regenerative property of biopolymers is an important feature that should not be neglected. It gives a clearer picture of the biopolymer utilization and makes it a good option for rapid temporary construction or long-standing construction in the areas with an arid climate.
Keywords: Guar Gum; Xanthan Gum; biopolymer-treated soil; cyclic wetting-drying; durability; soil strength.