Sustainable Reuse of Shredded Face Mask in Biopolymer Treated Expansive Soil

In recent years, the safe disposal of used face masks has become troublesome due to their non-biodegradable nature. This study focuses on the reuse potential of used face masks as a reinforcement to enhance the engineering properties of expansive soil treated with biopolymers such as Xanthan Gum and Guar Gum. The face masks were shredded into 5 × 5 mm chips and added to expansive soil at 0.5% by volume. A series of laboratory tests such as Unconfined Compressive Strength (UCS) Test, Splitting Tensile Test, Free swell Index (FSI) Tests, Swelling Pressure, Swelling Potential Tests, and California—Bearing Ratio (CBR) tests were performed for the evaluation of engineering behaviour of Shredded Face Mask Chips (SFMC) reinforced expansive soil treated with various dosages of Xanthan Gum and Guar Gum. The experimental test results showed that the inclusion of SFMC significantly improved the engineering characteristics of the soil. The maximum compressive strength and tensile strength have been attained at 2% inclusion of Xanthan gum and Guar gum into the expansive soil. The maximum values of compressive strength at optimum biopolymer content of 2% Xanthan gum and Guar gum were 369–437 kPa, respectively. The free swell index percentage for stabilized expansive soils with xanthan gum and guar gum decreased to 73.6–75.9%, respectively. The swell pressure of the treated soil showed up to a reduction of 90.2–94.1%. In all the tests, Guar Gum exhibited greater efficiency when compared to Xanthan Gum. Thus, the investigation results confirmed the efficient use of SFMC in biopolymer stabilization of expansive soil that would lead to the beneficial way for the safe disposal of used face masks.