Experimental study on freeze-thaw durability of high plasticity clay treated with waste glass powder and waste tire textile fibers

High-plasticity clayey soils are widely prevalent across the globe and pose major difficulties to geotechnical infrastructure due to their inherent swelling and shrinking behavior upon wetting and drying, particularly when exposed to freeze-thaw cycles (FTCs). Despite extensive research on conventional soil stabilizers for expansive soils, they significantly increase construction costs and environmental impacts. Moreover, these materials often render treated soils brittle, compromising their long-term durability under FTCs. This research focuses on using a specific waste glass powder (WGP) as the optimum amount of stabilizer and various amounts of waste tire textile fibers (WTTFs) as randomly distributed reinforcement to mitigate the detrimental effects of consecutive FTCs. Curing periods for all specimens were 7, 28, and 56 days, after which they are exposed to 0, 1, 4, and 8 closed-system FTCs. Multiple unconfined compressive strength (UCS), indirect tensile strength (ITS), and ultrasonic pulse velocity (UPV) tests, as well as comprehensive microstructural analyses were conducted on the samples before and after exposure to FTCs. The findings indicate that the utilization of WTTF, especially at its optimal percentage of 1.5%, significantly improves the UCS and ITS of WGP-treated expansive soil under deteriorating FTCs by forming interlocking zones within soil particles. The optimum mixture, including 10% WGP and 1.5% WTTF, resulted in a significant improvement of 6 times in the ITS after 56 days of curing, due to WGP's pozzolanic C-S-H gel formation and WTTF's crack-bridging reinforcement, as confirmed by SEM. The addition of WGP shifted the behavior of the sample from ductile to brittle; however, the introduction of WTTF reversed this trend, resulting in a return to ductile behavior. Adding 1.5% WTTF to the optimal amount of WGP (i.e., 10%) resulted in a 60% increase in the secant modulus (E 50 ) after 8 FTCs, while there was an opposite trend in the energy absorption capacity (E u ). Moreover, the incorporation of 1.5% WTTF into an optimal quantity of WGP led to a rise in UPV across all FTCs compared to the soil without WTTF. The superb contributions of WGP and WTTF in alleviating the negative consequences of severe environmental conditions on the mechanical performance and stiffness characteristics of expansive soil were further corroborated through diverse microstructural analyses.