Valorization of Waste Tires in Lime-Stabilized Adobe Blocks: Enhanced Thermal, Acoustic, and Hygroscopic Properties for Sustainable Construction in Arid Climates

The construction industry is increasingly oriented toward the development of sustainable materials aimed at reducing environmental impact while ensuring adequate mechanical and hygrothermal performance. This study investigates the effect of two distinct forms of waste tire particles—powder (UTWP) and granulate (UTWG)—separately incorporated into lime-stabilized adobe blocks at respective contents of 5–25% and 10–60%. The physical, thermal, mechanical, and microstructural properties of the blocks were evaluated through density measurements, ultrasonic pulse velocity, water absorption, thermal conductivity, mechanical strength tests, and microstructural characterization using SEM-EDX. The results show that the incorporation of powdered waste tires (UTWP) significantly enhances thermal, hygroscopic, and microstructural performance; thermal conductivity decreases by up to 21.6%, and a 40% reduction in capillary water absorption is achieved with only 5% DPUP, indicating improved insulation and increased resistance to moisture. In contrast, granular waste tires (UTWG) induce a notable increase in ductility and acoustic absorption at the expense of a more pronounced reduction in mechanical strength. The observed improvements in water resistance, microstructural stability, and ductile behavior impart a resilient character to the material, making it particularly suitable for arid environments. Overall, adobe modified with optimized fractions of waste tire particles emerges as a sustainable and multifunctional construction material that promotes waste valorization while enhancing the functional performance of earthen architecture.