The disposal of discarded rubber tires poses significant environmental challenges, including resource depletion and ecological damage. To address these issues and enhance the sustainability of construction materials, the potential application of rubberized concrete in airport pavement engineering is explored. In this study, rubber particles sized 3-5 mm, 6-10 mm, and rubber fibers sized 10-20 mm were incorporated into concrete by substituting sand at volumetric replacement levels of 5%, 10%, 15%, and 20%. Through four-point bending tests, the influence of rubber morphology and replacement levels on the flexural strength and flexural elastic modulus of rubberized concrete was systematically evaluated. Experimental results indicate that higher rubber replacement levels lead to a gradual reduction in flexural strength and elastic modulus. At a 20% replacement level, the flexural strength of concrete with 3-5 mm particles, 6-10 mm particles, and 10-20 mm fibers decreased by 13.5%, 15.6%, and 20.5%, respectively, while the corresponding elastic modulus declined by 20.3%, 18.5%, and 20.9%. Notably, concrete with 3-5 mm rubber particles exhibited the highest flexural strength, while concrete with 10-20 mm rubber fibers showed the lowest elastic modulus. These findings suggest that a rubber replacement level below 10% can optimize mechanical properties while minimizing reductions in strength, highlighting the potential of rubberized concrete for use in airport pavement engineering.
