Improved flexural fatigue behavior and strengthening mechanisms of rubberized concrete using pretreated crumb rubber

Investigating the flexural fatigue performance of rubberized concrete is essential for advancing its application in dynamic load environments, which aligns with the green and low-carbon objectives of modern building materials. In this study, comprehensive mechanical and fatigue tests-including assessments of static strength, fatigue life, and flexural fatigue strength-were conducted to clarify the mechanisms by which crumb rubber influences the fatigue resistance of concrete. Increasing the rubber content markedly improved fatigue life, although a reduction in compressive strength was observed. Specifically, compared to the reference concrete, concrete incorporating 10% pretreated crumb rubber by volume of fine aggregate exhibited a 21.2% increase in fatigue life. Furthermore, pretreatment of crumb rubber not only further enhanced the fatigue resistance of concrete but also partially mitigated the decline in strength. Additionally, the compressive strength of concrete with 7.5% pretreated crumb rubber was 15.0% higher than that of concrete with the same amount of untreated crumb rubber. Pretreated crumb rubber further augmented the energy dissipation capability of concrete, thereby enhancing its fatigue performance. Consequently, rubberized concrete emerges as a promising alternative material for fatigue-critical applications, and the pretreatment of crumb rubber is recommended as an effective auxiliary measure to optimize performance.