Impacts of Crumb Rubber Gradation on Fatigue Performance of Asphalt Mixtures

Abstract

Fatigue cracking poses a significant challenge in flexible pavement, leading to deterioration and failure over time. Understanding the fatigue behavior of asphalt mixtures is crucial for developing effective preventive measures. This research investigated the effect of crumb rubber gradation and the fatigue behavior of asphalt mixtures at various stress levels using Semi-Circular Bending (SCB) Test. Three types of crumb rubber-modified asphalt mixtures were examined, including a commercially available CRMB60 and two laboratory-prepared binders (AR-Coarse and AR-Fine). Dynamic SCB test was carried out at 25oC at three strain levels and the cycles to failure were measured to understand the fatigue resistance of asphalt mixtures. Statistical analysis showed that both viscosity and stress level significantly had a significant influence on the fatigue life (Nf) of the mixtures. Notably, CRMB60 exhibited superior fatigue resistance compared to AR-Coarse and AR-Fine binders. Moreover, higher stress levels accelerated fatigue failure, indicating the importance of load levels during testing. This study sheds light on the significance of crumb rubber gradation in enhancing fatigue performance. It underscores the potential of fine-graded crumb rubber for superior fatigue resistance in asphalt mixtures. It is envisaged that the findings of this study would provide important insights into the selection of crumb rubber gradation for superior fatigue performance, thus advancing the state-of-the-art pertaining to utilization of waste materials in the design and construction of pavements.