Fatigue characterization and assessment methods for the terminal blend crumb rubber/SBS composite modified asphalt binders

In this study, we investigated the fatigue performance of SBS/terminal blend crumb rubber (TB) composite modified asphalt binder to extend the service life of asphalt pavements. Six modified asphalt binders were prepared and subjected to Time Sweep (TS) and Linear Amplitude Sweep (LAS) tests to analyze fatigue damage and life. Utilizing the Taylor diagram and Threat Score (TS) method, we aimed to optimize fatigue damage evaluation models and indicators suitable for SBS/TB composite modified asphalt binder. The results demonstrate a significant improvement in the fatigue resistance of asphalt binders at low and high strain levels with the SBS/TB composite modifier. Analysis of the Taylor diagram and TS results revealed that the 20% DER deviation criterion and viscoelastic continuum damage (VECD) models yield similar simulation effects on DSR-C calculated fatigue life results. These models exhibit better standard deviation and root mean square error (RMSE), albeit with a slightly lower correlation coefficient. Conversely, the 50% G* criterion model demonstrates an excellent fitting effect on the correlation coefficient (Sample Correlation Coefficient, R=0.9289), albeit with significant standard deviation and RMSE. The SxN peak criterion model shows a better fit for the correlation coefficient while displaying a weaker fit with the standard deviation. Ultimately, we propose the DSR-C model, 20% DER deviation criterion, and VECD model as more suitable fatigue damage evaluation models for SBS/TB composite modified asphalt binder.