Investigating the performance of rubberised binders used in Iran based on multiple stress creep recovery and performance grading systems

Abstract

This study investigated the rheological properties of three original and eight rubberised binders based on the performance grading (PG) and multiple stress creep and recovery (MSCR) systems. The results were compared with 8 out of the 13 performance grade binders essential for specific climatic zones in Iran. The other five were not available and, therefore, were not considered in this study. The results of performance grade tests showed that crumb rubber modification (CRM) improved the physical and mechanical properties of rubber-modified binders. In addition, the base binder type showed a meaningful effect on high- and low-temperature quality of the CRM binder. Adding CRM resulted in an increase in the recovery percentage (R) and a decrease in the non-recoverable compliances (Jnr) in the MSCR test. The results of designated grades based on the PG and MSCR systems proved that rubberised binders fully covered the required PGs in Iran, while they did not completely satisfy the traffic-level requirements based on the MSCR method.