Applicability of Standard Rheological Evaluation Methods for High Content SBS Polymer Modified Asphalts

High content SBS polymer modified asphalt (HCPMA) can serve as pavements under heavy traffic and a wide range of temperatures. However, the applicability and validity of standard rheological evaluation methods to characterize HCPMA are still unclear. In this study, the influence of SBS content on the conventional properties and rheological behavior of HCPMA was analyzed. A higher content of SBS can improve the performance grade of the asphalt binder to PG100-34. The slope of the J_nr-σ linear curves from the MSCR under various stress levels decreases when the SBS content increases. The slope of the J_nr-σ linear curves can replace J_nrdiff as an indicator of stress sensitivity. A higher content of SBS can also decrease the flexural creep stiffness and increase the creep rate of the binders. The binder fatigue resistance parameter increases and the binder yields at higher strain, with increasing SBS content. These results show that a higher content of SBS can further improve the resistance to rutting, thermal cracking, and fatigue. Current standard rheological methods should be modified when evaluating HCPMA. The results also show that conventional tests are not valid for evaluating the performance of HCPMA.