High content waste tire rubber composite modified asphalt: Macro-Micro characterization of thermal storage stability and rheological properties

To solve the “black pollution” and improve the performance of asphalt pavement , high content rubber powder and SBS polymers are employed to develop high content rubber composite modified asphalt (HRCA). In this paper, the thermal storage stability of HRCA was characterized by cigar tube test, Fourier transform infrared (FTIR), fluorescence microscope (FM) and dynamic shear rheometer (DSR) segregation rate. Rheological methods were used to investigate the temperature properties before and after aging, the effect of experimental parameters on the multiple stress creep recovery (MSCR) test, and fatigue performance of HRCA. The results show that the degree of segregation in HRCA intensifies with the increase of rubber powder and the rise of storage temperature. Because rubber powder was increased while reducing the content of SBS, binders are not sufficiently stabilized, resulting in physical settling, and high temperature reduces the viscous component of binders, thereby weakening the hindering effect on phase separation. HRCA exhibits great low-temperature flexibility, resistance to permanent deformation and aging, but HRCA with a low rubber powder content is less resistant to aging because rubber powder absorbs a limited number of lightweight components. Although the MSCR is applicable to HRCA, the plate spacing of 1 mm is optimal to ensure that binders are uniformly stressed to form a stable torque. The pattern of fatigue life is roughly HRCA@50 % > HRCA@40 % > HRCA@30 % > HRCA@20 % > SBS-modified asphalt (SBSMA). This study effectively reduces the pollution from waste tires and accelerates the promotion and application of HRCA in pavement engineering .