Enhancement of rheological performance and compatibility of tire rubber-modified asphalt binder with the addition of graphene

Rubber segregation and workability are issues associated with tire rubber powder (TRP) modified asphalt binder, restricting its widespread application. Meanwhile, graphene nanoparticles have gained considerable interest in asphalt modification due to their outstanding properties. This work has explored the influence of graphene incorporation on the compatibility and rheological behavior of TRP-modified asphalt binder. Firstly, TRP-modified asphalt and two kinds of TRP/graphene composite-modified asphalt were prepared. Then, the rheological characteristics of the asphalts were investigated using the frequency sweep, temperature sweep, multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and bending beam rheometer (BBR) tests. The compatibility and microstructure of the different modified asphalt binders were evaluated using the cigar tube test and scanning electron microscopy. Results showed that adding graphene to the TRP-modified asphalt resulted in a notable improvement in rutting performance, as evidenced by the increase in rutting parameter (G*/sinδ) and % recovery (R) and a decrease in non-recoverable creep compliance (Jnr). The graphene addition also enhanced the anti-aging performance of TRP-modified asphalt. The results obtained from the LAS test, including the damage-characteristic curves and the number of cycles to fatigue failure, suggested that the fatigue performance of the TRP/graphene composite-modified asphalt was higher compared to the TRP-modified asphalt. Similarly, the BBR test results with 12% TRP and 0.5% graphene demonstrated that the composite-modified asphalt was more resistant to low-temperature cracking. Finally, the incorporation of graphene can potentially reduce the degree of phase separation in TRP-modified asphalt binder and improve its compatibility.