Carbon nanotubes for improving rheological and chemical properties of styrene-butadiene-styrene modified asphalt binder

This paper studied the effects of CNTs on high-temperature rheological and chemical properties of SBS modified asphalt. Molecular dynamics simulation, DSR, BBR, and FTIR spectrometer were performed to evaluate the molecular motion state, rheological and chemical properties of CNTs and SBS composite modified asphalt binders at different aging states. The MD results indicated that CNTs could absorb components in SBS-modified asphalt and restrict the movement and diffusion of SBS and asphalt molecules, which enhanced the stability of SBS-modified asphalt. Meanwhile, the addition of CNTs could improve the rheological properties, temperature susceptibility, and rutting resistance of SBS-modified asphalt at high temperatures. The heterogeneity between CNTs and SBS-modified asphalt was demonstrated and it was the key to the high-temperature performance improvement. Besides, the low-temperature performance also could be improved by appropriate CNTs content. In addition, the FTIR results suggested that there was a lack of change in chemical functional groups with CNTs modification in asphalt binder. Moreover, the CNTs had a limited impact on delaying oxidation and played an active role in enhancing high-temperature performance under different aging conditions.