SBS modified bitumen in the presence of hydrophilic or hydrophobic silica nanoparticles

The rheological behavior of bitumen/SBS modified by SiO2 is found to be strongly dependent on SiO2 surface nature and its fraction. The hydrophobic R974 modified bitumen/SBS blends have much better rheological property than the hydrophilic A200 modified blends due to the preferential attraction between bitumen and R974. The rheological property exhibits a nonmonotonic change with SiO2 fraction either in R974 or A200 modified blends, which is closely related to the dispersion of nanoparticles. The rigid nanoparticles themselves play a main role in the rheological behavior, rather than the unchanged droplet-matrix structure with different droplet size induced by phase separation.