▎ 摘　　要

Multilayer graphene nanoplatelets (GNPs) have the potential to become the next generation of asphalt modifiers for developing sustainable asphalt pavements. This study investigated the reaction mechanism, high-temperature rheological properties, and thermal stability of styrene-butadiene-styrene (SBS) asphalt modified with GNPs. The GNP-modified asphalts were prepared by incorporating 0.5, 1.0, 1.5, and 2.0 wt% GNPs into SBS asphalt. X-ray diffraction, Fourier-transform infrared spectroscopy, fluorescence microscopy, and atomic force microscopy were employed to investigate the interaction mechanism between GNPs and SBS asphalt, and the high -temperature rheological properties were systematically evaluated using dynamic shear rheometer tests. Satu-rate, aromatic, resin, and asphaltene (SARA) analysis was applied to investigate the fraction variation after incorporating the GNPs into the SBS asphalt, and grey relational analysis was performed to determine the relationship between the SARA fractions and rheological properties. Thermogravimetric analysis-differential scanning calorimetry experiments were conducted to characterize the heat absorption, specific heat capacity, combustion characteristics, and kinetic parameters of the GNP-modified asphalt. The asphalt molecules were intercalated between the GNPs sheets. The addition of GNPs promoted the development of a polymer-rich phase in the SBS asphalt and a stable three-dimensional network, which hindered the migration of particles at high temperatures. The GNPs improved the rheological properties of the asphalt and produced a more elastic response. Furthermore, the GNPs reduced the combustion intensity and stability of SBS asphalt by up to 12.6 % and 15 %, respectively. The specific heat capacity increased by 10.8 %-174.8 %, and the heat absorption decreased by 49.6 %-75.87 %. By reducing the energy of the system, GNPs decrease the degree of disorder. The highest activation energy and enthalpy were 102.83 and 96.72 kJ mol-1, respectively, and the Gibbs free energy decreased by 39.7 % at a GNP content of 1.5 wt%. However, excessive GNPs may lead to agglomeration and uneven dispersion in SBS asphalt.