Mechanical Properties and Micromechanisms of SBS-Modified Asphalt Binder under Multiple Aging and Regeneration Effects

AbstractThe multiple regeneration of aging asphalt pavements has emerged as a pavement maintenance approach. However, the micromechanisms and performance deterioration patterns associated with multiple regenerations remain unclear. The present work aims to investigate the rheological and physicochemical properties of styrenic block copolymers (SBS)-modified asphalt during multiple recycling processes. The rheological properties, nanostructure, and functional group evolution of SBS-modified asphalt during multiple recyclings were evaluated using rotational viscosity, frequency scanning, multistress creep recovery (MSCR), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) tests. The key findings demonstrated that the viscoelasticity of asphalt is affected by both SBS degradation and asphalt aging. During the initial aging phase, SBS degradation mainly affects the asphalt properties, whereas the subsequent aging process becomes the dominant factor. Moreover, the viscoelasticity of the asphalt binder is primarily influenced by aging rather than the SBS degradation. Importantly, the SBS-modified asphalt continues to meet specification requirements even after multiple recycling rounds, demonstrating the feasibility of aging SBS-modified asphalt binder through multiple regeneration techniques.