Using molecular dynamics and experiments to investigate the morphology and micro-structure of SBS modified asphalt binder

Abstract

The study aimed at investigating the compatibility between styrene-butadiene-styrene (SBS) and asphalt, and the influence of SBS on morphology and micro-structure of asphalt through molecular dynamics (MD) and experiments method. In this work, the solubility parameter and molecular structure parameters of SBS modified asphalt were calculated by Materials Studio software, and its morphology of were investigated by microscope techniques. The results showed that solubility parameter of SBS and asphalt fluctuated along with simulation temperature, and the difference between SBS and asphalt is around 10.5 (J/cm3)0.5, which means these two materials cannot reach a total miscible state, and the scanning electron microscope (SEM) and fluorescence microscope (FM) results on the compatibility between asphalt and SBS corresponding with the simulation results. The interaction simulation on SBS and asphalt indicated that van der Waals interaction makes a significant contribution to non-bond interaction and plays a dominate role in the miscibility between asphalt and SBS. The structure parameters of radial distribution function (RDF) and radius of gyration showed that SBS had an a evident influence on the structure of asphalt molecule, for it increased the tightness of the asphalt and reinforced the ractility of branched-chain of asphalt components. Through AFM test results, we also found that SBS increased the bee-like phase of asphalt, and bring asphalt a better physical properties.