Experimental Studies and Molecular Dynamics Simulations of the Compatibility between SEBS and Asphalt

Abstract

This study employs molecular simulation to construct styrene-ethylene-butadiene-styrene (SEBS)–modified asphalt at various temperatures and analyzes the structural changes during the blending process to investigate the compatibility of SEBS modifier with base asphalt. Solubility parameters (δ) and Flory-Huggins parameters (χ) are calculated to characterize compatibility, while a radial distribution function (RDF) and diffusion coefficient are used to analyze component distributions. Interaction energy is computed to determine intermolecular binding, and fluorescence microscopy as well as cigar tube testing are employed for verification purposes. The results indicate that δ and χ demonstrate optimal compatibility between the SEBS modifier and base asphalt at 160°C. RDF analysis along with diffusion coefficient measurements reveal that mutual diffusion and distribution between SEBS modifier and asphalt components reach their peak at 160°C. Analysis of interaction energy highlights the significant role played by van der Waals forces in forming a stable blending system. Pearson correlation coefficient analysis further confirms that χ, interaction energy, solubility parameter difference, and potential energy serve as key indicators for evaluating compatibility. This study offers a fresh perspective on optimizing the compatibility of SEBS-modified asphalt while enhancing our understanding of its blending process.