The Curing Time Effect on SBS-Modified Asphalt Performance: A Combined Molecular Dynamics and Mechanical Testing Study

The technology of SBS-modified asphalt has advanced significantly and is now widely used in pavement materials. However, compared to the current research that mainly focuses on the investigation of SBS and asphalt materials themselves, the influence of compatibilizers is often overlooked due to their minor composition. Particularly, the impact and mechanisms of compatibilizers' curing processes and curing time on the performance of modified asphalt are still not well understood. This paper investigates the effects of curing time on the high-temperature, low-temperature, and aging properties of SBS-modified asphalt, using a reaction temperature of 170°C and curing times of 1 hour, 3 hours, 5 hours, and 7 hours. Additionally, the molecular dynamics (MD) simulation was used to verify this process and explain the inherent mechanisms of the curing process. The results showed that when mixed with SBS-modified asphalt, compatibilizers reduced non-bond energy through non-covalent interactions, stabilizing, grafting, and dispersing the polymer molecules in the structure. As curing time increased, high-temperature performance improved, but the modified asphalt became harder, reducing internal adhesion and potentially suppressing low-temperature performance. The contribution of this paper is to propose an evaluation method combining experimental and MD simulation approaches to investigate the impact of compatibilizers and curing processes on the performance of modified asphalt. This study enhances the understanding of compatibilizers and curing mechanisms, providing a foundation for designing and evaluating new products in the future.