Quantifying the rejuvenation effects of soybean-oil on aged asphalt-binder using molecular dynamics simulations

Aging is responsible for the irreversible asphalt-binder stiffening and brittleness. However, various rejuvenators can recycle the aged asphalt-binder. In this study, molecular models of rejuvenators for aged asphalt-binders were constructed using molecular dynamic (MD) simulations. The diffusion coefficients of the rejuvenator, aged asphalt-binder, and four components of the aged asphalt-binder were calculated. The solubility parameters, storage stability, and morphology of rejuvenated aged asphalt-binder were analyzed using MD, softening point tests, and fluorescence microscope, respectively. The results showed that the rejuvenator exhibited excellent regeneration performance and a high diffusion coefficient in the aged asphalt-binder, significantly improving the diffusion of the aged asphalt-binder, especially the diffusion of the saturated and aromatic components in the aged asphalt-binder. The blended mixture of the rejuvenator and the aged asphalt-binder had good storage stability with less than 1.0 °C softening point difference after 48 h. The micro-morphology results showed that the rejuvenator could be evenly distributed in the aged asphalt-binder and form the cross-linking network structures blend with good consistency and compatibility. Overall, this novel organic rejuvenator (namely Soybean-oil) exhibited promising potential for rejuvenating aged asphalt-binders, especially the long-term and extremely aged asphalt-binders.