Molecular dynamics simulation and experimental validation on the interfacial diffusion behaviors of rejuvenators in aged bitumen

S. Ren, X. Liu, Y. Gao*, R. Jing, P. Lin, S. Erkens, H. Wang

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

43 Downloads (Pure)

Abstract

This study aims to multiscale investigate the effects of rejuvenator type, temperature, and aging degree of bitumen on the diffusion behaviors of rejuvenators (bio-oil BO, engine-oil EO, naphthenic-oil NO, and aromatic-oil AO) in aged binders. The molecular dynamics (MD) simulation method is performed to detect the molecular-level diffusion characteristics of rejuvenators and predict their diffusion coefficient (D) parameters. At an atomic scale, the mutual but partial interfacial diffusion feature between rejuvenators and aged bitumen molecules is observed. Moreover, Fick’s Second Law well fits the concentration distribution of rejuvenator molecules in aged bitumen. The magnitude for D values of four rejuvenators varies from 10-11 to 10-10 m2/s, and the diffusive capacity order is BO > EO > NO > AO. Meanwhile, diffusion tests and dynamic shear rheometer (DSR) characterizations are employed to validate the MD simulation outputs. The experimental results in magnitude and order of D values agree well with MD simulation outputs. Lastly, the increased aging degree of bitumen exhibits a negative impact on the molecular diffusivity of BO, EO, and NO rejuvenators, while the D value of AO molecules enlarges as the aging level deepens. The underlying mechanism may be composed of the free volume fraction in aged bitumen and the intermolecular force between rejuvenator and aged bitumen molecules, which differs remarkably for various rejuvenators.
Original languageEnglish
Article number111619
Pages (from-to)1-27
JournalMaterials & Design
Volume226
DOIs
Publication statusPublished - 2023

Keywords

  • Diffusion behavior
  • Rejuvenator
  • Aged bitumen
  • Molecular dynamics simulation
  • Experimental validation
  • Influence factors

Fingerprint

Dive into the research topics of 'Molecular dynamics simulation and experimental validation on the interfacial diffusion behaviors of rejuvenators in aged bitumen'. Together they form a unique fingerprint.

Cite this