Diffusion and reinforcement mechanism study of the effect of styrene/butadiene ratio on the high-temperature property of asphalt using molecular dynamics simulation

ABSTRACT

The performance of styrene–butadiene-styrene (SBS)-modified asphalt depends on the diffusion and enhancement mechanism between SBS modifier and asphalt, and particularly the styrene/butadiene (S/B) ratio is a crucial factor affecting the enhancement properties of the modified asphalt. In this study, the effects of S/B ratios (20/80, 30/70 and 40/60) on the interaction mechanism between SBS modifier and asphalt was studied using viscoelasticity characterisation and molecular simulations. The diffusion coefficient and binding energy were adopted to reveal the mechanism of dynamic shear rheometer (DSR) variation. The results showed that the binding energy of asphaltenes with light components (saturates and aromatics) was gradually raised with the styrene ratio, increasing from 11.5% to 22.1%, while the binding energy between SBS polymer and light components gradually decreases from 8.9% to 112.7%. In addition, as the S/B ratio gradually decreases from 40/60 to 20/80, the diffusion coefficients of asphalt molecular gradually increase from 1% to 20%. The DSR test result was consistent with the molecular simulation results as the deformation resistance of the modified asphalt is weakened as the S/B ratio increases. This study provided the reference for the high-performance block copolymer-modified asphalt design and application in the highway and building industry.

KEYWORDS:

• SBS-modified asphalt
• molecular dynamic simulation
• styrene/butadiene ratio
• high-temperature property
• reinforcement mechanism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by Innovative Funds Plan of Henan University of Technology (2020ZKCJ05 & 2020ZKCJ22), the Natural Science Foundation of Jiangxi Province of China (20202BABL214046), the Natural Science Foundation of Henan Province of China (202300410112), the Natural Science Foundation of Anhui Province of China (1908085QE217). Science and Technology Planning Project of Henan Province of China (192102310229), the Cultivation Plan for Youth Backbone Teachers of Institution of Higher Education by Henan Province (2019GGJS086), the Cultivation Plan for Youth Backbone Teachers by Henan University of Technology (21420154 & 21420156). Key Science and Technology Research project of Henan provincial department of education (21A580002) and the foundation for Distinguished Young Talents of Henan University of Technology (2018QNJH09) and the Central Public–Interest Scientific Institution Basal Research Fund (2020-9049).