Rheological analysis and chemical characterization of bio-rejuvenated laboratory-aged binders using partially epoxidized soybean oil with various epoxy values

• Published in: Construction & building materials 2024-06, Vol.432, p.136582, Article 136582
• Main Authors: Chen, Conglin, Ge, Chang, Quan, Xiujie, Ma, Tao, Ding, Feifan, Zhang, Yang
• Format: Article
• Language: English
• Subjects: Aged asphalt binder; Bio-rejuvenator; Epoxy value; Partially epoxidized soybean oil; Rejuvenation; Rheological property
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2024.136582

Bio-rejuvenators have been being extensively studied due to the advantages of environmentally friendly, cost-effective, and sustainable. Bio-based additives derived from vegetable oils have been proven to have significant potential and promising efficacy to be used as bio-rejuvenators for aged asphalt. In this study, the rejuvenation effect of partially epoxidized soybean oils (PESOs) with different epoxy values as bio-rejuvenators for use in aged asphalt was investigated. PESOs with different degrees of epoxidation were synthesized through an oxidation reaction. The successful synthesis and epoxy values of PESOs were determined by the Fourier Transform Infrared Spectroscopy (FTIR) test. The comprehensive rheological properties of PESO rejuvenated asphalt binders were investigated via Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) tests. The aging index (AI) was employed to explore the anti-aging properties of PESO rejuvenated asphalt binders. The rejuvenation mechanism of PESO rejuvenated asphalt binders was examined through quantitative analysis using the FTIR test. The findings suggested that PESO could improve the fatigue resistance of aged asphalt at intermediate temperatures and the thermal cracking resistance at low temperatures. The rejuvenation effect of PESO, the elasticity, and the anti-aging properties of PESO rejuvenated asphalt binders were positively correlated with the epoxy values of PESO. PESO with a lower epoxy value was noticed to be more conducive to the low-temperature and anti-cracking properties of aged asphalt. Meanwhile, the epoxide groups of PESO tended to react with the sulfur oxide groups of the aged asphalt. A higher epoxide group content in PESO was found to be more proactive in the chemical reaction with asphalt molecules, which resulted in a better rejuvenation effect regarding the restoration of elasticity. Overall, the feasibility of PESO as a bio-rejuvenator for aged asphalt has been well demonstrated based on the rheological and chemical analysis. [Display omitted] •PESO notably enhanced the low temperature properties and fatigue performance of aged asphalt binders.•The lower epoxy value of PESO showed more positive effects on low temperature and fatigue performance.•PESO’s epoxy value positively correlated with anti-aging performance and rejuvenation effect.•PESO’s epoxide group chemically reacted with the sulfur oxide groups of aged asphalt.