Effect of EVA on the rheological properties of SBR-modified asphalt binder and its behavioral evolution during the thermo-oxidative aging process

• Published in: Construction & building materials Vol. 454; p. 139159
• Main Authors: Ren, Xueyuan, Sha, Aimin, Jiang, Wei, Wu, Wangjie, Jiao, Wenxiu, Li, Jiarong, Li, Jingxiao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 06-12-2024
• Subjects: Aging tracking indicators; Asphalt binder; Ethylene–vinyl acetate; Styrene-butadiene rubber; Thermo-oxidative aging; Ethylene–vinyl acetate; Aging tracking indicators; Thermo-oxidative aging; Asphalt binder; Styrene-butadiene rubber
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2024.139159

The aim of this study is to enhance the high-temperature performance of SBR (styrene-butadiene rubber)-modified asphalt binder using EVA (ethylene-vinyl acetate) as well as to reveal its chemical and rheological behaviors evolution during thermo-oxidative aging. SBR-modified and SBR/EVA composite-modified asphalt binders were prepared and subjected to different thermo-oxidative aging durations, followed by a series of rheological and chemical tests. The results indicate that the addition of EVA forms a three-dimensional polymer network within the asphalt binder, enhancing deformation resistance and fatigue resistance. Specifically, SBR/EVA composite-modified asphalt binder shows a 37.57 % reduction in non-recoverable creep compliance compared to SBR-modified asphalt binder at 3.2 kPa, with a fatigue life (15 %) 9.59 times higher. With thermal-oxidative aging, the complex shear modulus and recovery rates of the binders increase while phase angle, accumulated strain, and non-recoverable creep compliance decrease. The yield strain and fatigue life (15 %) of neat asphalt and SBR/EVA composite-modified asphalt binder decrease with aging, while SBR-modified asphalt binder initially improves before declining. Additionally, the results show that as thermo-oxidative aging time increases, the G-R parameter and carbonyl index rise, while the crossover frequency drops. However, the rheological index and sulfoxide index do not show an apparent pattern during aging. The carbonyl index and crossover frequency are recommended as reliable indicators for assessing asphalt binder deterioration, and these two indexes also show a strong linear correlation. These findings contribute to advancing the understanding of the effects of EVA on the rheological and aging properties of SBR-modified asphalt binder.
•The addition of EVA to SBR-modified asphalt binder significantly improves deformation resistance and fatigue resistance.•The evolution of chemical composition and rheological behavior of SBR-modified and SBR/EVA composite-modified asphalt binders during thermo-oxidative aging are revealed.•The carbonyl index IC=O and crossover frequency ωc are very effective in tracking the aging of asphalt binder.