Investigation of rheological properties and modification mechanism of bio-oil/crumb rubber modified asphalt reinforced by fiber

The synergistic effects of crumb rubber (CR), epoxy soybean oil (ESO) and polyester fiber (PF) on rheological and comprehensive properties of asphalt and the modification mechanism were studied. The main objective is to address the challenges of high viscosity and incompatibility associated with single rubber modified asphalt, as well as oil volatilization and decomposition at high temperatures, and decreased high temperature performance of oil /CR modified asphalt. The response surface method was used to optimize the ratio of PF, ESO and CR, and the ideal mixing ratio of 0.294 % PF, 6.0 % ESO and 21.464 % CR was determined by analyzing the interaction characteristics of each pairwise of the three components to obtain the best rheological properties. The rheological results showed that PF improved the rheological properties at high temperature and ESO improved the rheological properties at low temperature. Compared with the traditional SBS modified asphalt, the three-component composite modified asphalt exhibited excellent low temperature rheological properties and enhanced fatigue resistance, which was due to the synergistic effect between PF, ESO and CR. Microscopic analysis showed that ESO effectively enhances the compatibility and phase structure of the composites, while PF promoted structural stability by limiting the flow of asphalt. In this study, the comprehensive effects of single-component modified asphalt and multi-component modified asphalt were analyzed and compared by radar map, and the advantages of three-component modified asphalt were obviously highlighted. This study provides valuable insights and scientific guidance for the technical progress of similar asphalt modification engineering.