Study on components selection and performance of bio-oil based asphalt rejuvenator based on softening and asphaltene deagglomeration effect

Abstract

The bio-oil, with environmental friendliness and good compatibility with asphalt, has been widely used in rejuvenating aged asphalt. In this study, based on the ability of bio-oils to soften aged asphalt and asphaltene deagglomeration on the molecular level, a composite rejuvenator (CD-rejuvenator) was prepared using cardanol and distilled tall oil, and macroscopic rheological properties tests and microscopic tests were used to determine the effectiveness of CD-rejuvenator. According to the outputs of a molecular dynamics simulation, distilled tall oil can shift the peak of the radial distribution function (RDF) of asphaltene back and decrease the aggregation probability of asphaltene. The cardanol's low molecular weight is most helpful in lowering the elastic modulus of aged asphalt molecules. The rheological test results revealed that CD-rejuvenator restored high-temperature rheological properties (G* and δ), and cracking resistance (Glover-Rowe parameter), of aged asphalt more effectively than soybean oil and aromatic oil. The crossover modulus of the rejuvenated asphalt binders shows that the CD-rejuvenator can deagglomerate the asphaltene agglomerates. Additionally, the CD-rejuvenator rejuvenated asphalt exhibited good viscosity behavior and crack resistance after PAV aging. Scanning electron micrographs show that the softening and deagglomeration components of the CD-rejuvenator have a synergistic effect on restoring the microscopic morphology of the aged asphalt surface, with the surface of CD-rejuvenator rejuvenated asphalt exhibiting the least quasi-bee structure and a more uniform surface. The molecular weight of rejuvenated asphalt also demonstrates the effectiveness of the CD-rejuvenator for deagglomerate asphaltene agglomerates. Overall, Regarding rheological characteristics and microstructure recovery effectiveness of aged asphalt, the rejuvenators prepared by using softening and deagglomeration components in blends performed better than the single-component soybean oil or aromatic oil rejuvenators.