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Multi-index evaluation of bio-oil for the performance recovery of aged asphalt
Gao Junfeng1,2, Zhang Silin1,2, Guo Peng2, Zhu Hongzhou1, Xu Ning1
2026, 45(10):
43-55.
DOI: 10.3969/j.issn.1674-0696.2026.10.05
To screen out suitable bio-based oils for restoring the properties of aged asphalt, four kinds of bio-oils, soybean oil (SO), waste cooking oil (WCO), palm oil (PO) and tall oil (TO), were selected and the multi-index evaluation and threshold system were studied. Through elemental analysis, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, thin-film oven aging, flash point and ignition point, contact angle and adhesion tests, the compositional characteristics, thermo-oxidative stability, construction safety, and interfacial adaptability of different bio-based oils were systematically evaluated. Furthermore, taking the aged asphalt prepared by RTFOT as the object, the effects of different bio-oils on the restoration of penetration, softening point, ductility, and rotational viscosity at 135 °C were analyzed, and theoretical optimal dosage was determined by combining regression analysis. The research results show that all four kinds of bio-oils exhibit good fluidity and construction safety, their flash points all meet the requirements for recycling agents, and the adhesion grade between the recycled asphalt and aggregates all reaches level 5. SO, WCO, and PO are mainly composed of C16~C18 fatty acid components, while TO, in addition to fatty acid components, also has a higher proportion of resin acid components above C18 and carboxylic acid polar functional groups, exhibiting better structural matching and interfacial compatibility. All four kinds of bio-oils improve the penetration and ductility of aged asphalt, reduce the softening point and rotational viscosity. Among them, TO shows the best overall recovery effect on aged asphalt and its theoretical optimal dosage is determined to be 6.5% based on penetration regression. On this basis, a stratified evaluation system for bio-oils consisting of admission threshold, optimization threshold and verification threshold is constructed, providing reference for the screening of bio-based asphalt rejuvenator base oil and the development of composite rejuvenators.
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