## 5 Conclusions  
This research comprehensively investigated the high-temperature performances of bio-asphalt binders. Bio-asphalts with different contents of bio-oil extracted from wood chips were prepared. Conventional performance indexes of bio-asphalt binder were tested. The temperature sweep test and frequency sweep test of bio-asphalt with different bio-oil contents were carried out, and the temperature sensitivity of the bio-asphalt was analyzed. The master curves of matrix asphalt and bio-asphalt were constructed, and the changes of complex modulus and rutting factors of bio-asphalt under different frequencies were studied. Based on this study, the following conclusions were obtained:  
1. With an increase of bio-oil content, penetration and ductility of unaged bio-asphalt increased gradually; the anti-cracking performance increased slightly; the softening point decreased, while the anti-rutting ability of unaged bio-asphalt decreased. For the RTFO-aged asphalt, the residual penetration ratio and the softening point difference were large, indicating that the bio-asphalt underwent a certain degree of aging after heating. The content of bio-oil had a significant effect on the mass loss of the bio-asphalt. 2. For the unaged and RTFO-aged bio-asphalts with 5\(\%\) bio-oil, 5\(\%\)-S, and 10\(\%\)-S, the results indicated that the penetration, softening point, ductility, residual penetration ratio, mass loss, and other indicators, could meet the requirements of 50\(\#\) grade asphalt. 3. The phase angle, complex modulus, and rutting factors decreased gradually with the increase of temperature for the unaged and RTFO-aged asphalts, which indicated that the high-temperature performances of bio-asphalt decreased with increasing temperature. The sequence of the phase angle, complex modulus, and rutting factors with different contents of bio-oil showed different changes, which were caused by the aging of the bio-oil. 4. The temperature sensitivity of both the unaged and RTFO-aged asphalts did not display regularity. The temperature sensitivity of unaged bio-asphalt was lower than that of the matrix asphalt. When the bio-oil content was higher than 10\(\%\), the temperature sensitivity of RTFO-aged bio-asphalt was higher than that of the matrix asphalt. The temperature sensitivity of RTFO-aged bio-asphalt with 5\(\%\) content bio-oil was the smallest. 5. According to the frequency sweep test, the phase angle, storage modulus, loss modulus, and complex modulus of the unaged and RTFO-aged bio-asphalts and the matrix asphalt changed greatly with the change of frequency, at the lower frequency. When the frequency was greater than 5 Hz, the viscoelastic curve stabilized gradually. As the temperature increased, the phase angle increased gradually, and the storage modulus, the loss modulus, and the complex modulus decreased gradually, while the viscous component of the bio-asphalt increased. This was consistent with the results of the temperature sweep. 6. According to the mater curve analysis, the complex modulus and rutting factors of bio-asphalt with 5\(\%\) content bio-oil and 50\(\#\) matrix asphalt increased with the increase of frequency, from the low frequency to the high-frequency range. Unaged bio-asphalt with 5\(\%\) bio-oil content in the lower frequency range had considerable rutting resistance compared to the matrix asphalt. In contrast, at the higher frequency range, the complex modulus and rutting factors of bio-asphalt with 5% bio-oil were lower than those of the 50# base asphalt, which was superior to matrix asphalt in low-temperature anti-cracking performance. The RTFO-aged bio-asphalt with 5% bio-oil had a higher resistance to rutting than the matrix asphalt at the low and high-frequency ranges. * Chemical reactions occurred when the 50# base asphalt was mixed with bio-oil.