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There are many types of asphalt anti-UV aging agents, and the differences in their UV resistance mechanisms result in varying degrees of UV aging resistance. This study utilized three types of anti-UV aging agents to modify asphalt. These include a UV reflector (TiO2), a hindered amine light stabilizer (HALS, LS770), and a UV absorber (UV326). The contents were 0.5%, 1%, and 1.5%. When the dosages of TiO2, LS770, and UV326 were 1.5%, the rutting factors of the modified asphalt at 64 °C increased by 61.18%, 43.54%, and 34.18%, respectively. As the dosage of LS770 and TiO2 increased, the rutting factor of the modified asphalt was gradually enhanced. However, the rutting factor of UV326-modified asphalt did not gradually increase with an increasing dosage of UV326. The recommended content of TiO2 and UV326 was 0.5%, at which the rutting factor aging index (RFAI) was approximately 75%. The recommended dosage of LS770 was 1%, at which the RFAI was only 35.23%. Compared to TiO2 and UV326, LS770 exhibited superior UV aging resistance. FM test results indicated that the fluorescent substance did not produce agglomeration in the modified asphalt. TiO2, LS770, and UV326 were well dispersed throughout the asphalt. The carbonyl and carboxyl aging indexes of UV-aged LS770-1% (LS770 dosage is 1%) were lower than those of UV-aged TiO2-0.5% and UV-aged UV326-0.5%. The anti-UV agents effectively protected the asphalt's structure, reducing surface degradation and preserving its integrity under prolonged UV exposure. The microscopic morphology of anti-UV aging agent-modified asphalt aligns closely with the conclusions drawn from rheological behavior results, indicating that LS770-1% provides excellent UV aging resistance. [ABSTRACT FROM AUTHOR]

A large amount of soybean oil (20%–30% mass ratio of neat asphalt) was selected to partially replace petroleum asphalt. The high-temperature behavior of soybean oil bioasphalt was enhanced by polyphosphoric acid (PPA). Polyphosphoric acid/soybean oil composite modified asphalt (PSMA) was prepared. Temperature sweep, frequency sweep, multiple stress creep recovery, and bending beam rheometer tests were conducted to reveal the rheological behavior. Fourier infrared spectroscopy (FTIR), scanning electron microscope, and fluorescence microscope tests were carried out to reveal its microstructure characteristic. The results proved that polyphosphoric acid obviously increased the high-temperature properties of soybean oil bioasphalt. Compared with the neat asphalt at 0.1 kPa, the recovery rates of 20% bio/6% PPA, 25% bio/6% PPA, and 30% bio/6% PPA increased by 139.2%, 113.5%, and 86.4% respectively. PSMA was less sensitive to temperature and loading frequency, with remarkable elastic recovery and antirutting degeneration ability. PSMA could maintain excellent low-temperature crack resistance at −18°C. PSMA had better rheological properties when soybean oil and PPA were 20%–25% and 4%–6%, respectively. The FTIR tests verified that some new functional groups emerged in PSMA. There were evenly distributed fluorescent materials in the soybean oil bioasphalt under the fluorescence microscope. Under the modification effect of PPA, soybean oil and PPA could be evenly dispersed in PSMA. Laboratory tests verified the superior properties of bioasphalt with high content soybean oil. [ABSTRACT FROM AUTHOR]