Investigation of the rheological properties and micromorphology of waste plastic/bio-oil modified asphalt

This study investigated the feasibility of waste plastic/bio-oil modified asphalt (PBMA). The rheological behavior and micromorphology of PBMA were investigated. The results demonstrated that PBMA exhibited better storage stability. As the bio-oil content was 10 %, increasing the waste plastic dosage from 9 % to 12 % and 15 % resulted in a viscosity increase of 43mPa·s and 85mPa·s. The addition of waste plastic significantly improved the high-temperature rutting resistance, as reflected by the increased rutting index, higher recovery rate, and lower Jnr. However, the waste plastic negatively affected the low-temperature performance. As the waste plastic content was 12 %, increasing the bio-oil dosage from 12 % to 15 %, the m-value of PBMA increased by 16 %, and the stiffness modulus decreased by 11.6 %. The bio-oil enhanced the crack resistance of asphalt at −18°C. Compared to neat asphalt, the fatigue behavior of PBMA showed a substantial improvement. When the bio-oil dosage was 10 %, the optimal dosage of waste plastic should be set at 12 %. As the bio-oil dosage was 15 %, the waste plastic dosage should be increased to 15 %. The uniform dispersion of fluorescent structures was observed in PBMA 12–10 and PBMA 15–15, indicating complete dissolution of waste plastic in bio-asphalt. The SEM micromorphology indicated that the three-dimensional network appeared in modified asphalt. The utilization of waste plastic and bio-oil in modified asphalt promotes sustainable practices in road construction.