Enhancing the High-Temperature Performance and Aging Resistance of Bioasphalt by Composite Modification

The aim of this study is to enhance the high-temperature performance and aging resistance of bioasphalt by composite modification. Biorubber composite–modified asphalts with waste rubber powder and various amounts of bio-oil were researched. Meanwhile, the control groups were bioasphalt and rubber asphalt. The aging simulation of asphalt was conducted in laboratory tests. Moreover, the rotational viscosity, viscoelastic properties, deformation resistance, antiaging properties, and crack resistance of asphalt were explored in this study. The addition of rubber powder was found to increase the rotational viscosity of bioasphalt to some extent, but it can still meet the technical requirements for construction workability. The rubber powder swells in asphalt, which increases the elastic component of binder and its complex shear modulus. Consequently, the biorubber composite–modified asphalt demonstrates outstanding resistance to high-temperature rutting and aging, as well as superior low-temperature cracking resistance. Optimal antirutting and crack resistance were attained with 10%–15% bio-oil, and the best aging resistance was achieved with 10% bio-oil. Short-term aging promoted the polymer chains of rubber powder to absorb more light components, forming more gel-like substances that were unevenly distributed in the binder system, thereby reducing the fluidity of asphalt and enhancing the flow activation energy. Incorporating rubber powder significantly enhanced the asphalt’s resistance to permanent deformation under low stress levels and exhibited excellent resistance to deformation under high stress levels. The recommended composite-modified asphalt incorporates 10%–15% bio-oil.