Properties of Asphalt Binder Containing Its Combustion Residue

Incorporating reclaimed asphalt pavement (RAP) materials directly into a rotary drum dryer to mix with virgin aggregates in a high-heat environment will produce binder residue. The characterization and potential effects of this combustion residue on the properties of asphalt binders remain unclear. Therefore, this study obtained the combustion residue and clarified its effect on asphalt binder performance. Initially, the physicochemical, morphological, and elemental characteristics of combustion residue were determined. Subsequently, the effect of the combustion residue on asphalt binder properties was analyzed using the rotational viscosity (RV) test, dynamic shear rheometer (DSR), bending beam rheometer (BBR) equivalent test, and atomic force microscopy (AFM) test. The findings revealed that the addition of combustion residue significantly affected the viscosity and high-temperature performance of virgin binder, and had a slight effect on the low-temperature crack resistance. Asphalt binder containing combustion residue exhibited more elastic behavior than virgin binder at lower frequencies or higher temperatures, and had similar viscoelastic performance at higher frequencies or lower temperatures. Additionally, asphalt binder containing combustion residue had enhanced elastic recovery compared to virgin binder. The addition of combustion residue improved the fatigue life of asphalt binder by more than 30% and enhanced its resistance to crack propagation. Furthermore, it increased the surface microroughness and AFM modulus of the virgin binder.