Evaluation of viscosity-temperature characteristics and rheological properties of rejuvenated SBS modified bitumen with active warm additive

The regeneration and utilization of reclaimed SBS modified bitumen require a high mixing and paving temperature, which result in a large of energy consumption and serious environment pollution. To reduce the mixing and paving temperature, polyethylene wax and active wax were selected to modify rejuvenated SBS modified bitumen, and their influences on the viscosity-temperature characteristics, physical and rheological properties of rejuvenated binder were thoroughly investigated in this research. The results indicate that active wax with epoxy terminal group shows a better performance on reducing the mixing and paving temperature of rejuvenated binder as compared with polyethylene wax. Meanwhile active wax modified rejuvenated binder shows the lowest flow activation energy 79.78 kJ/mol, indicating active wax is more helpful to improve the temperature sensitivity of rejuvenated binder at high temperature. Differential scanning calorimetry analysis shows the melting enthalpy of active wax is larger than that of polyethylene wax and polyethylene wax is easier to crystallize and solidify. These two warm additives all can improve the rutting resistance of rejuvenated binder. However, the cracking resistance of rejuvenated binder seriously decreases with the addition of polyethylene wax. While active wax could react with the active groups in rejuvenated binder that can inhibit the transition from viscosity to elasticity of rejuvenated binder and retain its excellent low-temperature performance more effectively as compared with polyethylene wax. (C) 2019 Elsevier Ltd. All rights reserved.