Impact of distillation temperature on the solvent residue and viscoelastic properties of asphalt binders

Asphalt used as a paving material is a mix of aggregates and bituminous binder. Due to reasons of acceptance tests after paving or for fault analysis, it is necessary to separate asphalt mixes into their components. Therefore, different organic solvents are commonly used. The European Standard defines a procedure for both, recovery of aggregates and the distillation of binder from solvent mixture. Within the distillation procedure, the applied maximum temperature and the time of its application are not defined clearly. This research is an approach to define the distillation temperature depending on the viscosity of the binder. Four different binder samples (unmodified, polymer-modified) were used to determine the impact of distillation temperature on solvent residue and the recovered binder and its rheological properties. The solvent residue was calculated by weight and the binder properties were obtained by a dynamic shear rheometer and rotational viscometer. These results show a dependence of the solvent residue on the viscosity at distillation temperature. Thus, it is possible to choose reasonable distillation temperatures with regard to binder viscosity instead of setting one temperature for all binders. It was also found that there is no impact of tetrachloroethene as solvent on the binder properties if its residue is low enough (<1% w/w).