Application methods of used vegetable oil were investigated in asphalt rubber to temporarily decrease viscosity. It was found that linear unsaturated hydrocarbons effect the dispersion of rubber in asphalt and are at the same time sensitive for oxygenation reactions. By using the appropriate raw materials a 36-38% viscosity reduction was achieved with 0.1% vegetable oil. An Arrhenius model based rheological equation was developed to improve the
ability to estimate the viscosity decreasing effect achieved by applying various vegetable oil concentrations. By comparing the viscosity decrease with different polymer modified asphalts, it was found the transport processes between the vegetable oil and the crumb rubber further reduces the viscosity of the crumb rubber containing binders.