Application of high percentage of RAP in asphalt mixture: Blending process and performance investigation

This study performed laboratory investigation of applying high percentage of reclaimed asphalt pavement (RAP, up to 50%) in asphalt mixture. The properties of aged binder were first determined and the rejuvenator and SBR latex were used to restore the binder properties. The optimum dosage of the rejuvenator and SBR additive are 2% and 4% of aged binder mass, respectively. Then the preheating temperatures of aggregate were determined according to the RAP content to meet the mixture temperature requirement. The effects of blending process, especially the feeding sequence of materials, on the mixture performances were investigated. This study recommended to add rejuvenator to RAP first and then SBR latex to mixture with a blending duration of 180 s.