Study on the Blending Behavior of Aged and Virgin Asphalt in Process of Hot Recycling

To accurately measure the participation degree of aged asphalt in process of hot recycling and optimize the mixing process of hot recycled asphalt mixtures, a series of laboratory tests were designed, including key procedures such as separating the new mineral aggregates and reclaimed ones, separating the asphalt and aggregate and calculating blending degree. The influences of mixing amount of reclaimed asphalt pavement (RAP), mixing orders, mixing time, mixing temperature, the thickness of asphalt film, and mixing amount of rejuvenating agent on blending degree of aged and virgin asphalt in process of hot recycling were evaluated by in-laboratory tests. The results indicated that the aged and virgin asphalt cannot be completely blended in the mixing process of hot recycled asphalt mixture and the blending degree is only about 40%~60%. The blending degree of aged and virgin asphalt decreases with the increase of thickness for asphalt film in the process of hot recycling. And it will be improved accordingly when the mixing amount of RAP, mixing amount of rejuvenating agent, mixing time, and mixing temperature are increased appropriately. In this paper, the quantization of the blending behavior of aged and virgin asphalt in process of hot recycling was studied by using Thin-Layer Chromatography with Flame Ionization Detection (TLC-FID) for the first time.