The performance of hot-recycling asphalt binder containing crumb rubber modified asphalt based on physiochemical and rheological measurements

Abstract

The stabilized crumb rubber modified asphalt is gaining attention from the researchers because of its excellent road performance and the environmental-friendly characteristic. Traditionally, the high-temperature performance of the hot-recycling asphalt binder was improved by adding low-viscosity recycling agent. In this paper, the stabilized crumb rubber modified asphalt was studied to investigate its improvement on physiochemical and rheological properties of the hot-recycling asphalt binder, especially high-temperature performance compared with traditional low-viscosity recycling agent. Three types of asphalt with different ingredients were investigated in this paper: (1) asphalt binder contains aged asphalt and crumb rubber modified asphalt; (2) asphalt binder contains aged asphalt and recycling agents; (3) asphalt binder contains aged asphalt, crumb rubber modified asphalt and recycling agents. The matrix asphalt, aged asphalt and stabilized crumb rubber modified asphalt was set as the control group. The physiochemical properties were evaluated by Fourier Transform Infrared Spectroscopy (FTIR), Gel Permeation Chromatography (GPC) and Atomic Force Microscopy (AFM). Moreover, the rheology experiments such as Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) were carried out to assess the practical performance of the three types of asphalt binder. In conclusion, it could be found that the mixing condition of different ingredient in the asphalt binder was mainly caused by physical mixing. Asphalt binder contains crumb rubber modified asphalt and aged asphalt was recommended considering the high and low-temperature performance. The optimal proportion was: 50% crumb rubber modified asphalt and 50% aged asphalt considering the economic benefits and rheological behaviors. In the extremely low-temperature environment, the high and low performance of crumb rubber modified asphalt and recycling agents in hot-recycling field still needs more investigation.