Study on rheological properties of warm mix large proportion recycled asphalt

Abstract

In order to explore the rheological properties of high content warm mix recycled asphalt binder, recycled asphalt was added into warm mix asphalt to prepare warm mix recycled asphalt. The optimum content of regenerant and Sasobit REDUX was determined by asphalt basic performance test and temperature scanning test. The chemical composition of recycled asphalt was studied by FITR. The rheological properties and low temperature crack resistance of warm mix recycled asphalt were analyzed by DSR and BBR tests, and the optimum content of recycled asphalt was determined. The results show that when the content of regenerant is 10%, its basic performance recovers to the level of base asphalt. Sasobit REDUX can reduce the high temperature viscosity of asphalt, and the optimum content is 1%. With the increase of recycled asphalt content, the shear modulus and phase angle of warm mix recycled asphalt gradually decrease, and its high temperature stability gradually increases. Under low frequency and high temperature conditions, warm mix recycled asphalt with 50% content has better high temperature deformation resistance. Under the action of stress, the strain accumulation decreases with the increase of the content of recycled asphalt. When the content of recycled asphalt is 50%, the ability of warm mix recycled asphalt to resist load deformation and temperature sensitivity in the middle temperature zone is similar to that of matrix asphalt, and it has good deformation resistance and low temperature crack resistance. Comprehensive analysis of the best content of recycled asphalt should be 50%, then warm mix recycled asphalt mixture has excellent road performance.

Keywords

• pavement engineering
• rheological properties
• sasobit REDUX
• recycled asphalt
• infrared spectroscopy