Optimum preparation and rheological properties of liquid rubber modified asphalt binder

Abstract

• The optimal preparation method of LRMA was provided. • As the increase of LR content, the high temperature performance decreased. • Low temperature cracking resistance of base asphalt can be enhanced by LR. • LR has greater improvement on fatigue resistance of base asphalt than CR. In order to overcome the limitations of crumb rubber modified asphalt (CRMA) in application such as the weak storage stability and construction workability, liquid rubber (LR) was adopted to improve the properties of base asphalt binder in this paper. The main research purposes are to explore the optimum preparation method and the rheological properties of liquid rubber modified asphalt (LRMA). Meanwhile, the modification effect of LR and crumb rubber (CR) on the rheological properties and micro characteristics of base asphalt binder was compared. Firstly, the optimum preparation method of LRMA was determined by analyzing the performance indexes of orthogonal experimental design. The results showed that the optimum combination of preparation parameters of LRMA is LR content of 8 wt%∼10 wt%, original CR of 60 mesh, reaction time of 1 h, and reaction temperature of 160 ℃. The modified asphalt binders containing 9 wt% LR and 9 wt% CR were prepared under optimum conditions. Next, scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), and differential scanning calorimetry (DSC) were carried out on base asphalt, LRMA, and CRMA. The results clarified that the thermal stability of LRMA are much better than that of CRMA. Moreover, the viscosity test results indicated that LRMA possesses excellent workability. Finally, the temperature sweep (TS), frequency sweep (FS), linear amplitude sweep (LAS), and bending beam rheometer (BBR) tests were conducted on three kinds of asphalt binder to analyze their rheological properties. The findings manifested that the addition of LR can slightly enhance the high-temperature rutting resistance of base asphalt binder, while has observably positive effect on the resistance to low-temperature cracking and fatigue.