Laboratory Evaluation of the Residue of Rubber-Modified Emulsified Asphalt

Emulsified asphalt has been widely used in various surface treatment methods such as chip seal for low-volume road preservation. Using modified emulsified asphalt made it possible to use chip seal technology on medium- and even high-volume traffic pavements. The main objective of the study is to quantify the residue characteristics of rubber-modified emulsified asphalt and to assess the effectiveness of using crumb rubber to modify emulsified asphalt binder. The four emulsified asphalt residues used the distillation procedure. Then, the rheology characteristics of emulsified asphalt residue were evaluated. The Fourier transform infrared spectroscopy (FTIR) test analyzed the chemical change of emulsified asphalt during the aging procedure. The results indicate that the evaporation method cannot remove all the water in emulsified asphalt. The mass change during the rolling thin film oven (RTFO) process only represented the component change of emulsified asphalt binder residue. Both the high-temperature and low-temperature performance grade of the two emulsified asphalt binders with rubber were lower. The original asphalt binder adopted to emulsification had a crucial influence on the performance of emulsified asphalt. The rubber modification enhanced the property of the emulsified asphalt binder at low temperatures, and the improvement effect was enhanced as the rubber content in the emulsified asphalt was raised. The C=O band was more effective in quantifying the aging condition of the residue. The findings of this study may further advance the emulsified asphalt technology in pavement construction and maintenance.