Effects of Environment-Friendly Rejuvenator on the Rheological Properties and Microstructure of Aged Asphalt

The purpose of this paper is to explore the feasibility of using waste soybean oil and the multi-epoxy compound trimethylolpropane triglycidyl ether (TMPGE) compound as a rejuvenator to recycle aged styrene-butadiene-styrene (SBS)-modified asphalt, and to develop an environment-friendly SBS-modified asphalt rejuvenator (ESMAR) to achieve dual waste reuse. The optimum ratio of each component of ESMAR and the production conditions of the formulation were firstly determined by the orthogonal test method. To evaluate the rejuvenation effect of ESMAR, the physical properties and rheological properties of SBS-modified asphalt before and after rejuvenation were studied. Physical properties test results showed that ESMAR can effectively soften the aged asphalt and decrease its softening point and viscosity, as well as increase its needle penetration. As far as rheological properties are concerned, ESMAR could improve the low-temperature cracking resistance and fatigue resistance of aged SBS-modified asphalt; however, there was a certain reduction in the rutting resistance. The microscopic characteristics of the rejuvenation of ESMAR were analyzed by fluorescence microscopy, infrared spectroscopy, and gel permeation chromatography tests for the aged SBS-modified asphalt before and after rejuvenation, which showed that ESMAR can not only reconstruct the degraded SBS molecules in the aged SBS-modified asphalt, but also has a “dilution” effect on the aged asphalt.