The property evaluation of recycled asphalt binder composed of an epoxy resin polymer and aged asphalt binder

Abstract

The reutilization of reclaimed asphalt pavement (RAP) is gaining importance in meeting the objectives of green and sustainable environmental policies. Meanwhile, epoxy asphalt (EA) is not widely used due to its high price. To facilitate the utilization of EA in RAP recycling, this study adopted an epoxy polymer (EP) to prepare the recycled asphalt binder and investigate the effects of different EP content on the properties of aged asphalt binder. Evaluation encompassed mechanical, microstructural, and chemical characteristics of EP-recycled asphalt (ERA) binders, which were compared against virgin EA binders. The addition of EP can significantly enhance the tensile strength, high-temperature properties, low-temperature properties, and fatigue resistance of the aged asphalt binder. However, the elongation of the aged asphalt binder became worse. As the EP content increased from 30% to 50%, the tensile strength, high-temperature properties, fatigue resistance, and construction allowance time of ERA consistently improved, while the elongation of ERA steadily decreased. A phase transition occurred between asphalt binder and EP phase as EP increased from 40% to 50%, resulting in a rapid increase in tensile strength, high-temperature properties, and fatigue resistance of ERA, as well as a significant reduction in elongation and low-temperature properties of ERA. The concentration of sulfoxide decreased as the EP content increased. The performance gap between EA and ERA was not significant under the same EP content. The EP content had a greater impact than the aging degree of asphalt binder on the properties of the ERA. A recommended EP content of 40% was suggested.