Emission characteristics and mechanisms of VOCs in recycled asphalt incorporating rejuvenators

Abstract

Rejuvenators play a key role in restoring the performance of aged asphalt and promoting the recycling of asphalt pavement materials. However, their impact on volatile organic compounds (VOCs) emissions from recycled asphalt remains poorly understood. This paper presents the first systematic investigation into the VOCs emission behavior of recycled asphalts incorporating rejuvenators. Results show that rejuvenators not only restore aged asphalt performance but also activate macromolecular compounds formed during aging. The VOCs emission characteristics vary with the type of rejuvenator: dilauryl thiodipropionate, with a simple composition, releases fewer VOC types but higher peak areas due to thermal decomposition into alkanes and oxygenated compounds; recycled vegetable-oil bottom and recycled bio-oil bottom, rich in light components, generate more diverse and complex VOCs. VOC emission characteristics from recycled asphalt depend on its physicochemical properties, such as Saturate, Aromatic, Resin, and Asphaltene components and molecular weight distribution.