A systematic review on rejuvenators in flexible asphalt pavement: types, content, methods, performance, and applications

Abstract The use of recycled asphalt materials represents an effective approach to creating sustainable road surfaces, contributing to the preservation of raw resources and energy. However, excessive use of these waste materials can result in structural issues, particularly concerning durability, which may manifest as cracks and surface degradation, largely due to the significant presence of aged binders. To mitigate these problems and reduce the complications associated with the use of deteriorated binders, the incorporation of rejuvenators has become increasingly popular. This paper reviews the application of various recycling agents within the paving industry and their effects on the properties of aged bitumen. Additionally, it examines methods for determining the optimal amount of rejuvenator to be used in bitumen and asphalt mixtures, enhancing their mechanical properties and durability. The discussion includes applications such as capsules, microcapsules, and microvascular systems (self-healing techniques) for rejuvenating aged binders and the underlying mechanisms of rejuvenation. This review aims to guide researchers in identifying potential avenues for further exploration regarding the use of rejuvenators in the asphalt sector.