An Examination of Reclaimed Asphalt Pavement's Role as Aggregate in the Composition of Structural Concrete: An Extensive Overview

Abstract

The process of renovating flexible pavement produces an extensive amount of reclaimed asphalt pavement (RAP). These aggregates are frequently discarded, whether through legal or illegal means, in nearby locations, thereby creating various challenges for regulatory bodies. The incorporation of these aggregates into portland cement concrete (PCC) mixtures represents an innovative strategy that could yield significant socio-economic and environmental advantages. Nonetheless, the inclusion of RAP aggregates may also adversely impact both the soundness and performance characteristics of the concrete. This paper delivers a detailed and critical evaluation of the practicality of employing RAP aggregates in concrete production, while also pinpointing several shortcomings that must be rectified to enhance sustainability in construction methodologies. This paper is structured in the following manner: it initiates with a detailed characterization of RAP aggregates, followed by an analysis of the characteristics of fresh concrete containing RAP, and culminates in an exploration of RAP containing concrete mechanical and durability characteristics. According to the literature review, it is evident that aggregates derived from RAP are generally of a lower quality than their natural counterparts. This may not pose a significant issue regarding the characteristics of the fresh concrete. The asphalt film and the presence of agglomerated particles within the RAP were identified as key factors contributing to the diminished strength and durability characteristics. The integration of RAP as aggregates has been associated with notable advantages, including improved toughness. Furthermore, existing research suggests that the performance of concrete containing RAP can be enhanced through the processing of RAP in conjunction with using supplementary cementitious materials (SCMs) or fibres