Concrete Mix Design Using Recycled Aggregates: Analysis of Review Papers, Characteristics, Research Trends and Underexplored Topics

Recycled concrete aggregate (RCA) has been widely adopted in construction and emerged as a sustainable alternative to conventional natural aggregates in the construction industry. This review paper aims to provide a comprehensive analysis of RCA, highlighting its properties, applications, and overall sustainability benefits. The paper explores the manufacturing process of RCA, examines its mechanical and durability characteristics, and investigates its environmental impacts. Furthermore, it delves into the various applications of RCA, such as road construction materials, pavement bases, and concrete materials, considering their life cycle performance and economic considerations. This review reveals that there is a need for systemic data collection that could enable automated concrete mix design. The findings of this review shed light on the potential of RCA as a viable solution to reduce resource depletion and waste generation while promoting sustainable construction practices. The critical research gaps now are durability of RCA concrete, feasibility analysis, and implementation of treatment methods for RCA improvement. An effective life cycle assessment tool, digitalization technologies, can be applied to enhance its sustainability. The equivalent mortar volume method to calculate the RCA concrete mix design, which can contain metakaolin and fibers, needs further assessment.