Recycled Aggregate Concrete Research (1983–2025): A Global Bibliometric and Thematic Evolution Analysis for Sustainable Material Design

The rapid expansion of sustainable construction practices has significantly increased research on recycled aggregate concrete (RAC) over the past four decades. However, despite the growing volume of studies, a comprehensive longitudinal assessment of the thematic and structural evolution of RAC research remains limited. This study presents a bibliometric and thematic evolution analysis of global research on recycled aggregate concrete from 1983 to 2025, based on 1624 documents indexed in Scopus and analyzed using PRISMA guidelines and VOSviewer mapping techniques. Results reveal four indicative stages of development: (i) an exploratory feasibility phase focused on compressive strength and replacement ratios (1983–2000); (ii) a mechanical validation phase emphasizing durability and interfacial transition zone performance (2000–2010); (iii) a performance enhancement phase integrating supplementary cementitious materials and service-life assessment (2010–2018); and (iv) a recent sustainability-driven phase characterized by life-cycle assessment, circular economy frameworks, and emerging AI-assisted optimization approaches (post-2018). China, India, and the United States dominate scientific production, while co-citation networks highlight the consolidation of specialized yet interconnected research communities. Keyword evolution analysis indicates a progressive shift from mechanical feasibility toward environmental impact mitigation and predictive modeling. Despite substantial advances, research gaps persist in tropical climate performance assessment, full-scale structural applications, and standardized mix-design methodologies for high-replacement RAC. The findings provide a structured understanding of the intellectual structure and evolution of the field, offering guidance for future research directions and performance-based sustainable concrete design strategies.