Industrial Waste Utilization in 3D Printable Concrete for Artificial Reef Applications: A Bibliometric Analysis (2013–2023)

The accelerating decline of coral reef ecosystems has intensified the search for sustainable restoration strategies. Artificial reefs (ARs) are widely recognized for their capacity to provide structural complexity and habitats for marine organisms. Recent advances in additive manufacturing, particularly 3D printable concrete (3DPC), create opportunities to design ARs with optimized geometries, tailored surface textures, and eco-friendly material blends. This review explores the role of industrial wastes in 3DPC for AR applications and examines global research progress between 2013 and 2023. By combining bibliometric mapping with qualitative synthesis, the study provides both a quantitative overview of research activity and thematic insights into material and ecological performance. The analysis highlights the rapid growth of interest in sustainable marine construction, the integration of industrial by-products such as fly ash and slag into 3DPC, and the emergence of interdisciplinary research bridging construction science and marine ecology. Beyond technical advantages such as improved strength and durability, these materials directly influence ecological outcomes by enhancing surface roughness, porosity, and long-term stability, which are critical for species colonization and biodiversity support. The findings reveal significant research gaps, particularly in standardized design protocols, ecological monitoring, and long-term performance evaluation. This study contributes a comprehensive perspective on how waste-based 3DPC can support sustainable reef restoration, while outlining future directions for advancing eco-friendly marine infrastructure.