Sustainable and high-performance solutions for radiation shielding in concrete: Recent advances and future directions

Radiation safety is a critical concern in nuclear power plants, medical, and industrial sectors. The three key factors of concrete to qualify its shielding effectiveness are density, thickness, and composition. Recently, researchers have focused on developing cost-effective, safe, and sustainable materials. The use of dense aggregates, such as barite or magnetite, reduces gamma-ray penetration. To produce greener shielding concrete, industrial by-products are used to partially replace cement, thereby refining its microstructure. Some investigators are developing entirely new, low-carbon recipes using geopolymers, which exhibit superior performance when combined with heavy fillers. Moreover, including nanoparticles and fibers further improves crack resistance and mechanical strength. Next-generation concrete offers a balanced solution combining structural performance, cost, sustainability, and radiation attenuation compared with conventional shielding materials (e.g., lead). This review integrates radiation physics, materials engineering, and future directions within a unified framework to guide research and practical implementation. Compared with recent major reviews, the article explicitly positions its contribution and provides a structured synthesis that links attenuation mechanisms to mix-design decisions, while adding dedicated coverage of UHPC-based shielding systems and a comparative sustainability–shielding trade-off analysis to highlight practical limitations and research gaps.