Review on radiation-shielding concrete: Advances in aggregate characterization, performance evaluation, and predictive modeling.

Radiation shielding is essential in nuclear energy, medical radiation facilities, space applications, and other environments exposed to ionizing radiation. Recent research has increasingly focused on improving shielding performance while reducing material weight, thickness, cost, and environmental impact. This review critically examines recent developments in radiation-shielding materials, with particular emphasis on radiation-shielding concrete, concrete aggregates, and predictive models used to evaluate and optimize their attenuation performance. The review summarizes the effects of aggregate composition, density, elemental constituents, microstructure, and material formulation on the attenuation of gamma and neutron radiation. Particular attention is given to experimental characterization methods and computational approaches, including attenuation measurements, spectroscopic and microstructural characterization, and Monte Carlo simulations, which provide complementary information on radiation transport and shielding effectiveness. Recent advances in the development of heavyweight, modified, and composite concretes are discussed, together with emerging approaches for improving shielding performance through optimized aggregate selection and concrete composition. The review also evaluates predictive and computational models developed to estimate key shielding parameters and support material optimization, highlighting their advantages and limitations relative to experimental measurements. Sustainable and locally available aggregate sources, as well as strategies for reducing shielding material requirements without compromising radiation protection, are also considered. By integrating experimental evidence with computational modeling, this review identifies current knowledge gaps and future research priorities for the development of high-performance and economically viable radiation-shielding concretes. Overall, the reviewed studies demonstrate that systematic control of aggregate characteristics, concrete composition, and predictive modeling can provide an effective pathway toward more efficient and application-specific radiation-shielding materials.