Assessment of the mechanical, radiation shielding, and durability of ultra-high-performance concrete for radiation shielding: A review

With structural concrete constituting the ultimate physical barrier in nuclear facilities, the safety of the latter is contingent on the quality of concrete used therein. A highly promising contender for propelling nuclear safety is ultra-high-performance concrete (UHPC). Given its intrinsically dense microstructure, exceptional mechanical properties, and superior durability, UHPC has the potential to provide better confinement of radioactive substances and higher radiation shielding, thereby enhancing the Defense in Depth strategy of nuclear facilities. Currently, published knowledge on radiation shielding UHPC (RS-UHPC) is both scarce and fragmented. This review is focused on how RS-UHPC ingredients, particularly heavyweight materials, affect mixture rheology, microstructure, mechanical performance, radiation shielding efficiency, and durability of the end product. The study also provides insights into how the various heavyweight materials affect the residual mechanical and radiation shielding capabilities of RS-UHPC post-exposure to elevated temperatures. Finally, while recapitulating existing relevant knowledge on how the RS-UHPC compositional domain can be tailored to achieve desirable performance, the article also identifies research gaps that need to be addressed to further extend RS-UHPC formulation boundaries. This, in turn, opens new vistas for enhancing RS-UHPC performance and unlocks the versatile potential of this material for research communities in concrete technology and nuclear safety alike.