Investigation of gamma ray shielding efficiency and mechanical performances of concrete shields containing bismuth oxide as an environmentally friendly additive

Concrete has a proven ability to attenuate gamma rays and neutrons without compromising structural property; therefore, it is widely used as the primary shielding material in many nuclear facilities. Recently, there is a tendency toward using various additives to enhance the shielding properties of these concrete mixtures. However, most of these additives being used either pose hygiene hazards or require special handling processes. It would be ideal if environmentally friendly additives were available for use. The bismuth oxide (Bi₂O₃) additive shows promise in various shielding applications due to its proven radiation attenuation ability and environmentally friendly nature. To the best of our knowledge, however, Bi₂O₃ has never been used in concrete mixtures. Therefore, for this research, we fabricated the Bi₂O₃-based concrete mixtures by adding Bi₂O₃ powder in the ordinary concrete mixture. Concrete mixtures with lead oxide (PbO) additives were used for comparison. Radiation shielding parameters like the linear attenuation coefficients (LAC) of all these concrete mixtures showing the effects of the Bi₂O₃ additions are presented. The mechanical performances of concrete mixtures incorporated with Bi₂O₃ additive were also investigated. It suggested that the concrete mixture containing 25% Bi₂O₃ powder (B5 in this study) provided the best shielding capacity and mechanical performance among other mixes. It has a significant potential for application as a structural concrete where radiological protection capability is required. - Highlights: • Environmentally friendly Bi₂O₃ can be added in concrete for shielding γ-rays. • γ-ray shielding properties improve with both the Bi₂O₃ and PbO additives. • Bi₂O₃-loaded concretes own superior attenuation at 0.01–1 MeV γ-rays. • 25% Bi₂O₃-loaded concrete provided the best shielding and structural capability.