Experimental evaluation of the effect of magnetite ore addition ratio on the X-ray shielding properties of concrete

In this study, the radiation shielding performance of magnetite ore (Fe₃O₄)-incorporated concretes was experimentally and theoretically investigated. Concrete mixtures were prepared by replacing standard sand with magnetite aggregate at ratios of 0%, 25%, 50%, 75%, and 100% (FO-0–FO-100). Microstructural characteristics were analyzed by FE-SEM/EDX, mechanical properties were evaluated through compressive strength tests, and X-ray attenuation performance was assessed under 6 MV photon irradiation using a medical linear accelerator (LINAC). Key shielding parameters, including linear attenuation coefficient (LAC), half-value thickness (HVT), and mean free path (MFP), were experimentally determined based on dose measurements. In addition, exposure buildup factor (EBF) and energy absorption buildup factor (EABF) were theoretically calculated using the EpiXS code. Results showed that increasing magnetite content produced a denser microstructure, higher Fe concentration, and improved mechanical performance, with compressive strength rising from 42.6 to 50.8 MPa. Radiation measurements demonstrated enhanced attenuation capability with increasing magnetite substitution, as indicated by higher LAC and reduced HVT and MFP values. Additionally, decreasing EBF and EABF values confirmed improved suppression of photon buildup effects. However, it should be noted that the attenuation results were obtained under polyenergetic clinical LINAC beam conditions rather than ideal narrow-beam geometry, and therefore represent effective shielding behavior under practical conditions. Furthermore, the relationship between microstructural features and radiation attenuation is interpreted qualitatively, and a direct quantitative correlation cannot be established within the scope of the study. The findings indicate that magnetite ore significantly enhances both mechanical and radiation shielding performance, making it a promising material for advanced shielding concrete applications. • Magnetite aggregate enhanced X-ray shielding under 6 MV LINAC beams • Linear attenuation increased while HVL and MFP significantly decreased • Compressive strength improved with increasing magnetite content • FE-SEM/EDX confirmed denser microstructure and higher Fe concentration • Magnetite concretes suppressed photon buildup (EBF and EABF reduction)