Microstructural, Elemental, and Density Characterization of Bismuth-Clay-Reinforced Cement–Sand Composites for Radiation Shielding Applications

Cement-based composites reinforced with high atomic number additives are increasingly investigated as environmentally sustainable alternatives to conventional lead-based radiation shielding materials. This study evaluates the microstructural, elemental, and physical characteristics of cement–sand composites reinforced with bismuth clay, with emphasis on parameters governing photon attenuation. Composite samples containing 0 g, 10 g, and 20 g of bismuth clay were fabricated and characterized using density measurements, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). Results revealed progressive microstructural densification, reduced porosity, and improved particle packing with increasing bismuth content. EDS confirmed successful incorporation and uniform dispersion of bismuth-rich phases within the cement matrix. Density increased systematically with both bismuth concentration and sample thickness. Given the dependence of photon attenuation on density and atomic number, the observed structural and compositional enhancements indicate strong potential for radiation shielding applications. The study establishes a foundational basis for further quantitative gamma-ray and X-ray attenuation investigations.