Radiation Shielding Properties of High-Density Concrete Incorporating Nigerian Barite Aggregate: A Theoretical and Experimental Investigation

This study presents a combined theoretical and experimental investigation of the radiation shielding properties of high-density concrete incorporating barite aggregate sourced from the Azara barite deposits in Nasarawa State, North Central Nigeria. Medical radiation facilities and industrial radiography installations are expanding in Nigeria, creating demand for radiation shielding materials, and the availability of significant barite reserves within the country provides strategic motivation for locally produced shielding concrete. The theoretical component applies Monte Carlo N-Particle (MCNP6) transport code simulations to model photon attenuation coefficients, mean free path, and half-value layer for barite concrete compositions across gamma ray energies from 0.1 to 10 MeV. The experimental component produces barite concrete specimens with barite partial and full replacement of conventional coarse aggregate (0, 25, 50, 75, and 100 percent) at a target density range of 2800 to 3500 kg/m3. Linear attenuation coefficients are measured experimentally using calibrated Cs-137 and Co-60 gamma sources and a scintillation detector system. Compressive strength, flexural strength, and density are measured following standard procedures. Findings show excellent agreement (within 4 percent) between MCNP6 predictions and experimental attenuation values. Full barite replacement achieves half-value layer reduction of 38 percent relative to normal density concrete at Co-60 energy. Keywords: radiation shielding, barite concrete, Monte Carlo simulation, Nasarawa State, gamma attenuation.