Understanding the effects of different aggregates on the neutron and gamma radiation shielding properties of ultra-high performance concrete using Monte Carlo methods

The aim of this study was to investigate the mechanical properties and shielding performance of UHPC produced with magnetite, barite, hematite, and limonite aggregates. The linear attenuation coefficients (mu) of UHPC containing different aggregates have been calculated using both the Geant4 program and XCom code, and compared with experimental data. In addition, the mechanical properties, density, buildup factors, and the effective fast neutron removal cross-section (& sum;R) of these UHPC specimens were also investigated. It was concluded that the mu values of samples containing magnetite, barite, and hematite increased with increasing aggregate content, while the mu values of limonite-loaded UHPC initially increased and then decreased with the increase of aggregate content. The HVL and TVL values for samples containing magnetite, barite, and hematite aggregates, as calculated by the Genat4 code, decreased linearly with the increase of aggregate content. It should be noted that when a single aggregate was utilized, the & sum;R value of the UHPC sample containing magnetite was the largest, followed by hematite, and barite was unsuitable as an aggregate for neutron shielding in UHPC. Furthermore, the EABF and EBF values for UHPC containing different aggregates were lower than those produced with quartz sand, with the exception of a few specific values. The findings of this research will provide a reference for the design of radiation-resistant UHPC in the future.