Effect of aggregate and fibre types on ultra-high-performance concrete designed for radiation shielding

This research examines the properties of ultra-high-performance (UHPC) and heavyweight radiation shielding concrete (UHPHSC). Several types of heavy-weight fine aggregates (sand, magnetite, hematite ilmenite and barite) were used to achieve these properties. In addition, the different types of fibres (steel fibre, lead fibre and basalt fibre) with a volume fraction of 2% were used. The fresh properties of workability and density, and hardened properties of compressive strength, splitting tensile strength, flexural strength, and water permeability were studied. Radiation attenuation was measured at two different gamma-ray energies at 137Cs0.662 and 60Co 1.173 (MeV) sources. Linear attenuation coefficient, half-value layer and tenth-value layer were evaluated. UHPHSCs were exposed to different temperatures at 22 °C, 250 °C, 500 °C and 750 °C to study their effect on the compressive strength and the mechanical shielding properties of gamma rays. The highest density of concrete, 3850 kg/m3, was achieved using magnetite aggregate and steel fibre. Although the highest compressive strength of 180.6 MPa was achieved using Ilmenite aggregate and steel fibre, the best radiation protection properties were achieved using lead fibre and magnetite aggregates.