Experimental investigation of the shielding performance of ulexite-added cement-based composites against X-ray, gamma, and neutron radiation

This study experimentally analysed the effect of ulexite, a boron-based natural mineral, on the gamma and neutron radiation shielding properties and mechanical behaviour of cement-based composites. Control samples with no ulexite and composite specimens containing 1%, 5% and 10% dehydrated ulexite by weight were prepared. The results showed that increasing the ulexite content considerably improved the attenuation performance against both X-ray and gamma radiation, as well as neutrons. Significant enhancements were observed in the mass attenuation coefficient (μ/ρ), particularly at low energies. For example, at 13.375 keV, μ/ρ increased from 18.7 cm2/g in the control sample to 19.1 cm2/g in the sample containing 10% ulexite. In neutron shielding experiments, the macroscopic removal cross-section (ΣR) showed a marked increase from 0.248 cm−1 to 0.400 cm−1 with the addition of 10% ulexite. However, mechanical tests revealed that the addition of ulexite significantly reduced the 7-day compressive strength, dropping from 32.4 MPa to 1.99 MPa due to boron's retarding effect on cement hydration. While these composites are not suitable for primary load-bearing structures, the results reveal that their high shielding capacity and environmentally friendly nature make them attractive candidates for non-load-bearing applications in nuclear safety and radiation protection.