Influence of heavyweight aggregates on the physico-mechanical and radiation attenuation properties of serpentine-based concrete

Abstract

To highlight the impact of barite and hematite addition on selected physical, mechanical, and radiation attenuation properties of serpentine concrete (A), different replacement ratios of barite and hematite aggregates (25, and 50% by volume) were used separately. The physico-mechanical properties of the prepared serpentine-barite (AB25, 50) and serpentine-hematite (AH25, 50) concrete mixes compared to those of the control (A) were evaluated. The radiation shielding properties of these concrete mixes against both γ-ray and thermal neutrons were experimentally measured. The linear attenuation coefficient of γ-ray, µ, and thermal neutron attenuation coefficient, Ʃth, were determined experimentally by the transmission method in a fine beam geometry setup using 60Co γ-ray source and a moderated PuBe source, respectively. The experimental results of γ-rays were verified by the correlation with the theoretical data obtained by the WinXCom program. Besides, many γ-ray attenuation parameters, such as a half-value layer, HVL, single-valued, and energy-dependent effective atomic number, Zeff, as well as effective electron density, Neff, were determined. It was found that the addition of barite and hematite aggregates to serpentine concrete increased its bulk density, and decreased its mechanical strength. Moreover, unlike barite, the hematite increased the water absorption and porosity of concrete. In conclusion, this study revealed that the prepared hematite- and barite-serpentine concrete mixes, except for AB50, have acceptable mechanical properties with enhancing radiation shielding performance.