Enhancing mechanical properties and radiation shielding of high-strength concrete with bulk lead oxide and granodiorite

Abstract

This paper evaluates the influence of bulk lead oxide (PbO) and granodiorite (GD) powders, individually and in combination at optimal replacement ratios, on the setting time, workability, compressive strength, and radiation attenuation properties of high-strength concrete (HSC). Twelve HSC mixes were prepared: a control mix, five mixes containing varying percentages of PbO, five mixes containing varying percentages of GD, and one hybrid mix combining 5 % PbO and 7 % GD. The optimal replacement ratio 7 % with GD powder increased the compressive strength of the concrete by 19.1 %. A comprehensive microstructural and compositional analysis of XBL/G-concrete was conducted employing X-ray Fluorescence (XRF), X-ray Diffraction analysis (XRD), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) techniques. Radiation shielding effectiveness was evaluated using Phy-X software and Monte Carlo-5 simulations (MCS), focusing on γ-rays and fast neutrons. 2 % replacement of PbO enhanced the compressive strength of the concrete. However, increasing the PbO content to 5 % resulted in an 8.57 % reduction in strength compared to the control mix. The hybrid concrete mix of 5 % PbO and 7 % GD demonstrated superior radiation shielding capabilities in terms of linear/mass attenuation, with a 3.12 % increase in compressive strength relative to the control sample. The combined concrete sample of 5 % PbO and 7 % GD were higher than the samples mixed with GD and lower than the samples mixed with PbO of concentrations 3, 4, and 5 % in terms of the linear/mass attenuation. The linear attenuation’s order of the XBL/G-concrete samples was: 1BG < 3BG < 5BG < 7BG < 9BG < 1BL < 2BL < 5BLG7 < 3BL < 4BL < 5BL. Also, the mixed concretes of 5 % PbO and 7 % GD demonstrated a superior from fast neutron shielding capabilities. The tested XBL/G-concrete samples provide adequate protection against γ-rays and fast neutrons for nuclear and medical facilities shield radiation.