Bentonite-clay bricks reinforced with fuel fly ash: Structural and gamma attenuation characterization

Abstract

A series of brick samples were fabricated for radiation shielding purposes as an Egyptian bentonite clay–fuel fly ash mixture from Saudi Arabia with various ratios. To determine the mineral distributions in the clay, the study utilized an X-ray diffraction spectrometer, which proves that the main minerals in the bentonite clay are quartz and montmorillonite mineral. Additionally, the study used energy dispersion X-ray spectroscopy and scanning electron microscopy to show the morphology, grain size, and chemical composition for both clay and fly ash used in the brick fabrications. Moreover, the NaI(Tl) detector and Monte Carlo simulation methods were used for experimental measurements to estimate the prepared samples' radiation shielding characteristics. The study shows experimental–simulation method agreement, where the prepared brick samples' linear attenuation coefficient decreases over the interval of 0.1483 ± 0.004−0.0967 ± 0.003 cm⁻¹, 0.1172 ± 0.002−0.0775 ± 0.001 cm⁻¹, and 0.1102 ± 0.001−0.0729 ± 0.001 cm⁻¹ at the 0.662, 1.173, and 1.332 MeV γ-ray energies, respectively, with a 0 to 40 wt% fly ash concentration increase. A higher shielding capacity was noted for the thicker fabricated brick samples, which are thus applicable for radiation shielding purposes.