Integrating the Petrographic, Structural, Mechanical Characteristics, and Gamma-Ray Shielding Performance of Monzogranite as a Multifunctional Natural Material

Abstract

This study describes a comparative assessment of the structural properties, mechanical properties and gamma-ray shielding effectiveness of monzogranite to determine whether or not they can be used for sustainable shielding construction materials. The results of the petrographic, X-ray fluorescence (XRF), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS) analyses reveal that the monzogranite is composed essentially of quartz, K-feldspar, plagioclase and biotite. The SiO2 contents of all the monzogranite studied also indicated that they are highly crystalline (70.77% to 73.34% SiO2 by weight) and chemically stable (therefore, monzogranite); other properties such as density (2.70 to 3.06 g/cm3), porosity (19 to 23%) and water absorption (12 to 15%) demonstrated the structural compactness and durability of the samples studied. Additionally, the mechanical properties of all of the samples were extremely high, and included: (a) the unconfined compressive strength ranged from 89.28 to 240.20 MPa; (b) the engineering modulus ranged from 40.6 to 66.5 GPa; (c) the Brazilian tensile strength ranged from 7.4 to 15.2 MPa; and (d) the flexural strength ranged from 9.3 to 16.4 MPa. The shielding effectiveness against gamma rays was rated over a wide range of photon energies (0.015–15 MeV) via Phy-X/PSD and experimentally using NaI (Tl) spectroscopy at specific gamma photon energies 0.662 MeV, 1.173 MeV and 1.332 MeV. The experimental measurements of gamma-ray attenuation were validated with Phy-X/PSD calculations, with the average variation being 5.8% and no single variation over 10%, and therefore, reliability has been successfully demonstrated. The linear attenuation coefficients (LACs) were measured from 24.674 cm−1 at 0.015 MeV to 0.065 cm−1 at 15 MeV, which illustrates the dependence of gamma-ray interactions’ mechanisms on the energy of the incoming radiation. The half value layer (HVL) went from 0.028 cm to 10.621 cm and the mean free path (MFP) increased from 0.041 cm to 15.323 cm. The best measured performance properties were attributed to specimen MB3, as it had the highest radiation protective efficiency (88.58% at 0.15 MeV) and the lowest radiation transmission (72.16% at 0.09 MeV) in comparison to all of the experimental conditions considered. The high attenuation properties of MB3 were attributed to its high density and high levels of iron oxide, Fe2O3. The present work demonstrates that monzogranite, specifically sample MB3, provides excellent mechanical strength, as well as effective shielding from gamma radiation. Therefore, monzogranite, and particularly MB3, is a creative alternative for sustainable construction, as it provides materials that will be used for radiation shielding in nuclear, medical and industrial applications.