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Heavy-oil fly ash (HOFA) is a graphitic carbon powder extracted in vast amounts as a waste material from burning crude oil in power plants. This HOFA has attractive structural properties besides its high amount of pure carbon (∼90 wt %). This powder exists in spherical, highly porous micron-sized particles, which implies its great potential as a mechanical reinforcement for different polymers. In this work, HOFA has been utilized to enhance the mechanical properties of epoxy flooring at HOFA weight fractions of 0, 1, 1.6, and 3.2 wt %. The obtained results revealed that the prepared epoxy-flooring/ HOFA composites at a HOFA content of 1.6 wt % showed significant mechanical improvements compared with the pristine polymer. The tensile strength and Young's module values were enhanced by ∼17 and 11%, respectively. Furthermore, the neutron-shielding performance was investigated. The composite with 1.6 wt % showed better neutron attenuation and lower transmittance than the pristine epoxy. The chemical resistance was also extensively studied against sodium hydroxide, nitric acid, and sulfuric acid. The changes in morphology, chemical elements, mass, volume, and molecular structures were investigated rigorously for pristine epoxy and its composite with HOFA at 1.6 wt %. After exposure to these chemicals for 21 days, the tested properties of the epoxy-flooring/HOFA composite showed better chemical resistance than that of the pristine epoxy. Where the epoxy-flooring/ HOFA composite showed a surface with low cracks and blistering, it showed lesser changes in mass and volume and fewer molecular structure changes. These results indicated that it is possible to use this multifunctional composite for several applications, including the petrochemical industry, radiation shielding, construction, and automobiles.

The industrial production of 3D printing is known as additive manufacturing (AM), in which a computer controls the process of producing 3D objects. Although X-ray computed radiography (XCT) is extensively used in the quality control and testing of additive manufacturing products, the gamma-ray radiography capabilities for these applications still need to be investigated. This study aimed to evaluate the performance of gamma-ray radiography using americium-241 (Am-241) as the gamma source. Here, we inspected fused deposition three-dimensional (3D) modeling products produced from polylactic acid (PLA) as thermoplastic samples. Radiographic testing of 3D-printed thermoplastic samples was performed using Monte Carlo simulations and validated by experimental studies. We used Am-241 (gamma-ray source) to conduct simulations and experiments investigations; two simulations were used: one by using 59.6 keV energy of gamma-ray and the other using all gamma-ray energies, including 16.96 keV, 26.3446 keV% 2.31 up to 662.40 keV. Also, we performed the X-ray radiography test to be used as a standard. The results showed that the defect detectability in the 3D-printed PLA samples using Am-241 as a gamma-ray source is comparable to that of X-ray results. This study concluded that the Am-241 could be used as the gamma-ray source to perform the radiography test for the products produced by 3D-printed thermoplastics.