LAUSR

Abstract In this study, the compressive strength , ultrasonic pulse velocity (UPV), impact resistance, gamma-ray radiation shielding properties, and investigation of microstructure by scanning electron microscope (SEM) analysis of concrete specimens produced from magnetite aggregate Fe 3O4 containing 0.6% of polypropylene fiber (PPF) and various percentages of 0, 2, 4, 6, and 8% of nano titanium dioxide (nano - TiO2) were evaluated. Also, the gamma-ray attenuation measurements were using two sources of 137Cs and 60 Co with three gamma-ray energies of 662, 1173, and 1332 keV are conducted on the specimens. Some gamma-ray radiation shielding parameters such as the half-value layer (HVL), tenth-value layer (TVL), the mean free path (MFP), linear attenuation coefficient (μ), and mass attenuation coefficient ( μ m ) were also examined in the gamma-ray attenuation. The results show that by increasing the (wt.) % of nano - TiO2 by 0–8%,(a), the compressive strength and the UPV initially increased and then decreased,(b) The impact resistance for the first crack and the ultimate failure was firstly increased and then decreased, (c) The μ and the μ m continuously increased, (d) The HVL, TVL and the MFP decreased,(e). The percentage of the ray transmission is decreased so that specimens containing 8% of nano - TiO2 had the lowest ray transmission percentage at every photon energy ,(f) A lower thickness of the absorbent material was needed to decrease the photon energy.