Effect of high temperature on mechanical and gamma ray shielding properties of concrete containing nano-TiO2

This paper is an experimental study of the shielding performance of heavy concrete (HC) containing magnetite aggregates and different content 0%, 2%, 4% and 6% of nanoscale particles of titanium dioxide (NT), replaced by weight of cement in various temperatures cycles of 25, 200, 400 and 600 degrees C. Weight loss, ultrasonic pulse velocity (UPV), compressive strength, gamma-ray shielding testes and scanning electron microscope (SEM) analysis are conducted on concrete specimens. To perform the radiation attenuation test, photon energy of 662 keV from source (CS)-C-137 and two energy photons 1173k keV and 1332 keV from (CO)-C-60 source were emitted on the surface of the specimens. The parameters evaluated for the radiation attenuation test include the linear attenuation coefficient (mu), the half value layer (HVL), tenth value layer (TVL) and the mean free path (MFP). The results showed that: (a) for all content of NT, when temperature increases, UPV and compressive strength increase and then reduction. (b): The whole mixes in different thermal cycles performed better in terms of compressive strength and mu compared to the reference concrete. (c): Specimens containing 6% NT particles meet the design requirements (higher compressive strength and mu) better than other mixes. (d): By increasing temperature, for all three values of photon energy, mu and density (rho) decrease.