Engineering and gamma-ray attenuation properties of steel furnace slag heavyweight concrete with nano calcium carbonate and silica

Abstract

As the nuclear energy sector continues to grow worldwide, the improvement of concrete’s radioactive isolation properties for preserving both the environment and human lives in nuclear power plant applications has received a global interest among researchers. Although nano-silica, nano-calcium carbonate, and steel furnace slag have high molar mass and favorable physical properties to improve the concrete’s radioactive insulation properties, scarce literature on the subject matter has been published. The goal of this study is to investigate the appropriateness of using nanomaterials such as nano-silica slurry and nano-calcium carbonate as additives for the production of steel furnace slag (aggregate of steel furnace slag: ASFS)-based heavyweight concrete (HWC) with improved durability, mechanical strength, and gamma (γ)-ray attenuation properties. A new contribution of the study is the use of nano-SiO2 slurry and nano-CaCO3 in concrete binder formulation to enhance concrete gamma-ray shielding capability. An optimized content was developed for the nano calcium carbonate, in combination with a constant amount of nano-silica slurry, to improve the performance of the HWC. An investigation program was implemented with eight concrete mixes, which were prepared by utilizing ASFS as the main aggregate with 3% of nano-silica slurry in combination with (0–3%) of nano-calcium carbonate as additives to produce high strength HWC. The hardened concrete samples were evaluated for mechanical strength, fluid transport and γ-ray shielding properties. The effect of 3% nano-SiO2 slurry and 2.0% nano-CaCO3 on the compressive strength and gamma-ray shielding increased by 10.3 and 3.4%, respectively, at 28 days as compared to the control mix without nanomaterials additives. The other mechanical and fluid transport properties of the concrete were also improved significantly. In conclusion, the combined use of nano-silica slurry and nano-calcium carbonate would enhance the mechanical strength, fluid transport and γ-ray shielding properties of steel furnace-slag heavyweight concrete.