Effect of nano zinc oxide and silica on mechanical, fluid transport and radiation attenuation properties of steel furnace slag heavyweight concrete

Abstract

Due to the growing nuclear energy sector worldwide, it has been a global interest among researchers to improve the harmful radiation isolation properties of concrete for preserving both environment and human safety in nuclear power plant applications. While nano zinc oxide, nano-silica and steel furnace slag have high molar mass and favorable physical properties to improve high energy radiation attenuation properties of the concrete, scarce body of literature on the subject matter was reported. Hence, the study was aimed to investigate the suitability of the addition of nanomaterials such as nano-silica and nano zinc oxide for improving the mechanical, fluid transport and gamma-ray attenuation properties of heavyweight concrete (HWC) containing aggregate of steel furnace slag (ASFS). A new contribution of this study was the use of nano zinc oxide and nano-silica in concrete binder formulation to enhance the gamma ray shielding ability of concrete. A method was established for the optimization of the nano zinc oxide content used in combination with a constant amount of nano-silica to improve the various performance of heavy weight concrete. An investigation program was implemented with six concrete mixes which were prepared by utilizing ASFS with the addition of a superplasticizer, 3% of nano-silica in combination with (0.5–2.5%) of nano zinc oxide as an additive to produce high strength heavy weight concrete. The mechanical properties, fluid transport characteristics and γ-ray shielding performance were evaluated for hardened concrete samples. The inclusion of 1.5% nano zinc and 3% of nano-silica enhances the gamma-ray shielding and compressive strength by 16.3 and 6.6%, respectively, at 28 days as compared to the control mix (without nanomaterials). Besides, all the mechanical and fluid transport properties of the concrete were improved correspondingly. In conclusion, the combined use of nano-silica and nano zinc oxide is suitable to enhance mechanical strength, fluid transport and high energy radiation attenuation performance of steel furnace-slag heavyweight concrete (SSHWC).