Valorization of nano-PbO as an additive to modify the properties and radiation shielding of alkali-activated slag mortar

In this work, for the first time, the possibility of employing nano-lead oxide (nPbO) in alkali-activated slag (AAS) mortar as a modifier agent for its properties was studied. Different ratios of nPbO (0 wt%, 1 wt%, 3 wt% and 5 wt %) were added to the plain AAS mortar. The effects of these ratios on flowability, mechanical strength, water absorption, total porosity, aging resistance, gamma-ray radiation shielding, crystalline phases, thermal analysis and microstructure were investigated. The gamma-ray attenuation coefficients were determined as a function of the additive percentages of lead oxide for gamma-ray energies of 1332, 1173 and 662 keV using Co-60 and Cs 137 sources. Different techniques were used to analyze the results. The results showed higher flowability of the mixtures with introducing nPbO. The flowability increased with increasing nPbO ratio. The mechanical strength and aging resistance increased with introducing 1% and 3% nPbO, then slightly decreased with including 5% nPbO. Water absorption and total porosity decreased with introducing 1% and 3% nPbO, then slightly increased with including 5% nPbO. Introducing nPbO in the AAS system improved the radiation properties, of which the attenuation coefficients increased with including nPbO. In a word, using suitable ratios of nPbO improved the fresh, hardened, durability and radiation properties of AAS mortar and can provide it for wider applications.

Automated summary

This study investigates the possibility of using nano-lead oxide (nPbO) as a modifier agent in alkali-activated slag (AAS) mortar. Different ratios of nPbO were added to the mortar, and the effects on various properties were studied. The results showed that introducing nPbO improved the flowability, mechanical strength, aging resistance, and radiation properties of the AAS mortar. Suitable ratios of nPbO can enhance the performance of the mortar and expand its applications.