Assessment of Lightweight Concrete Properties with Zinc Oxide Nanoparticles: Structural and Morphological Analyses

Abstract

In recent decades, the use of nanotechnology has increased in many disciplines. Specifically, in the concrete industry, nanotechnology has been used to develop more eco-efficient solutions. There is a rapidly growing interest in using nanoparticles in concrete to tackle environmental impacts. Among the nanoparticles investigated, zinc oxide (ZnO) shows great potential because of its material properties, such as reactivity, non-toxicity, a hard and rigid structure, photocatalytic and photoluminescence properties, and chemical, electrical, and thermal stabilities. This paper focuses on the analysis of the effect of ZnO nanoparticles in lightweight concrete at different concentrations (0.5, 1, 1.5, and 2.0 wt%) using two different methods including (i) addition and (ii) partial substitution for cement. Mechanical properties are determined by compressive strength tests. Chemical and morphological characterization is performed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. This study reveals that an increase in the percentage of ZnO nanoparticles as a substitute for cement directly decreases the compressive strength of lightweight concrete. For ZnO nanoparticles in the addition method, compressive strength is 10% lower than in the control specimens. However, the conclusions indicate constant compressive strength for all ZnO nanoparticle concentrations in the addition method.