Influence of ZnO nanoparticle ratio and size on mechanical properties and whiteness of White Portland Cement

Abstract

The impact of nanotechnology on the cement industry has been extensively studied. Much work remains needed to improve product quality, decrease cost, and minimize the negative environmental impact. The present study explores the influence of ZnO nanoparticles on physical, chemical, and mechanical properties of White Portland Cement (WPC). Zinc oxide nanoparticles were prepared by simple ball-milling to reach average particle sizes of 70, 37, 27, and 24 nm. For each of the four size groups, ZnO nanoparticles were added to WPC at each of four concentrations (0.1, 0.4, 0.7, and 1.0 wt%). Whiteness, setting time, expansion, and compressive strength of resulting mortars were investigated. The crystal structure and morphology of mortars were respectively characterized using X-ray diffraction and scanning electron microscopy. Hydration progress was inspected using Fourier-transform infrared spectrometry. The results show that addition of ZnO to WPC pastes increases the amount of water required for normal consistency and setting time. The addition of 37 nm ZnO nanoparticles to WPC mortars at a specific weight percentage of 0.4% ZnO enhanced compressive strength at 28 days by up to 28% via filler effects. The characterizations and physicomechanical parameters for high-ZnO (1.0 wt%) mortar indicate less hydration products before 28 days but improved at 28 days.

Investigating the release of ZnO nanoparticles from cement mortars on microbiological models

“…Similarly, Shafeek et al (2020) showed that the initial setting and final setting were delayed by 38 h and 55 h, respectively, when 1 wt.-% of ZnO nanoparticles was incorporated into the cement. Like our study, other researchers confirmed that higher dosages of ZnO nanoparticles can contribute to the decrement of composites' strength (Thangapandi et al 2020).…”

“…Thus, the strength development in the first weeks of hydration is impeded. However, at later testing ages, specimens exhibit satisfactory mechanical performance (Shafeek et al 2020). The calorimetric study held by Siler et al (2019) showed that in OPC system, induction period length increased from 3.3 to 97.4 h when 1 wt.-% of ZnO nanoparticles was incorporated into the cementitious system.…”

“…Briefly, the retardation effects of ZnO nanoparticles on the OPC hydration process can be attributed to the fact of ZnO presence in the cement mix resulting in the formation of CaZn 2 (OH) 6 •2H 2 O and Zn(OH) 2 layers of around anhydrous particles of cement at the beginning of the hydration reaction, thus preventing water from reacting to form the tricalcium silicate (C 3 S) phase. This phenomenon has been extensively studied and described in Shafeek et al (2020).…”

Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash

“…The effect of zinc on mechanical properties is not studied in this study. According to the available literature, it can be assumed that zinc reduces strength in the first days of hydration due to slowing hydration, but long-term strength may increase due to a different hydration mechanism and also, the possibility of zinc compounds acting as microfiller [ 40 ]. In the case of a combination with fly ash, long-term strengths may also increase due to a chemical (e.g., pozzolanic reaction) and physical effect (e.g., microfiller) [ 30 ].…”

Preparation, characterization, and feasibility study of Sr/Zn-doped CPP/GNS/UHMWPE composites as an artificial joint component with enhanced hardness, impact strength, tribological and biological performance

“…[12][13][14] Many studies suggested that zinc incorporation also could enhance bone repair. 15,16 Zinc has the ability to boost the expression of genes, including OPG (osteoprotegerin) and RANKL (receptor activator of nuclear factor-k B ligand) in the process of co-culturing with osteoblast. 17 We can deduce that Sr and Zn have a synergistic effect in promoting the formation of bone and inhibiting bone resorption aer introducing Sr and Zn into CPP (calcium polyphosphate).…”