The Effects of ZnO2 Nanoparticles on Strength Assessments and Water Permeability of Concrete in Different Curing Media

In this study, the effect of limewater on strength assessments and percentage of water absorption of concrete incorporating ZnO 2 nanoparticles has been investigated. Portland cement was partially replaced by ZnO 2 nanoparticles with the average particle size of 15 nm and the specimens were cured in water and saturated limewater for specific ages. The results indicate that ZnO 2 nanoparticles up to 2.0 weight percent could produce concrete with improved strength and water permeability when the specimens cured in saturated limewater while this content is 1.0 weight percent for the specimens cured in tap water. Although the limewater reduces the strength of concrete without nanoparticles when compared with the specimens cured in water, curing the specimens bearing ZnO 2 nanoparticles in saturated limewater results in more strengthening gel formation around nanoparticles causes improved permeability together with high strength. In addition, ZnO 2 nanoparticles are able to act as nanofillers and recover the pore structure of the specimens by decreasing harmful pores. Accelerated peak appearance in conduction calorimetry tests, more weight loss in thermogravimetric analysis and more rapid appearance of peaks related to hydrated products in X-ray diffraction results, all indicate that ZnO 2 nanoparticles could improve mechanical and physical properties of the specimens.