In this study, the effect of limewater on strength assessments and percentage of water absorption of concrete incorporating ZnO2 nanoparticles has been investigated. Portland cement was partially replaced by ZnO2 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 ZnO2 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 ZnO2 nanoparticles in saturated limewater results in more strengthening gel formation around nanoparticles causes improved permeability together with high strength. In addition, ZnO2 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 ZnO2 nanoparticles could improve mechanical and physical properties of the specimens.
ZnO2 nanoparticle; compressive strength; split tensile strength; flexural strength; percentage of water absorption; curing medium; concrete; TGA; XRD; pore structure
