The effects of TiO2 and ZnO nanoparticles on physical and mechanical properties of normal concrete

In the present study, compressive strength of normal concrete together with gas permeability of concrete containing various percentages of TiO2 and ZnO nanoparticles were investigated and the results were compared with each other and with that of the normal concrete. More types of tests were carried out on the specimens including X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The results indicated that TiO2 nanoparticles decreased the compressive strength after 28 days of curing; however, the permeability of concrete was lowered. Moreover, it seems that by adding TiO2 nanoparticles up to 4wt% of the cement the mechanical and physical properties of concrete may improve. The ZnO nanoparticles strongly retard the setting time and increasing the amount of ZnO nanoparticles in the mixture, thoroughly stops the hydration process within the concrete and prohibits the formation of mortar. As concluded from XRD diagrams, it seems that an amorphous layer of Zn(OH)2 is the main reason that prohibits C3S phase to participate in hydration process. Besides, with increase in percentage of the ZnO nanoparticles in concrete mixture, the lower compressive strength was obtained.