The Influence of Zinc Oxide nanoparticels on the microstructural properties of cement mortars and the performance on the removal of a type of algae

In recent years, several researches have been carried out to investigate the applications of nano science in the concrete technology. It appears that by combination of nano science and concrete technology, new scientific horizons could be opened and high quality construction and building materials may be produced. . As a matter of fact, some types of nano materials have photocatalytic characteristics and could disintegrate the pollutants and various types of organic substances. Hence, utilizing nano technology, multi-purpose materials with enhanced characteristics and new applications such as self- cleaning surfaces could be produced.
Several types of nano materials have photocatalytic characteristics, which among them nano ZnO and TiO2 have found higher attention. The influence of TiO2 on the cement based materials has been the subject of several researches. However, nano ZnO was not considered appreciably. Thus, in the present study, the performance of different percentages of Nano ZnO on the mechanical and microstructural properties of concrete has been investigated. The studied properties were setting times, compressive strength, hydration degree, reaction with calcium hydroxide and microstructural analysis by scanning electron microscopy images (SEM). Moreover, with regards to the photocatalytical properties of this material, the influence of nano ZnO on the removal of a type of algae was scrutinized. The results indicate that nano-ZnO could significantly increase the initial and final setting times, leading to the slow formation of microstructure at very early ages.Furthermore, the photocatalytic investigation showed that the mortar surfaces containing these nanoparticles could prevent the growth of the blue-green algae.