Effect of Zinc oxide and Al-Zinc oxide nanoparticles on the rheological properties of cement paste

This study aims to evaluate the effect of aluminum doped zinc oxide (AZO) and undoped Zinc oxide (ZnO) nanoparticles addition on the superplasticizer adsorption isotherm and rheological properties of cement paste composites. The adsorption isotherm and zeta potential of pastes containing different proportions of ZnO and AZO nanoparticles were also analyzed. The mechanism of superplasticizer adsorption by nanoparticles was found to be a dominant factor which governs the rheological properties. It was found that the amount of superplasticizer adsorbed increases significantly by incorporating nanoparticles which implies that nanoparticles compete with cement particles to adsorb the polymer. Consequently, the addition of both nanoparticles resulted in a considerable increase in saturation point, yield stress and viscosity values relative to plain cement paste. All mixtures containing 0.4 wt % nanoparticles or lower showed excellent workability retention as compared to the reference mix while, the poor workability retention was observed a higher dosage.