Effect of air-entraining admixture usage rate on dynamic yield stress and viscosity in Portland cement systems containing urea

Abstract

Air-entraining admixtures added to cementitious systems in order to increase freeze-thaw resistance also affect the fresh state properties of the mixture. In this study, the effect of the use of air-entraining admixtures on the rheological properties of urea-containing Portland cement systems was investigated. For this purpose, 3 different paste mixtures were prepared by adding 0.15% and 0.30% air-entraining admixtures to the control mixture containing 3% urea instead of cement. The dynamic yield stress and viscosity values of the prepared mixtures were determined in accordance with the Herschel Bulkley model. It was determined that the dynamic yield stress values of the paste mixtures increased and the viscosity values decreased with the use of air-entraining admixtures. It was understood that this behavior became more evident with the increase in the use of admixtures.