Rheological behaviour of gypsum plaster pastes with polyamide powder wastes

Abstract

This study investigates the influence of polyamide powder waste on the rheological properties of plaster pastes. Plaster blends are prepared using different volumetric proportions of polyamide by fixing the water/conglomerate ratio. A rotational viscometer is used to determine the yield shear stress and the plastic viscosity of the pastes. These results correlate with the data obtained with the paste fluidity test. Moreover, the effect of the polyamide on the thixotropy of the mixtures is analysed. The yield shear stress and the viscosity of the pastes decrease and increase respectively as a function of the amount of polyamide waste used in the mix. A strong correlation between the results of fluidity and plastic viscosity indicates the amount of polyamide waste influences directly the fluidity of the paste. The relation between shear rate and shear stress provides insight into the effects of the polyamide on plaster paste thixotropy. © 2012 Elsevier Ltd. All rights reserved.