Influência do coeficiente de atrito entre os agregados e da viscosidade da matriz no comportamento reológico suspensões concentradas heterogêneas. / Influence of aggregates friction coefficient and matrix viscosity in the rheological behavior of heterogeneous concentrated suspensions.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The rheological behavior of concentrated suspensions like concrete and mortars plays an important hole during their processing and application, and also has a great influence on the final product quality. The flowability of these suspensions is directly related to the ease of particle motion in the system, therefore reduction of friction phenomena contributes for a good flow behavior. The aim of this work was to determine the influences of aggregates friction coefficient and the liquid viscosity of the fluid matrix on the rheological behavior of concentrated suspensions. The friction coefficient of glass spheres with different particle size distributions were determined by shear box tests, while the rheological behavior of concentrated suspensions composed by these glass spheres and silicone oils was evaluated by squeeze flow tests. Results revealed that the particle size distribution influences the coefficient of friction, and this property is determined by the type and the area of contact between the particles. However, for the kind of flow and the speed used in the experiments, there was no relation between friction coefficient and the suspension viscosity. Additionally, matrix viscosity has an impact on the rheological behavior of the system, but no clear relation was identified, which may be caused by the occurrence of heterogeneous flow under the applied experimental conditions.

ASSUNTO(S)

matrix viscosity friction coeficient aggregates atrito reologia rheological behavior agregados

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