Rheological Behavior and Workability Box on Foamed Cement Pastes Made with Alternative Reagents

Abstract

Foamed concrete is a type of lightweight concrete. The porous structure is due to foam in addition to the cementitious mixture. The fresh state of foamed mixtures represents a critical point because workability conditions are not typically used for conventional concretes.  Also, the porous structure is highly influenced by the fresh state behavior and, therefore, the properties of the hardened state. Rheology is an alternative to determine the flow behavior of the fresh state. This paper presents the results from a rheological characterization of OPC foamed pastes made with alternative reagents. Results show the connection between rheological parameters and fresh-state performance. A workability box with three zones has been proposed to present this connection. Zone I includes foamed pastes with viscosity under 0.08 Pa∙s; Zone II represents mixtures with higher viscosity and yield stress, and Zone III, which is the optimal workability zone, is limited by yield stress under 9Pa. This tool is essential to design foamed concretes.