Rheological model selection and a general model for evaluating the viscosity and microstructure of a highly-concentrated cement suspension

Abstract

A better fit to rheological measurement of cement pastes is only part of model selection. The selected models are likely to describe the rheological behavior of cement paste, but they need to be generalized. This paper provides a generalization on the various models to describe the rheological behavior of cement pastes. The viscosity curve following Sisko model characterizes the steady-state response of cement paste. A power-law exponent called the flow behavior index is constant for all cement paste samples produced from various mix proportions. The flow consistency factor and infinite viscosity decrease with a higher water-to-cement ratio and a higher dosage of polycarboxylate. In the relaxation process, the viscosity shows exponential decay at a constant rate of shear strain. The generalized model is finally compared with Quemada's microstructural model, Roussel's thixotropy model, and the Bingham model.