(72a) Properties of Cement Pastes Based on a Comparative Study of Various Rheological Models

Cement pastes are used in a range of industrial applications. In addition to construction industry, there are other applications of cement pastes, such as their use in petroleum industry for isolating high pressure zones and maintaining well integrity. In recent years, 3D printing has been employed in housing construction using various novel composite materials comprising cement and admixtures. Rheology which is the study of deformation and flow of matter can predict the behavior of cement pastes in processes, such as 3D printing.

Under shear, cement paste may behave as a non-Newtonian fluid. Various rheological models are reported in the literature, describing the viscosity dependence of cement on the rate of shear. In this study, seven rheological models were investigated to determine the range of their applicability, using a set of data for Portland cement. The rheological models used are Bingham Plastic, Power law, Herschel-Bulkley, Casson, Ellis, Carreau-Yasuda, and vom Berg. The results show which models are best fitted to low, mid-range, and high shear rates. Additionally, the inherent differences among a selected number of models, including their limitations, are noted, and evaluated. The evaluation of each model was based on a linear regression analysis of a set of experimental cement shear rate-shear stress data.