Cyclic deformation of clay particles in clay-water suspensions

Abstract

The rheological study of clay-water suspension was studied by using Couette type rotational viscometer. The clay suspension presents a hysteresis loop when the suspension was subjected to a cyclic deformation which is composed of an upcurve process (the upcurve being a flow curve of s, rate of shear, versus f, shear stress, obtained which s was increased from zero to a maximum) and a downcurve process (the downcurve being a flow curve obtained by decreasing s from the maximum to zero). In this study, the dependence of the hysteresis (thixotropic) loop on the number of cyclic deformation, on the pH of the suspension, and on the electrolyte additives was investigated and was explained from a theoretical viewpoint. The Ree-Eyring equation of generalized viscosity was applied to the downcurves of the thixotropic loops, and the parameters, $\beta$ and $\frac{x}{\alpha}$ appearing in the equation were determined. The dependence of these parameters on the number of cycling, pH and electrolyte additives were also studied and were theoretically examined.