The intrinsic relationship between flocculation effect and apparent viscosity of fresh slurry

Abstract

Apparent viscosity considerably influence the migration and diffusion of the slurries. However, the effect of particle structure on the slurry viscosity is still indeterminate. In this study, the distribution of flocculent particles was measured using a particle track analyzer with focused beam reflectance measurement (FBRM) system. A rheometer was used to measure apparent viscosity of fresh slurry. Three factors of water-cement ratio (W/C), particle shape, and particle fineness directly change the particle structure, and indirectly affect apparent viscosity of slurry. Increased W/C reduces the flocculation degree, the particle fineness increases the particle interparticle in the slurry, and the microbead action of fly ash makes it challenging to form flocculent structures. These factors affect the ratio of bound water, flocculent water, and free water, as well as the interparticle force, thereby changing the slurry viscosity. Further, an effective volume fraction was proposed, and revealed a change in viscosity as the result of the particle structure. The results demonstrate the rationality of the analysis and the predictions. The established relationship provides design basis for the application of other materials and additives. The paper's originality is that the effective volume fraction (ϕm) is proposed and the relationship between flocculent structure and slurry viscosity is established under multiple factors.