Shear-Thickening Behavior of Cement Pastes under Combined Effects of Mineral Admixture and Time

Abstract

The fresh-state behavior of plain and silica fume (SF)-modified cement pastes was measured using a wide-gap viscometer. The Herschel–Bulkley (H–B) model was used to describe the rheology of fresh cement pastes. The H–B parameters (including yield stress, consistency coefficient, and flow index) under coupling effect of SF and water addition time were provided. According to the experimental results, the shear-thickening behavior was found to be strongly influenced by the SF content as well as the time after water addition. The flow index declined with SF and water addition time in general. Finally, simplified models were constructed by forecasting the value of flow index as well as H–B yield stress of pastes containing different mineral admixtures under coupled SF content and water addition time.