Effect of Admixtures on Pumpability for High-Strength Concrete.

In this study, the effects of mineral and chemical admixtures on pumpability of high-strength concrete were investigated through measuring rheological properties of concrete and the lubricating layer. A total of 32 concrete mixtures were manufactured and tested according to different types and dosages of silica fume, zirconia silica fume, fly ash, and high-range water-reducing admixtures (HRWRAs). From the experiments, it was found that zirconia silica fume is very effective in enhancing pumpability, and the increase of HRWRA dosage leads to the decrease of the viscosity of the lubricating layer and the increase of pumpability. [ABSTRACT FROM AUTHOR]