WORKABILITY OF SELF-COMPACTING CONCRETE

摘要

The slump test is widely used to evaluate the workability of concrete. However, it has serious drawbacks, especially for self-compacting concrete (SCC). Other flow characteristics such as viscosity or filling capacity or time of flow through an orifice are needed to characterize flow in SCC. The goals of this study were multiple: 1) to test flow characteristics of SCC using various devices: two concrete rheometers, several standard tests, and the widely used V-flow and U-flow tests; 2) to determine the correlation between the various tests and especially between the two rheometers; and 3) to attempt to determine the rheological characteristics of SCC. Thirteen mixes were prepared with varying dosages of viscosity modifying admixture (VMA) and high-range water-reducing admixture (HRWR) to achieve a wide range of flow behavior. It was found that the plastic viscosities measured with the two rheometers were correlated at 84 %, and that a SCC mixture is not defined by its high slump and slump spread alone.