Workability tests and rheological parameters in self-compacting concrete

Abstract

The characterization of the behaviour in the fresh state is critical for self compacting concrete (SCC), and it is usually performed through tests such as the slump flow or the V-funnel. A better description of SCC behaviour can be performed by using viscometers. It has been recognized that in SCC an adequate combination of the rheological parameters (yield stress and plastic viscosity) is required to obtain a mix with enough mobility but avoiding risks of segregation. This paper analyses the relationship between the engineering tests results and the rheological parameters. The experimental data corresponds to an extensive research program, where the effects of the mixing energy, time, concrete temperature and environmental exposure conditions on the rheological behaviour of SCC were studied. Simultaneous measurements with a BML viscometer, the slump flow and the V-funnel tests were carried out on different types of SCC. Relationships between the slump flow and the yield stress, and between the plastic viscosity and the flow times have been found for the same component materials. In addition, typical ranges of yield stress and plastic viscosity for each class of SCC have been identified.