Vibration of self consolidating concrete
Most of the work still has to be completed, but with over 40 participants, this team should be able to do it in a timely fashion Several tests have already been developed worldwide to characterize the performance of a fresh self-consolidating concrete.
A few of them are briefly presented in the following paragraphs.
Therefore, numerous test methods have been developed for SCC with ease of use in mind.
None of these test methods measures yield stress or viscosity, but they all simulate more or less real-scale casting environments.
Because conventional concrete is placed using external energy, there is no need for specific rheological characteristics.
As a matter of fact, the intensity of energy applied in the consolidation process is adjusted to compensate most plastic property variation.
However, the performance criterion remains the only objective means to evaluate the adequacy of an SCC mix.
Since criterion relates to measurements, test procedures need to be developed.
But at that time fluidity was obtained by adding water, superplasticizer, or a combination of both.
As the SCC viscosity can be adjusted depending on the application, the yield stress must remain significantly lower than other types of concrete in order to achieve self-consolidation.
At this time, various mix design methods have been proposed in order to obtain the unique rheological performances of SCC and may lead to different mix designs for a given application.
The dimensions may vary from one country to the other.
A rheometer is a device that applies a range of shear rates and monitors the force needed to maintain these shear rates in a plastic material. A few concrete and mortar rheometers are available on the market and have been and are still used for measuring the yield stress, viscosity and other rheological characteristics of SCC.