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.However, the performance criterion remains the only objective means to evaluate the adequacy of an SCC mix.Exploratory work has looked at existing SCC characterization procedures around the world.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.
Concrete vibrators will eliminate air bubbles by vigorously shaking the freshly poured concrete with a mechanical vibrator.
It's a truism in construction that most concrete is under-vibrated or improperly vibrated.
The best technique with an internal vibrator is to withdraw the vibrator very slowly -- at a rate of around one inch per second.
With SCC, other rheological requirements are needed to obtain good consolidation since no additional placing operations will compensate for any lack of rheological performances.
(In rheological terms, even though a significant amount of research tends to show that SCCs viscosity varies with the shear rate and acts as a pseudoplastic material, SCC is often described as a Bingham fluid (viscoelastic) where the stress/shear rate ratio is linear and characterized by two constantsviscosity and yield stress (Table 1).