Concrete consolidating self tawny kitaen dating
(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).
This latter model will be used in the following paragraphs because of its simplicity.)Back to the performance-based definition of SCC, the self-consolidation is mainly governed by yield stress, while the viscosity will affect the homogeneity and the ability to flow through reinforcement (Table 2).
None of these test methods measures yield stress or viscosity, but they all simulate more or less real-scale casting environments.
Some people may say that concrete that self-consolidates on its own weight without the use of vibration has been used for years in the construction field.
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.