Self consolidating concrete testing
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).
Martin Vachon describes how a special type of concrete self-consolidates without the use of vibration, its market share around the world, and the work of C09 in writing standards for it.
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.
In addition, that earlier type of concrete was not used in civil engineering structures with normal durability requirements because they either contained too much water or were not stable and led to unacceptable heterogeneity in the structure.
Since criterion relates to measurements, test procedures need to be developed.
ASTM Committee C09 on Concrete and Concrete Aggregates undertook this task in June 2001 in its Subcommittee C09.47 on Self-Consolidating Concrete.