Vibration of self consolidating concrete
Self-consolidating concrete allows for easier pumping (even from bottom up), flows into complex shapes, transitions through inaccessible spots, and minimizes voids around embedded items to produce a high degree of homogeneity and uniformity.
That's why SCC mixes allow for denser reinforcement, optimized concrete sections and shapes, and greater freedom of design while producing superior surface finishes and textures.
SCC does not use a high proportion of water to become fluid – in fact SCC may contain less water than standard concretes.
Instead, SCC gains its fluid properties from an unusually high proportion of fine aggregate, such as sand (typically 50%), combined with superplasticizers (additives that ensure particles disperse and do not settle in the fluid mix) and viscosity-enhancing admixtures (VEA).
The use of SCC concrete mixes has grown tremendously since its inception in the 1980s.
The development of high performance polycarboxylate polymers and viscosity modifiers have made it possible to create flowing concrete without compromising durability, cohesiveness, or compressive strength.
This kind of air content (unlike that in aerated concrete) is not desired and weakens the concrete if left.
As a result, pouring SCC is also much less labor-intensive compared to standard concrete mixes.
Once poured, SCC is usually similar to standard concrete in terms of its setting and curing time (gaining strength), and strength.
When normal mixes of concrete become to fluid, they segregate; large aggregates settle to the bottom of a placement and water and cement paste move to the top.
SCC mix designs must maintain a tight balance; they must be fluid without segregating.
SCC concrete is usually defined as having a spread of 18 to 30 inches wide, making it possible to place concrete under difficult conditions.