Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. The hardened concrete is dense, homogeneous and has the same engineering properties and durability as traditional vibrated concrete.
Self-compacting concrete (SCC) has higher fines content than conventional concrete due to higher binder content and a different combined aggregate grading curve. These adjustments, combined with specially adapted superplasticizers, produce unique fluidity and inherent compactability.
Self-compacting concrete opens up new potentials beyond conventional concrete applications:
- Use with closely meshed reinforcement
- For complex geometric shapes
- For slender components
- Generally where compaction of concrete is difficult
- For specifications requiring a homogeneous concrete
structure - For fast installation rates
- To reduce noise (eliminate or reduce vibration)
- To reduce damage to health (‘white knuckle’ syndrome)
Installation of Self-Compacting Concrete
Formwork surface
The formwork for self-compacting concrete must be clean and tight. The formwork pressures can be higher than for normal vibrated concrete. The formwork pressure is dependent on the viscosity of the concrete, the installation rate and the filling point. The full hydrostatic pressure potential of the concrete should be used for the general formwork design.
Placing method
Self-compacting concrete is placed in the same way as conventional concrete. SCC must not be freely discharged from a great height. The optimum flow potential and surface appearance are obtained by installation with a filling socket from below or by tremie pipes which reach beneath the concrete surface level.