Self-compacting Concrete

Self-compacting Concrete

Self-compacting concrete (SCC) has a higher fines content than conventional concrete due to a higher binder content and a different particle size distribution curve. These adjustments, combined with specially adapted super plasticizers, produce unique fluidity and inherent compact ability. Self-compacting concrete opens up new potential beyond conventional concrete applications:

·     Use with close meshed reinforcement

·     For complex geometric shapes

·     For slender components

·     Generally where compaction of the concrete is difficult

·     For specifications requiring a homogeneous concrete structure

·     or fast installation rates

·     To reduce noise (eliminate or reduce vibration)

·     To reduce damage to health (“white knuckle” syndrome)

Composition

·     Aggregate

Smaller maximum particle sizes of approx. 12 to 20 mm are preferable, but all aggregates are possible in principle.

·     Binder content

Based on the fines content, the following cement and aggregate contents can be determined, dependent on the concrete quality required and the sands used.

·     Water content

The water content in SCC depends on the concrete quality requirements and can be defined as follows.

·     Formwork facing

The forms for SCC must be clean and tight. The form pressures can be higher than for normal vibrated concrete. The form 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 installed 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 filling the form. This can be achieved by using tremie pipes etc.