In terms of structural and durability requirements, SCC is not different from conventional vibrated concrete and therefore existing design codes and standards are still valid.

The self-compacting concrete differs from conventional concrete in the following three characteristic features, namely, appropriate flowability, non-segregation, and no blocking tendency. An increase in the flowability of concrete is known to increase the risk of segregation. Therefore, it is essential to have proper mix design.

The basic constituent materials used in SCC are essentially the same as those of conventional concrete, although additional admixtures or fine materials may be necessary to achieve the required rheological properties. However, the biggest difference between the two concretes is the actual proportioning of these materials.

In order to achieve its defined purpose, SCC mixes contain:

¶ Lower coarse aggregate contents: to reduce the friction between them and therefore enhance the overall concrete fluidity

¶ Higher amounts of sand & higher amounts of cementitious materials including Portland cement: to further increase fluidity as well as enhance its cohesiveness and resistance to segregation and viscosity.

¶ Lower water/cementitious material ratio,

¶ Higher superplasticiser doses and

¶ Viscosity modifying admixtures

Control of the viscosity and cohesiveness of the paste ensures the flow of the SCC through obstacles such as steel reinforcement without any aggregate blockages.

Material, by volume	Conventional Vibrated Concrete (%)	SCC (%)
Admixtures	< 0.01	0.01
Water	18	20
Coarse Aggregate	46	28
Sand	24	34
Fines, including Portland cement	12	18