Self-consolidated concrete


Self-consolidated concrete has different properties other than slump concrete. Self-consolidated concrete is highly workable, without vibration, it can flow under the force of gravity, it can move through densely reinforced and complex structural elements under its own weight and adequately fill all voids with out segregation, excessive bleeding, excessive air migration , or paste separation of materials.

Flowing concrete is that is characterized as having a slump greater than 190 mm while maintaining a cohesive nature. Flowing concrete can be proportioned with an even higher slump to be self leveling, which means that is capable of attaining a level surface with little additional effort from the placer. But some compaction will always be required.

Self-consolidated concrete must have both dynamic and static stabilities. Its dynamically stable during mixing, transportation, handling and placement. While statically its stable when setting and curing. Workability of self-consolidated concrete is a function of its rheology.

Advantages

Cost savings is the main advantage. At lower costs of labor, materials and equipment coupled with tougher environmental and safety regulations it can be used. The less intensive construction environment results in labor and time savings from higher productivity and greater flexibility of design. Following are the advantages

Reduced cost . improved work environment and safety. Improved aesthetics. Enhanced design flexibility.

Due to higher strengths has found applications where high strengths are needed. Self-consolidated concrete is used greatly in precast/prestressed concrete.

Quality Control

It is required higher level of quality control than ordinary slump concrete. All production personal should be aware about combined aggregate grading water mix ratio, controlled cement source and use of admixtures. Special attention requires about coarse fine aggregate grading, coarse aggregate void volume and aggregate moisture. Flowability of concrete is a complex interaction of the inter-particle friction in the aggregate phase and the fluidity of the paste phase. The water to powder ratio and admixtures control the paste phase. Aggregate particle friction should be minimum and paste fluidity must be more for to get flowability. Paste fluidity should be controlled or segregation may occur.