Development of Self Compacting Concrete

Origination of self compacting concrete is in 1983 from Japan as a solution for the shortage of the skilled labor who is required for the compaction purposes which is adequately required for constructing of durable concrete structures. However, one solution for the achievement of durable concrete structures is the employment of the self-compacting concrete that is able to flow under its own weight and completely fill the formwork, even in the presence of dense reinforcement, without the need of any vibration, whilst  maintaining homogeneity. The necessity of this kind of concrete was proposed by Okamura in 1986.

Research have been carried out to development of self compacting concrete, including a fundamental study on the work- ability of concrete, by Ozawa and Maekawa at the University of Tokyo and first the  prototype of  self compacting concrete was completed using materials already in the market in 1988.

The prototype performed satisfactorily with regard to drying and hardening shrinkage, heat of hydration, denseness after hardening, and other properties. This concrete was named “High Performance Concrete”.

The method for achieving self-compacting ability involves

  • Limited aggregate content
  • Low water-powder ratio
  • Employment  of superplasticizer

The required material constituent to development of self compacting concrete are cement, Fine aggregates, Coarse aggregate, admixtures, additions, fiber etc…

The each material should meet certain characteristics to develop required concrete such as strength, durability, etc…The typical cement content is 350-450kg/m3, fine aggregate which are used to normal concrete both crushed and rounded sand can be used, normally coarse aggregate range may be 16-20mm, superplasticizer admixture is acting as water reducing and high mobility agent, viscosity modifying agent used to controlling the segregation when the amount of powder usage limited.

Remember, each material & constituent should be selected according to British standards (BS), ASTM or Euro codes to meet standard specification of project or body specified and mix design has to be done to calculate each material composition.