SCC or Self Compacting Concrete is the latest trend in the field of concrete. I was fortunate to do Project on SCC during my final semester of Engineering under Girish Sir .Here I will briefly tell you what SCC is and its advantages over the normal concrete.
SCC was first developed in Japan based on developmental work at the University of Tokyo, to offset a growing shortage of skilled labour. The concept of SCC was proposed by Okamura in 1986. It is a high fluid mix that has excellent deformability and resistance to segregation, that could entirely fill and self compact under its own weight in heavy reinforced form work. SCC that is highly workable, easy to place in the formwork and require no vibration has been more or less now globalised in the last few years and is gaining importance through out the world.
To achieve SCC, the concrete must be highly fluid and stable i.e., the concrete mix must remain homogenous during the entire process from plant to formwork with out separation of the aggregate, mortar and water. SCC is a very promising material since there is an implicit assurance of uniform quality unaffected by placement errors and poor compaction. Self-Compacting Concrete generally requires a hyper-Plasticizer to ensure fluidity and flow for a sufficient length of time without experiencing a large ‘slump loss’. Viscosity Modifying Admixtures [resins, colloidal matter] are also sometimes added to ensure stable and fully cohesive mixture even when subjected to vagaries at construction sites such as varying moisture contents of aggregates, accidental excess water, ambient temperature and humidity variations and others.
Self-Compacting Concrete mixes contains a large quantity of powder materials as these are required to maintain sufficient yield value of the fresh mix, to reduce bleeding, segregation and settlement. SCC has gained wide use in many countries for different application and high structural configurations. SCC requires a high slump that easily be achieved by incorporating the chemical admixtures.
SCC also plays a major role in increasing the utilization of Industrial by-products like Slag, Fly ash and Silica fume. It offers possibilities for utilization of quarry dust which are currently the waste products, with minimal practical applications and which are expensive to dispose off.
SCC offers many benefits and advantages over conventional concrete. This includes:
- Complete filling up of intricate and narrow moulds.
- Provides better working environment by eliminating the vibration noise.
- Extremely suitable for slim and complicated moulds.
- Complete enveloping of reinforcing steel even where steel congestion is present.
- A very rapid placement, limited only by the rate of concrete transportation and/or mixing.
- Improved health and safety on site.
- Faster construction time.
- Reduced formwork and equipment costs.
- Less manpower.
- Improved durability & good structural performance.
- Medium strength concrete with less quantity of cement.