Concrete has been the most preferred construction material for over five decades. It is being increasing day to day all over the world due to its versatility, mould ability, high compressive strength and many more advantages. For several years beginning in 1983, the problem of the durability of the concrete structures was a major topic of interest in Japan. The creation of durable concrete structures requires adequate compaction by skilled workers. One solution for the achievement of durable concrete structures is the employment of SCC which can be compacted into every corner of a formwork, purely by means of its own weight and the without the need for vibrating compaction. SCC was first developed in 1988 to achieve durable concrete structure. Investigations for establishing a rational mix-design method and Self-compact ability testing methods have been carried out from the view point of making SCC a standard concrete. Modern application of SCC is focused on high performance, better and more reliable and uniform quality. SCC has been described as “the most revolutionary development in concrete construction for several decades”. It has proved to be beneficial because it allows faster construction, improved durability and greater freedom in design etc. EFNARC, making use of practical experiences of its members with SCC, has drawn up specification and guidelines to provide a framework for design and use of high quality SCC during 2001. Generally SCC is used in situations for concrete requiring high strength say over 40MPa to 100MPa or more. It is being blindly believed that SCC is much costlier than normal or high strength concrete. Though the material cost for SCC is high, if other components of costs such as cost of compaction, finishing etc are considered, one can realize that SCC is certainly is not a costly concrete for comparable strength.
Contents Page no * Introduction 3 * Development3
* Material requirements 4
* Fresh properties6
* Hardened properties6
* Indian scenario of SCC 10
* How economical is SCC?11
SCC is defined as a concrete which can be placed and compacted into every corner of a formwork, purely by means of its self-weight by eliminating the need of either external energy input from vibration or any type of compacting effort. Portland cement concrete mixes are being used over 150 years. They are mixed, placed into the form and then compacted. It is essential to compact the concrete so that it completely covers the reinforcement bars and fill the space within the forms, for meeting strength and durability requirement. If the compaction is not complete, it will lead to loss in strength and also effect the performance of the structure. The compaction becomes difficult when percentage of reinforcement is high and rebars get congested without allowing for insertion of the vibrator at some places. In such places the concrete should be flowable in nature and should be self compacted.SCC has more favorable characteristics such as high fluidity, good segregation resistance and the self compacting ability without any need of vibration during the placing process.
Development of SCC
For several years beginning in 1983, the problem of the durability of concrete structures was a major topic of interest in Japan. The creation of durable concrete structures requires adequate compaction by skilled workers. However, the gradual reduction in the number of skilled workers in Japan’s construction industry has led to a similar reduction in the quality of construction work. Recognizing the lack of...