The use of self compacting concrete has been encountering a gradual increase ever since a prototype of the concrete developed in the year 1988. Some of the main reasons for employing self compacting concrete are:
- To minimize the period of construction.
- To ensure structure compaction, particularly when vibrating compaction is tough in confined zones.
- To eliminate noise produced due to vibration; this can be particularly effective in concrete product plants.
This just goes to imply that the present state of self compacting concrete is indeed a special one rather than the standard concrete.
A good example of an application of this concrete is the Akashi-Kaikyo (Straits) Bridge anchorages. The bridge that was opened in April 1998 is a suspension bridge that has the longest span in the world, at 1991 meters.
The cast concrete volume that was required for the two anchorages reached around 290,000 m3. A novel construction system that takes complete advantage of this concrete performance was specially introduced for this. The concrete was missed at the batcher plant that was located beside the site and then was discharged out of the plant. The concrete had to be transported 200 meters via pipes to the casting site. Here, there was an arrangement of rows of pipes, about 3 to 5 meters apart. After this, the concrete was cast from gate valves that were located at an interval of 5 meters alongside the pipes.
To ensure that the cast concrete surface level is maintained, the valves were controlled automatically. Subsequently, it was noted that the self-compacting concrete reduced the period of anchorage construction by 20 percent, from 2.5 years to 2 years.
This concrete was also utilized for the wall of a huge LNG tank of Osaka Gas Company. The concrete casting of this wall culminated in June 1998. And the self compacting concrete volume that was used in the tank came to a consolidated 12,000 m3. The fact that self compacting concrete was adopted naturally implies the following:
The lots number reduced to 10 from 14, since the height of one concrete casting lot was increased.
There was a reduction in the number of workers to 50 from 150.
The period of construction of the structure reduced to 18 months from 22 months.
Usually, self compacting concrete is made use of in concrete products to remove vibration noise. The working environment is thus enhanced at plants and it becomes possible for concrete product plants to be situated in urban areas.
In 1996, the annual production of concrete products that make use of self compacting concrete was over 200,000 tons
The undeniable truth is that self compacting concrete requires a lot of care and experience, when compared to conventional vibrated concrete. Personnel at plants definitely require training and the right amount of expertise for successful production and handling of SCC. Initially, it might be necessary to perform several tests than usual in order to learn about the intricacies and skill involved.