The production of self-compacting concrete needs to be carried out in plants where the equipment, operation and materials are suitably controlled. Production should therefore be carried out at ISO9000 accredited plants or plants with a quality systems that conforms to ISO9000 or similar. It is recommended that production staff involved in the production of self-compacting concrete have been trained and also have experience in self-compacting concrete.
Self-compacting Concrete Production Line
Storage of Constituent Materials
If possible, aggregates should be covered to minimise the fluctuation of surface moisture content. It is also necessary to have good storage capacity for aggregates and additions (if used).
Storage of concrete admixtures can be done in the same way as for normal concrete. The supplier’s recommendations should be followed.
Mixing Process
At the start of a contract and in the absence of previous experience with the particular mix design, additional resources may be needed for supervision of all aspects of initial production of SCC.
Since the quality of freshly mixed concrete may fluctuate at the beginning of production, it is recommended that workability tests should be conducted by the producer on every load, until consistent and compliant results are obtained. Subsequently, every delivered batch should be visually checked before transportation to site, and routine testing carried out to the frequency specified in EN206.
More frequent adjustment of mix proportions, particularly water content, may need to be made, depending on the results from monitoring aggregate moisture content.
Delivery and Transportation
Depending on the size of the concrete structure to be produced in SCC, production capacity, journey time and placing capability need to be balanced. Unexpected production stops can result in consistence variations that adversely affect the end result.
SCC should be designed so that workability is maintained to meet the requirements of the contract. Placing is faster, especially if a pump is used, but it is still essential to make sure that delivery and placing can be completed within the workability-retention (self-compactability) time of the concrete.
