Details about compaction of concrete
Compaction in concreting refers to the method required for dissipating air voids from the concrete. Due to the existence of air voids, honey comb is created in concrete and the strength of concrete is reduced significantly. The concrete strength is decreased by 6% if there is 1% of air voids.
Compaction of concrete is accomplished by manually or mechanically. Manual compaction is performed by hand through tamping rods.
Mechanical compaction is performed with vibrators.
Methods of compaction of concrete: Selection of compaction method is based on various factors like reinforcement quantity and spacing, deepness of concrete structure, sort of availability of machines, position of concrete structure, conformity of concrete paste, formwork difficulty.
Given below, different types of compaction methods :-
Hand compaction method: Hand compaction is performed with three methods ranging from roding, ramming and tamping.
In roding method a 2 meter long and 16 mm dia rod is applied. The edges of the rod should be harsh. Here, the thickness of concrete remains between 120 to 150 mm.
Compaction process is carried out during the concrete area. The compaction should be in progress unless it is completely compacted.
Another popular method is tamping. Under this method, cross beam with 10 cm x 10 cm sizes are utilized to compact the concrete. Compaction and concrete surface level is retained consistently. It is effective for road pavement flooring concrete and roof concrete works.
Mechanical Compaction: Mechanical compaction is performed with vibrators. Vibration leads to temporary liquefaction so the air accumulated among aggregates is eliminated instantly.
Different types of vibrators are utilized which range from internal or needle vibrators, external vibrators, table vibrators, surface vibrator etc.
To get more details about the vibrators, go through the following link learntocivilfield.com