Though self compacting concrete is used, these bulbs may not be filled completely. So, reinforcement is lowered after concreting, after clearing the muck on top, if any, either by vibration or driving, so that concrete is forced into the bulb. Heavy vibration is not used as the concrete can segregate.
Why vibrators are not used during concreting in piling works? Why vibrators are not used during concreting in piling works?
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Following are the reasons behind the vibrators are not used during concreting in piling works:
Vibrators are used:
- For removing air voids
- Avoiding the formation of the honeycomb structure
- For proper compaction
In the case of pile construction work, the depth of the pile is very high, and a vibrator is not capable of reaching up to that height.
The soil will get damaged due to vibrator at a very high height. It is a possibility of sewer collapse.
Concreting in piling should be a high-slump self compacting mix which is capable of flowing between reinforcement cage with ease. Since concrete is designed to be self compacting, vibrators are not used for providing further compaction. Moreover the concrete in piles is compacted by energy derived from free falling.
However, if vibrators are used the vibrated concrete may be compacted to the sides of the concrete casings and hinders the lifting up of casings.
The concrete mix for piles should be high-slump self-compacting mix which is able to flow between r/f confine easily. Since concrete is intended to act self-compacting, vibrators are not utilized for giving further compaction. In addition, the solid in heaps is compacted by vitality got from free falling. Be that as it may, if vibrators are utilized, the vibrated cement might be compacted to the sides of the concrete casings and hinders the lifting up of casings.
The vibrator is used to compact the concrete properly and remove all the voids and avoid the formation of the honeycomb structure.
In piling construction depth of work is very high where vibrator does not rich in a proper way.
At a very high depth soil may also damage due to vibrator if it misplaced and causes a sewer collapse in the substructure.
To avoid the formation of honeycomb structure and voids, self-compacting concrete which has higher slump value must be used. so that there is no need to vibrate the mixture externally.
Hope you get the answer.
- Piling works have high depths (around 30 m or above) and at such depths vibrators can’t be used.
- At these depths it is advisable not to use vibrators because soil may get collapsed.
- Concrete used in piling works have high slumps so it can easily flow through reinforcement cage and the mix is designed to compact itself .
- In some cases vibrators can be used to compact the concrete by vibrating the concreting pipe during pouring.
For In-Situ piles, we don’t generally use vibrators because Vibration in such depths may alter the soil structure and may even cause collapse. Therefore the type of concrete used is self-compacting concrete. This concrete does not need external vibrations to compact.