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How to avoid Honeycombing in RCC Structures
Description of a Honeycombing: Honeycombing indicates a structural error in a RCC structure. Also, honeycombed surface is the concrete surface’s spaces wherein the coarse aggregate are highly visible.
In case safety measure isn’t applied/taken with regard to honeycombed surface, the RCC structure can’t accomplish best possible functioning as per its design (structurally unstable). Moreover, it allows harmful agents such as unclean water as well as air going via the formed openings which can affect the structure’s strength significantly.
Reasons for Honeycombing: Honeycombing in RCC structure is occurred due to the subsequent causes:
- Concrete mix isn’t consistent.
- Concrete flow isn’t spread to each and every corner because of steel congestion.
- Concrete’s applicability is inappropriate as well as not equivalent with its positioning requirement.
- Formwork isn’t inflexible or watertight/waterproof.
- Inappropriate compaction/compression to concrete.
- Concrete is set earlier before placing.
- Concrete’s high free fall, during pouring.
- Inaccurate detailing and/or steel’s fixing.
In what way Honeycombing in Concrete can be averted?
Verify concrete formation periodically to prepare the entire concrete batches.
Concrete workability must match the arrangement requirement. Like for instance, a light/lightly reinforced column must comprise 75 mm slump, a heavy reinforced column might need 150 mm slump.
Ensure that the placed concrete’s compaction is ideal, vibrators must have been removed like large air bubbles stops to emerge (excess vibration can cause bleeding). Several sizes [60 mm, 25 mm, as well as 40 mm] of vibrator needle must have been used as per RCC sections.
Concrete must be thoroughly condensed as well as fully operational nearby the region of the reinforcement, nearby the region of fixed fittings as well as within the formwork’s corners.
Be careful and take precautionary measures right through/all through vibration to avert honeycombing, Five % gaps in concrete can reduce concrete robustness by thirty %. Furthermore, cover to formwork, spaces bars as well as pins to reinforcement’s layers to permit accurate compaction.
Moreover, concrete must comprise slump before it is organized/set. Exclusive of first slump, the concrete’s design must be formed in an approach in order that it can keep slump the moment it is organized.
Least concrete fall must be kept, in case essential concrete bucket with concrete hose pipe, canvas pipes, must be utilized to reduce concrete free fall height.
Moreover, formwork must be waterproof; cement grout must be kept during concrete placing. Furthermore, steel detailing as well as fixing must be conducted to distribute the concrete throughout the entire corners as well as depths efficiently.
In case it isn’t probable to get free of steel congestion, specific concrete arrangements such as concrete having less highest aggregate size (12.5 mm), self compacting concrete/self-compacting concrete, and so forth must be suggested.
To get more detail, go through the following video tutorial.
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