Honeycomb in concrete – Evade and Rectification

In the site, we construct the different shape of concrete structure like slab, beam and column etc., Mostly the worker eager to complete the concrete pouring and like to get away from the site in early.
So the worker does the concrete pouring very fast and regards that we might face some quality related issue.
In this post, we are going to discuss one of the quality issues named honeycomb in concrete including how to avoid the formation of honeycomb in concrete and how to rectify.

Hold on, did you hear the word Bulge? before discussing the concrete honeycomb, shall we take a little conversation about bulging meaning in concrete.

Bulging meaning

Bulging is one of the usual problems we may facing while concreting. The concrete was poured on the shuttering area at a gradual force and the force may oscillate the shuttering board.

So the concrete shall bleed out from its original alignment, it is called bulge.

How to avoid bulging?

Use steel shuttering and provide proper supports.
Do proper vibrating while concreting.
Ok, now come to our topic!.

What is meant by honeycomb in Concrete?

At the time of concrete pouring voids are formed between the concrete and reinforcement due to the presence of air bubbles and it seems to be a nest of the honey bee. So it is called in the name of honeycomb. 

We should avoid the honeycomb formation in concrete. In future, the steel bars will be corroded and it will affect the life of the structure.

How does honeycomb form in concrete? and how to avoid?
Honeycombs are formed in concrete due to the following reason.
Reinforcement Design
Due to the high reinforcement design, the concrete cannot be able to spread over the formwork.
Aggregates
The coarse aggregates should have good granular shape and right size because inappropriate aggregates the concrete can’t be pass in all area.

Mixing of Concrete

The mixing of concrete material should be an appropriate water-cement ratio. The workability of concrete depends on the water-cement ratio.
If the concrete is rigid then it can’t be spread the entire formwork. At the same time if the concrete is too slurry then the concrete was flowing out from the formwork area.

Formwork

Mostly honeycombs are formed in column and beam junction. Because those are a possible location where formwork not be done in proper. So the formwork should be done very rigid and it should not oscillate.
Before concrete pour, we have to ensure the formwork has done in good condition without any lack.

Workability

We should be vibrating the concrete while pouring the concrete because it could help for concrete consolidation. Don’t do too much of vibration because there is a chance for the shuttering oscillate, then the concrete bleed out from the shuttering.

Rectification of Honeycomb

Whatever we do precaution action to avoid the honeycomb, it will happen due to our minor mistake. Now we see how to rectify the honeycomb!.
Mostly the site engineers instruct the worker to apply the cement mortar or cement slurry on the honeycomb. It is not the correct solution for honeycomb rectification because after the certain period the plaster may drop from the honeycomb.
To rectify the honeycomb proper chemical adhesive should be injected into the location.
Remove the honeycomb area by chipping thereafter place a fresh concrete or do cement grouting on the honeycomb.
Hope you understand well!. You may interest to read the concrete material calculation.