HONEYCOMB IN CONCRETE

Honeycomb In Concrete

Honeycomb in concrete refers to cavities in the concrete formed due to presence of air bubbles present in the concrete.Honeycombs are hollow spaces and cavities left in concrete mass on surface or inside the concrete mass where concrete could not reach.These looks like honey bees nest.Honeycombs which are on sides are visible to naked eyes and can be detected easily as soon shuttering is removed.

Honeycomb in concrete is normally seen at the column and beam junction due to overcrowding of reinforcement bars which leads to poor concrete fill.Concrete honeycomb not only reduces the strength also provides passage for water which in turn corrodes reinforcement bars.

Types Of Honeycomb In Concrete

1. Small Size Honeycomb
2. Medium  Size Honeycomb
3. Large  Size Honeycomb

1. Small Size Honeycomb

Small size honeycomb has a depth of less than 25 mm.

2. Medium Size Honeycomb

Medium size honeycomb is deeper than 25 mm but in which steel bar is not exposed.

3. Large Size Honeycomb

Large size honeycomb is deeper than 25 mm and in which steel bar has come out.

Causes Of Honeycomb In Concrete

• Improper workability in concrete.
• Insufficient compaction to concrete.
• Improper clear cover to reinforcement bars.
• Improper vibration of concrete in formwork.
• Formwork is not rigid and watertight.
• Use of larger size aggregates in excessive amount.
• Concrete is poured from more than allowable hight.
• Improper placement of bars at column and beam junction.
• Over reinforcement.
• Bad workmanship.

Effects Of Honeycomb In Concrete

• Honeycombing makes the concrete weak.
• Water and air penetrate inside the structure.
• Due to honeycombing moisture easily entered in RCC.
• It reduces the structural strength of concrete components. 
• It reduces the load-bearing capacity eventually affecting the strength of the structure.

How To Repair Honeycomb In Concrete

1. Mark the affected area of honeycombing and remove all loose aggregate.
2. With the help of wire brush clean the affected area.
3. Remove the finer particles and wash the concrete surface with water.
4. After 2-3 hours apply Chemi-fix glue on the affected area.
5. Prepare a grout mix with white cement and add the required amount of water.
6. Fill the affected area of the concrete surface.In case of large-area affected by honeycombing make patch hole before applying grout for proper bonding.
7. Remove formwork if any applied and cure surface properly for at least 24 hours.