🕑 Reading time: 1 minuteHoneycombs are hollow spaces and cavities left in concrete mass on the surface or inside the mass where concrete could not reach. These look like honey bees nest. Improper vibration and workability of concrete are main causes of honeycombs in concrete. Honeycombs which are on sides are visible to naked eyes and can be detected easily as soon shuttering is removed. Honeycombs which are inside mass of concrete can only be detected by advanced techniques like ultrasonic testing etc.
Causes of Honeycombs in ConcreteHoneycomb is due to non-reaching of concrete to all places due to which cavities and hollow pockets are created, main reasons are:
- Improper vibration during concrete.
- Less cover to reinforcement bars
- Use of very stiff concrete (this can be avoided by controlling water as per slump test).
- Places like junction of beam to beam to column and to one or more beams are the typical spots where honeycombs are observed. This is due to jumbling of reinforcement of beams and column rods at one place; special attention is required at such place during concreting and vibrating.
- Presence of more percentage of bigger size of aggregate in concrete also prevents concrete to fill narrow spaces between the reinforcement rods.