Honeycombs in Concrete–Their causes and remedies

 are hollow spaces and cavities left on the ground or inside the building in concrete bodies where concrete could not reach. They look like nesting honey bees. Improper concrete vibration and workability are the primary causes of concrete honeycombs.

Honeycombs on the sides are noticeable to naked eyes and can be readily identified as quickly as shuttering has been removed. Honeycombs inside concrete mass can only be identified by sophisticated methods such as ultrasonic testing, etc. The causes of Honeycombs in Concrete Honeycomb are due to the non-reaching of concrete wherever cavities and hollow pockets are created, the primary reasons being: improper vibration in concrete.
Use very rigid concrete (this can be prevented by regulating water as per slump test).
The typical places where honeycombs are observed are places such as the intersection of beam to beam to column and to one or more beams. That's because of the jumb

Remedies for Concrete Honeycombs Strictly speaking, wherever in concrete honeycombs are observed, the affected area should be broken and the portion should be re-concreted after application of the grouting chemicals to the old surface.

Honeycombs as a deficiency not only decreases the ability of the load bearing, but water also finds an easy way to reinforce pipes and start rusting and corrosion.

Corrosion is a method that continues even in solid concrete through reinforcement rods, resulting in a loss of grip between rods and concrete that is very hazardous to the safety and life of concrete constructions.

Reinforced concrete structures have failed owing to honeycombs, which is less than half of their predicted lives, within 20 or 30 years of their building. Especially for columns, machine foundations, rafts, beams etc., where breaking and refurbishing is the only best way, no risk should be taken.

In the situation of honeycombs on surface pressure grouting with cement-based chemicals that are non-shrinkable can be accepted following the designer's view and acting as recommended by the designer.

It will not be out of context to point out that contractors and their managers are used to hiding honeycombs by applying super-facial cement plaster on the honeycombs, so site engineering must be Very attentive.

Concrete with strictly 20 mm and down aggregates with slightly more water and cement should be used at the junction sites of columns and beams to prevent honeycombs.

Taping the sides of the shuttering from outside with a wooden hammer during concreting and vibrating will help to minimize honeycombs in columns and beams to a great extent.

Using thinner needle to say 25 mm or less with vibrator in complex concreting locations will also assist to reduce honeycombs.