honeycomb in concrete surface
honeycomb in concrete surface

Honeycomb and large surface voids require the same procedures as typical concrete repairs. But there is nothing specific about the recommended methods for repairing these voids. They differ greatly.

When repairing voids or honeycombs in a concrete surface, the most common question that arises is what should be the thickness of the repair, Some agencies do not require a minimum thickness, while others set limits such as 1 inch or 2 inches (25 mm to 50 mm). Some suggest using epoxy as a bonding agent while others suggest using cement grout.

In any case, good concrete repair practice calls for the removal of any loose material within the void. According to scientists, honeycombs often contain loose coarse aggregates if caused by leakage in the void form. If void is caused by poor concrete consolidation; Coarse aggregates often remain intact.

honeycomb repair process in concrete

  1. Use light chipping hammers weighing about 7 kg or less to remove the required amount of concrete, as impact hammers can dissolve the surface of the concrete. Follow up the chipping with sandblasting or water blasting to remove this fractured surface.
  2. A common way to keep repair material is to simply throw it into the void. But Glenn Smoke (author of the book) Guide to Concrete Repair) Contractors may achieve better results by using a small pneumatic mortar gun to apply grout similar to a dry pack applied by hand. (as shown below)

    Repair of honeycomb voids in concrete
    Pneumatic gun for shooting mortar or cement grout

  3. A suitable mix contains 1 part Portland cement and 4 parts sand and has a water-cement ratio of about 0.35. If the repair is deeper than 1 inch (or 25 mm), apply the mortar in layers no more than 3⁄4 inch thick to avoid thickening and loss of bond.
  4. After placing each layer, wait about 30 minutes before placing the next layer. You don’t need to scratch or otherwise prepare the first layer before applying the next, but don’t let the mortar dry out.
  5. To complete the repair, fill in the blanks a little more. After the material has hardened slightly but can still be cut with the edge of a steel trowel, work off the excess material from the center to the edges. When completing the repair, take extreme care to avoid damaging the bond.


Guide to Concrete Repair by W. Glenn Smoke

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.