Honeycombs, especially in columns, have to be repaired with great care since colors are very crucial to structural failure. Follow these steps :
- Firstly, all loose concrete from the honeycomb should be strictly removed. Use a light chipping hammer (<7kg) to remove all the loosened coarse aggregates and mortar. Then use a brush to wipe off the remaining mortar. Follow this with sandblasting or water blasting followed by drying. Finally, just brush the surface once again.
- Next step: measure the depth of the area you are grouting. If the honeycombs are greater than one inch deep at multiple spots, note it down.
- Now, either wet the exposed surface, or apply chemi-fix glue.
- Now, prepare the grouting mix with mix proportions 1:4 and w/c ratio = 0.35. Remember, at all costs. The grout should be non-shrink.
- For applying, either trowel the grout into the honeycomb or for better results, use a small pneumatic mortar gun. If the voids we’re deeper than one inch, apply in layers of thickness <= 3/4 inch and wait 30 minutes between each layer.
- Overfill the honeycombs with grout a little bit. When everything dries up, trim or smooth off the excess from center to edges.