GeneralQ I have a very small job to do that would normally be handled by a gunite or sprayed-on application. I need to form the inside of a concrete box into a cylindrical shape. I would like to get a few hints or suggestions on how I might accomplish the “gunite” solution using my hands/tools only. Does this require a special mix of the mortar mixture?
Shotcrete is concrete placed at high velocity to achieve compaction. It is dependent on the projection of material with air velocity of 60 to 80 mph (97 to 129 km/h) from the nozzle to consolidate the concrete material in place. It cannot be hand-applied. You may consider hand-applied pre-packaged mortar mixtures to achieve your results, although strength and durability may be less than a similar section with shotcrete because the hand-applied material is not fully compacted. Another alternative is to create an inner cylinder and cast concrete in the space between the box and the form. The concrete could then be vibrated for consolidation.
