Whats the difference between Gunite and Shotcrete?
Generically speaking, Gunite is a term that is loosely used to describe material that is pneumatically applied.
Specifically speaking, Gunite and Shotcrete are similar in the sense that they are both a pneumatic or force applied material application. However, the difference between Gunite and Shotcrete is this:
The Dry process (Gunite) is a mixture of mainly sand and cement. The dry process is shot though the hoses like a sand blast operation with the water being applied at the very end of the hose. When applied to a pool, the crews mainly do the floors first due to the large amount of rebound produced. When the walls, benches and spas are shot, the crews must throw out the rebound. If any rebound is incorporated into the floor, a weak sand-like pocket will form. If it doesnt stick, it must be removed.
The Wet process (Shot Crete) is a mixture of sand, cement, small pea gravel and water. The wet process is brought out by a ready-mix concrete truck and pumped via concrete pump with the air applied through a nozzle at the very end, to spray the material in place. This method produces little or no rebound so the walls are applied first, then the floor shot last. All excess material pulled from walls can be incorporated into the floor area and then shot over. This can't be done with the dry process.