Shotcrete is not a special product of concrete and it is not a special method of placing concrete.
In dry-mix method the dry cementitious mixture is blown through a hose to the nozzle, where the water is injected immediately. The dry-mix method appears to be better for low volume placements. The nozzleman should pay great attention in adding the necessary amount of water during shooting operation.
Wet-mix method involves the pumping of ready mixed concrete to the nozzle. Compressed air is introduced at the nozzle to impel the mixture onto the receiving surface. The wet-mix method is more favorable for large volume placements. Rebound is less than in the dry-mix method. The nozzleman does not need to be concerned with the control on water addition.
