Which shotcreting method is the more satisfactory, using a wet mix or a dry mix?
Each has certain advantages, and the choice may depend on the nature of the job and local costs. The cost of equipment, cost of maintenance, and various features of performance must all be considered. In the dry mix process the consistency of the mix can be adjusted by the nozzleman to suit his immediate requirements. Shotcrete made with lightweight porous aggregates can usually be handled better by dry mix equipment. Longer hoses may also be utilized with dry mixes than with wet mixes. In the wet mix process mixing water is measured and accurately controlled at the equipment, permitting fidelity to established mix proportions. Wet mix equipment assures that mixing is thorough and reduces the amount of rebound. Gunning of wet mixes also produces less dust.