The dry-mix and wet-mix methods are the two most popular ways to spread shotcrete. The word gunite is commonly used to describe the dry-mix method; other terms used in the past to describe the process include air-placed concrete, gunned concrete, and sprayed concrete.
SHOTCRETE DRY-MIX PROCESS
Cement and moist aggregate are mixed in this method, and the mixture is then meter into a stream of compressed air by a system. Compressed air transports the material to the nozzle via a delivery tube, where water is applied under pressure via a perforated ring. When the mixture is jetted from the nozzle at high velocity onto the surface to be shotcreted, the water completely wets the other ingredients.
SHOTCRETE WITH WET MIX
To make mortar or concrete, all materials are mixed together first in the wet-mix phase. Following that, the mortar or concrete is loaded into distribution equipment. The material is delivered to the nozzle through a delivery hose, where compressed air is pumped to increase velocity.
COMPARISON OF SYSTEMS
Because of the low water-cement ratio and high impact velocity, dry-process shotcrete has excellent bonding capacity. The ability to adjust the water-cement ratio more precisely is one of the more appealing features of wet-mix systems.