8.7 : 숏크리트

Shotcrete involves spraying mortar or small aggregate concrete rich in mortar through a hose at high velocity onto a surface that is typically reinforced.

The impact of the high-velocity jet on the surface compacts the material, facilitating its adhesion to vertical or overhead surfaces.

Shotcrete is sprayed and layered incrementally to reach a thickness of about 4 inches. The operator's skill in managing the nozzle is crucial to ensuring the quality of the shotcrete. 

Applying shotcrete using the dry mix method involves mixing cement and moist aggregate initially, then feeding the mix into a feeder and propelling it through a hose using a stream of compressed air.

Upon reaching the delivery nozzle, water under pressure is injected into the dry mixture, turning it into wet concrete ready to be sprayed.

In the wet mix shotcrete process, the dry ingredients and water are mixed before being loaded into the delivery equipment.

This wet mixture is then pneumatically conveyed through a hose, and at the delivery nozzle, compressed air is introduced to increase the velocity at which the mix is projected.