Dry sprayed concrete process means delivery (transport) of a ready-mixed sprayed concrete consisting of aggregate, cement and any sprayed concrete admixtures but without mixing water.

This ready-mixed formulation is either completely dry (oven dry) or is wetted by the inherent moisture in the aggregate. For the spraying operation, the dry sprayed concrete is mixed with water and shotcrete accelerators and then applied. Instead of shotcrete accelerators, special rapid-hardening cements that set in a very short time after wetting with water can be used in the dry spraying process. The thin-flow process must be used for delivery of dry sprayed concrete.

Dry sprayed concrete is a process that has long proved successful but is being continuously developed and improved.

Uses

Dry sprayed concrete is always used when smaller quantities and outputs are required and high very early strength is essential, for example for preliminary sealing against high water penetration with gunite. The final, the choice of process is also determined by the contractor’s preferences!

Applications for dry sprayed concrete and ready-mixed gunite:

  • concrete repairs
  • preliminary sealing against water inleakage
  • medium spraying works
  • waterproofing works
  • logistics concept not time dependent (local storage)

Advantages

The advantages of dry sprayed concrete lie in its flexibility. It is the traditional method of applying sprayed concrete, better known throughout the world.

  • high very early strength for preliminary sealing or stabilizing
  • almost unlimited holding time (availability) of silo stored material
  • no concrete waste

With dry sprayed concrete, the economics are affected by the high rebound quantities and dust generation and the higher wear costs.