Dry-Mix Shotcrete is a construction method where dry concrete materials are mixed and then sprayed through a hose using compressed air. Water is added at the nozzle just before the mixture is sprayed onto the surface. This technique is often used for repairing concrete, stabilizing rock surfaces, and building tunnel linings.

   Process:

   In the dry-mix method, dry ingredients (cement and aggregate) are combined and fed into a delivery equipment. This mixture is pneumatically conveyed through a hose to the nozzle, where water is introduced under pressure just before application. The water and dry materials mix as they are projected onto the receiving surface.

  Advantages:

   ① Control Over Water Content: The nozzle operator can adjust the water content in real-time, allowing for adaptability to various surface conditions and orientations.

   ② Equipment Simplicity: Dry-mix equipment is generally simpler and more portable, facilitating use in confined or hard-to-reach areas.

   ③ Convenience for Intermittent Application: Suitable for projects requiring frequent starts and stops, as the dry material can remain in the hose without immediate cleaning.
   Disadvantages:

   ① Higher Rebound Rate: Tends to produce more rebound (material that doesn't adhere to the surface) and waste.

   ② Dust Generation: The process can generate more dust compared to the wet-mix method.

   Dry-Mix Shotcrete is fast, efficient, and useful in places where formwork is difficult to install.