How does a shotcrete pump work? A shotcrete pump is a specialized piece of equipment used to apply concrete in a spray form, commonly used for structures like tunnels, swimming pools, and slopes. Shotcrete, which is a mixture of concrete or mortar, is sprayed at high velocity onto a surface, allowing for rapid layering and solid structural support. Shotcrete pumps facilitate this by using either the wet-mix or dry-mix process. Here’s how each one works:

　　1. Wet-Mix Shotcrete Pump

　　In the wet-mix method, the concrete mixture （including water） is prepared in advance and poured into the pump. The pump then delivers it through hoses to a nozzle, where compressed air is added at the end to propel the mix onto the target surface. Here’s a breakdown of the wet-mix process:

　　- Mixing: The concrete mix, including water, is premixed in a mixer and then loaded into the shotcrete pump.

　　- Pumping: The pump moves the mix through hoses or pipes to the nozzle.

　　- Air Injection: Compressed air is introduced at the nozzle to increase the speed and force of the sprayed concrete.

　　- Application: The high-velocity concrete bonds strongly to the surface, allowing for layers to build quickly.

　　2. Dry-Mix Shotcrete Pump

　　In the dry-mix process, only the dry concrete materials （cement, sand, and aggregates） are loaded into the pump. Water is introduced at the nozzle, mixing with the dry materials just before they are sprayed onto the surface. The dry-mix process works as follows:

　　- Loading: Dry concrete ingredients are loaded into the pump’s hopper.

　　- Pumping: A blast of compressed air propels the dry mix through the hoses to the nozzle.

　　- Water Injection: At the nozzle, water is injected and mixed with the dry materials, creating wet concrete just before it exits the nozzle.

　　- Application: The high-velocity spray bonds to the surface, similar to the wet-mix method.

　　Key Components of a Shotcrete Pump

　　- Pump （usually piston or rotor-stator type）： Provides the force to move concrete through the system.

　　- Hopper: Holds the concrete mix before pumping.

　　- Compressor: Supplies compressed air for high-velocity spraying.

　　- Hoses/Pipes: Transport the concrete from the pump to the nozzle.

　　- Nozzle: The point where air and, in the case of dry-mix, water are added to spray the concrete.

　　Applications

　　Shotcrete pumps are valued for their ability to create smooth, durable surfaces in hard-to-reach or vertical areas, with applications in construction, repairs, and reinforcement.