The shotcrete process is to mix the aggregate, cement and water in a designed proportion, press it to the nozzle with a wet spray machine, and then spray it out by adding a quick-setting agent to the nozzle.

The difference between dry spray process and wet spray process

1. When mixing outside the hole, the dry spray process does not add water, forming a solid mixture. The wet spray process must add water according to the mixing ratio to form a fluid mixture.

2. Due to the different forms of the mixture formed by the two processes, the transportation mode is different. The transportation requirements of the dry spray mixture are relatively simple, and can be transported by shuttle or mine truck, but the wet spray mixture must be transported by rail concrete car;

3. Different accelerator. The dry spray process uses solid accelerator， while the wet spray process uses liquid accelerator, and the price between two types of accelerator are also different.

4. Different spraying equipment . The dry spray process uses dry shotcrete machine, while the wet spray process uses wet shotcrete machine. The price difference between two types of shotcrete machine is large.

5. Different feeding way.Dry shotcrete machine uses solid mixture, so it must be fed manually, while the wet shotcrete machine can directly connect the concrete tanker without manual feeding;

The advantages of wet spraying machine

1. Sealed structure, reducing dust pollution

2. Small rebound ，saving materials

3. Since the concrete has been mixed well before spraying, the concrete mix ratio is ensured, thus ensuring the quality of the concrete.

The disadvantages of wet spraying machine

1. Piston wet spraying machine is expensive

2. It is difficult to transport wet concrete mixture, sometimes it requires a concrete tanker.

3. Machine must be cleaned with water after every shotcrete operation.