What is Sprayed Concrete?
Sprayed concrete is a method of applying concrete that is generally self supporting without the need for form work.
Sprayed concrete is often referred to as Gunite (dry mix) or Shotcrete (wet mix)
The Gunite process was developed in 1895 and was commercially available in the early 1900´s.
Material is conveyed in a dry or semi dry state using compressed air to the nozzle where water is added to hydrate and mix the concrete before application with velocity onto the substrate.
Shotcrete was commercially developed after the 2nd World War but was not in general use until the 1970´s. The concrete mix is supplied in the wet form and is pumped to the spraying nozzle where air is added to project the concrete onto the substrate. The use of accelerators added at the nozzle can assist in applying the concrete in overhead situations or to increase early strengths gain requirements in ground support and tunnelling.
Both methods provide a means of applying concrete that is as good and in many cases superior to conventional concrete.
Why Should You Use Sprayed Concrete?
- High strength, low permeability, high durability
- Reduction in formwork saving time and money
- High early strength gain
- Low water / cement ratio
- Good adhesion and bond strengths
- Ability to convey material over 200 metres to point of application
- Proven process in use for over 100 years