Sprayed Concrete

Here at Gunite we provide both wet-mix (shotcrete) and dry-mix (gunite) methods of sprayed concrete.

The word Gunite to describe a shot sprayed concrete was originally a name that specifically referred to the dry-mix pneumatic cement application process. In this particular process, the dry sand and cement mixture is fed through a delivery hose using compressed air, with water being added at the nozzle to fully hydrate the mixture, immediately before it is discharged onto the receiving substrate. The word Gunite was the original term coined in 1909 and patented in North Carolina. The concrete mixture is applied by pneumatic pressure from a gun, hence the term “gun”-ite.

As our founding business we have provided sprayed concrete solutions to a wide variety of sectors. It is a common procedure to use sprayed concrete for structural repair, fire protection to steel framed buildings and linings to a range of structures such as tunnels and river walls. Installed properly by experienced applicators, it provides designers with a cost effective and adaptable method to create and repair concrete structures.

Both wet and dry sprayed techniques are ideal for large volume repair sites such as sea defence walls or overhead applications within structural slabs or bridge decks.

Gunite also use wet spray techniques for the relining and reprofiling of reinforced concrete tanks and silos. Many cementitious linings are chemical and abrasive resistant and sprayed concrete techniques are used to reline and reprofile ageing structures to prolong the service life of the asset.

Shotcrete machines are available which control the complete process and make it very fast and easy. Manual and mechanical methods are used for the wet spraying process, but wet sprayed concrete is traditionally applied by machine.

The high spray outputs and large cross-sections require the work to be mechanised. Concrete spraying systems with duplex pumps are mainly used for working with wet mixes. Unlike conventional concrete pumps, these systems have to meet the additional requirement of delivering a concrete flow that is as constant as possible, and therefore continuous, to guarantee homogeneous spray application.

Gunite sprayed concrete works have included: Free-formed architectural finishes and features, sealing of contiguous and secant piled walls, Tunnel linings, Acoustic roofs, Water retaining structures, including pools, Sea defences, Bank, and cliff stabilisation.