What Is Gunite & Other Questions To Gunite [7 FAQs]

Sprayed Concrete

Sprayed Concrete have its advantage over concrete pouring in some construction site. It can be easily applied and can have incredibly high bonding with the applied surface.

Some of the construction that can be done by sprayed concrete are mining and tunnel construction, slope stabilization, retention walls pools and even dams.

Sprayed concrete can be of dry mix (gunite) and wet mix (shotcrete). These different application of sprayed concrete are done the same, a high velocity of air pushed the material through the hose into the nozzle angled/ applied to the surface.

what is gunite

Gunite is also known as the dry-gun concrete. It is called a dry-gun concrete because it involves the dry mixtures that forms a concrete which are the cement and the aggregates. In short, concrete without the water content.

The process used in gunite concrete is also through a shotcrete but with atomized spray that dispenses the water concrete. The dry mixture of concrete is being fed into the machine and is pressurized with high velocity airstream that will be conveyed on the hose to the spraying nozzle.

In the spraying nozzle area, the atomized spray arrangement of water is found for the purpose of hydrating the cement mixture.

This way, the operator can control the water content of the concrete mixture without the need of admixtures.

Is Gunite Same As Concrete

One of the difference between gunite and concrete is the materials being mixed together. As discussed, gunite composes of the dry mixture of a concrete which are the cement and aggregates while concrete is the mixture of the dry and wet material which are the cement, aggregates and water.

Another would be the kind of aggregate being mixed into the mixture. For the gunite, it consists of cement and fine-grained aggregates or particles. For concrete, it consists of cement, small & large aggregates and water.

Next would be the application of the gunite and concrete. For gunite, the dry mixture is being placed in a shotcrete and are pressurized through the hose, exiting to the nozzle.

Once the dry mixture hit the surface, it will be then applied with water content, enough for it to bond with the surface. For concrete, it can arrive on-site which is the ready mix concrete or for smaller construction site which can be mixed on-site with ratio depending on the compressive strength of the concrete.

Which Is Better Shotcrete Or Gunite

Shotcrete or gunite can have its advantage over the other but depends on the construction application.

For shotcrete, it takes shorter time in application because it is pre-mixed and the only thing you need to do is to spray it towards the surface. Since it is also pre-mixed, the material is more consistent and thus, quality and performance.

Another advantage would be rebound can be lesser which equates to lesser waste and weak spots. The drawbacks would be because it is pre-mixed, the wet mixture should be applied quickly before it hardens giving no room for delay or pauses in between application.

Lastly because it needs to cure, shrinkage cracks are more evident.

For gunite, it can be harden quickly compared with shotcrete because the operator can control and adjust the water content after the mixture is being sprayed to the surface.

It gives you more room during the application since the mixture is dry and there’s no problems with it being hardened during the application.

Lastly, it creates smoother finish and lesser shrinkage finish. The drawbacks would be because the operator is the only one who controls the water content, it can have higher risk of error resulting to weaker spots. Another because the dry is being applied to the surface and then the water, it creates rebound which are the material that falls on the ground. These rebound cannot be used thus, waste.

What’s Stronger Gunite Or Concrete

Gunite is more durable that concrete. By using gunite, the compressive strength can be 9500 psi or even higher. With this higher quality, the appearance is also better compared with concrete which have smoother finish and lesser shrinkage cracks.

Therefore, for construction that have an expectable large amount of pressure or weight, gunite is the better choice.

How Long Does Gunite Last

Because it has higher compressive strength, gunite can last longer compared to other concrete application. Gunite can last for more or less hundred years considering that the application is being done with an experience shotcrete operator and that the materials are of high-quality.

Many of the pools that have used gunite application last for hundred years and the pool builder even gives a lifetime warranty which attest the high quality of the application and material.

With this gunite is an investment in terms of the application.

How Do I know If My Pool Is Gunite Or Concrete

Knowing how the pool is being constructed is harder if you only look visually. In order to know the type of concrete application, the materials used should be exposed.

But there are some surface that you can visually investigate and can say that is applied using gunite.

For pool constructed by gunite method, plaster is always evident. Plaster is done after the gunite have fully cure.

The plaster is being added to waterproofs the gunite pool and gives a smoother and more appealing structure.

What Happens If You Don’t Water Gunite

The gunite should remain moist for at least a week after it is applied into the surface. The need for it to be moisten is to have a better compressive strength as it cures which results to a better quality of the application.

When the gunite is not watered consistently during the curing period, the strength will deteriorate which will result to lesser structural integrity of the surface.

To properly moisten the gunite during its curing period, use a water hose or a water nozzle. It is recommended that during the water spraying, you should start at the shallow end portion of your structure, example the pool, working your way to the end portion of the structure.

To know how long you need to spray water, the color of concrete should be your indication whether it needs to be watered more or not.

Avoid walking into the gunite surface unless cured.

After it has cured, it is important to seal the surface because concrete can be porous. The pores will be prone with water penetration which will lead to leak of structural integrity deterioration.