Difference Between Shotcrete And Gunite


Introduction

As we know, both gunite and shotcrete work by spraying wet cement onto the walls and floor surfaces. But they are not the same. In this article, we will explain the differences between shotcrete and gunite.

In guniting, the water is added to dry concrete as you spray it. And in shotcrete, it already comes with wet concrete, so you don’t need to add any extra water while spraying.

Below we have mentioned both gunite and shotcrete advantages and disadvantages. So, by that, you will understand the differences between gunite and shotcrete. Before we go into detail, 

In short, we can say that both will produce a high-quality, watertight, durable concrete layer if you do the processes correctly. It all depends on the workmanship.

What Is Shotcrete?

Shotcrete is similar to gunite, which is also made of cement, sand, water. The prepared mixture is sprayed on the surface just like guniting.

In guniting, water is added to the material to form concrete onsite. While in shotcrete, a “wet mix” is prepared by mixing the water and dry mix before arrival. This pre-mixed cement is shot out or sprayed of a nozzle to form the pool.

In shotcrete, the water-cement ratio usually ranges from 35 to 0.50 by mass which is somewhat lower than most conventional concrete mixes. Shotcrete can be used as both wet mix and dry mix.

Advantage Of Shotcrete

The various advantages of the shotcrete process are as follows.

  1. The shotcrete process forms a uniform and strong layer of concrete on the surface.
  2. Like the guniting process, the shotcrete process is more economical than conventional concrete, which requires wooden or steel formwork.
  3. Shotcreting can be used in construction where the formwork cannot be installed.
  4. The concrete can be applied to one nozzle from a safe distance.
  5. The required materials in this process can be accessible in most places.
  6. Specialized admixtures can be added to the concrete to achieve more efficiency
  7. As it is pre-mixed, there is no additional need for water while applying.
  8. Shotcrete helps to achieve high production rates.
  9. No Need for skilled workers. As it is a pre-mixed mixture.
  10. In terms of pressure application, shotcrete is faster than guniting.
  11. Material requirements are fewer.

Disadvantages Of Shotcrete

  1. If the hose gets blocked, It will be very tough to clear it, which could be dangerous for the crew and property.
  2. Though it does not need any additional water during its application, some water is required for pumping. 
  3. The hoses are very heavy, which would be more challenging to use for the crew
  4. Like guniting, You can’t start and stop the application. Doing so may create weak points in the concrete.
  5. The application process is quick. As the mixture is pre-mixed.
  6. Chances of developing cracks are more if the excess water is added to the pre-mixed concrete.
  7. This process is not so economical when compared to guniting.

Applications Of Shotcrete

  • Dome construction
  • Retention walls
  • Tunneling
  • Artificial Ponds
  • Mining Applications
  • Dikes and Dams
  • Ditches and Channels
  • Water tanks and Ponds
  • Slope Stabilization

What Is Gunite? 

Gunite is a mixture made of cement, sand, and water. Gunite is similar to concrete, but the traditional pouring method is not adopted here; instead sprayed with a gun in several layers. Hence it is named gunite. 

While preparing the mixture, water is added to the dry concrete mix at the gun-shaped nozzle opening. Generally, concrete is made in the air just before hitting the target.

As per pool professionals, gunite is a “dry mix” because the water is added to the material to form concrete onsite, and it is also known as Dry shotcrete.

Advantages of Guniting

The advantages of guniting are as follows:

  • Guniting is highly durable and gives the flexibility to create structure in any shape. 
  • Gunite gives a more variety of finishes. Plaster finishes come in an array of shades from which we can choose according to the outdoor living area and house design.
  • The preparation process of dry mix is speedy compared to wet shotcrete mix.
  • The guniting process helps to achieve a high compressive strength of concrete.
  • The guniting process is mostly used in artificial caves and swimming pools to create unique shapes and features.
  • Gunite also makes it easy to design and build features like waterfalls and customs steps. 
  • The guniting process is less expensive than shotcrete.

Disadvantages Of Guniting

The various disadvantages of the Guniting process are as follows.

  • During the application of dry mix concrete, the Chance of clogging or blockage of a hosepipe is more. 
  • Skilled workers are needed for the guniting process. 
  • Skill workers are directly proportional to the quality of work. That means the quality of the job depends upon the operator.
  • In the guniting process, there may be chances of wastage of concrete.

Applications Of Guniting

  • Dome construction
  • Tunneling
  • Artificial Ponds
  • Mining Applications
  • Dikes and Dams
  • Ditches and Channels
  • Water tanks and Ponds
  • Slope Stabilization

Difference Between Shotcrete And Gunite

Shotcrete Vs Gunite

Sl. NoGuniteShotcrete
1The guniting process is economicalWhile shotcrete is a bit more expensive.
2The guniting process involves only dry mix, hence it is also called dry shotcrete.The Shotcrete process involves both dry mixes as well as wet mixes.
3The guniting process is most suitable for small works.The shotcrete process is most suitable for large works.
4The guniting process requires skilled workmanship.The shotcrete process requires less skilled workmanship.
5The waste generated while applying in guniting is more.The waste generated while applying shotcrete is less.
6The guniting process requires more time duration.The shotcrete process requires less time duration.
7There are no shrinkage cracks in guniting.High chances of shrinkage cracks in shotcrete.
8Higher compressive strength (from 7,000 to 9,500psi)Less compressive strength (6,500 to 7,500psi)
9Guniting has low production rates.Shotcrete has high production rates.
10The process can be halted in between and can be continued without any problem.In shotcrete the application process must not be halted, doing so may result in weak points in concrete.

Also Read

Types Of Concrete Used In Construction

Stamped Concrete – Advantages & Uses

Grasscrete – Installation & Benefits

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2 thoughts on “Difference Between Shotcrete And Gunite”

  1. It would be more informative, the ratio of the mix is given for general guide. Here it says we can have a quite big compressive strength, using only cement and sand. Thanks.

    Reply

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