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Shotcrete and Gunite | Difference Between Shotcrete and Gunite | Features

Shotcrete and Guniting are important terminologies that are followed in the civil construction. The two methods have proven to be beneficial in the applications of soil stabilization, slope protection in swimming pool construction, fluid tanks, tunnel, in the works relating to concrete repair and many.

The difference between shotcrete and Gunite is actually a matter of concern in some countries of construction alone. Say the American Shotcrete Association(ASA) do not use the word guniting. They are only aware of Shotcrete, that can be carried out in the dry mix and wet mix.

Shotcrete and Guniting


The process in both the methods involves spraying of the concrete or the mortar mix pneumatically with the help of a spraying gun or nozzle. This is done at a higher velocity on to the surface of application.


When the mix used to spray is dry, the method is called as guniting. When a wet mix is used in the process of spraying or application, the method is called as shotcrete.

Dry Mix Process or Guniting


The preparation of dry mix will involve:


Fig.1.Guniting a Pool
1. Mixing of cement and aggregates in dry condition inside a bin

2. Pumping the dry mix through a hose using compressed air with a higher pressure through a spray gun.

3. At the nozzle of the gun, water is introduced to the dry mix. This happens just before the mix comes out of the nozzle on to the surface

Wet Mix Process or Shotcrete



The preparation of wet mix will involve:


1. A pre-mixed concrete or mortar is sprayed in high pressure on the surface

2. These methods eliminated the need for adding water at the nozzle

Fig.2.Shotcreting for Reinforced Walls


Difference Between Shotcrete and Guniting




GUNITING OR DRY SHOTCRETING
SHOTCRETE – WET PROCESS


1.    History

The first technique of spraying concrete under pressure and high velocity by using a spray -gun developed in the US. The use of gun gave the name guniting

The technique of spraying concrete that came after guniting in the 1930s. This was conducted by using a nozzle spray. The mix can be dry or wet

2.    Mix

The guniting process is a trademark given for shotcrete process carried out with the dry mix. This process can also be known as dry-mix Shotcreting

The shotcrete process can be done with dry or wet mix and hence can be called as dry-mix shotcreting and wet mix Shotcreting

3.    Size of Aggregates

Smaller sized aggregates are used in the range of 10mm or so

Maximum size of aggregates is 1 inch for the wet process of shotcrete

4.   Strength of Product

Less strong Product than wet Shotcreting

Stronger product that guniting


5.    Quality Control

Quality Control is less compared to wet process

As the wet process will involve premixing of all the ingredients of the mix before pumping through the gun, a better quality of the product is obtained, unlike Gunite.

6.    Rebound Property

The spraying of dry mix tends to make it rebound off the surface and hence fall off.

The rebound in wet Shotcreting is less compared to guniting

7.    Waste

More – Due to high rebound of material

Lesser – less rebound of material

8.    Applications

Small Quantity of Work

For large quantity of work

9. Labor and Experience

High-skilled labor who knows to properly control and operate the nozzle so that a good mix is sprayed out reducing maximum rebound.

As the ingredients are premixed before spraying there comes the need for normal operating labors.



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This is a center to bring up and collect all bits of knowledge and technologies flourished and flourishing to reach out for those who wish to acquire knowledge in a broader way. I am a structural engineer by profession and would like to share all information I have acquired all these years till date. This site also aims in researching new topics, works on your questionnaires and fill it up with good facts and information.

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