Rock Salt Finish Concrete | Properties, Uses, Advantages & Disadvantages

  1. Introduction  

Salt finish concrete is cheap concreting which provides aesthetic beauty to concrete surfaces.

For salt finish concrete is done by using different types of salt crystals. One of the commonly used salt crystals for salt finish concrete is Rock salt (Halite).

The concrete which is prepared by using Rock salt crystals is known as a Rock Salt finish concrete. Rock salt is also known as Halite. Rock salt is formed by Sodium Chloride (NaCl).

The Rock Salt finish concrete is an easy and cheap way to decorate concrete surface which provides a mind-blowing aesthetic beauty to the concrete surface.

It’s done by pushing coarse or extra rock salt into the surface of fresh concrete, permitting the concrete to set, and then washing the salt away with a stream of water.

Rock salt finishes concrete is smooth and broom-finished concrete, but it is slip-resistant which makes it a better and ideal material for a pool deck.

Not only does it permit people to get around safely, but it also helps objects like food carts, vehicles, and others to get around easier as well.

It is very necessary to seal the salt concrete with a sealant (acrylic or siliceous).

Rock salt concrete is majorly used in the Swimming pool area, Garden, House backyard, and also in the parking area.

  2. Manufacturing Process of Rock Salt Finish Concrete  

The preparation of Rock Salt Finish concrete is done as like as normal concreting. The main work of Rock Salt Finish concrete starts after placing freshly mixed concrete in formwork.

The surface is made smooth by using hand or bull floats which provide a high-quality surface finish. Now following steps are carried out,

a. Spreading of salt crystals

b. Removal of Salt Crystal

c. Application of sealant

 a. Spreading of  Rock Salt crystals  

Coarse Rock salt (Halite) is a majorly utilized salt crystal in Salt finishing concrete. The concrete placed in formwork is given to dry until when you press the thumb on concrete, no concrete paste or grayish color should attach in your thumb.

If concrete paste attaches in your thumb then let it dries more. Now, if no concrete paste attaches in your thumb, then the Rock-salt crystal is spread over the Concrete surface at a concentration range of 3 to 12 pounds per 100 square feet.

With the help of a trowel, salt roller, or float (Hand or bull) the salt crystal which was spread on concrete is then lodged into concrete by pressing it. Those salt crystals are lodged at half of their diameter.

The concrete surface is now cleaned gently with the help of a broom. Now, the concrete surface is allowed to dry for 24 hrs. This whole process is known as salting.

 b. Removal of Rock Salt Crystal  

After completing 24 hours, the concrete where salt crystals were placed is wash out with the help of water. The water and salt completely or partially mix and leaves lodged crystal which is rinsed with the high velocity of the water and brush.

The concrete is fully dried so, you can directly apply water to concrete without any tension. The crystal salt leaves a shallow mark on the concrete in a spot pattern which forms a good texture on the concrete surface.

  c. Application of Sealant  

Before applying, sealant you should allow the concrete to dry completely. Clean the concrete with the broom, so that no dust is left.

The first coat of sealant is applied by using a roller, so that sealant is completely applied on the concrete surface.

After drying, the first coat within 2-3 hours, apply the second coat of sealant in a similar process to the first coat.

  2.1 Rock Salt Finish Concrete  

1. The size of Rocksalt crystal must be between 1/3 to 1/8 inches.

2. The size of Rock-salt crystal should not be more than 3/8 inches.

3. The Rocksalt crystal should not be pressed more than half of its diameter.

4. The concentration of rocks crystal should vary according to the finish needed.

5. The concentration of rocks crystal should vary between 3-12 pounds per 100 square feet.

6. The surface should be smooth and the marks left should be lined by a Salt roller or float.

7. The Rocksalt crystal should be spread all over the concrete surface to obtain a smooth finish.

8. If the concrete surface is wet or too dried then, it will provide a poor quality concrete finish.

9. The Rocksalt crystal should be washed off fully and cleaned with a broom, otherwise can cause discoloration in colored concrete.

10. The sealant should be applied carefully in two coats, otherwise, moisture/ water will be trapped on it.

  3. Properties of Rock Salt finish Concrete  

1. It should be able to resist hammering action.

2. It should withstand chemical and weathering agencies.

3. It should be capable of resisting fire.

4. It should provide a smooth and broom-finished concrete surface.

5. It should be slip-resistant.

6. It should have high strength and Durability.

  4. Uses of Rock Salt finishing Concrete  

1. It is used as a decorative Edge for swirl-troweled or broom-textured concrete.

2. It is also used in large panels bordered by bands of smooth concrete.

3. It is used to provide texture to Coloured concrete overlays.

4. It is commonly used in house courtyard, parking, and area near to Swimming Pools.

  5. Advantages of Rock Salt finish Concrete  

1. It is very cheap as compared to others.

2. It requires less manpower, equipment, and materials.

3. It provides a smooth and broom-finished concrete surface which increases the aesthetic beauty of the structure.

4. It has high slip/skid resistance.

5. Salt has less effect on hardened concrete.

6. It saves a lot of time and cost.

  6. Disadvantages of Rock Salt Finish Concrete  

1. During low temperature, causes water and moisture are trapped on the surfaces.

2. The moisture and water trapped in the surfaces increase pressure causing the concrete to crack.

3. If no sealant is provided then the concrete will absorb moisture near to it.