Table of Contents
Shotcrete
Shotcrete is also known as sprayed concrete. Shotcrete is pneumatically projected or sprayed with the help of a nozzle at high velocity on the prepared surface. The complete system is also called spraycrete.
Shotcrete is poured and consolidated at the same time due to the load ejected from the nozzle. Shotcrete can be placed at vertical, inclined, or any other surface.
Concrete, water, sand, and aggregate are the fundamental materials utilized in shotcrete alongside different plasticizers and admixtures to improve its working. High water-cement proportion gives slow setting and impacts end quality, while dampness content in sand/total is aggregate acutely estimated. The ideal W/C proportion is around 0.45.
Synthesis of sand/aggregate relies on water interest, functionality, gas pedals, bounce back, shrinkage and durability.
Types Of Shotcrete
There are two types of shotcrete as follows
- Dry-mix process shotcrete
- Wet-mix shotcrete
1. Dry-mix process shotcrete
There is no settled technique for proportioning dry-blend shotcrete. Since it isn’t reasonable to perform research facility preliminary combinations for dry-blend shotcrete, field testing of dry-blend extents is profoundly fitting, particularly in the event that no field information exists for a given dry-blend. The setup total evaluating will be better than the bunched reviewing because of bounce back, particularly assuming that bigger total sizes are utilized. Similarly as with wet-blend shotcrete, the set up concrete component will be higher moreover.
2. Wet-mix shotcrete
Combination proportioning methodology for the definition of traditional cement for siphoning applications are materials for wet-blend shotcrete. The ostensible total size is normally 10 mm. The bunched concrete substance will ordinarily go from 350 to 450 kg/m³.
Rich combinations are normal for shotcrete, particularly if vertical or upward shotcrete arrangement is required. The restricting component for concrete substance in a blend is regularly represented by how much concrete is essential for the shotcrete to stick to a divider or roof, not the predefined compressive strength.
Advantages of Shotcrete
- Shotcrete can be poured from a long distance.
- The bond with the applied surface is very strong.
- Formwork requirement is very less.
Disadvantages of Shotcrete
- The manufacturing cost is very high.
- There is a dusting problem with Shotcrete.
- In this process wastage is high.
Application of Shotcrete
- Vertical or horizontal thin overhead wall.
- Shotcrete used to line tunnel walls.
- Shotcrete used in hard rock mining.
- Shotcrete used in swimming pools.
- Restoration of old buildings.