WHAT IS SHOTCRETE

Shotcrete

Shotcrete or gunite or sprayed concrete is a method of applying concrete projected at high velocity primarily on to a vertical or overhead surface.The impact created by the application consolidates the concrete.Although the hardened properties of shotcrete are similar to those of conventional cast-in-place concrete, the nature of the placement process results in an excellent bond with most substrates, and rapid or instant capabilities, particularly on complex form or shape.The shotcrete required less formwork and can be more economical than conventionally placed concrete.

Shotcrete is mortar or concrete conveyed through a hose and pneumatically projected by a nozzle with high velocity on the prepared surface.The whole system is also known as spraycrete.Shotcrete is mainly used in underground construction projects as preliminary or permanent structural supports.About 90% of the shotcrete applied into underground construction projects like road tunnel,rail tunnel, waterways etc.Annually more than 12 million cubic meters shotcrete by volume used globally. Shotcrete was invented by Mr.Carl Ethan Akeley (1864-1926) in 1910.

Types of Shotcrete

1. Dry-mix process
2. Wet-mix process

Advantages Of Shotcrete

• Shotcrete technique is flexible and easily modified.
• Shotcrete method has less impact on nearby properties.
• Excellent bounding nature makes the concrete very strong.
• The concrete can be applied by a nozzle from a safe distance.
• Shotcrete required less formworks.
• Economical.

Disadvantages Of Shotcrete

• Too much dust.
• Too much wastage of concrete.
• The production cost is very high.
• It requires skilled and experienced labours.

Applications Of Shotcrete

• Waterproofing walls.
• Stabilized rock slopes.
• Thin overhead vertical or horizontal surfaces.
• Excavation stabilization in tunnelling and underground construction.
• Restoration and repairing of old building and fire-damaged structure.
• Rehabilitation of reinforced concrete structures such as bridges, chemical processing and handling plants.