The properties and application of sprayed concrete
Sprayed concrete is also known as guinite or shotcrete. It is extensively applied for concrete construction. Sprayed concrete” is considered as a groundbreaking construction method that can provide good support to the structures as well as keep the longevity of the construction.
The sprayed concrete has superior performance and it combines man, machine, and the concrete. quality and the interaction between these three materials governs the ultimate strength and the performance of the sprayed concrete.
Under this method, a man performs as the nozzle man and he should possess sufficient expertise and dedication in the use.
Properties of Sprayed Concrete: The spray concrete contains some exclusive properties as diverse methods are utilized for mingling, transporting and arranging instead of the component materials which are applied.
The properties are given below:
• Water-Cement Ratio
• Density and Permeability
• Freeze and thaw resistance
• Adhesion and Bond Strength
Water Cement Ratio of water and cement in Sprayed Concrete: The water cement ratio is lower as compared to a traditional poured concrete. This condition is mostly found in the dry process, where sagging is circumvented with a lesser water-cement ratio. For a wet process, this low value of water cement ratio is acquired by applying a plasticizer.
The effectiveness of Sprayed Concrete: It is found that the sprayed concrete can acquire greater compressive strength at an initial phase with the use of a lower water-cement ratio. The compaction of the sprayed concrete mass is performed by spraying at a higher velocity. Therefore, compaction is likely to increase the strength. If batched materials are applied, rapid strength gain can be obtained. It is assumed that 30 % higher strength as compared to the poured concrete is gained for the sprayed concrete.
Density and Permeability: The compaction of the mix is applied by the high-velocity application. With this compaction, the mix becomes solid and free from voids. It will reduce the permeability of the sprayed concrete structure.