At present, the main equipment of sprayed concrete in China is the coexistence of dry sprayers and wet sprayers, and mainly rely on manual spraying. There is still a lot of way to replace dry spraying in wet spraying. However, in recent years, with the development of modern science and technology and the widespread promotion of wet spraying technology, concrete wet spraying machines have also been rapidly promoted in China, and more and more attention has been paid to concrete wet spraying machines. With the increase of people's awareness of environmental protection and the improvement of the quality requirements of sprayed concrete, wet sprayers have become the mainstream equipment of concrete spraying.
The wet spray technology can fundamentally solve the dust problem, reduce the outbreak of the occupational disease "silicosis", and better reflect the "human-oriented" modern humanistic care spirit. The wet spray technology can establish a corresponding and complete quality assurance system for Layer quality can be effectively controlled; wet spray technology is more suitable for the future development of the construction industry and can provide space for concrete composite material technology; wet spray technology is more relevant to the future construction industry in environmental protection, green construction and energy conservation; wet spray The application of technology can also promote the development of single-layer lining technology, which is also the technological basis for the modification of sprayed concrete.
The main advantages of wet spray technology are as follows:
1. The dust concentration near the machine and outside the nozzle is greatly reduced, and the harm to workers' health is eliminated.
2. High productivity. Dry concrete spraying machines generally do not exceed 7m³ / h, while wet concrete spraying machines can reach 20m³ / h in manual operation and 30m³ / h in manual operation.
3. Low rebound. When dry-blasted, the rebound of concrete can reach 15% to 50%, and the rebound rate of wet spray technology can be reduced to less than 10%.
4. In wet spraying, because the water-cement ratio is easy to control and the concrete has a high degree of hydration, the quality of sprayed concrete can be greatly improved and the homogeneity of the concrete can be improved.
Wet shotcrete technology has the advantages of less dust, low rebound rate, low consumption cost, safety and environmental protection. By fully and accurately adjusting the mix ratio, the construction benefit of wet shotcrete is greatly guaranteed, and the strength of concrete And supporting capacity, the adhesion of concrete to the base of the tunnel, and the anti-seepage ability of concrete all play a huge role.
