The construction quality issue is getting more and more attention from the regulatory authorities and construction units. As the key process of tunnel construction, the concrete wet shotcrete machine, how to improve the quality of spraying?
1. Appropriate operator Whether the operator has a sense of responsibility and the level of operation technology is one of the key factors that determine the quality of injection. Professional operators should go through the professional training of the manufacturer's wet shotcrete machine, not only to understand the theory, but also to practice.
2. Reliable equipment Choosing a wet spray machine manufacturer with many sales performance, rich service experience, and good market reputation is an important guarantee for good equipment; choosing a wet spray manipulator with stable performance and mature technology can improve the construction quality and spray anchor. effectiveness.
3. Qualified raw materials Cement grade is not less than 42.5 grade, coarse aggregate should use strong and durable gravel or pebbles, particle size is generally not greater than 15mm; fine aggregate should be hard and durable medium and coarse sand, fineness modulus should generally be greater than 2.5; Before selecting the accelerator, the compatibility test between the accelerator and cement and the setting effect of the cement paste should be tested, and the parameters of the accelerator should be strictly controlled to 3-5%.
4. Proper mix ratio The mix ratio must meet the basic requirements of the sprayed concrete process, that is, easy to spray, not easy to block the pipe, reduce the amount of rebound and dust, and must meet the requirements of good quality, high strength, high compactness and good waterproof performance, while achieving other physical mechanics Indicators and other requirements. The sand content of shotcrete should generally be controlled at 50% to 60%. The mix ratio design is placed on the workability of the concrete to ensure that the slump is controlled within a reasonable range and has good cohesion.
5. Correct operation method In order to ensure the quality of sprayed concrete, reduce the amount of rebound and reduce dust, the spraying should be carried out in sections, sections, and blocks. The length of the section should not exceed 6m, and it should be strictly in the order of wall first, then arch, first down, then up Spray to reduce the occurrence of concrete sliding or falling off.
