The rebound rate of dry shotcrete machine in the construction process of foundation pit support, roadway support, highway slope protection, tunnel support, etc. is a problem that we always face. Since the dry shotcrete machine inevitably rebounds, So let us face the problem of concrete rebound. We must find a way to minimize the rebound rate of dry shotcrete machine, which greatly improves construction efficiency, reduces material waste, and saves costs. The rebound rate of shotcrete of shotcrete machine is affected by many factors. Among them, the distance of feeding pipe, working wind pressure, concrete mix ratio, and the operation of the sprayer are the important reasons that affect the rebound rate of shotcrete. To reduce the rebound rate, a comprehensive treatment method must be adopted. Now China Coal Group will take you to understand the method of dry shotcrete machine to reduce the rebound rate of shotcrete:
When spraying concrete, the dry material enters the conveying pipe from the dry shotcrete machine, and the dry material is transported to the sprinkler through the force of wind pressure, and then mixed with water and sprayed onto the rock wall. In the process of conveying coagulated dry materials, the force of wind pressure acting on the inner section of the pipe is the same at every point, and the specific gravity of cement, sand, and stones in the dry concrete material are different, and the particle size is also different. For example, the fineness of cement is 4900 holes/cm2, the sand particle size is generally 0.25~1.5mm, and the gravel material diameter is generally 5~20mm. Their particle weights vary greatly, but the forces they receive are the same. Therefore, the scope and state of the movement of cement, sand, and stones in the pipeline are different. Usually the cement is suspended in the upper part of the pipeline, the sand is semi-suspended in the middle of the pipeline, and the stones are rolled in the lower part of the pipeline, so that the originally mixed concrete dry material is separated again. The longer the pipeline, the longer the force of the wind pressure on the dry concrete, and the more serious the separation of the dry concrete. This phenomenon is called the "pipe effect". In order to reduce the rebound rate, it is necessary to choose the distance of the conveying pipe according to the construction conditions to reduce the "pipe effect".
Above, we have introduced for you the impact of conveying distance on the rebound rate of dry shotcrete machine. Next, we will continue to introduce you to the impact of working wind pressure, concrete mix ratio, and shotcrete operation on the rebound rate of dry shotcrete machine. influences. Please continue to pay attention to the website of China Coal Group, we will continue to provide you with answers to difficult questions about the construction of the shotcrete machine.
