Wet spraying manipulators are widely used in concrete construction, but there are many precautions that need to be strictly followed in actual operation to ensure the construction quality and mechanical life. The following are some important points that should be paid attention to during the use of wet spraying manipulators.
1. Equipment lubrication and cleaning
Before spraying concrete, the wet spraying machine and feed pipe should be lubricated with mortar. Lubrication can not only effectively reduce resistance, but also extend the service life of the equipment. After the spraying work is completed, the pipeline must be cleaned with water in time to avoid the residual concrete solidification and clogging the equipment, which is essential to maintain the normal operation of the equipment.
2. Water-cement ratio control
During the construction process, strict control of the water-cement ratio is the key to ensuring the quality of sprayed concrete. The best state of concrete should form a layer of dark and weak luster on its surface. Improper control of the water-cement ratio may lead to insufficient strength or excessive flow of concrete, affecting the quality of the project.
3. Seepage section treatment
When treating the seepage section, if the amount of water is small, it can be blown by high-pressure wind first, and then concrete can be sprayed according to the conventional construction procedure; if the amount of seepage is large, a blind pipe should be buried close to the rock surface and gradually approach the seepage point from a distance. At the same time, the dosage of the accelerator is temporarily increased, but it should be controlled within 6%. This operation can help the concrete to solidify gradually, thereby effectively blocking the water seepage area.
4. Equipment blockage treatment
Once the pipeline is blocked, the machine must be stopped immediately and the gas source must be turned off, and then the pipeline must be checked and cleared in time. Avoid construction interruption due to blockage problems and affect the progress of the project.
5. Post-spraying inspection
After each concrete spraying, a full inspection should be carried out before the next blasting. Usually, the time interval between spraying and blasting should be no less than 4 hours. After blasting, it is necessary to check whether there are cracks on the concrete surface. If there are cracks, the blasting time should be adjusted or the blasting parameters should be changed.
6. Material and accelerator management
Before construction, the quality of the raw materials used should be ensured to be qualified, especially the management of accelerators. Accelerators should be properly stored to avoid moisture failure and affect the construction effect. At the same time, the water-cement ratio of the mixture should be strictly controlled to ensure that the slump of the concrete is between 140 and 180 mm.
7. Operational specifications during spraying
During the spraying process, attention should be paid to the rebound rate and actual mix ratio of concrete. The rebound rate of the concrete side wall should not exceed 15%, and the arch should not exceed 25%. In addition, the sprayer needs to maintain the distance and angle between the nozzle and the sprayed surface during operation to ensure the best compaction effect. The angle between the nozzle and the sprayed surface should be kept as close to 90 degrees as possible, so as to obtain the minimum rebound and maximum compaction effect. When the spraying surface is covered with a steel frame or steel mesh, the nozzle can be slightly tilted, but the angle should not be less than 70 degrees.
Wet spraying manipulators play an important role in projects such as tunnels and mines, but the accuracy of their operation and the maintenance of equipment directly affect construction efficiency and safety. Therefore, when using wet spraying robots, strictly abiding by operating specifications and strengthening equipment maintenance and construction management are the key to ensuring project quality and safety.