What is a shotcrete machine?
The shotcrete machine is a new type of high-efficiency shotcrete machine. The equipment uses a concrete pump to transport the concrete to the nozzle of the manipulator through a pipeline and uses compressed air with an accelerator to spray the concrete to the wall of the roadway to be sprayed.
Shotcrete is used to reinforce temporary and permanent excavations. It can be used with ground anchors and other forms of ground anchors to stabilize the excavation of underground parking structures or high-rise buildings during construction. This provides a large waterproof enclosure in which the structure can be erected. Once the structure is completed, the area between its foundation and the shotcrete will be backfilled and compacted.
Shotcrete is also a feasible means and method for pouring structural concrete.
Shotcrete is very useful in hard rock mining. The development of descending channels to the underground is essential for the movement of heavy machinery, miners, and materials. Shotcrete helps protect these paths from any ground falls.
The scope of application of the shotcrete machine
(1) Bridge. Shotcrete repair can be used for bridge deck repair, but it is usually uneconomical for major full-story repairs. However, from a technical and cost point of view, it is very useful for beam repairs, caps, columns, abutments, wing walls, and lower decks of different depths.
(2) Buildings. In building maintenance, shotcrete is usually used to repair fire and earthquake damage and deterioration, strengthen walls and wrap structural steel for fire protection. Repair of beams, columns, connections, and other structural components
Commonly seen in structures damaged by earthquakes.
(3) Marine structures. The damage to the marine structure may be caused by the deterioration of concrete and steel. Damage conditions include steel corrosion, freeze-thaw effects, impact loads, structural damage, physical wear caused by waves, sand, gravel, and ice floes, and the chemical attack caused by sulfates. These problems may occur in most marine structures, such as bridge decks, piles, pile caps, beams, bridge piers, ship locks, diversion walls, dams, power stations, and discharge tunnels. In many cases,
Shotcrete can be used to repair the deteriorated surface of these structures.
(4) The surface of the spillway. Surfaces subjected to high-speed flow may be damaged by cavitation erosion or abrasion erosion. Shotcrete repairs are advantageous because relatively short downtime is required. Complete the repair.
Bay underground excavation. In most cases, shotcrete is used for underground excavation of rocks; but sometimes, it has been successfully used to propel tunnels through modified, non-cohesive, and loose soil. Typical underground shotcrete applications range from supplementing or replacing traditional
Support materials, such as rubber lagging and steel frames, sealing rock surfaces, directing water flow, and installing temporary supports and permanent linings.
What is the difference between dry shotcrete and wet shotcrete?
Comparison of dry and wet processes. The sprayed concrete suitable for most requirements can be produced by the dry or wet process. However, differences in equipment costs, maintenance requirements, operating characteristics, placement characteristics, and product quality may make one of the more attractive for specific applications.
(1) The bonding strength of dry shotcrete and existing materials is usually higher than that of wet shotcrete. Compared to conventional concrete, these two shotcrete mixtures generally provide significantly higher bond strength to existing materials.
(2) Under normal circumstances, the application speed of dry shotcrete is much slower than that of wet shotcrete. Dry shotcrete is usually used at a rate of 1 or 2 cubic yards per hour, while wet shotcrete is used at a rate of up to 7 or 8 cubic yards per hour. Depending on the application, on-site productivity may be significantly reduced due to obstacles, bounces, and other features that can cause delays.
(3) Rebound is the shotcrete material that “rebounds” from the spray surface. Under optimal conditions, the rebound of conventional dry shotcrete is expected to be at least 20% of the total material passing through the nozzle. The rebound of wet shotcrete.Slightly lower than dry shotcrete.
Maintenance of shotcrete machine
After a day of work, the shotcrete machine will enter a “rest” state. Although it is about to end the operation, we should not relax, and we must draw a successful conclusion to today’s homework.
1. Stop the machine and blow out the remaining materials in the conveying pipe.
2. When the pipeline is clean and there is no material sprayed from the nozzle, then close the water valve at the nozzle.
3. Finally, close the main air pipe valve.
4. The mixture can be stored in the hopper when the spraying operation is temporarily interrupted:
5. At the end of a long pause or concrete spraying operation, first stop the feeding and let the machine continue to run until the residual material in the hopper and rotor is exhausted. At the same time, add a little wet sand to transfer the residual material in the hopper and the cavity. The material is cleaned and sprayed out.