Cement Spray Machine: What Is It And How To Use It
Cement plastering is a laborious and time-consuming process, from preparation of the mixture up to skimming the surface to have a smooth finish. This type of work often decide the schedule of work as many works depend on the surface finish. A cement or mortar plastering machine is made to address this issue.
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Why Do You Need To Spray Cement
Spraying cement is another method of applying cement during the construction. Using spraying machine in cement application is a technique to make the cement application quicker. The advantages of using a spraying machine in cement application are:
- It saves more material. Because the cement application is by a machine, the material being fed into the feeder of the spraying machine is utilized well. Lesser material will be used for its intended purpose which also means less wastage.
- Lesser labor. Because the machine does more work, the involved men are only to fed the material into the machine and make sure that the mixture is of the right mixture.
- The cement is of quality. Since the materials are pre-mixed or are being mixed together, the cement mixture sprayed are consistent. The cement applied are in solid application.
- It is quicker. The cement application is done faster compared than the conventional way of cement application. The application is not just quicker but the curing as well. The faster the curing of the cement being applied, the lesser the chances of cracks because of lesser time of shrinkage.
What Type Of Cement Sprayed
The properties like the strength, durability and workability depends on the ratio of the cement and water mixture. The cement mixture achieves its desired properties as it hardens over time. There are different type of cement used in different purposes.
- Ordinary Portland Cement – OPC is an excellent binding material to different structural elements. Ordinary Portland cement can be used not only for concrete but also in mortar for joining masonry and plaster to create a smooth finish of different surface like walls and ceilings.
- Portland Pozzolana Cement – PPC has finer particles compared with OPC which results to lesser water content required and will have high durability. The PPC can be use for marine structures, sewage works, bridges, dams and during mass concreting works.
- Quick Setting Cement – QSC is also known as rapid hardening cement because it gains its strength quicker as it hardens,
- Blast Furnace Slag Cement
- High Aluma Cement
- White Cement
These cement can be used is spraying depending on its intended purposes which can be for plastering and concreting. Make sure that the machine used is applicable for the material used.
What Is Cement Sprayer Machine
Cement is used as a binding agent that achieve its desired strength as it hardens. There are two common uses of cement which is for concrete application and mortal and plastering. Different machine is used for different purposed. For cement used for concrete application a shotcrete or gunite is applicable. For plastering, a plastering spraying machine is used.
Concrete Spraying Machine
Dry Process of Sprayed Concrete
The dry process of shotcrete is using a predetermined ratio of concrete and aggregate, depending of the strength it should achieve, without mixing it to water. The dry mixture will be fed into the machine and is pressurized with high velocity airstream that will be conveyed on the hose to the spraying nozzle.
In the spraying nozzle area, the atomized spray arrangement of water is found for the purpose of hydrating the cement mixture. Just like achieving the right ratio of dry mixture between cement and aggregate, the right amount of water will be sprayed consistently to achieve the right compressive strength.
Wet Process of Sprayed Concrete
The wet process of shotcrete is by using a batch of a mixture of water, cement and aggregates. This mixture can be of readily mixed or are being mixed on site. The batch of the mixture should be done before feeding in to the machine especially for larger concrete spraying application.
The mixture will be then feed, wherein the water-cement ratio be controlled depending on the strength to achieve, and a high velocity air is applied in order for it to pass through the hose to the nozzle.
If being used in a large batch or longer time, admixtures should be on the side to control the hydration of the mixture.
Plaster Spraying Machine
Spray plastering can be done in different types. It can be through a pneumatic sprayer which is the most common and easiest to use. It only requires an air pressure and air hose to do the job.
Next is, screw pump which the plaster is pump into the spray gun with a large nozzle where the plaster will pass through. These pump is not suitable for solvent-based materials as it has rubber stator.
Another would be peristaltic pump which has a peristaltic pump that requires a compressed air to produce a spray. This pump can be used for different type of plaster finish like textured coating providing that they are not solvent-based materials.
Lastly is the piston pump. The piston pump is used for smooth finish with sufficient pressure without the need of compressed air. The challenge with this equipment is it has lower volume.
The good thing with this is that compared with the first two pumps, a piston pump can be used for solvent-based materials.
How Does A Cement Spray Machine Work
Cement can be for concrete and mortar and plaster which different machines are used for these application. The machine has different methods but all are done by spraying.
Dry Process of Sprayed Concrete
Fed the dry mixture into the open hopper/ barrel of the shotcrete. To avoid clogging, provide liners on the chamber to lessen lumps of dry mixture. With the control, allow the dry mixture to be blown by the compressed air into the spraying hose nozzle.
As the dry mixture pass the nozzle, control the separate water nozzle to hydrate the dry mixture with the right amount of water. In using the shotcrete, the nozzle should be far from the area with at least 0.6 meter to 1 meter.
The shotcrete operator should maintain the right amount of water to hydrate the dry mixture to achieve the compressive strength.
Wet Process of Sprayed Concrete
Fed the wet mixture (water, cement and aggregate) into the equipment. Control the air velocity to be used in pushing the wet mixture through the hose to the nozzle. The nozzle should be at least 0.2 meter to 0.5 meter away from the area where the concrete should be applied.
The shotcrete operator should be able to use the equipment in a consistent and constant rate with no pulsation to achieve the right compressive strength. To adjust the wet mixture especially when used in a long time, admixtures should be readily available whenever to avoid clogging of the nozzle when the mixtures gets dry.
Plaster Spraying Machine
You will need to connect the hopper to the sprayer. After connecting these, make sure that everything is tight and sealed to not allow any leak to happen during the application.
After sealing the hopper and the sprayer, feed the the plaster material unto the hopper. Adjust the sprayer into the consistency of the material. Make sure that the plaster material is in the right consistency to achieve the right finish of the surface.
After these steps, align the nozzle to its working condition and do a test spray to make sure that everything is working fine and that the consistency and volume of plaster is right before spraying it to the work surface.
Now that you’ve tested the sprayed plaster, spray it to the work surface in even rows with a consistent distance away from the surface.
How To Use It
The spraying method is used for cement application whether for concrete or mortar and plaster. The differences is that it is quicker and are of better quality because of the consistency of the material.
How Do You Use Cement Spraying Machine For Rendering
The cement spraying machine can also be used in rendering your wall. The purpose of rendering the wall is to make the exterior wall smooth or textured depending on your desire. Rendering is like plastering but on the exterior wall.
The process of spraying machine for rendering is the same with plastering the most concerning method in this process is making sure that mixture is in the right ratio.
Conclusion
Mechanizing the different methods in the construction is always an advantage because it is created to address the issues of time-consuming process which takes material and labor cost.
Upgrading your methods and utilizing the advancement in the construction industry may cost you more at first but is an investment in the long run.
You aren’t just investing in the material but also the quality of work you deliver which reflects on the success of the project.
What is the admixtures used in the spray cement morter plastering machine.
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