6 FAQs to Shotcrete Pump You Should Know
Shotcrete is one of the most innovative method in the construction industry.
The choice of shotcrete in certain construction elements is growing in numbers and are in demand which shows how advantageous it is. Shotcrete is flexible, economical and lesser time consumption during the process.
It can be down with no or lesser formworks, can be applied in higher elevation, and can be designed with great adhesion and very flexible.
What Is Shotcrete Used For
Shotcrete machine is an equipment used for concrete or mortar spraying. With the lower cement and water ratio, shotcrete can acquire higher compressive strength in a short span of time compared with the conventional method which needs to cure for some time.
Because of the high velocity due to the use of shotcrete, the compaction of the concrete is also carried out which increases the strength of the concrete.
Gaining high compressive strength in a shorter span of time gives you a high output which positively affects your cost and schedule.
Shotcrete can be used in different construction which are and not limited to
(1) Tunnel, Underground & Mining Stabilization and Construction,
(2) Slope and Trench Stabilization,
(3) Honeycomb/ Structural Concrete Repair,
(4) Historical Building Restoration and
(5) Sealing Works.
What Machine Is Used For Shotcrete
A shotcrete machine/equipment are made of different components. These components are pump, compressor, the control and the remote, the arm or hose and the nozzle.
With this different components, the concrete or mortar is being conveyed by the trapped air to the nozzle and being controlled to be sprayed into any area.
The method done for shotcrete can be of dry mix and wet mix. The dry mix shotcrete is made from a predetermined ratio of concrete and fine aggregates without mixing it with water.
The water will be added through an atomized spray arrangement after the dry mix is being sprayed into the surface.
The shotcrete operator is the one controlling the quantity of water achieving the right ratio to reach the right compressive strength.
The wet mix is a batch of concrete, aggregates and water sprayed together to the surface. The concrete being fed into the machine can be delivered on-site or are being mixed on site.
How Far Can You Pump Shotcrete
For most concrete application, the distance between the nozzle and surface should be a minimum of 1 meter and a maximum of 2 meters.
This is because the impact force can affect the adhesion as well as the rebound quantity which is considered as waste material. What affects greatly with the distance of the nozzle and the surface is the nozzle velocity.
During the application, it shall be done consistently and 90 degrees unto the surface of application to be able to maintain the layer thickness which if not done properly will cause sagging and drop-out.
How Fast Can You Pump Shotcrete
The output of the shotcrete machine can be depending on the application. It can range from 0.8 to 23 cubic meter per hour.
Lower output can be used for patch repair which can be from 9 to 17 cubic meter per hour. While for bigger concreting project, it can range from 17 to 23 cubic meter per hour.
How High Can A Shotcrete Pump Reach
Shotcrete can reach up to 500 feet (152.4 meters) vertically considering that it has a high concrete output as well as the pump has greater horsepower.
This is required to achieve the right volume of concrete sprayed at a certain time with the right pressure to create a strong adhesion of the concrete to the surface.
The greater the horsepower, the faster and farther the shotcrete pump can do and reach.
Is Shotcrete Pumping Hard
Every beginning is hard but as long as you are consistent with your learning, everything is possible which also applies with being a shotcrete operator.
To be a qualified shotcrete crew you must be consistent with the training as well as with your experience.
A shotcrete crew is compose of the foreman, nozzleman, assistant/trainee nozzleman, blowpipe control, wireman, rodman/ finisher, pump operator and the mixer man which each crew has its different roles.
The foreman should be able to supervise the team and should have a great experience minimum of two years.
The nozzle man should be certified and must be able to perform the different application, dry mix and wet mix.
The trainee should have an experience with being a different crew before it becomes a nozzle man assistant.
The blowpipe should be knowledgeable with the different finishes of the sprayed concrete. The wireman is responsible with the line or grade of the application.
The rodman/finisher should be able to make sure that the application is consistent free from bulging, loose concrete, sagging or unstable sprayed concrete.
The pump operator should be skilled with the preparation and mixing depending on the type of application.
Lastly, the mixer man should be able to perform the preparation and mixing of the different material with the right ratio and proportion before it is fed into the pump machine.
The shotcrete should be able to know the requirements laid down by the engineer or test panel. These rules should be followed:
(1) Proper cleaning of the surface before spraying
(2) Able to apply bonding coating before heavier shotcrete application
(3) Proper distance of the nozzle and the surface to achieve the right consistency and thickness of the shotcrete layer
(4) Lessen the bulging, air pockets, sagging and rebounds
(5) Lastly, clean the equipment immediately after application to prevent accumulation of the materials in the pump, hose and nozzle which will after the succeeding application.
Now that you have picked up commonly asked question regarding shotcrete and want to consider this application, you must be able to know how big your concrete project is, how quickly you want it to be done and the right qualification of your shotcrete crew.
Shotcrete, when done right, will result to good and long-lasting quality of material and be able to achieve the different advantages of this application.
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