June 2, 2022
Shotcrete is one of the most used ways of applying concrete among concrete contractors. This is mainly because of its durability and easy-to-use characteristics.
However, not everyone can use shotcrete to apply concrete because only a certified concrete contractor who knows all the rules and regulations can easily use the method.
There are some essential prerequisites for achieving the best results in concrete spraying. Number one is mix design, all the shotcrete components such as water, cement, fine material, chemical additives, and fibers form a mixture that determines the quality of the cement finish. Hence the mixture should be made with utmost care and precision to get the best results.
Another critical aspect for getting the best results is the correct application technique. This is important to ensure minimized rebound and adhesion of the shotcrete to the surface, and all of this can only be achieved by hiring a certified concrete contractor.
In this blog post, we will outline the top 5 rules of shotcreting that will help you achieve the best results and maximum operator safety.
In an underground application to prepare the surface, the first step is to evaluate the risk of loose materials and falling rocks.
All the loose material and debris need to be removed, and the surface has to be cleaned from dust using air or water before applying concrete.
If the surface is not cleaned and you use the shotcrete method, the surface will become uneven and bumpy. So when the concrete is shot on all the dust, rocks and loose material, it will not form a smooth surface.
Before applying the first layer of concrete, make sure to even out the surface by filling all the cracks and holes.
This is the most important rule of applying shotcrete no matter which surface you are using it on, make sure that all the holes and cracks are properly sealed.
If the cracks and holes are left open, they will hamper the application and durability of shotcrete, and after some time, you will see cracks and holes in the shotcrete.
Hence, make sure to hire a professional shotcrete contractor who, before applying shotcrete, closely examines the surface and fixes all the holes and cracks before applying the shotcrete.
Remember that the shotcrete should be applied in layers. The shotcrete layers should be applied starting from the bottom of the surface and continue upwards.
The first layer of shotcrete serves as the excavation support and as an adhesive bridge for the following layers.
The number and thickness of layers depend on the job site requirements and the desired homogeneity of the shotcrete finish.
Applying shotcrete is a tough job that requires skills and precision, so make sure that you always hire an experienced concrete contractor for all your concrete projects.
Another important rule of applying shotcrete is to clean the machine immediately after application.
An integral part of machine maintenance and cleaning is preventing accumulation of material in the nozzle, concrete pump, additive pump and hoses.
Cleaning all these parts is essential as it will help you avoid the increased discontinuity of flow and will guarantee smooth operation.
So make sure that after shotcrete application, you clean all parts of the machine immediately. If the concrete dries, it will become tough to clean the machine.
The impact of force that guarantees the adhesion of shotcrete to the surface is determined by the distance between the substrate and the nozzle.
If the distance is too short between both there will be rebound and with distance too great, the impact force will become too weak and will not provide the proper adhesion of shotcrete.