Pitfalls To Avoid In The Shotcreting Process

October 13, 2022


To err is human and what makes a human magnificent is their ability to create the most excellent structures out of mere concrete and water. Shotcrete has been used in the construction process for decades now.

Shotcrete offers distinct advantages over conventional cast-in-place concrete, which is why the use of shotcrete in the construction sector has grown in popularity.

However, while shotcrete has several advantages over traditional concrete, the application procedure necessitates a significant degree of knowledge and expertise.

Due to the unique application, mistakes are often expected with the application of shotcrete, which is why hiring reliable and experienced shotcrete services is the right choice for you.

Types Of Errors Made With Shotcrete

The most crucial aspect lies within the application of shotcrete, which is spraying the concrete onto the receiving surface, so we’ve developed a list of the top mistakes made while spraying shotcrete.

Want to avoid all these mistakes? Make sure you hire accredited shotcrete concrete contractors to work without any errors that can cost you time and money.

Also Read: Shotcrete Malpractices That Are Costing You Money

Adding Water In Access

The cement-water ratio is a very delicate process that must be altered to perfection for proper shotcrete application. If the cement-water ratio fluctuates, the quality of the concrete will suffer, resulting in diminished resilience and compressive strength.

Uncontrolled Accelerator Dosing

What makes concrete the most popular material used around the globe? Additives! Additives play a vital role in giving concrete their unique properties. Unlike additives, which are normally introduced during the mixing process, accelerators are incorporated immediately before spraying.

As accelerators are the single most expensive component consumed by a machine throughout the shotcreting process, their improper use incurs extra expenses.

Temperature Of The Air

Shotcrete can be applied using a standard material ratio when the air temperature is above 50°C and less than 370°C.

If the air temperature falls outside of this range, contractors must use either retarding agents or accelerants to ensure the shotcrete can be applied and mixed properly. Shotcrete is frequently sprayed when the air is excessively hot or cold.

Not Keeping The Surface Clean

A clean surface is essential to ensure an optimal application of shotcrete for two reasons: first, it helps to eliminate residue, which improves shotcrete’s ability to adhere to the surface; and second, to support the work on a stable surface, it is necessary to remove any loose materials.

The Strength Of The Concrete Deteriorates

Wet and dry mix approaches rely on maintaining optimum moisture content. Concrete loses strength when there is too much or too little water. This commonly occurs when the concrete mix truck has been waiting too long (in the wet mix) or injecting too much water (in the dry mix).

Contractors must always spray the products within 90 minutes of loading the truck or 45 minutes of placing the components in the dry mix gun. The correct cement, water, and aggregate ratio are critical to how well the components mix and bond with the receiving surface.

Inadequate Equipment Setup

Another common blunder is positioning the shotcrete pump and nozzle too far apart from each other. When the pump is working too hard, heat accumulates and causes the concrete’s composition to alter, causing the fines, liquids, cream, and aggregate to separate and the shotcrete to be incorrectly mixed when applied.

While this only occurs during the wet mix method, the pump must be positioned as close to the nozzle as possible to ensure the entire process proceeds smoothly.

Nozzleman Employs An Ineffective Technique

The nozzleman should spray the shotcrete at a 90-degree angle to the receiving surface, with a gap of no more than 6 feet between the nozzle and the surface. To reduce trapped rebounds, the nozzleman should first begin spraying in the corners. When spraying in a layered fashion, each layer must be adequately prepared with substrate before applying any additional materials.

About SprayForce Concrete

We are Calgary’s most sought-after shotcrete service provider, with an ocean of technical shotcrete expertise and various application talents. Learn more about Sprayforce Concrete and our team of professional nozzlemen.

Need high-quality shotcrete services? Contact us now.

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