Understanding Shrinking And Cracking In Shotcrete

September 8, 2022


Shotcrete is a process that is booming in the construction industry as it offers reliability and strength that lasts for decades. It is also one of the most cost-effective methods for constructing different infrastructures, tunnels, buildings, bridges, swimming pools, and more. Because of these and many other benefits of shotcrete, many people and construction companies have opted for this method and are looking forward to further developments in this area.

However, despite all this, some problems still arise during the shotcrete process, making many construction workers question the reliability of this process. Still, many companies overcome those challenges in the shotcreting process and minimize the related issues.

Shrinking and cracking are one of the common issues reported in the shotcrete process, and there are various reasons for this. These potential problems must be addressed immediately if identified. This blog post discusses the cracking and shrinking issue in the shotcrete process and tells how it can be minimized.

The Problem Of Cracking And Shrinking In Shotcrete

Shrinking and cracking are potential problems in this process that can lead to further issues. Such issues can lead to accelerated corrosion rates, especially during the reinforcement of steel in certain types of structures, for example, bridges.

Shrinking is also a potential problem that can give rise to interfacial bond stress between the substrate and the shotcrete. Therefore, shrinking and cracking can be a particular problem for architectural structures and can negatively impact their aesthetics.

Moreover, reliability and strength are also compromised. Therefore, you need to hire reliable shotcrete service providers who understand such types of problems and have the ability to mitigate these issues using quality materials and careful observation.

Shrinking and cracking can also lead to problems in water retaining structures such as tanks, reservoirs, or swimming pools. It can also result in curling and peeling at the repair edges, ultimately causing cracks to appear due to it shrinking.

What Causes Shrinking?

Shrinking happens due to numerous reasons, but the main reason is the loss of water from the mix. This loss of water from the mixture can make the mixture dry and brittle, which ultimately leads to the shrinkage of the materials used upon application. There are various types of shrinkage which we will be discussing briefly below to help you understand their causes.

Drying Shrinkage

This type of shrinkage usually occurs in hard shotcrete surfaces due to moisture loss.

Plastic Shrinkage

This type of shrinkage occurs in fresh shotcrete before it has hardened as a result of loss of moisture.

Thermal Shrinkage

Such a type of shrinkage or contraction occurs due to thermal effects.

Autogenous Shrinkage

Is caused by the consumption of water by cement hydration reactions.

What Causes Cracking?

Just like shrinkage, there are also various causes of cracking. For example, plastic cracking is caused by drying freshly applied shotcrete before it has gotten the chance to develop tensile strength.

Drying shrinkage cracking occurs when the surface’s tensile strength exceeds the shotcrete’s tensile strength. Similarly, some cracking occurs before the material gets the chance to develop sufficient tensile strength.

Similarly, a shotcrete material is made up of cement, silica fumes, water, fine aggregates, and superplasticizers for both dry mix and wet mix shotcrete. All these ingredients can have an effect on the amount of shrinkage in the final mixture.

How To Prevent Shrinking And Cracking In Shotcrete?

A professional can help you overcome shrinking and cracking problems in shotcrete. Shrinkage-reducing admixtures reduce the surface tension in the water solution and pores. They can also help reduce the contraction forces. Similarly, steel and synthetic fibres can help reduce drying shrinkage. Moreover, you can consult with your shotcrete company about the possibility of shrinking and cracking and find ways to eliminate them.

About SprayForce Concrete

SprayForce Concrete Services Ltd is COR certified and a BBB – A+ accredited business. Our ACI-certified nozzlemen have over 10 years of experience providing complete shotcrete services to all sizes of residential, industrial, commercial, and architectural-based projects. We offer quality shotcrete services with superb quality materials and machines. Our professionals are experts in this field and leave no room for complaints. Contact us today for more information.

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