What Is Shrinkage In Concrete & How Do You Prevent It?

There are a range of factors that can influence the behaviour and properties of concrete products, but what is shrinkage in concrete? The following guide looks at what is meant by concrete shrinkage, how it’s caused and most importantly, how it can be prevented. Let’s start by answering the question of “what is shrinkage in concrete?”.

What Is Shrinkage In Concrete?

Shrinkage in concrete occurs when there is a change in moisture content. When concrete is mixed, water is added to enhance its workability. It’s essential that the correct amount of water is used in the concrete as this has a large impact on how the concrete behaves. When concrete is laid and starts drying, the water starts to leave the concrete. This creates a volume change in the concrete known as shrinkage. As a result, tensile forces can cause the concrete to crack if it’s not strong enough. Additionally, where the top of the concrete is drying faster than the bottom of the concrete, this can cause thermal differential cracking.

What Is The Impact Of Shrinkage In Concrete?

Now that we’ve answered the question of “what is shrinkage in concrete”, you’re likely to be wondering why it’s so important to be aware of. The main problem with concrete shrinkage is that it causes cracks in the concrete structures. Concrete can crack naturally over time through wear and tear meaning that not all concrete cracks are a problem. However, more severe cracks can affect the strength and durability of concrete structures. That’s why, when thinking about what is shrinkage in concrete, it’s important to know how to prevent it so as to avoid potentially hazardous cracks from forming.

How Is Concrete Shrinkage Prevented?

When discussing the question of “what is shrinkage in concrete”, we mentioned the importance of moisture content. That’s why the best way to prevent concrete shrinkage is by mixing less water into the concrete. When adjusting the water ratio, it’s essential to balance strength with workability so that the concrete can be laid effectively without being prone to shrinking. Admixtures can also be used to improve workability. 

Another method that contractors will often use to reduce the impact of shrinkage is to add control joints. Joints are cut into the concrete, meaning that when the concrete starts to crack due to shrinkage, it cracks along the control joints, minimising the impact on the integrity of the concrete itself.

The Importance Of Quality

When discussing the question of “what is shrinkage in concrete”, it’s important to emphasise the importance of choosing high quality concrete products to use in construction projects. Choosing the best materials for your project is essential for preventing problems such as shrinkage in concrete and cracking. At Al Manaratain, our ready-mix concrete, alongside all our other concrete products, go through strict quality control measures. As an ISO 9001:2015 certified company, our dedicated team of quality control laboratory technicians are continuously checking and monitoring the quality of our materials from start to finish. 

For more information on any of our concrete products please don’t hesitate to get in touch with us.