5 Types of Concrete Cracks: What Are They Telling You

Decipher what these concrete cracks mean.

Concrete, be it decorative or not, is considered to be durable and long-lasting. However, despite those traits, its prone to cracking. And when you see a crack in your concrete, you might think something's wrong with it.

You shouldn't worry much about it since most cracks are nothing major. Cracks appearing in concrete is common, and some are inevitable. From the foreword by the American Concrete Institute, says that no matter the best floor design or proper construction, one shouldn’t expect 100% crack-free and curl-free floors.

But how will you know that the cracks you are seeing aren't something you should worry about? And what kind of cracks will you have to watch for? This blog post will show you the common types of concrete cracks and what they tell you.

1. Plastic Shrinkage Cracks

Plastic shrinkage cracks appear on the surface when the concrete dries too quickly before it has set. Low humidity, high temperatures, and exposure to high winds are the leading causes of the appearance of plastic shrinkage cracks. The concrete mixture containing too much water can also be a reason for this type of crack to occur.

The cracks typically look thin and nearly invisible but can extend throughout the entire thickness of the concrete. You can prevent this type of crack from happening by pouring concrete at night if temperatures are too hot or if it's too windy. You can also cover the surface to slow down evaporation or place concrete in thin layers so it can dry evenly.

2. Heaving Cracks

Heaving cracks form when concrete is lifted from beneath the ground. This often happens during the winter season, when the ground freezes and lifts the concrete. And when the warmer climate arrives, the frozen ground thaws and settles the concrete back down.

This occurrence, called the freeze-thaw cycle, is mainly the cause of heaving cracks in concrete. Other than that, tree roots growing underneath can also cause heaving cracks to appear on concrete surfaces.

3. Settling Cracks

If there are heaving cracks, settling cracks on concrete is the counterpart. This happens when the ground beneath the concrete settles or compacts. This type of crack is mainly caused by soil erosion, leaving a void and making the concrete sink. Settling cracks can also happen if a tree was removed nearby and the roots that grew underneath started to decompose, leaving space where the concrete can settle.

4. Cracks from Overloading

Concrete is known for being durable and sturdy. However, everything has its limits. Cracking is inevitable if excessive weight is placed on top of the concrete. The chances for this to happen are higher if the concrete gets overloaded after heavy rain or snowfall. This is because the ground under the concrete is soft and can cause depression if too much weight is on top of it, which can result in cracking.

5. Cracks from Premature Drying

Two types of cracks can happen caused by premature drying of concrete. Crusting cracks and crazing cracks.

Crazing cracks are thin and resemble spider webs or shattered glass. They appear when the concrete loses moisture too quickly. Even though the cracks can be unpleasant-looking, they are minor and aren't a sign of any structural issue.

Crusting cracks, on the other hand, occur during a stamping process. This is where the concrete's surface is stamped with a pattern or design. In a windy or sunny environment, the surface of the concrete dries quickly. When the stamp is placed, cracks appear on the outer edges of the pattern. They might look unsightly, like crazing cracks, but they are harmless and not a cause for construction concern.

Cracks are inevitable when it comes to dealing with concrete. Many factors come into play in contributing to the formation of cracks on the surface, such as environmental conditions, the quality of materials used, and the ratio of the mixture.

Learning how cracks form will help you avoid them from appearing if you do pour your own concrete. But if you want to have better results with less cracks appearing on your concrete, it's best to leave the pouring to the professionals.

If you want to know more, contact us, and our concrete contractors will be more than happy to assist.