Why Does Concrete Crack?

Concrete is one of the more durable building blocks in existence, and one of the most affordable. That’s why it’s no surprise that concrete has remained a popular building material since its invention. However, concrete is not indestructible. One of the most common issues concrete runs into is cracking. Let’s take a closer look at why concrete cracks, and how it can be avoided. 


There are several reasons concrete can crack, but the most common by far is a result of excess water in the concrete mix. Every concrete mix is different, but using a mix with too much water will almost always result in cracks in the concrete. 


Technically water isn’t directly responsible for the cracking,  but the shrinkage that occurs as the water evaporates is. As concrete hardens, it dries and shrinks as the water in the mixture evaporates. The more water in the mixture, the more evaporation, which means more shrinkage. The more shrinkage, the more cracks. 


To avoid this, make sure to carefully measure everything that goes into your concrete mixture. If you’re worried about cracks, it might even be best to keep your mix on the dry side. 


The second most common reason that concrete develops cracks has to do with rapid drying. All concrete mixtures have a set amount of time that they need to dry in the strongest and most durable way possible. If that curing process is too fast, or to slow, you’re going to have issues with your concrete. 


If concrete dries too quickly, it almost always results in cracking. This is something that should be of particular concrete for people who live in warm climates. An extra hot day can easily cause an outdoor concrete project to dry to quickly and crack. Keep extra water on hand and make sure your concrete surface stays moist during the curing process. 


Concrete can also crack if an improper strength mixture is applied to the wrong job. For example, concrete driveways need to be stronger than sidewalks so that they can absorb the weight of vehicles. Every concrete mixture has a specific strength rating, make sure to do your research before deciding on the mix that’s right for you. 


Of course, sometimes you want concrete to crack! Think about the cracks in the sidewalk that divide sections. These cracks are created using control joints. Control joints force concrete to crack in specific places. Not every project needs control joints, but the ones that do will crack in random places if the control joints are not properly placed. 


If you’re worried about concrete cracking, or want to hire a professional to complete a concrete project for you, reach out to Razorback Concrete at www.razorbackconcrete.com

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