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Why Does Concrete Crack, and How Can You Prevent Cracks?

Why Does Concrete Crack

Because of its hardness, durability, and cost-effectiveness, concrete is the most popular material used in the construction of pavements and parking lots. It is the backbone of our modern world, supporting our buildings, roads, and sidewalks. But just like any sturdy structure, it's not immune to cracks. Let’s discover why those pesky cracks happen and find out how we can prevent them from happening.

Why Does Concrete Crack?

1. Excessive Water

When plenty of water is added to the cement mix, some of it will manage to escape through evaporation. This reduces the size of the concrete slab and creates stress, which in turn will lead to cracks. The more watery the concrete mix, the greater the shrinkage will be.

2. Lack of Control Joints

Concrete expands and contracts whenever there are changes in temperature. Control joints are installed to take the stress off of the concrete slab during expansion and contraction. This is the part where the concrete is allowed to crack in a controlled manner, so that they occur in a place where they won't compromise the structure's integrity. If the control joints are not properly installed, cracks may appear all over the concrete surface.

3. Not Enough Curing Time

Think of concrete as a bit like a fine wine or an aged cheese – it needs time to mature and strengthen properly. When the curing process is rushed, the concrete hasn't had the opportunity to fully hydrate and bond together. This premature interruption can result in weaker concrete that's more susceptible to cracking under stress.

How to Prevent Cracks

Now that we've pinpointed the culprits, here are some tips on how we prevent cracks from appearing on our concrete pavement projects. 

1. Starting Strong

Just like building a house on shaky ground is a recipe for disaster, laying concrete on a flimsy subgrade is a no-go. We make sure your base is solid and compacted to give your concrete the support it needs.

2. Mixing it Right

When mixing concrete, the ratio of water to cement is critical to achieve the desired strength and durability of the concrete. Water allows the cement particles to hydrate and bind together, but adding too much of it can lead to shrinkage as it evaporates during curing, leaving behind gaps and weak spots in the concrete.

This reduction in volume creates internal stresses within the concrete, which can ultimately lead to cracking if not controlled. By aiming for a low water-to-cement ratio, we can minimize shrinkage and reduce the likelihood of cracks forming.

3. Joint Effort

By strategically placing control joints at regular intervals, we can help relieve the stress that builds up within the concrete as it shrinks and expands due to changes in temperature and moisture. Without these joints, the concrete would be more prone to random cracking, which can compromise its strength and longevity.

4. Patience is a Virtue

While it may be tempting to rush through the curing process to move on to the next phase of the construction project, allowing the concrete to cure properly pays off in the long run. A well-cured concrete slab is stronger, more durable, and less prone to cracking, ensuring a solid concrete foundation.

Understanding the whys behind those concrete cracks is the first step to effectively addressing them. If you are planning to install a concrete pavement, Wright Construction has the people, skills, and equipment you need. Contact us today to get started on building a solid concrete foundation for your project!


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