You have probably stared at your concrete driveway, sidewalk, or patio and thought it would look so much better if it weren’t for those unsightly cracks. And you might also wonder if you are to blame; perhaps you are doing something wrong, which is why your concrete is cracking. However, there is no need to blame yourself; cracked concrete is ubiquitous and almost inevitable. According to the American Concrete Institution, even with the best design and proper construction, it is normal to expect at least some cracking in concrete.
So there you have it; even under the best circumstances, cracking in concrete is to be expected. Of course, as a homeowner, this doesn’t sit well with you; there must be ways you can prevent or at least prolong the manifestation of cracks in your concrete driveway, patio, or sidewalk. Well, there are a few ways in which you can better protect your concrete surfaces from cracking, but let’s first understand the reasons why concrete cracks.
Related: Why is My Concrete Driveway Settling?
Reasons Why Concrete Cracks
There are several reasons why concrete cracks, and it doesn’t always mean that there is a flaw or that it was improperly poured. Where concrete cracks, when it cracks, and why it cracks varies. Concrete is very durable, but it is also not very flexible, so something as simple as too much tension or movement can cause cracks. Here are a few other reasons why concrete cracks.
- Too Much Water in the Mix
- Dries Out Too Fast
- Overloading
- Poor Base
- Expansion
- Settlement
Too Much Water in the Mix– You don’t need very much water for concrete to achieve maximum strength, but there are contractors that add too much water to make pouring easier. Not only does too much water in the mix cause cracks, but it also reduces the strength of the concrete.
Dries Our Too Fast– The curing process is critical for concrete durability and avoiding cracks. A chemical reaction occurs during the curing process in which the concrete dries. Hydration should continue for days after the concrete is poured to prevent rapid drying.
Overloading– While concrete is very sturdy, it does have weight limits. Therefore, having heavy equipment parked on your driveway, like a large dumpster, for example, for an extended period of time can lead to cracking.
Poor Base– Settlement cracking in concrete can occur if the base was poorly compacted. Poorly compacted soil should be dug out and replaced with crushed rock for a sturdy base.
Expansion– Heat causes almost everything to expand, even concrete. When your concrete sidewalk expands, it is pushed up against anything that might be in its way, like a brick wall, for example. Since concrete is not pliable and cannot flex, the force caused by expansion can cause it to crack.
Settlement- There are several instances that can cause the ground underneath your cement patio or driveway to settle. If the utility company has to dig a trench near a concrete slab, it could cause settlement that increases the chances of cracks. Should you have a tree removed that was close to a concrete surface, bear in mind the hole should be filled and compacted to prevent settling.
Crack Types
Cracks in your concrete driveway or other concrete surfaces might not look good, but often they aren’t cause for concern. However, there are cracks that should be dealt with as they can become a problem in the future. Here are a few types of cracks and how you should deal with them.
- Hairline Cracks
- Structural Cracks
- Settlement Cracks
- Shrinkage Cracks
Hairline Cracks– Hairline cracks are quite small and harmless, but they are still unsightly. Hairline cracks can get wider over time, so you may want to have them repaired.
Structural Cracks– Structural cracks that are wider than the width of a credit card should be either repaired or replaced.
Settlement Cracks– If the ground under your concrete patio or driveway has settled and produced cracks, you should have it repaired or replaced and make sure the base is adequately compacted and otherwise prepared.
Shrinkage Cracks– Shrinkage cracks occur when the concrete dries too quickly. The cracks can be repaired, but ultimately, having the concrete replace and properly cured is the better option.
There is much debate as to what is the acceptable width of a crack in the concrete. While there is no definite answer, many contractors and other experts in the field agree that any cracks that are wider than the width of a credit card and run the depth of the slab are likely structural and could be a sign of something more serious. If you are not sure what to do about cracks in your concrete driveway or patio, here are a few thoughts to consider. If a crack is small, but you notice it is getting wider, you should have it repaired before it becomes a bigger problem. If a crack is uneven, it can become a tripping hazard and should be dealt with sooner than later.
Preventing Cracked Concrete
One of the best ways to prevent cracking in concrete is to hire a reputable and thorough concrete contractor. When searching for a concrete contractor, make sure to take your time and do your homework. You can start by checking reviews to see what previous customers have to say about them. It is also a good idea to ask a lot of questions when talking with the contractor. For example, ask them if they ensure that the subgrade is properly compacted.
Cracks in your concrete driveway, sidewalk, or patio are inevitable. If the cracks are small and not caused by structural problems or settlement, they shouldn’t affect the integrity of the concrete. If you aren’t sure about the cracks in your concrete and would like more information, please feel free to give us a call, and we will be more than happy to answer your questions.
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