Concrete cracks for several reasons and understanding the cause of the cracking is important for determining the appropriate steps to address the issue. Living in freeze-thaw laden Northeast Ohio doesn’t help one bit! Here are some common reasons why concrete may crack and what you can do to prevent it.
Shrinkage Cracks: Concrete naturally shrinks as it cures and dries. This process takes about a week initially, but around twenty-eight days to fully cure. Shrinkage cracks are often small, fine cracks that appear as the concrete hardens. Proper curing and control joints can help minimize these cracks.
Settlement Cracks: These occur when the ground beneath the concrete settles or shifts. This can happen due to soil compaction issues, changes in moisture content, or inadequate base preparation. The best way to avoid this type of cracking is to ensure that the ground is compact, and that any base underneath the concrete is compacted fully as well.
Overloading: Concrete has a weight limit, and if it’s subjected to excessive loads, it can crack. This might happen if heavy vehicles or equipment are placed on the concrete surface without adequate support. Residential concrete doesn’t have as high of a PSI compared to commercial grade applications, so being aware of this will help a lot.
Freeze-Thaw Damage: In colder climates, like Cleveland, water can penetrate the concrete’s pores, freeze, and expand, causing cracks. This is especially problematic if the concrete isn’t properly sealed or if it has a high water-to-cement ratio. Rapid temperature changes, such as extreme heat or cold, can cause concrete to expand or contract, potentially leading to cracks.
Improper Mix: Using the wrong concrete mix or not following the manufacturer’s recommendations can lead to cracking. It’s essential to use the appropriate mix for your specific application. Make sure that the concrete being delivered is approved by your contractor. They will be able to tell if the concrete has too much/little water, or if it isn’t mixed right. Bad concrete can begin to spall within a few weeks.
Improper Mix: Using the wrong concrete mix or not following the manufacturer’s recommendations can lead to cracking. It’s essential to use the appropriate mix for your specific application. Make sure that the concrete being delivered is approved by your contractor. They will be able to tell if the concrete has too much/little water, or if it isn’t mixed right. Bad concrete can begin to spall within a few weeks.
Inadequate Reinforcement: If the concrete was not properly reinforced with rebar or mesh, it may be more prone to cracking under stress. Sometimes concentrators can save a buck by not using the right amount of support, so make sure to inspect the work or get someone who knows concrete and can verify that the concrete is supported correctly.
Chemical Reactions: Certain chemicals or aggressive substances like acid (rust removal) can corrode or degrade the concrete, leading to cracks or surface damage. When power washing concrete, it’s vital not to use too much pressure. A good PSI range is 1700-2700. Walk behind surface washers are excellent tools to use when washing concrete because the pressure is evenly distributed through three nozzles.
Lack of Control Joints: Control joints are intentional cuts or grooves in the concrete that control where cracks occur. Without these joints, cracks may form randomly.
Curing Issues: Proper curing involves keeping the concrete moist and at the right temperature for an adequate period. Inadequate curing can lead to cracks as the concrete dries too quickly. Contractors who try to speed up the curing process by using an aggressive cure-and-seal or by using too much fly ash can make cracking an almost sure thing.
To address concrete cracks, you may need to consult with a professional concrete contractor or engineer, depending on the severity and underlying cause of the cracks. They can assess the situation and recommend appropriate repair methods, which may include filling, sealing, or even replacing the damaged concrete. Additionally, taking preventive measures like using the right mix, proper reinforcement, and control joints can help minimize future cracking.
If you are interested in learning about our concrete washing and sealing services to protect your concrete from cracks, please reach out for an estimate.