Why Do Concrete Driveways Crack? [5 Common Reasons]
Due to its durability and low maintenance needs, concrete is a popular choice for homeowners when they consider installing a new driveway. If properly installed and maintained, concrete driveways last for decades. However, even the best-laid concrete gets cracked, which may reduce the aesthetic appeal of the property and cause safety hazards if cracks are too large. Here begs the question, Why does driveway concrete crack? There are many reasons. They may be cracked due to weather changes, or poor installation can be a reason for cracking.
Let's explore the five common reasons for concrete driveway cracks and what preventative steps you can take to keep these cracks from getting worse.
Temperature Fluctuations and Seasonal Changes
Even though concrete is a strong and sturdy material, it does not do well when the temperature fluctuates. It contracts due to cold weather and expands when temperature goes up. This constant pattern of expansion and contraction puts stress on the surface, which causes cracks to appear over time.
Seasonal changes like freeze-thaw cycles in colder places can make this problem worse. Water expands when it freezes, this puts pressure on the concrete around it, which can cause bigger cracks to appear or, in the worst cases, the concrete begins to fall apart.
Too hot weather also has a major impact on the concrete surface. It can expand if it is exposed to strong UV rays for a long time. This makes the concrete weaker and more likely to crack.
Preventative Step
To minimize the chances of cracks before the weather goes up and down, taking preventative steps is crucial.
You can place control joints in your driveway that give the concrete "comfort zones" where it can stretch and shrink with little stress. These joints are cuts that were planned ahead of time in the concrete. They show where cracks should show up, which helps stop random cracking.
Using a high-quality concrete sealer, especially before winter, will also keep the surface from moisture, UV exposure, and temperature fluctuation, which can make cracks worse during freeze-thaw cycles.
Improper Curing Process During Installation
One of the most important parts of installing the concrete is curing , which makes it harden and reach its maximum strength. It involves maintaining the moisture level in the freshly poured concrete so that it does not dry out too fast. It can become weak and easy to crack if it cures too quickly due to its minimum tensile strength.
Concrete takes 28 days to gain its maximum tensile strength with proper cure. During the curing process, the right chemical reactions between cement components and water are essential for the development of concrete's thick texture and pore structure.
To ensure that concrete gets the required properties, moisture loss during cement hydration must be avoided or controlled. The formation of cracks and a loss of strength may result from the concrete losing moisture too quickly.
Preventative Step
Newly installed driveways should be sprayed with water, left to soak, or covered with sacks, canvas, or something similar to keep the surfaces wet. It is best to keep the concrete wet continuously for at least 14 days after installation. It is crucial to prevent the concrete from drying out in between soakings. The concrete is really affected by the surface's frequent wetting and drying.
Curing compounds, including waxes, resins, chlorinated rubbers, and epoxies, can also slow down moisture loss. These are easy to use, cheaper, and provide a longer curing action, lasting seven days.
Heavy Loads and Vehicle Pressure
Concrete is a sturdy and strong artificial material that withstands heavy traffic. Residential driveways are made less thick as compared to commercially used driveways. Heavy vehicles like trucks and RVs put more stress on the concrete surface. If they stay in the same place for a long time, the concrete can begin to crack from the tension. This issue is common for usually 4 inches thicker slabs.
Although the driveway surface can handle the extra weight, the ground below the concrete cannot. If the soil beneath your driveway is some kind of clay, it does not have the capacity to withstand. It will shift, leaving a gap and a stress crack in the surface. This is more likely to happen after heavy rain when the soil below the driveway is soft.
Preventative Step
Consider using reinforced concrete in your driveway if you need to carry heavy loads, or use almost 6 inches thicker slabs if the soil beneath your driveway is clay or silt. Reinforced concrete has steel bars embedded in it, which makes it stronger and less likely to crack.
Observing the weight limit for your driveway is important. If the weight limit is exceeded, do not park or drive heavy cars on the driveway. Spread the weight over larger areas and keep stress from building up in a certain area by using parking pads or extra support, like pavers.
The driveway should be inspected often for signs of stress, cracks, or damage to the surface.
Tree Roots and Soil Movement
Even though tree roots may not seem to be close to the ground, they can put a lot of pressure on a concrete driveway. As roots grow, they spread and move up against the soil, which in turn influences the concrete above it. This can cause cracked or even raised sections of concrete, which can be undesirable and even dangerous.
On the other hand, they are always in search of water and continuously obserbing the moisture from the soil. Soil that is losing water shrinks and leaves voids in the ground. The gaps under your driveway can make the base unstable and cause cracks.
Preventative Step
If your driveway is close to trees, you might want to put up a root barrier to keep tree roots from growing in your driveway. This is especially important if your trees are big, old, and have deep roots.
If you already have a driveway, keep an eye out for cracks that roots have made and fix them right away to stop the cracks from getting worse. Make sure the trees you plant are far enough away from your driveway to be safe. If possible, talk to a professional landscaper to help you figure out the proper placement for the new plant.
Improper Drainage
Not having enough drainage can really damage the driveway surfaces and cause them to crack. Water doesn't drain away from your driveway properly, so it pools on the top. This standing water may penetrate into the pores of the concrete over time, making it weaker and more likely to crack.
Also, soil erosion can happen around and under the driveway if there isn't enough drainage. When water flows or pools near it, it may decompose the soil, causing it to settle unevenly. This uneven settlement puts stress on the surface and makes it possible for cracks to appear.
Additionally, if your drainage isn't right, water can soak into the ground under your driveway. Soil expands when it gets wet, especially if it has a lot of clay in it. The rising ground puts pressure on the concrete from below, which causes it to lift, become uneven, and crack.
Preventative Step
Consider taking the following steps to protect driveways from cracking caused by bad drainage.
Make sure your driveway has a good drainage system. To do this, you may need to add extended downspouts, a drainage system, or surface channels to move water away from the driveway and keep it from pooling or building up.
If you grade the driveway correctly, it will help control water runoff and keep it from pooling on the surface. The driveway must slope away from the house and send water to a certain area. Check often to ensure that the gutters and drains are clean and working properly.
When to Call a Professional
Some minor cracks less than ¼ inch are normal as your driveway gets older, but larger cracks that spread quickly could mean there are bigger problems underneath. Consulting with a professional is the best way to figure out how to fix and take care of your driveway. Small cracks can usually be filled or resurfaced, but if the damage is too severe, a complete or partial replacement might be necessary. Investing in a quality concrete driveway and keeping it in excellent shape will make it last longer and enhance its aesthetics and functionality for years to come.
Conclusion
It can be annoying when your driveway cracks, but if you know the exact causes and take action, you can lower the risk of damage being severe and make your driveway last longer. To keep your driveway in excellent shape, you should do regular maintenance, fix drainage problems, reinforce any weak spots, and get professional help when you need it. Remember, a properly installed, well-kept, and crack-free driveway not only increases the aesthetic appeal of your property but also gives you and your family safe and smooth surfaces to walk and drive.
