Why concrete cracks
Despite its strength, concrete can crack due to several factors. For one, the material expands and contracts in different ways due to temperature changes. This phenomenon is also known as plastic shrinkage cracking and occurs in a variety of structures. It can happen anywhere in the concrete, but it almost always happens at re-entrant corners. For instance, when you pour concrete around a square column, there are four re-entrant corners. This creates stress and causes cracks from the corner.
Another reason concrete cracks is due to internal tensile forces. When a building is under stress, the pressure will be relieved through a series of cracks. These cracks appear as fine lines or veins on the surface. The shape and pattern of the crack can help you to determine which type of crack it is. Cracks that result from compression stress will have parallel lines and those that result from tensile stress will be perpendicular to the applied force.
Another common cause of cracks in concrete is excessive weight. This is caused by the concrete slab expanding and contracting. Heat can also cause concrete to expand and contract. If you want to prevent cracks in your concrete, you must plan ahead and plan for them. Otherwise, you can't prevent them from occurring.
Cracked concrete is a serious problem, but there are several ways to avoid it. Cracks can vary in severity, so you should pay attention to the location and type of crack. Cracked concrete is unsightly, but it can affect the integrity of your building. Cracks in concrete can also affect its performance, so it is essential to get rid of them as soon as possible.
Another cause of concrete cracks is salt. This common chemical is used for many purposes, including melting ice and providing a non-slip area. However, it can cause cracks in concrete if the amount of water is too much. Adding a plasticizer to the mixture can minimize this problem.
The surface layer of concrete is prone to crazing, which is characterized by fine cracks. It results from excessive floating of cement and water during the curing process. This causes the concrete to shrink and crack. The cracking usually happens in the first 30 days. Crazing can also be caused by too much or too little moisture. In addition, concrete can also crack if it dries too quickly.
Other causes of concrete cracks include ground movement. In some climates, the ground can move up and down several inches due to freeze-thaw cycles. The ground can also shift because of large tree roots, which can lift the concrete slab. In addition, large amounts of weight can cause ground movement to change and crack the concrete.
While there are other reasons for concrete cracks, drying shrinkage is the most common cause. When concrete freezes, the water it contains expands by up to 9%. This causes the concrete to shrink, which can lead to cracking and curling. Concrete shrinks about one eighth inch every twenty feet. Adding salt to the concrete will also exacerbate the free-thaw and freeze-thaw cycles and accelerate cracking.
When the soil beneath the concrete slab is soft, the weight of a vehicle pressing on it can push the concrete down. Additionally, cracking is more common in homes with large vehicles. This is because concrete's compressive strength is not as high as its flexural strength, which makes it liable to break if it is pushed too far.
Small cracks may not pose any structural risk, but they can ruin the look of your concrete. To repair a small crack, apply masonry filler and clean the area around it with a wire brush. Next, apply a thin layer of bonding adhesive to the crack. Lastly, use a trowel to apply a layer of vinyl reinforced patching compound. Make sure to smooth the patching compound so that it matches the surrounding surface. Cracks that are deeper may require a professional's services.