Concrete cracking is a common problem that affects the safety and durability of buildings. This article will ** the causes of concrete cracking and propose some ways to prevent concrete cracking.
First, the cause of concrete cracking.
There are many causes of concrete cracking, the most common of which are due to shrinkage and temperature changes. When concrete solidifies, it shrinks, and if the shrinkage is restricted, stress is created. Cracks occur when the stress exceeds the tensile strength of the concrete. In addition, temperature changes can also cause cracking of concrete. When the temperature difference between the inside and outside of the concrete is too large, temperature stress is generated, which leads to cracking of the concrete.
Second, the method of preventing concrete cracking.
1.Control the concrete mix ratio.
Controlling the concrete mix ratio is an important measure to prevent concrete cracking. A reasonable mix ratio can reduce the shrinkage rate of concrete and improve the tensile strength of concrete. When selecting materials, cement with low heat of hydration and low shrinkage should be selected, and an appropriate amount of admixtures should be added to improve the performance of concrete.
2.Strengthen conservation.
Enhanced curing is a key measure to prevent concrete cracking. After the concrete pouring is completed, moisturizing and curing should be carried out in time to keep the concrete surface moist. During curing, temperature and humidity should be controlled to reduce the temperature gradient and humidity gradient inside the concrete. At the same time, excessive vibration and excessive plastering should be avoided, so as not to affect the uniformity and compactness of the concrete.
3.Set up crack-resistant reinforcement.
Setting up crack-resistant reinforcement can effectively enhance the crack resistance of concrete. In the parts that are prone to cracking, the reinforcement ratio of the steel bar should be increased to improve the ultimate tensile strength of the concrete. At the same time, the position and spacing of the reinforcement should be reasonably set to ensure that the reinforcement can effectively transmit and disperse the stress.
4.Increase prestress.
Increasing prestress is an effective way to prevent cracking in concrete. By applying prestress, the shrinkage and temperature stress of the concrete can be eliminated or reduced, thus preventing the concrete from cracking. Prestressed tendons can be set inside or outside the concrete, which should be determined according to the actual situation of the project.
5.Control during construction.
In the construction process, control and management should be strengthened to ensure the quality of concrete pouring, vibration and curing. At the same time, the construction temperature and humidity should be strictly controlled, and the construction should be avoided under unfavorable conditions such as high temperature and strong wind. After the construction is completed, a comprehensive inspection and acceptance should be carried out to ensure that the quality of the concrete meets the requirements.
III. Conclusion. Preventing concrete cracking is essential to guarantee the safety and durability of buildings. In this paper, the methods to prevent concrete cracking are introduced, such as controlling the concrete mix ratio, strengthening curing, setting anti-cracking reinforcement, increasing prestressing and control during construction. In the actual project, the appropriate method should be selected according to the specific situation, and the construction process should be strictly controlled to ensure that the quality of the concrete meets the requirements. At the same time, for the concrete structure that has cracked, it should be repaired and treated in time so as not to affect the safety and performance of the building.