The types of cast-in-place slab cracks include cracks caused by external loads, temperature shrinkage cracks, cracks caused by uneven settlement of the foundation, shrinkage cracks caused by the use of product concrete, floor cracks caused by embedded pipelines, construction factors Causing cracks in concrete floor slabs. Let’s take a closer look at these types and solutions.
1. Types of cracks in cast-in-place slabs
Cracks caused by external loads: Structural cracks that occur under the effect of external loads usually have strong regularity , the correct conclusion can be read through calculation and analysis.
1. Temperature expansion cracks: Temperature expansion cracks are the most common cracks in buildings. They are mainly caused by the temperature deformation of the structure and the obstruction of the contraction deformation of materials and excessive stress.
2. Cracks caused by uneven settlement of the foundation: Uneven settlement of the foundation causes additional stress in the superstructure, resulting in cracks in the floor slab.
3. Shrinkage cracks caused by the use of product concrete: The water-cement content is relatively large, which causes shrinkage cracks in the concrete during the hardening period.
4. Floor cracks caused by embedded pipelines: surface cracks appear along the direction of the pipeline at the embedded pipelines; some irregular cracks appear in the form of divergences or cracks.
5. Construction factors cause cracks in concrete floor slabs: maintenance is not in place, and mandatory standards require concrete maintenance to be covered and sprinkled with water.
2. Solutions to cracks in cast-in-place slabs
1. For cracks on the surface of ordinary concrete floor slabs, the cracks can be cleaned first, and then filled with epoxy slurry or filled with epoxy slurry after drying. Close with surface paint. If cracks are found before final setting during construction, they can be treated with troweling. For other common cracks, 1:2 or 1:1 cement mortar can be used to smooth and maintain the cracks after cleaning the board joints.
2. When the cracks are large, an eight-shaped groove should be cut along the cracks. After cleaning, use 1:2 water.
3. When the floor has large cracks , a static load test should be conducted on the floor to check its structural safety. If necessary, a layer of steel mesh can be added to the floor to improve the integrity of the floor.
4. For a single full-length, penetrating dangerous structural crack with a crack width greater than 0.3mm, structurally bonded flat steel should be used for reinforcement. The seams between the boards are filled with high-pressure glue.
Therefore, during the design period, corresponding pile foundations should be selected for different soil textures and house structures. First of all, the following aspects should be considered: ① Ensure that the load acting on the foundation cannot exceed the bearing capacity of the foundation, so that the foundation has a sufficient safety factor. ② Control the settlement of the foundation so that it does not exceed the allowable deformation coefficient of the foundation.
Set up reasonable settlement joints and post-pouring strips in soil with obvious differences in compressibility, in places with different foundation forms, in transitional areas, in complex planes, in uneven areas, and at the edges where there are basements. The corresponding pouring time should be controlled for the post-pouring belt in the house. It is usually advisable to pour it after the uneven settlement at both ends is basically stabilized.
Conclusion: I will introduce the types and solutions of cracks in cast-in-place slabs here. I hope it will be helpful to you. To learn more about decoration knowledge, please continue to pay attention to Fuwo decoration guide.