What are the causes of gaps in concrete?

1. Causes of concrete cracks.

1. Concrete is a material with very low tensile strength, to be precise, concrete is still relatively brittle in nature, so we must pay attention to the changes in temperature and humidity during construction, and the concrete construction environment is very important.

2. In addition to the impact of the environment, if the construction workers are uneven during the foundation construction, then the concrete will settle, and it is very easy to produce cracks in the later stage.

3. If the content of concrete is too large during construction, resulting in the shrinkage of concrete, the material proportioned to concrete will shrink poorly, and cracks will occur in the later stage of concrete. If you choose a cement with no guaranteed quality, the quality of the concrete must be problematic, and there will definitely be cracks in the later stage, so we are better to be careful in choosing materials.

4. In addition to the problem of materials, there may be construction technical problems of construction workers, in the construction process, the need for proportioning, mixing, transportation, watering, any defects or omissions in these processes will lead to cracks in the later stage of the concrete ground.

There are load-induced, temperature-induced, and load-induced together with temperature.

Hello dear! We'll be happy to answer for you. What are the causes of cracks in concreteAnswer:

Hello dear dear, the cracks caused by the load in the concrete under the conventional static, dynamic load and secondary stress are called load cracks, which can be summarized into two main types: direct stress cracks and secondary stress cracks. Direct stress cracks refer to cracks caused by direct stress caused by external loads, and secondary stress cracks refer to cracks caused by secondary stress caused by external loads. The characteristics of load cracks vary according to different loads, and present different characteristics.

This type of crack mostly appears in the tension zone, shear zone or severe vibration area. However, it must be pointed out that if there is peeling or short cracks along the compression direction in the compression zone, it is often a sign that the structure has reached the limit of bearing capacity and is a precursor to structural failure, and the reason is often that the cross-sectional size is too small. 2. Cracks caused by shrinkage concrete has the properties of thermal expansion and cold contraction, when the external environment or the internal temperature of the structure changes, the concrete will be deformed, if the deformation is constrained, the stress will be generated in the structure, and when the stress exceeds the tensile strength of the concrete, temperature cracks will be generated.

In some long-span bridges, temperature stresses can reach or even exceed live-load stresses. The main characteristic of temperature cracks that distinguish other cracks is that they will expand or close with temperature changes. 3. Cracks caused by loadIn actual engineering, cracks caused by concrete shrinkage are the most common.

Among the types of concrete shrinkage, plastic shrinkage and shrinkage shrinkage (dry shrinkage) are the main causes of concrete volume deformation, as well as autogeneous shrinkage and carbonization shrinkage. Thank you for your patience. The above is my full reply, if you are satisfied with my service, please give a thumbs up, and I wish you all the best!

Peace and joy!

Four common causes of cracks in concrete building structures.

Causes of cracks in concrete:

1. Cracking, which may be related to insufficient maintenance, such as after pouring concrete, the surface is not covered slowly, and it is exposed to wind and sun, and the moisture on the surface shrinks rapidly, reducing the strength. Unable to resist this stress, cracking occurs.

2. There are also some cracks in the concrete that have been formed, but are affected by the temperature, mainly because of the cracks in the surface temperature, and the cracks caused by the large temperature. This kind of crack is called a temperature difference crack, generally speaking, its direction is not a law, some of them are larger, and some are smaller in area.

3. Cracks in concrete may also be caused by uneven settlement, mainly because of the settlement of the foundation, resulting in the foundation beam, including the ring beam, etc., which is too large, and cracks appear from the late cluster.

4. Cracks may also be related to inadequate construction, such as pouring too fast and low fluidity. In addition, if the vibration is not timely, tight and uneven in the later stage, there will be honeycomb or hemp surface.

How to avoid cracks in concrete.

1. Selection of concrete materials. We need to choose cement with low heat and low dry shrinkage. For example, Portland cement, ordinary Portland cement, or slag Portland cement. It should be noted that the content of tricalcium aluminate in the cement we choose should not be greater than 8%.

2. We also have to strictly control the mud content of coarse aggregate and fine aggregate and the particle size of coarse aggregate. At the same time, it is also necessary to strictly control the mix ratio of concrete, reduce the water-cement ratio and sand rate. Choose some concrete with a low amount of cement per unit.

3. Mix some suitable water reducers. What we need to pay attention to is to reduce the unit of water consumption. We can mix some fly ash with good water retention performance and fine particles, so as to improve the aggregate gradation and use low-flow concrete.

4. We should choose some concrete with small thermal expansion coefficient, good thermal conductivity, large specific heat, low elastic modulus, large virtual change, and small micro-expansion dry shrinkage rate. These contents need to be paid attention to when purchasing concrete, and explain to the manufacturer in advance.

The construction of the decoration workers is not standardized, and the ratio of cement mortar to water is not well adjusted.

Under the influence of the external environment, the temperature should not be too low, try to be above 0, and pour water directly on the concrete to ensure humidity.

If there is a problem with the quality of the raw materials, do not buy the cement if it is agglomerated or damp.

Ground settlement can also cause cracks in concrete. When pouring a large volume of concrete, the heat of hydration generated inside it will increase the temperature of the concrete, and the resulting deformation may be constrained by the existing structure or formwork, resulting in restraint stress. After the concrete is poured, the rise in temperature will cause the concrete to expand and deform.

1. The construction of decoration workers is not standardized.

Construction technical problems, to a large extent determines whether the concrete is cracked, if the decoration workers do not debug the ratio of cement mortar and water, it will lead to concrete cracking in the later construction.

As for the correct ratio of cement to water, it is about 1:, that is, 1kg of cement should be mixed with 400g of water.

2. The influence of the external environment.

If you want the concrete to solidify, the temperature and humidity must meet certain requirements, the temperature should not be too low, try to be above 0, and pour water directly on the concrete to ensure humidity. Especially in summer, you need to sprinkle water 5 times a day, every 2 hours.

Because concrete releases heat as it sets, it needs to be watered to maintain temperature and humidity, otherwise it will crack.

3. There is a problem with the quality of raw materials.

Good cement must have information such as production date, production license, product factory inspection report, etc., if you don't have it, don't buy it. Do not buy the cement if it is agglomerated or damp, as this will reduce the strength and eventually crack.

4. Foundation settlement.

Concrete cracking caused by foundation settlement is rare, but it is not impossible, so before building a house, you must tamp the foundation to prevent it from having voids to settle, and severe settlement will even lead to the collapse of the house.