What happens when the crack width reaches 3mm

Hello! General floor cracks will not affect the safety and quality of the house, but it is clearly marked in the national building code that cracks larger than are harmful cracks, mainly considering that water leakage corrodes the steel bar and affects the durability of the house.

However, a little repair can not affect the whole, if the property or construction unit is responsible for maintenance, choose the correct method to repair, do not affect the normal use.

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The limit of the maximum crack allowable width of a structural member is that the maximum crack allowable width should be determined according to the type of structure, the environmental category crack control level. See the figure below for details:

What is the maximum allowable value of cracks in concrete floor slabs? The allowable value of the maximum crack in the concrete will not exceed the range of its use, and if it does, there will be a certain danger.

There is no specific regulation on the length of the wall crack, only the width. If it is greater than or equal to it, it needs to be repaired.

There are several reasons for cracks in the surface:

1.Cracks in the cracks between the wall insulation board and the board;

2.Shrinkage cracks caused by wall slotting and trunking plastering;

3.Stress cracks that appear unevenly in the plastering scraping putty.

Several ways to repair cracks in the wall:

1.Treatment of cracks in insulation boards. Use a putty knife to cut the crack as deep as possible and fill it with plaster.

Pay attention to be sure to fill it up and fill it evenly. Then use a bandage, bean cloth or white cloth to paste the cracked area, dry it, and then scrape putty or do other processes. If the crack is severe, you can also use kraft paper or newspaper to repair the joint, the effect may be better.

2.The reason for the cracks after the trunking is that the drying speed and shrinkage rate of the cement mortar are different from the putty powder, and the putty on the surface of the wall has been dried, and the cement mortar inside has not dried thoroughly, so cracks appear. Therefore, the effect of gypsum powder for the wire repair duct is better.

3.Cracks can also occur if the wall putty is scraped too thick at one time, or if the thickness of the entire wall is too different. In severe cases, it will also fall off.

If necessary, you should scrape several times, each time thinner and longer. However, it should be noted that the putty is scraped more times and is easy to fall off.

This depends on what kind of wall you are, and the inner wall is scraped putty. Generally 1-2mm, if it is plastered wall 2-3mm.

When the crack width is not greater than , the surface sealing method can be used;

When the crack width is larger, the caulking sealing method can be used; When the crack is deep, the method of grouting repair should be adopted.

This can have an impact on the rebar in the floor slab, such as corrosion. It is also possible to have an impact on the next layer, such as water seepage. Cracks too building slabs may break and the consequences can be imagined. But if the crack width is within the design allowable range, it is not a concern.

For example, from the requirements of structural durability, bearing capacity and normal use, the most stringent allowable crack width is. In recent years, many countries have broadened it to a large number of trials and experiences with pumping concrete.

When the environment of the structure is normal, the thickness of the protective layer meets the design requirements, there is no erosion medium, and the crack width of reinforced concrete can be relaxed to; in moisture and soil; In seawater and alternating wet and dry. Cracks along the reinforcement are highly harmful and must be treated.

Cracks in reinforced concrete are inevitable, and their microscopic cracks are determined by their physical and mechanical properties, but their harmful degree can be controlled, and the standard of harmful degree is determined according to the conditions of use.

The capillary cracks on the surface are usually temperature cracks, which have no effect on the main structure, and if they are penetrating cracks, then they must have an impact on the main structure.

Cracks in the floor slab generally do not have a great impact on the main structure. However, it is still necessary to pay attention to the thickness of the crack, if the thickness is too large, it will be a great threat to the safety of life and affect the appearance.

There is no problem if it does not exceed the scope specified in the specification, and under normal circumstances, the concrete components work with cracks; Exceeding the regulations will have an impact on the safety of the structure.

There is no big problem with local microcracks in beam-plate roofs. Beamless floors are dangerous.

The impact depends on the extent of the cracks. No matter how big or small the cracks are, if you don't take chances, if you don't deal with the light ones, they will definitely expand; Needless to say, step up the repair.