The main causes of floor cracking are:

The main reasons for cracks are: the base is not firm, the wall is too thin, the structure of the house is unreasonable, and the wall is not dried to paint the cement.

If the ground is leveled and cracked, it is a common construction quality problem, which is an abnormal phenomenon, and the reason is mainly due to the fact that the base is too dry and does not do sprinkling treatment or the temperature is high and the water evaporates quickly and does not do a good job of sprinkling and maintenance.

Precautions that need to be taken in the early stage.

1. The floating slurry and floor ash sunk on the base should be cleaned off with a chisel or wire brush, and then cleaned with a broom and water;

2. Strictly according to the mix ratio of the test, the measuring machine mixes, and the water-cement ratio is controlled.

3. Find the elevation, use fine stone concrete to beat the column, and the spacing is not more than 2m in both directions (the room with slope should be pulled out of the line and the slope pier should be wiped out);

4. Before laying, the base should be moistened, and a plain cement slurry or cross-sectional binder should be brushed on the substrate, and the brush should be paved with the brush, and the room should be paved from the room to the outside;

5. Use a shovel.

Spread fine stone concrete, the thickness is slightly higher than the leveling column or pier, and then roll back and forth with an iron sieve, until the surface forms a slurry, and then press twice with a hand iron plate, and the slope requirements should be done according to the slope requirements of the design;

6. It should be sprinkled with water for maintenance about 12 days after the completion of construction, and it is strictly forbidden for the Master, and the maintenance period is not less than 7 days.

Doing a good job of early prevention can effectively reduce the probability of ground cracking in the later stage.

There are many kinds of cracks that appear after ground leveling:

1. Cracking, refers to the appearance of tortoise-like fine cracks on the surface of cement mortar, which is mainly caused by improper maintenance or excessive mud content of the mortar.

2. Straight cracks in the corners of the wall refer to the cracks in the dark corners of the corners of the wall, which are mainly caused by the different shrinkage of the ground and the wall. 3. Contour cracks refer to the cracks generated along the contours of underground burials, which are mainly caused by the thickness of the cement mortar surface layer on the buried objects is too thin and the cement mortar shrinks unevenly, and the above cracks are not a big problem.

4. The cement mortar surface has irregular characters or oblique lines, and the depth of the lines is large and has a tendency to expand and even extend to the wall. It may be that the paving is too heavy, causing the ground to deform or the house to settle. Reinforcement treatment is required.

When cracks appear in the floor, the cause of the cracks in the floor should be found first, and then the nature of the cracks in the floor should be identified, and then appropriate methods should be taken to deal with them according to the actual width of the cracks in the floor. Depending on the cause of cracks in the floor, the treatment method will be different.

1. If the stability of the cement used in the concrete is not qualified, it will inevitably lead to cracks in the floor. If the cement used in concrete is produced by multiple brands, there will be a chemical reaction between the cements.

As a result, the floor is destroyed and cracks appear. In this case, the crack location should be thoroughly treated, that is, the concrete should be knocked out and the concrete should be poured again.

2. If the cracks in the floor are due to the cracks caused by force, then the appropriate reinforcement plan should be taken according to the cause of the cracks. If the floor crack is serious enough to affect the structural safety of the building, then it should be grooved along the floor crack position, cut into a V-shaped groove, and then use clean water to clean the groove, and then use pressure epoxy resin.

The liquid is poured into the crack to seal it, and then the flat steel is used.

Reinforcement of floor slabs.

3. If the crack in the floor is due to the shrinkage crack of the concrete itself due to the temperature, and the width of the crack is kept within the allowable range, then the crack surface can be closed for treatment, so as to prevent the steel bar and air contact at the crack site from causing rust, which will bring great damage to the structure.

4. If the floor is only cracked on the surface, then the crack position can be cleaned first, and after the ground is dry, the epoxy resin liquid is poured into the crack position, or a layer of epoxy resin liquid is applied to the surface of the crack position for sealing. During the repair process, if there is cracking on the surface before final setting, it can be treated with a single wipe and press.

5. If the width of the crack on the floor is between millimeters and millimeters, the crack position should be cleaned first, and then the cement mortar should be stirred in a ratio of 1:2 or 1:1.

The cement mortar is then applied to the cracks, and it needs to be flattened and cured. If the width of the crack on the floor is more than millimeter, it should be grooved along the crack position, cut into a figure-eight groove, and then use clean water to clean the groove, and then stir the cement mortar in a ratio of 1:2, and then apply the cement mortar to the crack position, and to smooth it, and then use epoxy cement to embed the crack position.

There are many reasons for cracks in concrete floors, or they are more complicated. Among the main reasons: 1. The foundation is not done well.

If the foundation is not done well, there will be the problem of uneven settlement, which will lead to cracking of the concrete. 2. The expansion joint was not cut in time or the expansion joint was not cut at all. In this way, because the expansion joint is not cut in time, or the expansion joint is not cut, and the concrete shrinks, cracks will occur.

3. Cracking caused by untimely maintenance or improper maintenance. After the concrete is poured, there will be a process of solidification, this process needs to be cured, if there is no water in time, or the water is not sufficient in the solidification stage, the concrete will not be completely solidified, the label is not up to standard, and the cracking will be produced in serious cases.

The above are the three main aspects of concrete pavement cracking. The subject can find out the reason by comparison.

1. Causes of cracks:

The 5 main causes of cracks:

1. Structural cracks (structural settlement);

2. Expansion cracks;

3. Curing cracks;

4. Stress cracks;

5. Creep cracks.

2. Crack generation and prevention

1 Structural Cracks:

a.It is mainly due to the uneven settlement of the foundation that is not compacted or caused by uneven stress;

b.Performance: It usually occurs between adjacent plates, wall edges, column feet, etc., and there is obvious concave and convex feeling at the cracks;

The opening is wide, wide at the top and narrow at the bottom, running through the entire plate.

c.Pre-control measures: According to the design requirements and construction specifications, the foundation needs to be backfilled in layers and compacted (the degree of compactness is greater than;

Adding a force transfer rod between adjacent plates; The column base is preset to separate the separator from the floor, etc.

2. Expansion cracks;

a.Due to the mismatch of concrete expansion or reinforcement, the expansion joint is not reasonably arranged, and the rear cutting joint does not reach the design depth.

The most common crack problem;

b.Manifestations: Regular cracks in plates 1 2 or 1 3;

c.Pre-control measures: reasonable allocation of steel bars and adding nylon fibers to concrete, reasonable design of cutting joints and cutting depth.

In place, the collapse degree and water-cement ratio of concrete can be solved by strictly controlling it. It is generally recommended to add steel fibers, nylon fibers or surface layers of binding steel bars or wire mesh sheets to concrete. In the case that the amount of reinforcement cannot be changed, the spacing of the cracks of the concrete should be reduced, and the recommended size:

The thickness of the concrete is 5 cm, the cutting is not more than 3m*3m, and the cutting depth is more than 4 cm;

The thickness is 8-10 cm, and the cutting is not more than 4m*4m; The cutting depth is more than 5 cm;

The thickness is 15 cm, and the cut is not greater than; The seam depth is 6 cm or more.

The thickness is 20 cm, the cutting is not more than 6m*6m, and the cutting depth is more than 7 cm.

When the surface reinforcement is non-structural reinforcement, it should be cut off, and the steel wire mesh sheet should be cut off.

1. Basal reasons.

The concrete floor is below the base surface of the concrete, and the flatness of the base surface determines whether the concrete plate can be evenly stressed, and when encountering heavy loads, there will be different thicknesses of the plates and different bearing capacity, resulting in the fracture of the demarcation part due to the different strength of the force. 2. Cement problem.

Cement is the main component of concrete, is the guarantee of concrete strength, if the use of expired cement or unqualified cement products, the concrete floor will be very prone to cracking and sand and dust drawbacks.

3. Aggregate problem.

Aggregates need to be added to concrete, mainly sand and gravel, but there are many choices of aggregates, and the size and material are different. If you choose fine sand and gravel (such as fine stone concrete used for the surface layer), it will be easy to sand and dust due to the increased shrinkage of the concrete. To reduce the possibility of concrete sanding, materials that are clean, contain less activated silica, and are continuously graded should be selected as much as possible.

4. The problem of water-cement ratio.

Concrete is composed of water, cement, sand, and gravel, and the general ratio is required.

The proportion of solid, liquid and gaseous states is 80%, 18% and 2% respectively. 5. The influence of temperature.

Because the concrete does not conduct heat, the heat dissipation is slow, but when the temperature rises and falls, the internal temperature is still high, and the external temperature of the concrete has been lost. If the concrete floor expands and shrinks externally, the concrete floor will be deformed due to temperature changes, especially when the large-area concrete is not cut according to the standard (6x6).

6. Maintenance issues.

After the construction of the concrete floor, there will be a dry shrinkage reaction in the case of water shortage, so it is necessary to retain water and cure, and surface cracks can be prevented by sprinkling water or using concrete curing agent.

What are the causes of cracks in cement floors? With the development of cement concrete pavement, the hazard of pavement slab cracks has attracted widespread attention, and the cement floor cracks caused by various reasons such as imperfect design theory, unreasonable design assumptions, construction quality does not meet specifications and design requirements, and unqualified materials have seriously affected the quality of pavement, and certain preventive measures must be taken to prevent these.

What to do if there are cracks in the cement floor].

Position joints: cracks that exist at a certain position near the design joints and construction lap joints, and the position joints are divided into three types: artificial lap joints, cut joints, and longitudinal and horizontal joints.

Artificial lap joint: lap joint and joint joint of cement concrete pavement slab caused by construction. Caused by construction gaps, delays, etc.

For example, paving machinery shutdown caused by night rest, mechanized construction paving and paving can not transport pavement mixture in time, and construction discontinuity caused by natural factors.

Cutting joints: Failure to comply with the requirements of the specification, the cutting time is too late, the cutting depth is not enough, the spacing between the cutting joints is too long, or the pouring continuation time is long, resulting in the actual tensile stress generated by the concrete shrinkage is greater than the allowable value of the concrete and cracks near the cutting joint.

Cement floor crack treatment method].

First, we should pay attention to the plate seam treatment process; Second, the embedded pipeline should be fixed in the specified position before watering.

The main causes of transverse cracks in the prefabricated floor slab at the supports:

The deflection of the floor slab under the load is the largest in the middle of the span, and the end of the slab is upturned. If there is no reinforcement mesh that is subjected to negative moments in the concrete layer at the end of the slab support, cracks will occur on the ground surface at the support. If the temperature difference between the floor slab is large during use, the longitudinal shrinkage of the floor slab will also cause and aggravate the damage of this crack.

Due to the uneven settlement, it rotates freely at the floor support, causing cracks on the surface. When the floor slab is installed, there is no slurry or the slurry is not real; Poor quality of concrete grout joints at the end of the slab will cause cracks at the end of the slab. In addition to doing a good job in the construction of the plate joint, the negative moment reinforcement mesh can also be added at the meeting place of the components, and the mesh is arranged below the surface layer and above the leveling layer.

Concrete cement pavement crack repair method].

Slotting repair: Extend the cracks on the pavement, sandwich the cracks in the middle with 2 parallel lines, open a groove with a width of 2-3 cm and a depth of 5-10 cm, clean up the inside and pour the good HX-1 cement pavement crack repair material into the trunking, and compact and smooth it.

Precautions: 1. The cracks should be opened as far as possible so that the stirred materials can flow into the cracks victoriously.

2. The gravel and slag in the cracks must be cleaned and moistened with water, and there is no open water in the cracks during construction.

3. Prepare some small stones, the diameter is in centimeters, mix according to the ratio of 1:1, add water (generally 17%-20%) and stir well. The filling of the cracks must be compacted, but there can be no hollowing.

4. Maintenance: sprinkling water for maintenance within 2 hours, try to keep the surface not dry within 2 hours, and it can be released to traffic after 2 hours.

Through the above learning and understanding, you must now have a certain understanding of cracks in cement floors. Well, I hope today's content was helpful to you.

1. Pouring quality defects.

Second, the concrete curing of the floor slab joint is not in place, or there is no maintenance at all, so that the concrete strength of the slab joint is reduced, and the shrinkage crack will be produced at the slab joint, thereby affecting the shear strength of the slab joint.

3. The ground surface layer is bonded with the floor slab, and under the joint action, its tensile strength is larger, and at the filling joint, because the concrete has shrinkage cracks, the tensile stress here is completely borne by the ground surface layer, and its tensile strength is very low, and the ground produces cracks. The slab is stressed too early and too much.

Fourth, in the construction and use, the floor load is too large, and the action of the construction load may crack at the joint of the slab.