What s going on with cracks in concrete floors?

Causes of cracks in cement floors.

1.In terms of materials: the cement grade is low or the cement is expired, which affects the strength and wear resistance of the ground; The sand particles are too fine, the water secretion of the mixture increases, and the mud content of the sand exceeds the standard, which affects the adhesion between cement and sand. The aggregate gradation is not good, so that the mixture produces segregation.

2.The dispatch (slump) of the mixture is too large: the water-cement ratio of the mixture is too large, resulting in coarse aggregate precipitation and mortar water leakage; At the same time, during the hardening process of mortar and concrete, excess water evaporates, forming a large number of capillaries, which reduces the mechanical strength of the ground.

If the water-cement ratio is too large, it will also delay the time of ground calendering, which will become a potential factor for ground sanding.

3.Calendering time too early or too late: the purpose of cement floor calendering is to make the ground dense and smooth, generally calendering three times to survive, but only at the appropriate time to carry out this process, in order to receive the expected effect, too early or too late will cause sand on the ground.

Method Step 1:

First of all, you need to make sure that the cement used is hot cement that has just been milled, because the cement that has just been ground has a large shrinkage when it sets and hardens.

Moreover, the mixed use of cement of different grades on the same floor will also cause surface cracks due to the different shrinkage amount during coagulation and hardening.

Method Step 2:

The thickness of the sand will also have a certain impact, the finer the sand and the larger the surface area, the amount of cement slurry adsorbed on the surface of the sand will increase accordingly, and the strength of the cement mortar will decrease under the condition that the amount of cement remains unchanged.

The excessive mud content in the sand causes the volume of the soil in the cement mortar to shrink during the hardening and dewatering process, resulting in cracking of the floor surface.

Method Step 3:

After the cement mortar is finally set, the hydration will continue, and in the season of high temperature and dry air, if it is not cured or cured in time, there will be dry shrinkage cracks in the cement surface layer.

Method Step 4:

If the soil quality of the backfill is poor or the ramming is not solid, the ground will produce uneven subsidence and cracks when the ground surface layer is completed.

In addition, when you are doing large-area cement mortar ground construction, the structure will be deformed without leaving construction joints, which will cause the ground surface layer to crack.

Pure cement floor cracks, the smaller reason is caused by the quality of the cement and the level of the master, and the more likely is that the cement floor cracks caused by the floor breaking and sinking are not solid when the ground is leveled.

It is very likely that the quality of the cement is seriously poor, it may be because the temperature is relatively high, or it has been used for a long time, so cracks appear.

It may be that the quality of the cement floor is not very good, and some bad materials are used, and it may also be because it has been too long, so the cracks will appear.

This is because the masters are not rigorous enough when smoothing the cement, and when mixing the cement ash, it is not well integrated, so it will crack after drying.

If there are cracks in the cement floor, then you can observe the width of the crack, if the width is between 2 mm, you can choose to use the injection method to make the code to repair, directly use AB resin repair glue, you need to clean the crack, and then inject the glue directly into the crack, so that you can repair. If the crack width is relatively wide, then the crack needs to be cleaned up, and then it can be repaired with cement mortar, and the surface should be smoothed, and the surface of the cement mortar should be maintained after drying, mainly to keep it moist in order to better decorate it later.

Cement floor polishing is still very good, and the advantages of general cement floor polishing are still more, mainly the following points:

1. Cement floor polishing is more wear-resistant, and can improve compressive strength, in addition, it can also play an anti-weathering effect, and the cement floor can also be hardened after polishing.

2. If you want to polish, because the original material of the cement floor penetrant will have some precipitation after standing, it needs to be stirred evenly before using it after opening the barrel. Then it is necessary to ensure that the ground is flat and clean, and then the cement floor is sanded with a grinder.

The construction method of cement floor curing agent is as follows: first clean the cement floor, if there are cracks and holes, you need to repair it first, then use a grinder to smooth it, then stir the curing agent, apply it to the ground, wait for it to dry thoroughly and then apply it twice, and finally you can clean the ground and grind it with a grinder to make the ground look more shiny and smooth.

That's all there is to it about cracks in concrete floors. If there are cracks in the cement floor, it may be that the quality of the materials selected during construction is relatively poor, or it may be that the mixing ratio of the mixtures is not right.

1. It has a lot to do with cement. Because when the cement is solidified, a part of the water will evaporate, which will cause the ground to shrink and shrink the cracks, so the ratio of cement mortar back to the cavity is very important, and the cement with slightly higher strength must be selected, and at the same time, it is necessary to mix correctly according to the proportion.

2. There is also a great relationship with the construction process. If the ground is uneven, or there are cracks, and there are still dust and debris that have not been removed, it will affect the later cracks.

3. It is also directly related to the later maintenance. The later maintenance must not be missing. After the ground hardens, it also needs to be sprinkled with water to maintain, so as not to destroy the state of the surface leakage, and the wetting time should reach at least 1 week.

There are two ways to deal with cracks in <> cement floor. 1.First of all, take out the dirt in the cement cracks, clean them, and then pour the cement curing agent into the cement cracks, to ensure that the depth of the curing agent can reach 3-8 mm; After the curing agent is completely dry, use a sander to polish the ground.

The hardness of cement curing agent is very high, and the wear resistance can reach 289% at grade 8, which is the best material for cement crevice repair. 2.If it is on the first layer, fill the leveling with cement mortar, and then brush it with waterproofing.

If it is on the second layer or above, it depends on the situation of the cracks, and the cracks are at the bottom of the plugging king, and then brush the waterproof coating; If it is underneath, then the cement mortar is blocked, leveled, and then waterproof paint is applied in the same way as the first layer.