What causes the cracking of ordinary plastering mortar?

[Ankur]

The plastering mortar cracks at the base laye. How to solve this situation? After the plastering and surface finishing, the surface will not crack.

 

[Ankur]

This is a sample photo.

 

[Daria]

From the picture, it looks like the powder is too much or the sand gradation is not good, too fine. No water retention agents added. Maybe there are no additives at all. Cement is mixed with sand on site, and the mud content of the sand is relatively high.

 

[Luis]

Too much powder and unreasonable gradation of sand in the formulation.

 

[Ramon Doria]

This kind of crack is generally plastic cracking. Had the crack happen right after workers putting the powder on the wall? What kind of sand do you use? Is the mud content too high?
Is tailings or the floor ash is used or material is stored for too long?

 

[Ankur]

From the picture, it looks like the powder is too much or the sand gradation is not good, too fine. No water retention agents added. Maybe there are no additives at all. Cement is mixed with sand on site, and the mud content of the sand is relatively high.

It is unlikely that there are no additives, it is possible that the mud content is high, only the base layer is cracked, and the surface is not cracked after finish

 

[Ankur]

This kind of crack is generally plastic cracking. Had the crack happen right after workers putting the powder on the wall? What kind of sand do you use? Is the mud content too high?
Is tailings or the floor ash is used or material is stored for too long?

It took half a year to find out the reason. The biggest problem was that the mortar contained a lot of powder, and the temperature of the drying sand was too high, and the water lost quickly after being placed on the wall. The temperature of the mortar after adding water can reach 40 degrees.

 

[Rony]

The cracking caused by this plastic shrinkage is generally based on the difference in water consumption, water retention additives and different walls.
Is there a phenomenon that the brick wall cracks more than the shear wall? The cracking time is generally at the end of the surface.
It has little to do with the thickness of the mortar

 

[Shamil]

For this kind of crack, first of all, you have to consider the powder and mud content of the mortar. Initial observation, the powder content is too high, shrinkage cracks, if the construction site is in the tuyere, it will also crack, the water loses too fast.