Anti-cracking mortar formula, ask for advice

[Luis]

ordinary Portland cement P.O42.5 350

Quartz sand 70-140 mesh 600

Heavy Calcium Carbonate 150-200 mesh 50

Redispersible Polymer powder? 15

Cellulose? 2

PP fiber? 1

Starch ether? 0.1

 

[Scott Kaplan]

You are doing thin plastering, right? The viscosity of cellulose ether is slightly higher, and a thickness of 4-100,000 is more suitable. So 6 kg of RDP is useless. Recommend adding it to 15 kg. Heavy Calcium Carbonate powder can add less. Starch ether can omit.

 

[Cassie]

There is a big problem with this formula structure. Do you make anti-crack mortar for polystyrene board thin plastering or slurry insulation materials?
Generally, the formula of anti-cracking mortar must first have good construction performance and not be too sticky; it must also not crack.
Therefore, the amount of cement in the design is generally about 25%, composite fiber, and RDP, so the material's folding ratio is less than 3. Sometimes even 20% cement content. Therefore, 35% of the cement is the bonding mortar. Anti-crack mortar can be a little weak, and you add thin sand and Heavy Calcium Carbonate to reduce the strength.

 

[Chanliss]

Is there any gradation of sand for plastering mortar?

Too thin, it should be ideal for 40-70 and 70-140 gradation.

If the sand is too thin will cause the wet mortar to become sticky and difficult to apply.

If too thick, it is easy to form chapped.

 

[Ramon Doria]

Is it too much to put 15 kg of RDP? We put up to 10 kg, about 8 kg, and 2 kg cellulose. Therefore, I suggest replacing PP fiber with wood fiber.