There are many pores on the self-leveling cement surface!

[Johnson]

po42.5 cement	305
sulpho-aluminous cement	75
baked sand 70-140 baked sand 40-70	400 50
coarse whiting	150
anhydrite	40
hpmc	0.8
Water-reducing agent	1.2
tartaric acid	0.9
Sodium gluconate	0.6
Wacker 5010	5
defoaming agent	0.8

The self-leveling surface I am making with this formula has many pores. Is it a problem with my gypsum raw materials?

 

[Shamil]

Does the interface need to be done better? Roll on the interface agent twice and then do the self-leveling. The problem is caused by the base layer not being sealed.

 

[Allen]

For such big bubble, it is a matter of substrate. However, looking at the surface texture, the viscosity appears high.

 

[Cassie]

Generally, the amount of water added for self-leveling is 25%.

There are several bubbles on the surface because there are holes in the base surface, and they are not sealed properly, which will not affect the final efficiency.

The problem with your construction can be seen on the surface. The obvious bleeding should be that the layer has already formed, and the water surface has already reached it.

This formula needs to be adjusted:
1. The total water volume is high. The dosage of ordinary Portland cement can be lower; otherwise, the shrinkage value may be significant.

2. The two retarders can be used together, but Sodium gluconate are not recommended when using tartaric acid. Your opening time is not a big problem, which can be seen by looking at the surface. Moreover, too many retarders can also easily delaminate.

3. Cellulose ether does not necessarily play a decisive role in bleeding. You need to test other methods. Consider adding a little microsilica powder.

4. Do not use 40-70 medium sand. According to the amount of coarse sand in your formula, the water you add should be around 20~22%.

Overall the formula is good.

 

[Rony]

Judging from your bubbles, they are crater-shaped, which may be more related to the substrate. Regarding base treatment, how long did it take for your interface agent to be self-leveling? It would help if you considered whether the interface agent is arid. In addition, you can add more defoaming agents, as 0.1-0.2%.

 

[Ankur]

What viscosity do you use for hpmc here? The bubbles' surface tension is high and not easy to break. This may be related to the viscosity. In addition, the water consumption is a bit large. The self-leveling we produce is controlled at 24% of the water added.

 

[Luis]

The overall formula design is fine. Look at the initial setting time and whether the defoaming agent is performing poorly or the amount added is insufficient.