The surface of the cement-based water-resistant putty is shiny and delaminates after grinding, forming a psoriasis-like appearance.

J

Johnson

Member
The surface of the cement-based water-resistant putty is shiny and delaminates after grinding, forming a psoriasis-like appearance. How to improve it? How to avoid this problem from construction side?

Here is the formula: 32.5 white cement 15%, redispersible polymer powder 0.5%, cellulose 0.4%, starch ether 0.06%
 
The feature of cement-based putty is that its strength increases slowly, and it is easy to crust. There is a shell on the outside, and the cement particles are relatively thick. , It is easy to powder inside after polishing, but after a long time, the inside strength does not increase and cannot be moved.

There is also a problem with the formula; the amount of cellulose should be higher. Otherwise, the strength will be prolonged.
 
Either use white cement and ash calcium powder together, or use white cement and redispersible polymer powder together.
 
Your cement amount is estimated to be between 150 and 200, and the cellulose is about 3.5. Once it encounters rainy or humid weather after construction, even if it is only a day or two, the surface will be shiny and cannot be polished. Either reduce the amount of cement, assist the use of redispersible polymer powder, or polish within a day after construction, but basically, it will polish the time arranged on the construction site after a week. So when I make this kind of interior wall putty, the amount of cement will be controlled at about 80-100.
 
Nothing is wrong with this formula; how about the construction environment? Don't polish it after too long.
 
Let’s mix some retarder; the strength should be low in the early stage, will benefit the water-resistant bonding in the later stage.
 
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