The thin-layer mortar test block shrinks. Is it the water-reducing agent that causes the shrinkage to be so severe?

L

Luis

Member
The thin-layer mortar test block has shrunk and has not dried after being left overnight. Is it because the water-reducing agent contains that causes the shrinkage to be so severe?
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How much water should be added?
Early shrinkage is mainly due to the amount of water added and aggregates.
 
From the picture, there is only one crack on one side. Did the scraper press the edge when making the mold test?
 
Thin-layer repairs that are too thick will dry slowly and contain many retarding ingredients, including water-reducing agents, cellulose ether, and redispersible polymer powder.
 
155 water, 170 cement, 70 white powder, 40-70 mesh sand 380, 70-120 sand 380. The additive manufacturer compounds the admixture. The water-reducing agent should contain many ingredients, about 30 grams less than those made with cellulose ether. Is it a problem with the water-reducing agent? I have never used any water-reducing agent when making mortar before.
 
Luis said:
Thin-layer repairs that are too thick will dry slowly and contain many retarding ingredients, including water-reducing agents, cellulose ether, and redispersible polymer powder.
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I suspect that too much retarder was added.
 
Shrinkage is mainly due to high water consumption. Mud content also has a significant influence. If the test block is inaccurate, you can use the standard if you really want to test.
 
There isn't much water at 155; it's time to catch up with the grouting material.

Whether the contraction is severe or the retarding time is extended, this problem generally does not occur with standard maintenance.

Thin-layer mortar is not suitable for this kind of test block. Free water evaporates quickly, and the test block will not harden for a long time. Shrinkage is inevitable, especially for mortars with fast surface film formation. This is more likely to happen. Replace the large potato flour with fly ash.
 
The amount of cement you have needs to be more significant. It will lose strength when it dries. There is too much water-reducing agent.
 
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