Ask for advice on gravity mortar formula?

[Ramon Doria]

I'm a novice. I'll ask you for advice
Sulfur aluminum Cement425:350kg
PO 425:50kg (ordinary portland)
1.18-2.36 machine-made sand: 300kg
0.6-1.18 machine-made sand: 150kg
0.15-0.6 natural sand: 100kg
Silica fume: 20kg
Ground Calcium Carbonate: 30kg
Polycarboxylate superplasticizer: 1.8kg
Defoamer: 1kg
Tartaric acid: 2kg
Lithium carbonate: 0.3kg
Plastic expansion agent: 0.5kg
Question 1kg
Since there is no gypsum powder and the mortar has settlement, the effect is improved by adding Ground Calcium Carbonate. However, 2-3 minutes after mixing, the mortar still has settlement. After mixing again, the situation is improved. How to adjust

Question 2

The fluidity loss is fast. After about 25 minutes, the mortar has not been initially set, but there is almost no fluidity. Tartaric acid can not be added any more.

 

[Ankur]

Have you got the cement upside down? concrete segregation, go back to test the sand gradation

 

[Luis]

Sulfur aluminum cement 425:350
PO 425:50
1.18-2.36 machine-made sand: 110
0.6-1.18 machine-made sand: 300
0.15-0.6 natural sand: 150
Silica fume: 30
Anhydrous gypsum: 10
Polycarboxylate superplasticizer: 2.0
Defoamer: 1
Tartaric acid: 2
Lithium carbonate: 0.3
Plastic expansion agent: 0.5,
Try it. Make it according to this ratio.

 

[Daria]

Your sand proportion is not correct. It should be better if you turn it upside down. If the settlement fails to be improved, 400cps cellulose ether can be used for low mixing, and the strength will drop a little. The high ratio of sulfur aluminum cement and tartaric acid counteract each other. In my previous test, XXX sulfur aluminum cement was added up to 200KG, and the remaining PO cement was added, and then the rate of tartaric acid can be greatly reduced.

 

[anna]

The cement is not right. Try less sulfur aluminum cement and more PO42.5R cement. Less medium sand, more fine sand, try about 250kg medium sand. Fine sand 330kg. There is no need to add ground calcium carbonate and gray calcium. Add some hardening agent or anhydrous sodium sulfate.

 

[Rony]

Sedimentation is also a factor of large loss of fluidity; too high silica fume content will also affect, its effect on suspension and prevention of segregation is weak, use cellulose ether will be better; in addition, too much coarse sand will cause poor fluidity.