Admixtures play a vital role in improving workability of concrete.
The new construction structure and technology are solved.
There are many kinds of additives, and water retention agent can improve the performance of concrete and a kind of admixture.
But each kind of admixture uses has certain standard, exceeds or does not reach this standard, may not achieve the expected effect, or causes the cost waste.
So the use of additives must be cautious.
The following highlights some water-retaining agents:
The advantage of cellulose ether is the content is not high and comprehensive cost is not high, but the actual effect is obvious.
Usually the incorporation is below 0.05%.
According to the chemical structure of the substituents, they can be classified into cation, positive and nonionic ethers.
According to the viscosity classification of methyl cellulose can be divided into 50 thousand, 100 thousand, 200 thousand, 10 million, etc.
According to the solubility into instant, dissolved water, insoluble water.
But each is different in nature.
Methyl cellulose has twice the result with half the effort to improve the water solubility and workability of concrete, solid packaging production and manufacturing application is very convenient, but if the addition of excessive methyl cellulose will significantly reduce the concrete slump of the actual effect.
The compressive strength and compressive strength of concrete are also adversely affected.
To synthesize the advantages and disadvantages of methyl cellulose, using cellulose to retain water can be the first choice, but the amount should be strictly controlled.
Polyacrylamide can be divided into cationic, anion, but cationic price slightly more expensive.
The molecular content is 7 million, 10 million, 20 million, etc.
In fact, if only to improve the workability of concrete alone, then the use of polyacrylamide is not very cost-effective.
The obvious advantage of polyacrylamide is its flocculation effect, which ensures that concrete does not disperse even in water.
In addition, the negative effect of polyacrylamide is higher than methyl cellulose, such as increase the concrete setting time, reduce the compressive strength tensile strength, static time will be long will also appear.
The advantage is also in addition to the water application, and methyl cellulose compared with the same intake under the actual effect is similar, the cost can be about cost-effective.
Above are two common water - retaining agent, in addition to warm round gum, xanthan gum.
The price of these products is very expensive, the production of paste dissolution is a very difficult thing, first according to a certain proportion of dilution, and then stir evenly, finally can be used for compounding.
Dilution mixing can then be added again to the mixture.
It can adjust the performance of concrete to a certain extent.
But the production process is cumbersome, so the general application is not much.
