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Efflorescence (leached white, "frosty" crystalline salt bloom deposit)
2

Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

(OP)
I am looking for a concrete addmixture to eliminate efflorescence from appearing with out jeopardizing strength & durability in plastic concrete and morters. I have seen some products that claim to controll it but, do they totaly eliminate it from appearing? If anyone knows of such a product that really works please let me know your help is much apprciated thank you.

RE: Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

The white stuff is calcium hydoxide and can be eliminated with a reduced permeability in concrete.  You can use pozzolans such as silica fume or fly ash to reduce the permeability of concrete.  A reduced water to cement ratio will help as well.  Super plasticizers can help to acheive the workability you need with a reduced water to cement ratio concrete.

RE: Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

(OP)
Thanks mkashi for the tip. Do you know of a particular product I could use that has these quality's that you spoke of?

RE: Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

Well, I don't know if fly ash is available in your area.  This is the least expensive alternative.  You should use clean type F fly ash with a free Carbon content of less than 4%. Fly ash with Carbon content of more than 4% will work as long as you are not using plasticizers or air entraining agent.  The free carbon in fly ash will prevent the action of these admixturs.

Good Luck
Mohsen

RE: Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

Metakaolins are another pozzolan that can be used.  Lime is the culprit as mkashi mentioned. Pozzolans react with the lime which takes it out of the equation. As a result of the pozzolan and lime react yielding a stronger mortar. Pozzolans are very fine particle sizes compared to cement and as a rule of thumb their use lowers permeability.

RE: Efflorescence (leached white, "frosty" crystalline salt bloom deposit)

(OP)
Thanks for the tip hornet2 your tip was well recieved.

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