Admixture Dosage ??

[Contech2011]

Hi there,

We have a different mixes with cement varying from 400 to 480 Kgs/ cum. The W/C is kept constant = 0.35 for all the mixes. The mixes are like this

Cement W/C %Dosage

400 0.35 0.5%
420 0.35 ??
440 0.35 ??
460 0.35 ??
480 0.35 ??


Now, the first mix was trial batched and slump was found acceptable @ 60 mins with a dosage of 0.5% of admixture by v/w of cement.

Can you please let us know for the remaining trials for a given slump wheather the dosage of admixture will increase, decrease or remain the same???



With Regards,

Farhan

 

[Ron]

If the dosage is dependent on the amount of cement (which most admixture dosages are based on) then if you increase the cement content, you will logically increase the admixture dosage.

Check with the admixture manufacturer. They know their products better than anyone (or at least they should!).

 

[concretemasonry]

Definitely get some information from the manufacturer of the admix and the cement supplier since there are ranges of properties within the allowable limits that could be important. They have a wealth of test/research information that may be tied to the specific cement being used - both publicly and private. They have a lot of sophisticated labs and test facilities that are always busy on research.

When I traveled internationally, I routinely grabbed local cement samples for friends. It was a bit of a problem getting the white cements through customs.

They are usually willing to supply recommendations, especially if not put in a adversary position against a competitor.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.