ACI Recommended ratio of cement / coarse aggregate / fine aggregate?

[StrEng007]

Does ACI have a reference document that specifically addresses the required ratio of cement to coarse aggregate to fine aggregates?

I've found some sources online for ready mix type applications. I'm looking for the requirements for batch plant mixes.

This question is aside from water/cement, air entrainment, and all the other typical durability considerations.

 

[phamENG]

I'm not sure that ACI does. PCA (Portland Cement Association) does, and most things I see labeled as "ACI Mix Design" actually have PCA tables in them.

Design and Control of Concrete Mixtures

ACI PRC 211-22 (I was mistaken, ACI does have a document.)

 

[StrEng007]

I went through a copy of PCA's reference. At first glance there isn't anything that explicitly spells out the recommended proportions by %. I'd have to do a lot of reading through this documents to make heads from tails.

I don't have a copy of ACI PRC 211-22. I'll see what I can make out of the PCA document before moving onto ACI. Too many times I've rushed to buy specs or guides only to find they are so highly theoretical and don't have the actual information I was hoping to find.

Thanks for the information!

 

[hokie66]

You specify the properties of concrete you want and leave the mix design to the concrete suppliers. There are an infinite number of combinations.

 

[StrEng007]

You specify the properties of concrete you want and leave the mix design to the concrete suppliers.

So when reviewing a mix design, the ratio of coarse to fine aggregates is not something the EOR needs to check or regulate?

We check w/cm, aggregate size, air entrainment, slump, etc... I thought there would be some sort of check to make sure they use enough (or a minimum amount) of coarse aggregate in mix.

 

[hokie66]

Sure, you can specify those sorts of requirements: aggregate size, minimum cement content, type cement, etc. But then you will be assuming a certain amount of responsibility for the results, and the price of the concrete will likely be affected. Performance specifications are the norm. But having said that, I have often specified minimum cement content for durability reasons.

 

[lexpatrie]

You specify max aggregate size so you can properly space the rebar.

 

[dik]

and reduce water:cement and reduce shrinkage. I almost never consider reinforcing spacing/.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[StrEng007]

Yes, the things you're mentioning I specify on my general notes.

I talking about reviewing a mix report. If the mix design had an error in which the volume of fine aggregates was disproportionate to the typical accepted range of coarse aggregates, whos fault is that? The concretes mix designer or me, the EOR who accepts it?

I'm trying to define what that typical proportion should be. I've noticed about 30% to 40% of the total volume of cement, wet coarse aggregate, and wet fine aggregates is due to the fine aggregates.

 

[dik]

In Canada, we can either establish a mix design, or leave this to the concrete supplier. There is less liability with the latter.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[dauwerda]

Typically part of the submittal is showing past performance/break results of the proposed mix. If there was an issue with the aggregate proportioning, I would think it would have come out in the historic testing.

 

[lexpatrie]

"usually" there are sealed P.E. stamps on the mix designs, they tend to have expired or be from 1900, but they usually have that. That should put it fairly squarely as under their design purview with you delegating the design of the concrete mix to them based on your review. This is going to drift into shop drawing review stamp language soon, I suspect. "appears to conform".

 

[HTURKAK]

I have the old version of ACI PRC 211-08 . It's scope for high strength concrete fc greater than 6000 psi . I do not have any idea for the latest edition but AFAIK , this guide is not applicable for light weight conc and self levelling concrete.



He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[lexpatrie]

Fine aggregate is more expensive, as I recall, so there's a financial benefit to using coarse aggregate, the two interact for water absorption and other finer details of mix design that we don't much get into as design engineers (specifiers) of the concrete mixes.

To me the maximum aggregate size is of greater concern (effects minimum bar spacing) than the ratio of coarse to fine aggregate, and I'm not aware of any requirements, but they may be in place for an "effective" concrete mix in terms of ability to pump it, pour it, place it, finish it, amount of cementitious needed, etc.

This might be useful:

http://www.ce.memphis.edu/1101/notes/concrete/PCA_manual/Chap05.pdf