Concrete Shrinkage strain

[ajk1]

For a standard concrete mix made with 40 mm coarse aggregate, 25 MPa, southern Ontario aggrgates, high range water reducer, what shrinkage strain range should be expected? I am told 0.05% to 0.07% by a concrete supplier, but for a concrete with 40 mm aggregate that seems to me to be rather high, particularly if it is at the 0.07% end of the range. That is what I would have thought would be the case with 20 mm coarse aggregate.

Any comment?

I am well aware that lower shrinakge concrete (less than or equal to 0.04% as specified in CSA A23.1) can be achieved, and have successfully used it on a number of projects, but that comes at a premium cost to "standard" mixes and is meeting some resistance from our client.

 

[asixth]

Don't concrete suppliers normally have test results for their mixes of which I would think that should have a shrinkage tests. If possible, ask a local supplier, they might be a bit reluctant to give results unless you are purchasing the concrete.

 

[ajk1]

to asixth - no they do not. They only have it for a realtively few mixes i.e. where they had to determine it in the past for specific project specifications. In general they do not have it. I am on CSA Technical Committee A23.1 and am quite familair with what the local concrete industry does and does not have. On this specific project, they have already told me that they do not have the shrinkage strain for the mix that they propose to use. Perhaps you are in another geographic location where the concrete industry has more comprehensive data of tested mixes...is that what you have found in your location? I am intrigued ... where are you located that you have such sophisticated concrete suppliers?