Air content in concrete

[kngpenn]

I have a project in which I've just received the concrete mix design. The air content is 10% (by volume). I know the normal range should be around 6% to 7% (if subject to freeze/thaw) so I'm trying to figure out what would be the adverse effects of high air content in concrete. I know it may affect the compressive strength. Does anyone else know what may be other effects?

 

[MiketheEngineer]

It will be lighter!!

 

[JAE]

I also believe with excessive air content you get progressively lower strengths.

 

[concretemasonry]

A 1% range (2% is more common) and non-entrained can considered to be about 1 1/2% without entrainment. This is a very tight spec considering the timing and nature of the test. You are lucky if you actually get totally repeatable results from the same truckload.

When it comes to design, you design for range that is specified and use the history provided. I base this on a "hands-on" 3 concrete credit course in college when we quickly tested a truckload. - A lot of sweat and mess, but it paid off!!

Dick

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

 

[Ron]

Can cause excessive bleeding and lower strengths.