Air Content

[Rinku12]

hi,

We are using sika concrete on one of our project site. The specifications on the bag ask for air content 7% (+/- 2%). We are using pressure test to measure air content. Its a SCC mix. We performed two tests and we are getting 4.5%. The project is in Northern Ontario region. I know its is measure of more of durability against freezing and thawing but I would like to hear from experts opinion for the situation like this as I am off from my range. Let me know.

Regards

 

[RobertJeffery]

@Rinku12, Northern Ontario receives less freeze/thaw cycles than Washington, DC where they routinely specify 5% +/- 1%. 4.5% air content will not be an issue I suspect, adding a disclaimer that I am not an engineer, just experienced with placing concrete.

To help others to answer your question perhaps a description of use and location within the project site (i.e. sidewalk repair, etc.) where the concrete is being placed is in order.

 

[Rinku12]

@RobertJeffery, Thanks for your response . The concrete is placed as second stage concrete for the vertical embedded parts of gate structure. The total cross section area I am placing is about 0.7m^2 ad the height i am placing is about 9m. The is close to kapuskasing town in Ontario and this town is 1.0 hr from Timmins city, Ontario. Also to add this concrete will always be under water.

 

[dik]

In Winnipeg... we have two freeze-thaw cycles a year and it is common to spec 6%+/-.


Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[CarlB]

Dik-I've seen you post something similar before. Sounded quite unlikely to me...

I found this weather-nerdy blog that says Winnipeg has more like 75 cycles per year.

http://edmontonweathernerdery.blogspot.com/2019/03/freezethaw-cycles-part-2-versus-round.html

 

[dik]

Just the number of freeze-thaw cycles... I may have exaggerated a bit. We do have cold winters and we typically use 6% air...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Ron]

FYI...dik has a hell of a lot more experience with concrete than the weather nerds. Listen to him,.

 

[dik]

Ron... I was trying to be funny about freeze-thaw... with our winters it seems to freeze in November and thaw in April... just seems like a long cold winter. The exaggerated cold conditions are so unlikely that I wouldn't have bothered to research it.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik