Concrete Curing 1

[hairman]

Is Oxygen used in the concrete curing process? I am trying to determine the cause of low oxygen concentration in a new concrete manhole. Oxygen concentration was 2% and C02 concentration was 8% in a manhole that was three weeks old.

 

[SlideRuleEra]

No, water is the "active ingredient". Here is a typical article on concrete curing:
ftp://imgs.ebuild.com/woc/C710279.pdf

http://www.SlideRuleEra.net

 

[Ron]

Oxidation does occur during the curing process but not to extent of depletion of ambient oxygen supply. Assuming this is an active manhole, I would look to the influent/effluent as being a probable cause.

Considering the levels you have noted, I would also check the instrument to see if it is reading properly. Two percent oxygen is extremely low. Have you checked for volatiles (methane, etc.)?

Also....try not to "double post" in the forums. This is the appropriate forum for your question, but it is also posted in the ACI Code Issues forum (which it is not).

 

[hairman]

The manhole in question is a water valve manhole with the penetrations sealed with a rubber boot. The manhole was tested with three different monitors and the only gasses that were abnormal were O2 and CO2. Any other ideas?