structural drawings / general notes / concrete non-carbonated
structural drawings / general notes / concrete non-carbonated
(OP)
I'm looking at a set of structural drawings that has a general note in the reinforced concrete section which reads:
--- Concrete shall be non-carbonated in areas exposed to weather.
I've never seen this requirement called out like this so before I ask him what his intent was I wanted to bounce it off you guys.
I understand the basics of carbonation, that it is the result of the dissolution of CO2 in the concrete pore fluid, blah, blah, blah.....
I assume it is engineer’s intent that the contractor place dense concrete of low permeability made with a low water/cement ratio that is less susceptible to carbonation. Since porous and permeable concrete made using a high water/cement ratio is more susceptible to carbonation it should not be used.
However, is it possible to place totally "non-carbonated" concrete? Or is his phraseology just awry?
--- Concrete shall be non-carbonated in areas exposed to weather.
I've never seen this requirement called out like this so before I ask him what his intent was I wanted to bounce it off you guys.
I understand the basics of carbonation, that it is the result of the dissolution of CO2 in the concrete pore fluid, blah, blah, blah.....
I assume it is engineer’s intent that the contractor place dense concrete of low permeability made with a low water/cement ratio that is less susceptible to carbonation. Since porous and permeable concrete made using a high water/cement ratio is more susceptible to carbonation it should not be used.
However, is it possible to place totally "non-carbonated" concrete? Or is his phraseology just awry?






RE: structural drawings / general notes / concrete non-carbonated
Perhaps the designer meant C-XL class, without explaining this sufficiently to the craftsman? Weird for sure... Ask for clarification.
RE: structural drawings / general notes / concrete non-carbonated
Essentially all concrete is non-carbonated at time of placement and curing.
RE: structural drawings / general notes / concrete non-carbonated
RE: structural drawings / general notes / concrete non-carbonated
RE: structural drawings / general notes / concrete non-carbonated
RE: structural drawings / general notes / concrete non-carbonated
There are some factory processes for concrete products that can partially or totally complete the process since they are small enough for equipment to make them or create an ideal environment. Some products are subjected to carbon dioxide and warm temperatures (140F) for 24 hours or to high pressures in saturated steam at 360F that requires about 6 hours including transporting and cooling down (reducing the pressure). The latter is referred to as "autoclaving" that essentially ties up all the free lime immediately.
Autoclaving is better than "autocorrect" because it is managed and controlled. That is why surgical implements in hospitals are "autoclaved" between uses.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.