Foundations - ACI 19.3 Exposure Category F

[MJC6125]

What exposure category F do you use for foundation walls and footings per ACI 318-14 Table 19.3.1.1? I see there's a table in the commentary of ACI 318, Table R19.3.1, that sums it up pretty well. But, I'd like to see what other engineers typically choose or think is required per code.

Based on table R19.3.1, it looks like foundation walls can fall into either category F1, F2, or F3.

In my area, frost depth is typically 3'-0" down, and we usually locate the tops of footings at 3'-0" below finish floor. However, since grade is also held down slightly around the building perimeter, I don't think the entire footing is typically below the frost line, therefore I don't know if footings can fall into class F0. I remember when I used to test concrete in Wisconsin, wall mixes were typically air-entrained and footing mixes were not.

My current standard is to have air entrainment in both mixes, however I don't think I'm necessarily meeting the w/cm and minimum fc' requirements.

 

[JAE]

My interpretation:
For foundation walls extending above grade - F2.
For footings below grade - F1

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[MJC6125]

JAE,

Do you always use F2 for foundation walls regardless of how much of the foundation wall may be exposed above grade? For example if you have brick ledge that makes it so brick veneer is exposed above grade and concrete is not, are you still going with an F2 mix design for that foundation wall?

 

[JAE]

Not necessarily for that case - only where the concrete is exposed to moisture, rain, snow, etc.

If the brick ledge is only 8" below grade, then the wall surface below that can still get wet and freeze, though.

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