Thanks for the vids. I'm not sure "water is good for concrete, or doesn't care" is accurate. In a controlled environment that may be true, however with corrosion from polluted rain (the lime in concrete is dissolved with acid rain), expansion and contraction (especially with freeze thaw cycles), and biological processes that may be encouraged to grow in damp conditions, water is pretty bad for concrete; these are examples of what I've encountered that caused degrading concrete structures.

That said, I was thinking about it more and things like dams and drilled t shaft concrete piles are obviously exposed to constant water. I'm wondering if what I experienced has to do more with exposure to aerobic and temperature fluctuating environments as opposed to drilled shafts and dams which would be more isolated from those conditions I described above.

Even if water itself isn't the primary mode of failure, I guess my point still remains regarding the vegetation of "green"buildings; roots and what not definitely will start to degrade concrete.

Thanks for the comment, it gave me some points to think about.