Smitty Two wrote:

Concrete fully cures in about a month

The time frame I've always heard is a hundred years. Seriously. Maybe a
moot point since it's a log curve, but hell it's Sunday.

No, it's not a moot point. Air cured concrete has about 30% of it's final
compressive strength in 7 days, about 50% after 28 days, and it gradually
increases from there over years. As you say, very close to a log function.

It's also important to get the correct mix and reinforcement. Cheap concrete
might be 2500psi - better to get 4000psi and then use rebar or steel mesh.