I have some concrete sack mix that has gone stale from being exposed
to exterior humidity for too long. I discovered this when the small
step I tried casting was very crumbly 24 hours later. So a few
I'm wondering if the unused bags of sack mix are still useful as an
aggregate mixture. Can they be combined with fresh portland cement to
make a good concrete mix? Or will the presence of the hydrated
portland cement interfere somehow?
Also, what about the crumbly non-concrete? It easily breaks up into a
mixture resembling aggregate and wet sand, so I was wondering if it
too could be combined with fresh portland cement and reused. Of
course, it is easy to imagine that it would be too wet, or the mix of
particle sizes is wrong, or whatever. Note that I'm just casting a
concrete bottom step, so I'd be happy with 2000 psi concrete.