Reuse of stale concrete sack mix
 

Hello,

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
questions:

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.

Thanks, Wayne

Reuse of stale concrete sack mix
 

"Wayne Whitney" wrote in message
...
Hello,

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
questions:

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.

Thanks, Wayne


I think the labor in making the step justifies using known good material,
which isn't very expensive. I would not use the old mix for anything but
fill.

Don Young

Reuse of stale concrete sack mix
 

Wayne Whitney wrote:
Hello,

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
questions:

I'm wondering if the unused bags of sack mix are still useful as an
aggregate mixture.

You will greatly weaken the resulting product. Hardly worth it.

--
Joseph Meehan

Dia 's Muire duit

Reuse of stale concrete sack mix
 

Wayne Whitney writes:

I'm wondering if the unused bags of sack mix are still useful as an
aggregate mixture.

No. Aggregate must be hard material in a certain mathematical population
distribution of relatively large particle sizes from sand to gravel. You
have weak material in very small sizes.

Your sack contains negative value. That is, garbage.