Ook wrote:

-snip-

Maybe I should have bought redimix?

I think I used the wrong term there- so just so we're both thinking
about the same thing. I'm talking about the bagged concrete that has
all the ingredients. They actually make one for setting posts. I
think the difference is in type of cement- If I remember correctly
it says on the bag- 'place post- dump in hole- moisten'. One bag per
hole- simple.

I'm thinking the cracking was
because I didn't use enough cement powder, and premixed concrete might
have saved me the trouble. But what is done is done, and it's only 8
posts.

Amen- It isn't brain surgery- and chances are everything will be fine.

I'm doing 20 more this weekend, and this time I'll mix it 5:1
instead of 6:1. But I already had the pile of aggregate, so all I
needed was cement powder. I don't know who pre-mixed it or where it
originated from. I got it from my neighbor 2 years ago, and he had it
for a few years before I took it shrug

For setting posts, it will probably be fine. The last guy I remember
mentioning 'premixed aggregate' was doing a sidewalk. That's tough
enough if your mix is good and consistent- but without knowing how
much stone vs gravel you've got it is nigh impossible.

Jim