I am General Contractor, but working alone and simply can't take big concrete job as concrete will not wait for me to finish like the pavers did.
Anyway, what I know about good concrete is that it needs to be vibrated to release air bubbles and be really strong.
I did vibrate several smaller pads and they never had even haircracks.
I hire contractors to lay 300 tons of my house foundation and it took 7 people to pour concrete with vibrators. No cracks.
But when I observe other contractors working in the area - they never use vibrators.
So I yet have to see pad in CA bigger than 8' with no crack on it.
We do have very nasty clay here who in summer can develop ground cracks big enough to slide your hand in.
Once more time I will recommend recycled concrete base rock.
Our county is selling it for like $14 a ton, so next to nothing and I have my RV driveway done with it like 15 years ago, still semi-solid and easy to blow the leaves from.
