First, never ever use a masonry blade in a circular saw. They are nearly useless. I knew I should have gotten that diamond one and then I could have scored properly, which would have meant this situation wouldn't have happened (a huge amount of concrete came out because it started cracking up to the walls).
Anyway, the main area here including the big chunk with the huge crack is about 5X5. I need to pour 3" thick to get back to how it was originally but I may go thicker if I can.
All of the existing and the new concrete will sit on a vapor barrier. Thus this huge chunk is "floating" on gravel. I deliberately moved it to the left expanding this crack to a thickness of one inch. Can I reuse this chunk? If so, I have another couple I'd like to reuse:
I want to reuse them because then I don't have to dump them but more because I feel it could be a lot easier dealing with fewer bags of concrete and troweling/floating it would be a great deal easier. I'm more interested in doing this right than easy, but keep in mind I've never done it before and it's a one-shot deal, plus I really think of why I shouldn't re-use these (they are not cracked underneath, visibly)
This is a "floating slab" with the 1/2" gap between the wall, which I'll maintain with new forms in the corner.
So can I fill that one inch crack with quikrete or sakrete? Should I instead make it a little wider? I know I can force all the concrete down in that gap.
I was not going to bother putting in mesh to toughen up this concrete because it just may not be the right thing to do.
For curing a guy at Lowes who appeared very knowledgeable said I should mist it every hour for the first several hours, then go down to twice/day. Since I have a ton of left over 6 mil poly would it be better to cover it with that and just leave it for a week? This guy also said use a paint brush to help rub up/paint the new concrete up against the existing edges to help the bond (plus spraying it with water). Seemed like a good idea.
Is the cheap sankrete or quikrete ok or should I splurge on the 5000 psi? I don't need the strength obviously; I just want to avoid cracking. I'm using so few bags the money isn't a huge concern.