Grinding Concrete help - Enough

[mbruckner87]

I have a new concrete floor that I have been grinding for the last 8 hours. Roughly 400 sq ft
It seems that no matter what direction or how many times I go over it it still has darker spots.
I have attached a few more pictures for reference.

Could i have a bad blade on the grinder? Is this ground enough for polyurea flooring?

Thanks in advance.

 

[F-22]

Sorry can't help you much in this regard, but I just wonder how a full grinded, polished and sealed concrete floor would hold up compared to epoxy or PU. I have some 70's grinded concrete stairs in my house that are still pretty much like new, and I know normal tiles wouldn't hold up as well.

 

[benwah]

Those dark spots are low spots in the floor that the grinder is having difficulty touching. It wasn't finished very flat, looks like.

Look really closely at the dark spots, are there grinder swirl marks/scratches in them?

The only way to get those consistent with the rest of the floor is to either hand grind them, or just keep grinding the high spots down until they get touched... Which I wouldn't recommend because you'll hate your life.

 

[Armorpoxy]

We have found that on floors like this as long as you have a good scratch pattern and no loose or flaking areas you should be ok to coat without issue. Make sure though whatever you are using to use the proper matching primer since the floor has very uneven porosity so the first coat evens out this issue.