Floor pores?

[Kaizen]

Getting closer to doing my floor so i'm really trying to pin down the prep work and make sure I have it right. Currently when I pour water on the floor I hear bubbles popping briefly. The floor was poured last fall and i'm just now finishing the roof to be dry inside. No cracking at all. 4k mix. power trowel finish except for some rough patches that I have to grind.
Is it safe to say that although the floor feels smooth it does that bubbling thing that its porous enough to not need grinding on the whole thing? I will be etching it and using a primer in hopes of not needing to worry about bubbles in the epoxy.
also I have a 30x36 area with one garage door presently and one man door. Am I just asking for trouble using a power washer and trying to get it all out the one garage door? It definitely has some dirt as its been exposed for a year.

 

[Shea]

Generally speaking, power troweled floors do not react as effectively to acid etching as floors that were not power troweled. It doesn't mean, however, that a good acid etch won't be enough. You will have to test it after it is completed.

If you have areas to grind anyways, you would better off just grinding the entire floor. That way you know the floor will be properly prepped. You will have a great foundation for a coating with the combination of the grinding and epoxy primer.

 

[Kaizen]

The area of issue is only 10x10 or so. We ran short on concrete and it took a while to get another truck. We ran into cold night and I ended up with some issues on that section i'm hoping grinding will help.
How do I test after the etch to see if its enough? I thought since i'm hearing bubbles it was porous and therefore plenty of tooth for the primer to bond to?

 

[Shea]

No, hearing bubbles has nothing to do with it. Once you etch the surface and it has dried, you should have a rougher feel to the surface - similar to 120-150 grit sandpaper. Do water drop tests in multiple areas. If a water drops immediately turn the concrete a darker color and get absorbed rather fast, then you are good to go. If the water sits on the surface for a while before being absorbed or beads up, then you have more etching to do.

 

[Armorpoxy]

One note on this pour is that you most likely have now two different porosities which can be noticeable with an epoxy due to different absorption rates unless you prime first with the matching primer for the epoxy you buy.