What is this on my concrete?

[av1]

These are some pics of a basement garage floor that was prepped using a diamond grinder, acid etched then top coated with apolyaspartic urethane. I can't figure out what the "diaper rash" is from. It's almost like small strings of something embedded in the concrete.

Scott....can this be lightly sanded down a little without compromising the integrity of the polyaspartic? Am I farther ahead to just leave it alone & pretend it's some sort of anti-skid? I think adding additional coats, at least enough to bury the imperfections, will be cost prohibitive. Is there an easy fix?

Over all, I'm very happy with the project. Any thoughts? Thanks....Scott

 

[clutch93]

I'm no expert, but it looks like you have fiber re-inforced concrete and now that you used a diamond grinder on it, it's exposed and showing more because of the stain that's been applied.

 

[jdaallen]

I'm no expert, but it looks like you have fiber re-inforced concrete and now that you used a diamond grinder on it, it's exposed and showing more because of the stain that's been applied.

I agree completely. The same thing happened in or shop and it was the fiberglass fibers in the concrete.

 

[stafford]

Look at as a traction adder. doesn't look bad to me

 

[LegacyIndustrial]

I am with the boys. Looks like fiber in the crete.
I thought perhaps it was a cheap roller linting, but it's pretty consistent.

The only remedy would be to de-gloss and re-coat.
Frankly, it looks like a light skidproofing.

 

[av1]

I am with the boys. Looks like fiber in the crete.
I thought perhaps it was a cheap roller linting, but it's pretty consistent.

The only remedy would be to de-gloss and re-coat.
Frankly, it looks like a light skidproofing.

That area already has 2 coats. When I receive my order this week I was planning on just applying a 3rd coat. I need to de-gloss it first? I did not do that between the 1st & 2nd coats. How do I do that? with sandpaper? I guess I was under the impression I could just throw on an additional coat........

 

[LegacyIndustrial]

That area already has 2 coats. When I receive my order this week I was planning on just applying a 3rd coat. I need to de-gloss it first? I did not do that between the 1st & 2nd coats. How do I do that? with sandpaper? I guess I was under the impression I could just throw on an additional coat........

All these coatings need something to hold them together. When you re-coat (prior to a full cure) after the first coat you get a chemical bond. When you try to re-coat after the first coat has completely cured you don't get the chemical bond any longer.

You need to create a mechanical bond and that can be done by lightly sanding the floor to the point that the gloss is gone. Clean it and re-coat.
This can be achieved with a pole sander and a little elbow grease.

Anything short of this is a dice roll.

 

[av1]

Scott....if I use a sander to grind the bumps down, will it compromise the clarity of what I have now? I've got a couple of electric sanders....what grit would you think?

 

[LegacyIndustrial]

120 grit for scuffing off the gloss.
You could go a little more abrasive and try to level the imperfections.
Be careful with the small electric sander. They have a tendency to create low spots.
Make sure you do everything evenly.