Fiber concrete question

[wef]

We are getting ready to put down Epoxy-Coat in the 784 sq. ft. garage. I, mistakenly, used fiber in the concrete. We just did the etch and this morning I'm out there looking for the hairs I'll have to burn off and I don't see anything. Are they easily visible? I've even used a light and magnifying glass but see nothing. It looks like it's been etched OK, very clean and dull. Any clue?

 

[brownbagg]

they break off pretty easy so they are proberly gone, but with the epoxy anyway the fiber will lay down, you never see them

 

[pauls340]

IMO, you did not mistakenly use fibre...fibre is good. ACI say any fibre in concrete makes is hold together better and should havefewer dry shrinkage cracks. It's possible the contractor or batch plant went alittle light on the fibre? I paid $90 for fibre in my 5" slab...still haven't found one.

 

[bobscogin]

Same opinion as brownbagg. Unless you used an unusually high dose rate, you'll be OK. They're just polypropylene and won't have any material affect on the coating.

Bob

 

[wef]

they break off pretty easy so they are proberly gone, but with the epoxy anyway the fiber will lay down, you never see them

Should I be able to easily see the hairs? In a square foot should I see many or just a few? I used a torch on several square feet and nothing flared. Epoxy-coat says the floor will look bad if they are not removed so I want to be sure I'm doing the job correctly.

 

[Gary S]

Using fiber is a plus. Not using it would have been a mistake. I used fiber, and sealed the concrete with a cheap sealer. There is no fiber to be seen on the surface because I had a friend with great finishing skills do the finish work on my floor.

 

[bd8134]

I had fiber added in my mix. After acid etch and sweeping I did not see the hairs, though I did not look that close. With the primer/first epoxy coat I still did not notice anything. I added a non-slip 'grit' in my clear coat, its dangerous otherwise in New England. With a shiny finish you might have to be more careful but my floor takes too much abuse to go that route.
If the fiber is polypropylene I would have thought you would still see the hairs after an acid wash, maybe the squeegee I used knocked them off. Maybe you have invisible fibers like mine wef..