Quote:
Originally posted by southernfriedcj
After the concrete was poured(about a 20 months ago) I sealed it with a clear sealer(to keep it clean during construction and to slow the cure). I also had fiber added to the mix(to control micro cracks). Now I have a hairey slab. I acid washed it, and the sealer didn't allow etching. I pressure washed it, and the fibers didn't break off. I'm thinking a floor machine(buffer), with a fine screen will take the fibers down, and possibly cut most sealer off.
What would you reccomend?
Thanks, Jim
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JIm - you do have 2 problems on your hands.
Concrete curing compunds are usually chlorinated rubber based, (unaffected by acid washing as they are acid-resistant) and serve the function of retaining moisture in the concrete as it cures, to improve surface strength. Ideally this is a good thing - as most of the problems with coatings are usually related to the weak surface - all coatings will bond well if proper prep is done... However, when you know a coating is going on, it is better to use alternate curing methods - what is referred to as a "wet cure" - ie - cover the slab with burlap bags and keep the burlap wetted with a hose for the first 7-14 days - it achieves the same thing as a sealer. Alternately, use polyethelyne sheet over the slab to retain the moisture during the 1st 7-14 days.
Nonetheless, you have a sealer - the only way to now address this is by mechanical removal means such as the previously mentionned shotblaster or scarifier - these machines mechanically abrade the surface, removing the sealer in the process, and providing an ideal surface for subsequent coating - check in your yellow pages for a professional for this - try the concrete floor finishers section.
Use of a buffer with a coarse grit may also achieve this - I do not have experience with this equipment for this purpose - I suggest you evaluate your existing sealer with a magnifying glass, and then try the buffer and recheck - you will have to make the dermination as to whether it comes off - if you go this route, let me know what you find - it is probably worth trying, as the professionals will cost you probably $1.00-1.50 per SF for shotblasting - maybe more due to small area upcharge - these guyts are often doing 5-10000 sf at a go.
As for the fiber reinforcing - this again a good thing in theory and makes for a better slab - unless a coating system is going on. The usual method to resolve this is to rent a propane "tiger torch" - you see hot asphalt roofers using this equipment - try your local industrial rental equipment shop - it blows out a flame from a 4-6" wide mouth that is 8-12" in area - and burn the hairs off - they are polypropelyne and will melt easily.
Try the buffing first, or if you go with the professional use the professional mechanical means first - I think you will find the fibers are still there - then do the tiger torch.
Good luck,
