How do I determine the fiber content in cured FRC?
How do I determine the fiber content in cured FRC?
(OP)
My client suspects that the fibers are forming clumps when the fiber reinforced concrete is placed. I need to determine if this is the case. Are there any test methods available for determining the fiber content per area of concrete? Any suggestions or references are appreciated.





RE: How do I determine the fiber content in cured FRC?
You may find that the client decides that all is well !!!
RE: How do I determine the fiber content in cured FRC?
What would I do with the cores to determine the fiber distribution?
RE: How do I determine the fiber content in cured FRC?
RE: How do I determine the fiber content in cured FRC?
RE: How do I determine the fiber content in cured FRC?
As far as a test method for determining clumping, petrographic analysis cannot be beat. But, be prepared to spend some cash, as petrographic tests can run as high as $500 each, and you will need to run at least 3 to prove it.
RE: How do I determine the fiber content in cured FRC?
RE: How do I determine the fiber content in cured FRC?
Good luck.
RE: How do I determine the fiber content in cured FRC?
This is in lieu of a better established method for forensic analysis of your fiber content. You could order small amounts of concrete, one w/ no fiber at all, and one with an unacceptable low/high amount of fiber, and one with an acceptable amount. Have all other variables stay the same- company, mix design, ect. In this case, I would hire two inspectors- one at the batch plant to verify the mixes, and one on site, for sampling. You can either sample the mixes directly or take cores from a similiarly-finished slab. Take samples/cores, and make a visual analysis. Here a thin section may be more valuable- you might even be able to do a sort of fiber-count, or some similiar analysis. Thus you would have have a convincing visual model for the acceptability limits of your fiber, and whether the cores in question fall in that range. If the project is still ongoing, you could take samples from active pours if you're sure to have one inspector at the batch plant verifying batch weights. It would save the cost of ordering trucks special for the analysis, though ordering small amounts of concrete is relatively cheap, compared with the price of litigation. I know this analysis would be an easy task for my lab, though we'd have to outsource if we thought a thin sections were necessary. I think this would be a convincing method, for lack of an ASTM.
Anyway, just a though. Best of luck.