We made a few small test mixes of our own to see how we could best handle concrete containing steel fibers but we had trouble with clumps of fiber in the mixes. Is there any way to avoid them?
This phenomenon, known as "balling," is normally avoided by shaking the fibers into the mix through a screen after all the other ingredients have been added. Another method is to utilize the kind of fibers supplied in bundles of 20 or 30 plain or deformed strands glued together side by side. They can be added with the aggregate without passing through a screen and are said to eliminate trouble from balling. The glued strands become separated from one another during mixing.