Maybe our Concrete plants do not get the mix right but here in georgia there are 2 things that are guranteed with concrete. It will not burn and it will crack. The fiber has no bearing on frequency of cracks Here but if you compare 2500 psi with fiber to 3500 psi which cost the same I was told 3500 will out last the 2500 with fiber. Friends of mine owned one of the larger concrete companies here in the Metro area. My info came straight from them. Also not sure why but most of the fiber mixes do leave the hairs showing at the surface on slabs? The good concret guys use rebar, 4500+, and fiber in all of the footings. I have never busted up fiber concrete so you my have a valid point about it making it stronger. Nothing like a real world test.LOL Maybe the guys misinformed me? I am no concrete expert.