According to Bob Morrison :
In a previous post Chris Lewis wrote...
If the OP thinks he's got a good chance to avoid having to use rebar,
using fiberglass fiber reinforcement works quite well (not as well as
full blown rebar, but...), and is _much_ cheaper than rebar or mesh.
Cheap insurance for marginal situations.

The jury is still out on the effectiveness of fibermesh in preventing
random slab cracking. Fibermesh does give fuzzy slabs. In my opinion,
you will get better results by simply increasing the cement content and
reducing the water content at roughly the same cost as the fibermesh.

My garage slab (machine polished fibermesh, 32'x24'x4") isn't fuzzy...

The fibermesh was $50. Are you going to make an equivalent difference
with upping the concrete content by $50 worth?
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.