[Bicycle Bob]

"Bicycle Bob — One reason I specified basalt is that it bends instead of shattering as carbon fiber will. I know small percentages of graphene make a lot of difference in concrete mix. So — flash graphene in the resin. "

You got me to look up the current data on a range of fibers, and basalt still falls between E-glass and S-glass, but with only 3.15% elongation, vs 5.2% for S-glass. Aramid (Kevlar) only has 1.5% elongation, but its combination of properties causes the resin to fail first, producing a very tough structure in general failure mode. Aramid and Carbon are also about half the density of glass or Basalt. There is a huge and growing variety of carbon reinforcements, but I'm quite wary of their effect on biology as microplastic waste, as they don't seem to be eliminated as easily.