Have been around aviation for decades, but more on the periphery of homebuilts, so forgive me if I am discussing something that is either common knowledge or already disgussed. BTW: I did try a search here. In another world, my passion is to eliminate steel as a re-inforcement in concrete (at least steel as a bar). The absolute best solution is to make carbon fiber bar, but you can guess the cost issues involved. The second best choice - and not that far away in values for carbon - is basalt. Basalt fiber has been around for a while, but lately production methods have managed to drop the price a bit. There is one concrete rebar manufacturer that uses it now - has been accepted under the same approvals as for glass fiber, but is far stronger material and much more chemically inert. The aviation question came as a result of someone asking me about the properties of basalt fiber as they wanted to investigate it for manufacture of radomes. I will measure some electrical properties on basalt/epoxy samples, but beyond that, I am not sure where to go or what to suggest to them. Since, let's face it, just about anything "new" in genav was tried and understood first in experimental aircraft, I was hoping there was a bit of knowledge in the composite side of homebuilding. After all: "better" than glass and cheaper than carbon should be something that makes sense in aircraft construction, shouldn't it?