rebar

I've seen enough rusty rebar inside spalled concrete to have wondered if there's something better than iron rebar. Concrete is good under compression, but has poor tensile strength--metal is pretty good at the latter, and can help provide residual cohesion and strength even when there's been earthquake damage. interesting article on tradeoffs, read it Most concrete lets air and water in, and the rebar rusts, swells, and bad things happen. I'd figure that differential thermal expansion wouldn't be good either (leading to cracking), but the sources I've perused haven't mentioned that as a significant problem.

Of course the first thing I didn't think of was stainless steel, which holds up to corrosion a lot better, albeit at quite a bit more expense. For the rebar, that is.

I wondered about non-metallic rebar, but didn't have wide enough experience in materials science to guess at good alternatives. How about rebar made from basalt melted and spun into fibers mixed with resin? You can guess at some downsides (no sharp bends, more expensive, transverse strength is low compared to steel), and there's some degradation of tensile strength if it gets hot.

Something new every day...