Basalt is a pretty amazing material. This is just one use. Basalt is also used to make insulation, low skid tiles, and corrosion resistant pipe liners.
It's what it sounds like: rebar made from basalt (basalt fibers specifically): melt the basalt, extrude it, mix it with polymers, shape into a REinforcing Bar.
Problem's it's way more expensive than steel. It's also a pretty young material so I don't know how much safety and longevity information we have. Steel's well understood.
The expense is an upfront cost. Using basalt rebar we could be building 100 or 150 year bridges instead of 50 year bridges. We know basalt concrete structures wont fail from the reinforcement rusting away. We just haven't been using basalt rebar long enough to know the long term failure modes.
Basalt rebar does not have the tensile strength of steel rebar. During extreme stress, steel rebar allots time for escape, increasing the survivability of an event. The behavior of basalt is significantly different.
Just different materials, with different performance profiles, that you can use to beneficial effect in different environments. But you have to know and understand the implications of the different performance profiles.
I'm not going to do a whole engineering lecture here, but there is a really good concrete nerd who can outline this, and so much more, for you on his youtube channel if you're interested. He's a good engineer and I've been impressed with the accuracy of the material he presents as well as the accessibility with which it is presented.
