4 ms·

Something I recently learned of is basalt fiber rebar. It won't rust, but I guess on a long enough time frame it will devitrify. https://en.wikipedia.org/wiki/

• vlehto 11y ago
  Thanks for the info, I learned something. The trick usually in reinforcing is that you need to find two materials that have relatively equal heat expansion coefficient, while the fiber needs to be lot stiffer than the matrix. Luckily concrete is quite "springy" compared to most metals and ceramics. In composite structures the ultimate strength of the fiber is often not the limiting factor. The limit is how large share of the load is carried by the reinforcement, which is proportionate to the ratio of Young's moduli of the matrix and the fiber (+ fiber length, average direction and volumetric proportion). Steel has almost same expansion coefficient as concrete. Basalt is significantly lower. So it would probably best suit reinforcing in stable climates or used as relatively short fibers. You would not want hundreds of meters long basalt fiber rope to be pretensioned inside concrete bridge, as the rope might crumble the surrounding concrete at hot weather.