Steel in concrete is mainly there for it's tensile strength and to resist moment.
There will come a day imo when an extruded polymer or composite material - with enormous strength but much lighter, will replace steel in almost all concrete structures.
It will replace the steel tendons used in bridges, tanks etc and it will provide the crack control that steel does now.
Ditto for steel structures, columns and beams.
And it will be made with a combination of common materials like carbon, silicon etc.
I can also see a day when maybe carbon nano tubes or something similar are mixed in the concrete when it's batched and it replaces the need for any steel in raft slabs, footings etc.
There already is fibre concrete but this would be much stronger.
Technology and research and education will enrich and employ us forever, steel mills will not.
