What is another alternative instead of steel which currently use in concrete?

While no alternative has become a standard to replace steel, materials like engineered timber and metal composites are becoming more common in new construction projects. Timber companies tout wood as a durable, renewable resource, and engineered timber is gaining some traction as an alternative to steel.
Composite materials like Fiber Reinforced Plastics (FRP) and alternative metal alloys are gaining popularity in commercial construction, as well. Composites can be more durable than steel, and repairing damaged composite components is often less
costly and requires less heavy machinery