Iron has been and continues to be a relatively cheap material when it comes to construction. This material is difficult to mine but easy to obtain because it is so plentiful in the Earth’s crust and recycling the metal proves to be easier but not all iron is worth recycling. Sometimes the metal is so cheap that salvaging it from old ships and other large structures outweighs the value of the metal and it is instead sunk or buried whole after the more valuable metals are removed. So, why not make it a little more useful by increasing it’s volume of use in something that is beneficial and unique.
I propose that we engineer custom plates of steel that are two to three inches thick to use as a roadway surface. Each plate section mates up to an identical plate to create both sides of a roadway with all the proper slope and traction requirements. These plates are then welded to each other but are held in place by spikes and hooks on the bottom and at the sides. A steel road would have all the same benefits of a concrete or asphalt road but would be more durable and easier to repair as fractures can be healed with simple welding.
So, that’s my idea in general. Go ahead, steel it.