See, gets back to cost of energy. If energy is vastly lower, this allows us to build bridges that last far longer. This is called maturation in engineering land.
If we had ~~~ free energy ~~~ we would pave our roads in stainless steel, not concrete. Poof, goes all those hundreds of thousands of workers who do NOTHING in their lifetime except RESURFACE ROADS.
Um, stainless steel would be a pretty crappy road suface. Sure it may last for ages but it's got much lower friction than asphalt or concrete making it less safe to drive on.
Oh, and I think it would retain heat less well that asphalt or concrete, so it might tend to ice or freeze sooner.
Less importantly it would also make it harder if you have to dig up the road for utility work. Finally I'm not sure how stainless steel would handle roadbed shifting (whether from earthquakes, frost heaving, moisture [whether abnormally saturating or abnormally drying out], etc)
Some of that can be fixed by applying a no-slip coating to the metal plates (like on carrier decks) but the coating is a wear item so you're back to needing people periodically resurfacing (well, now recoating) the road.
Stainless is nice stuff, but its not an answer to everything
Friction coefficient is directly proportional to roughness... As for "tearing it up", well they make these wonderful machines called plasma torches... With energy dirt cheap, it is just as likely that under every street would be a maintenance tunnel where all of the utilities would reside. Power, water, communications. Therefore repair is simple. Could we do this today with concrete? Sure, but the cost would be astronomical. Once done, sure would save enormous amounts of costs later, but initially, ouch.
Frost heaving/moisture content/etc, all you have to do is jam spikes into the ground so the entire road surface is partially suspended. Think of the exact same way that nearly all skyscrappers foundations are built. Long, deep, pilings driven deep into the subterranean ground. Obviously on a road surface one does need to do this. Of course frost heaving is caused by poor road subsurface treatment when the road was built to begin with. So, if energy is free, driving down the cost of transportation and excavation, then excavating poor road materials first becomes palm in face obvious along with bringing in rock creating a stable road bed before the final top waterproof high durability road surface is applied.
Could just as easily go with a silicone carbide road surface or vanadium carbide embedded in aluminum or...
Pretty much the cost of energy ultimately drives the cost of every product everyone touches. Why civilization will remain fairly stagnant until the next breakthrough in CHEAP energy. Might have noticed, the Concorde does not fly any more. Energy costs.
PS. If energy cost for materials truly does cost little, creating a maglev system for all roads should be doable. Combine that with vacuum lines for long distance travel. Drive your maglev car onto a platform, egg encloses, enters a vacuum tube, and blasts you along at Mach 3 or whatever speed is deemed sufficient before the oxygen runs out of your "egg". All of this infrastructure which we could DO TODAY, is ultimate not possible due to the cost of energy required in investment to create the infrastructure in the first place.
