Putting old concrete into roads loses almost all of its value and is a pretty atrocious form of downcycling; notice that the linked article is literally about “disposing” of concrete, not re-using it meaningfully. Most of concrete’s primary use case is as a structural material in buildings/infrastructure - beams, columns, slabs, etc, and we unfortunately have very little by way of re-using concrete structurally, partly due to demolition processes, documentation, rebar etc etc. While pre-cast concrete is potentially more up-cyclable, again, it’s not really designed for disassembly, re-assessment, etc, and there are very few actual use-cases/projects that have done anything of the sort, though some very cool research is being done on this at places like MIT and EPFL, including novel pre-cast concrete systems specifically designed for dis-assembly and re-use.

Part of what makes the article and methodology linked here interesting is that it a) uses waste heat which b) is already theoretically able to come from renewable sources and c) can be used to to support manufacturing of structural components further upstream in the lifecycle of cement/concrete.