I am wondering that where could be more friction, whether on a concreted road or tarred roads. My question is that which road will have less wear and tear of tires, the concreted or the tarred roads?
I think the concreted road surface is more closely packed than the tarred roads. So it can provide more area of contact. Hence there will be more frictional force as frictional force depends on the area. But in the case of tarred roads there will be irregular shape of rocks, hence it may provide some additional force other than friction. So the frictional force is reduced on the tarred roads. Friction is the reason for the wear and tear of roads, therefore tarred roads will have less wear and tear for tyres
I can't really answer this. But I think the concrete road will have more sharp edges that make tiny cuts in the tires, and the tar will be a little bit sticky and pull at them in multiple directions.
The tar might tend to slightly dissolve in the tire and vice versa. Would that make the tire wear faster or slower? It would surely reduce miles-per-gallon, to the extent it really happens in hot weather.
It looks complicated. Better to get experimental data than try to sort out the theory.
Here is one experiment where they paid a lot of attention to a lot of things. I can't immediately judge whether they ignored important variables, but they at least went to a lot of effort not to. They are using not regular asphalt but asphalt that has waste rubber mixed into it.