I came across an interesting old thread on 18th century Irish roads, and it got me wondering about the changing nature of road-surfaces.
I cannot find much information online about the history of materials used in road construction, except for this Wikipedia article on the History of Roads in Ireland -- it mainly deals with routes and networks, but it does say that at the time of independence, "most road surfaces were made up of undressed and unrolled water-bound macadam which did not use tar as a sealant. "
I assume the use of tar grew rapidly from the 1920s onwards, with the popularity of the motor car.
When did macadam arrive in Ireland, and how widespread was it throughout the 19th century? Were the famine-relief roads made using the macadam method, and what kind of machinery was used to roll these surfaces, if any?
How old are the cobblestones in places like Temple Bar, Dublin; and how widespread was this method of road-building in the cities?
If you know of any book or journal article on this topic I'd be grateful