How was early macadam different from modern paved roads?
Macadam roads, developed originally in England and France, are named for the Scottish road builder and engineer, John Louden MacAdam (1756-1836). The term “macadam” originally referred to a road surface made of clean, broken, or crushed ledge stone (from a flat shelf of rock), that was rolled over and flattened by a heavy weight. The gaps between the stones were filled with stone dust and the entire surface was “set” with water. In the next era of roadbuilding, bituminous material (tar or asphalt) was used. This new type of surface was called bituminous macadam. The terms “plain macadam,” “ordinary macadam,” or “waterbound macadam” were then used to describe the old type of madacam. Plain macadam surfaces are almost never constructed now in the United States. This is because they are expensive; in addition, the stones become…
