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Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam c. 1820, in which crushed stone is placed in shallow, convex layers and compacted thoroughly. A binding layer of stone dust (crushed stone from the original material) may form; it may also, after rolling, be covered with a cement or bituminous binder to ...
John Loudon McAdam, 1830, National Gallery, London. John Loudon McAdam (23 September 1756 [1] – 26 November 1836) was a Scottish civil engineer and road-builder. He invented a new process, "macadamisation", for building roads with a smooth hard surface, using controlled materials of mixed particle size and predetermined structure, that would be more durable and less muddy than soil-based tracks.
Tarmacadam is a concrete road surfacing material made by combining tar and macadam (crushed stone and sand), patented by Welsh inventor Edgar Purnell Hooley in 1902. It is a more durable and dust-free enhancement of simple compacted stone macadam surfaces invented by Scottish engineer John Loudon McAdam in the early 19th century.
A road of such material is called a "metalled road" in Britain, a "paved road" in Canada and the US, or a "sealed road" in parts of Canada, Australia and New Zealand. [ 48 ] A granular surface can be used with a traffic volume where the annual average daily traffic is 1,200 vehicles per day or less.
This method involved spreading tar on the subgrade, placing a typical macadam layer, and finally sealing the macadam with a mixture of tar and sand. Tar-grouted macadam was in use well before 1900 and involved scarifying the surface of an existing macadam pavement, spreading tar, and re-compacting.
The macadam road was extended to Kensington by 1927. [5] MD 192's original western terminus was at St. Paul Avenue, which was the original course of MD 193. [6] The highway was extended west along Metropolitan Avenue and Plyers Mill Road—MD 193 (now MD 185) was relocated around the center of Kensington after its grade separation of the ...
St. Augustine Road was paved as a macadam road from George Street to the right-angle turn by 1910. [3] The remainder of the road to St. Augustine and MD 310 east of St. Augustine were constructed as a 12-foot-wide (3.7 m) macadam road by Cecil County with state aid by 1915. [4] [5] MD 342 was resurfaced with bituminous concrete in 1988. [6]
The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the wearing course and sometimes an extra binder course. If there is a sub-base course, the base course is constructed directly above this layer.