محصبة

Also known as makadam, macadamized

thumb|An illustration of the first macadamized road in the United States between Boonsboro, Maryland|Boonsboro and Hagerstown in [[Maryland in 1823; in the foreground, workers are breaking stones "so as not to exceed in weight or to pass a ring".]] Macadam is a type of road construction pioneered by Scottish engineer John Loudon McAdam , 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 keep dust and s