Pavement, flat stones or 'flags,' seldom exceeding 4 inches in thickness, used for covering footpaths, courtyards, kitchens, &c. (see FLAG-STONES). The name is also given to the stone covering of the carriage-way of streets. The Romans paved both their streets and their highways with stones in a most substantial manner, but until the 12th century mediæval cities were almost all unpaved. At Pompeii the stone pavement of the narrow streets remains in the same state as it was before the city was destroyed, and shows the ruts made by the bigæ or carriages. It is formed of polygonal blocks of stone, like cyclopean masonry, the largest pieces being about 3 feet across the face. This kind of ancient Roman pavement, the remains of which are found at other places in Italy, is laid on a carefully prepared basis or foundation, sometimes composed of several layers of suitable materials.
Modern streets in Europe and elsewhere are still most largely paved with hard stones of various kinds, roughly dressed into oblong blocks, say 12 in. by 4 in. and 6 in. deep, and smaller sizes. These are generally laid on a foundation of sand or very fine gravel, sand being also used for filling up the joints. But the jointing is now sometimes done with pitch. Granite and some varieties of Basalt (q.v.) are extensively quarried for these paving-stones.
Wooden pavement consists of pieces of wood (in northern Europe usually that of Pinus sylvestris) about the size of paving-stones, laid end up on boards, with asphalt or concrete below them, and with the joints of the wood blocks pitched. Vehicles make least noise on this kind of pavement, which, though expensive to maintain, if under heavy traffic, continues in favour. Asphalt pavement is also a good deal used both for foot and carriage ways. It is described under ASPHALT. Both this and wood pavement are apt to be slippery in wet, and the latter in frosty, weather.
For foot-pavement a Portland cement concrete has been much employed of late years. Small stones, such as granite, crushed into small chips like beans, or not much larger, are mixed with the cement, which is laid on a bed of broken whinstone or 'road-metal.' Pavement so made is cheaper than when flagstones are used, but longer experience of it is necessary before we can say that it is in the long run more economical. The frequent necessity for lifting pavement when laying down or repairing gas or water pipes is a great drawback to the keeping of it in good order.