Brick was used to pave roads in Holland as early as the seventeenth century and has been used extensively for both roads and city streets since. Brick pavements are said to have been used in Japan for more than a hundred years. The first brick pavement on a roadway in the United States was laid at Charleston, W. Va., in 1370, and in 1873 the city adopted the system for certain streets. This example was followed by many Central Western cities, but Philadelphia was the first large city to make use of this material, laying some brick roadway pavement in 1SS7.
Wood blocks were laid in New York as early as 1S35-36, and in 1839 wood pavements were al ready in use in both Philadelphia and Boston, be ing mentioned in a report made to the Franklin Institute (Philadelphia ) by a committee on pav ing materials. London laid its first wooden pave ment in 1839; Glasgow, in 1841; Paris, much later.
Stone blocks of the modern type, of 3 X 9 inches, granite, with mortar joints, were laid on Blackfriar's Bridge, London, in 1840. Glasgow laid granite blocks in 1841. A concrete foundation was used in London, the first in that city, in 1872, and tar and gravel joints were employed in both London and Liverpool about the same time, although used in Manchester, England, prior to 1869. Prior to IS49 scarcely any pave ments but cobblestone were used in New York. About 1850 the Belgian blocks were introduced.
Granite blocks similar to those now used were in troduced in New York about IS76, succeeding some much larger blocks, known as the Guidet patent. Concrete foundations for stone pave ments were not used regularly in New York until 1888. Large stone blocks were used in Saint Louis as early as 1818. being from three to Li inches thick, t; to 14 inches long, and 6 to 10 inches deep, set on 6 inches of sand. In 1842 stone blocks of about the present size and shape were used in Saint Louis.
In America the pavements now being laid are principally asphalt, brick, and stone block.
Rock asphalt is used to some extent in Lon don, Paris, and other European cities, and stone blocks are common. Brick does not appear to have gained the footing in Europe that it has in America. There is still another sort of im proved street surface which is very common on roads and on streets of light traffic throughout the United States, Canada, Great Britain, and at least the western part of Continental Europe, namely the compacted broken stone, known ft9 macadam or tellord. See ROADS.
Foundations are to pavements what floors are to carpets: or, conversely, the visible parts of pavements are hut the wearing surfaces of streets.
Failure to recognize the importance of good foun dations has been the bane of most American and many foreign pavements. If the foundation yields, through deficient drainage or bad ma terial and workmanship. the destruction of the pavement follows. In some soils natural drain age is ample. Where it is not. either a drain in the centre or at one or both sides of the street is required to remove the subsoil water. These drains may be of stone, tile, or sewer pipe. ac cording to the relative cheapness of the several materials in the locality concerned and the char acter of the drainage work. Drainage provided. and the surface on which the pavement is to be laid shaped and compacted, the foundation is next put in place. For serviceability nothing surpasses concrete as a foundation. The chief argument against it is its cost, which may range from 50 cents per square yard upward. The thickness of the concrete should rarely be less than six inches, and may run as high as ten inches. Sometimes broken stone, alone, is used for foundation, and again stone, brick, or wood is laid directly on sand.
If the traffic is not heavy, sand, gravel, or broken stone may sometimes be used with a fair degree of success. particularly if the earth be neath is well compacted and thoroughly drained. Asphalt should always have a concrete founda tion, except where laid on top of an existing pavement of some other material, which will form a good bed. The finished surface of the founda tion should he brought to such a curve, or crown, crosswise of the street, as will shed the rainfall to the gutters. A four-inch crown on a street 30 feet wide is considered good practice. Greater widths should have more crown, but the increase is not necessarily proportional.
Cushion coats. composed of one to two inches of sand, are generally placed on concrete founda tions for all materials save asphalt, and also on brick laid flatwise for foundations. They allow the separate blocks or bricks to be brought to a firm bed by ramming or rolling. They also pro vide for uneven depths in blocks or bricks, thus aiding in bringing the finished pavement to a true surface.