Pave′ment.
The hard covering of the surface of a road or foot-way.
According to Pliny (A. D. 79), “pavements are an invention of the Greeks.”
As usual, he forgets
Egypt and is oblivious of
India and
China.
Sosus of
Pergamus (founded 283 B. C.) made ornamental mosaic pavements representing natural objects.
The first Roman pavement in blocks of diamond (rhombal) form was laid in the temple of
Jupiter Capitolinus during the third Punic war.
The
Greeks invented (says the same author) terrace-roof pavements, and he gives the following directions for their construction : —
“Begin with two layers of boards crossing each other and nailed together at their extremities, to prevent warping.
Next place a layer of pounded pottery and lime; upon this place a layer of broken pottery with a large proportion of lime, one foot thick and rammed.
Another layer of pottery three parts, lime one part, is laid down, six fingers in depth.
Square stones, two fingers thick, are laid on this on a slope of 1 1/2 inches to 10 feet. Then polish the surface.”
Pliny gives a formula for pavement which has the ordinary appearance of the ground when in the rough, but may be polished to resemble marble : —
Upon well-rammed ground place a layer of broken crockery, above this a layer of charcoal well trodden down with a mixture of sand, lime, and ashes, making the upper layer a depth of six inches.
Strabo informs us that the city of
Babylon was paved at a very early date.
The date assigned (2000 B. C.) is perhaps fabulous, though it was quite within the capacity of the builders of the city walls, palaces, and the bridge across the
Euphrates, to pave the city in good style.
Isodorus says that the Carthaginians had the first paved streets, and that their example was soon copied by the Romans.
Appius Claudius, the censor, constructed (312 B. C.) the road named after him, the
Appian Way, which was, on account of its excellence, called the
queen of roads. This was about ten years after the death of
Alexander the
Great.
The time, however, when the streets of
Rome were first paved cannot be determined with certainty.
We are informed by Livy, that in the year of the city 584 (about 170 B. C.), the censors caused the streets to be paved from the ox-market to the temple of
Venus.
The extravagant
Heliogabalus caused the streets around the palace or on the
Palatine Mount to be paved with foreign marble.
Streets paved with lava, having deep ruts worn by the wheels of carriages, and raised banks on each side for foot-passengers, are found at
Pompeii and
Herculaneum.
Roman country roads were 8 feet wide on the straight lines, 15 feet at angles.
Cattle might be driven on each side, if not fenced in.
Abderahman, the khalif of
Cordova, Spain, caused the streets to be solidly paved, A. H. 236 (A. D. 950), and a man might walk after sunset ten miles in a straight line by the light of the public lamps.
700 years after this,
London and
Paris were unpaved and had no public lamps.
The capital of
France was not paved in the twelfth century, for Rigord, the physician and historian of Philip 11., relates that the king, standing one day at a window of his palace near the Seine, and observing that the carriages which passed threw up the dirt in such a manner that it produced a most offensive stench, his majesty resolved to remedy this intolerable nuisance by causing the streets to be paved, which was accordingly done.
The orders for this purpose were issued by the government in the year 1184, and upon that occasion, it is said, the name of the city, which was then called Lutetia, on account of its dirtiness, was changed to that of
Paris.
In 1641, the streets in many
quartiers of
Paris were not yet paved.
Dijon, at that time reckoned one of the most beautiful cities of
France, had paved streets as early as 1391; and it is remarked by historians that after this period dangerous diseases, such as dysentery, spotted fever, and others, became less frequent in that city.
The streets of
London were not paved at the end of the eleventh century.
It is related that in the
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1640]
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Wooden-block paving. |
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1641]
year 1190 the church of St. Mary le Bow, in Cheapside, was unroofed by a violent wind, and that four pillars, 26 feet in length, sunk so deep into the ground that scarcely four feet of them appeared above the surface of the soft earth forming the bed of the street.
The pavements of this great city appear to have been gradually extended as trade and opulence increased, though the period of their first introduction is unknown.
Several of the principal streets, among which was Holborn, were paved for the first time in 1417.
Smithfield cattle-market was first paved in 1614.
Blocks of wood set endways are a common pavement in
Russia and
Germany.
Blocks of wood or stone inclosed in iron frames were in use in
England thirty or forty years ago.
In 1812,
Loudon suggested laying cubic blocks on a foundation of flag-stones, or cast-iron plates on a bed of mortar.
George Knight (
Loudon, P. 3720),
London, 1829, suggested laying the granite blocks on a macadamized foundation.
This, with grouting for rendering the pavement water-tight, and with under-drainage, is pronounced by
Loudon one of the best modes of paving.
Lieutenant Brown (
England, 1830) suggested a gravel foundation, dressed blocks of granite laid in mortar and grouted.
One form of the
London pavement has granite blocks 6 × 4 inches on a bed of gravel, filled in with grouting, and solidified by a hot liquid cement of gas asphalt.
A part of
Broadway, between Chambers and Warren Streets, was laid in 1835 with hexagonal wooden blocks.
Various foundations were tried: cobble-stones, flagging, and macadam.
The upper surface of the pavement was coated with a layer of tar and gravel.
An English patent, 1838, describes tapering wooden blocks boiled in tar and doweled together.
A subsequent English inventor aggregated his blocks in clusters in iron frames, which were fitted together.
In
Parkin's English patent, 1840, the blocks are placed at angles of from 40° to 70°. The surfaces of the blocks were channeled, and they were cemented together in the pavement, their interstices being filled with pitch.
Sand or ashes and tar was used in the foundation.
Previous to 1841, a system of foundation-boards was exhibited in New York, and in 1841 the blocks were interlocked by notched shoulders.
A pavement has been suggested, composed of iron perforated in such a manner as to afford a footing for horses, and to permit the sweepings to fall through upon a sub-pavement made of cement and depressed at the center, so that the offal can be swept therefrom to the sewers by simply flushing with water.
It is said to have been put in operation in
St. Louis.
Cost, $3.66 per square yard.
Knight's patent consisted of blocks made of iron run into molds packed with hot granite fragments.
This saved metal, which nevertheless could be run into form, and the granite gave the requisite roughness to the wearing surface.
Among the pavements now in common use may be enumerated:—
Ashlar, consisting of squared blocks of stone, generally granite, usually 12 inches deep, 8 to 12 long, and 5 to 7 wide.
Asphalt, a foundation of coarse broken stone and a top dressing of finer stone and perhaps sand or gravel, all cemented together by an asphalt.
Belgian, similar to ashlar, but of smaller blocks.
Bowlder, irregular stones brought to a comparatively even surface by resting on an uneven foundation of sand or gravel.
Cobble, stones naturally rounded, and of nearly equal size, rammed down in a bed of sand.
Concrete, similar to asphalt, except that tar or pitch is used, sometimes in conjunction with natural asphalt.
Granite, blocks of granite, either ashlars or irregular broken stones from the quarry.
Slag refuse from the furnace, sometimes concreted; at other times run into molds to form blocks.
Wooden, blocks sawed to an even length, set endwise to the wear of travel.
Macadamizing was named from the inventor, and introduced in 1824.
It consists in substituting broken granite for gravel as a top dressing, and is much superior to the latter for country roads, but will not stand the heavy wear of city travel.
Haussmann laid 1,250,000 yards of macadam in the streets of the city of
Paris, as a substitute for the stone blocks, the material of barricades in revolutions.
In the
Snow pavement no natural asphaltum is used; the raw coal-tar is treated with sulphuric acid, and mixed with lime and cement, and is said to produce a compound similar to the
Neufchatel rock.
The
Scharff pavement uses bitumen and the heavy tar-oils for the base, bitumen and a small quantity of natural asphaltum for the top courses.
The
Vulcnite pavement makes
Trinidad asphaltum the basis of the composition, treating the same with sulphuric acid or sulphur and cement.
The
Neufehatel rock pavement has a base of a concrete of broken stone and bituminous or asphaltic compounds.
This base being perfectly dry, a coating of that peculiar formation known as the
Neufchatel rock, and which is a natural and intimately combined mixture of asphaltum with calcareous matter, is spread in a powdered state, well heated, and compressed by beating down with heated cast-iron pestles into a hard, smooth mass.
The compression is completed by heavy rollers.
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Concrete pavements. |
Fig. 3575 shows three varieties of concrete pavement.
Solid concrete and asphaltum pavements are hard and elastic; are not affected by the alternations of heat and frost; they have no joints to encourage the growth of weeds and accumulation of filth are therefore free from dust and mud. They dry in a few moments after a rain, are smooth, and yet not so even as to become slippery, especially when occasionally sprinkled They afford an easy, noiseless, and pleasant drive; decrease the cost of keeping the street in repair, by confining the latter to the top dressing; and effect a large annual saving in horse-flesh and wear and tear of vehicles.
The
Nicolson pavement, which was among the first wooden pavements used extensively in this country, consists of a foundation of boards laid flat upon the ground, and a superstructure of blocks sawed to an even length of 4 to 6 inches, and 2 1/2 or 3 inches thick.
The blocks are laid across the street, and secured by a thin strip of board nailed at the bottom, reaching not quite to the surface.
The space thus left above the strip is filled with fine gravel, to afford a holding surface to horses' feet.
The whole then receives a top dressing of tar. Another form has alternate short blocks, the spaces filled with gravel.
Numerous varieties of wooden pavement have been patented in the
United States, and some of them are very extensively used.
Plate XXXVIII.
shows forty varieties of patented pavement.
The difference between them lies in the form of blocks, method of laying, foundation, and chemical treatment or otherwise of the wood.
The greatest enemy to wooden pavements has been dry-rot from below.
The surface of a well-laid pavement soon becomes water-proof from dust beaten into the pores of the wood, and if sufficient incline is given to the surface rain will flow off as from a roof.
Dampness from below is drawn into the blocks by capillary attraction, and the lower part of the blocks crumbles into dust while the shell on top remains perfect.
To prevent this decay, compound pavements, which exclude the absorption of the moisture of the soil by means of a layer of asphalt, would seem to offer more chances for duration than
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1642]
any other system, especially if the wood has been chemically treated.
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Compound pavements. |
Of these compound systems used, two forms are shown in
Fig. 3576, one employing square blocks and the other round blocks on a concrete foundation.
See wood, preservation of.
