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the bidder proposing to use brick of such manufacture will not be required to submit samples. The quality of brick furnished must conform to the samples presented by the manufacturers and kept. in the office of the Street Commissioner.

"The Street Commissioner reserves the right to reject any and all bricks which, in his opinion, do not conform to the above specifications.

"Any brick may have a proper shrinkage, but shall not differ materially in size from the accepted samples of the same make, nor shall they differ greatly in color from the natural color of the well-burned brick of its class and manufacture.

"No bats or broken bricks shall be used except at the curbs, where nothing less than half a brick shall be used to break joints.. The bricks to be laid in straight lines, and all joints broken by a lap of at least two inches, to be set on edge on the sand as closely and compactly as possible and at right angles with the line of the curb, except at street-intersections, where they are to be laid as. the Street Commissioner may direct.

"The pavement to be thoroughly rammed two or three times. with a paver's rammer weighing not less than seventy-five pounds. The pavement to be surfaced up by using a long straight-edge and by a thorough rolling of the pavement with a road-roller weighing not less than three nor more than six tons, and when completed to conform to the true grade and cross-section of the road

way.

"All joints in the pavement shall be completely filled with Portland-cement grout. The cement to be of brand approved by Street Commissioner, to be fine ground; eighty-five per cent shall pass through a sieve having ten thousand meshes to the square inch. All cement shall be capable of withstanding a tensile strain. of five hundred pounds per square inch of section, when mixed neat, made into briquettes and exposed twenty-four hours in air and six days under water. All cement shall be put up in wellmade barrels, and all short weight or damaged barrels will be rejected. Cement without manufacturers' brand and other certificate will be rejected without test."

The grout shall be mixed in portable boxes in the proportion of one part cement to one part sand. The cement and sand to be

thoroughly mixed together dry, then sufficient water to be added to make a grout of proper fluidity when thoroughly stirred.

"The grout shall be transferred to the pavement in handscoops, or as the Street Commissioner may direct, and rapidly swept into the joints of the pavement with proper brooms.

"Teams, carts, and wagon traffic and wheeling in barrows, cxcept on plank, will not be allowed on the pavement for at least seven days after the grout is applied.

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The surface of the pavement, when completed, shall be covered with one-half inch of clean, coarse sand of approved quality, which, with all dirt, shall be removed from the pavement and sewer-inlets, by or at the expense of the contractor, at such time, before the final acceptance of the work, as the Street Commissioner may direct."

The following are extracts from the Philadelphia specifications: "The bricks or blocks must be set vertically on edge in close contact with each other, in straight rows across the street excepting at intersections, which shall be paved at an angle of forty-five degrees to the lines of the intersecting roadways, and those in adjoining rows so set as to regularly break joints. No bats or broken. bricks or blocks can be used except at curbs, where half-bricks or blocks must be used to break joints. The bricks or blocks, having been set, must be rolled with the above-mentioned steam-roller. "After being rolled, the surface of the roadway must be true to grade, and show no continuous lines of unequal settlements produced by the roller.

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After being thoroughly rolled, the bricks or blocks shall be grouted with Portland-cement grouting until the joints are filled flush with the surface of the bricks or blocks. The grouting to be composed of one part fresh-ground Portland cement and one part clean bar sand, and mixed with clean water to a consistency that will readily permeate the joints between the bricks."

While brick pavements have been in use in this country for only about twenty years, according to the bulletin of the Department of Labor issued in 1899 there were 18,665,000 square yards in cities having over thirty thousand inhabitants, Philadelphia having the most, with 1,777,123 square yards, Des Moines, Ia., being next, with 1,509,195 square yards, Columbus, O., third, with

1,505,015 square yards, Cleveland, O., with 800,000 square yards, and Louisville, Ky., with 659,733 square yards.

The following are the lowest bids received for brick pavements

at different places in the spring of 1900:

Hampton, Va., May 3....
Olean, N. Y., April 25.
Norfolk, Va., April 25..

$2.25

1.80

2.17

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CHAPTER X.

WOOD PAVEMENTS.

WITHOUT doubt the crudest and probably the earliest form of a wooden roadway was that which is generally known as the corduroy road. This was constructed roughly by laying logs cut to the desired length across the roadway in close contact with each other. This construction was used at low places in roads across swamps, and, while being very rough and uncomfortable, was fairly serviceable and made many of the roads passable which, without this, could not have been used for a considerable portion of the year. This form of roadway is in use now to a limited extent on wood roads in certain parts of New England.

In Alpena, Mich., roadways, and even entire streets, have been graded with sawdust, while in other parts of the State roads have been constructed of charcoal. The method was to pile logs along the road two or three feet high, and burn them in practically the position in which the material was to be used. After the coal was burned, it was raken off and graded down to the required width and depth of the road. This construction gave very good satisfaction, and in 1845 the Commissioner of Patents in his report stated that at the season when the mud in an adjoining road was half-axletree deep, on the coal road there was none at all, and the impress of the feet of horses passing rapidly over it was like that made on hard-washed sand as the surf recedes on the shore of a lake.

Russia, however, is reported to have had the first real wooden pavements, as hexagonal blocks are said to have been in use there several hundred years ago. They could not have been used to any great extent or for any great length of time, as no detailed record is obtainable of them.

In London, Eng., the first wooden pavement was laid in 1839.

This consisted of hexagonal blocks of fir, some 6 to 8 inches. across and 4 to 6 inches deep. They were laid on a foundation of gravel that had been previously compacted. The blocks were either bevelled on the edges or grooved on the face to afford foothold for the horses. These first pavements were not very successful, but others soon followed. Mr. Hayward, the engineer of the Sewer Commission, stated in a report made in 1874 that, counting the size of blocks as constituting the difference, there must have been more than two dozen different kinds of wood pavements experimented with in the city previous to that time.

Another system known as Carey's consisted of blocks 61 to 7 inches wide, 13 to 15 inches long, and 8 or 9 inches deep, the sides and ends having projecting and re-entering angles, locking the blocks together to prevent unequal settlement. Pavements of this kind were laid in 1841 and 1842. They required renewing every three or four years. The dimensions of the blocks were afterwards modified and finally reduced to a width of 4 inches and a depth of 5 or 6 inches, and the re-entering angles were also discarded.

Another system, known as Improved Wood, was first adopted in 1871. On a subgrade a bed of 4 inches of sand was laid, and upon that two layers of inch deal boards, saturated with boiling tar, one layer across the other. The blocks were 3 inches wide, 5 inches deep, and 9 inches long. They also were dipped in tar and laid on the boards with the end joints closed, but the transverse joints were of an inch wide, the space being maintained by pieces of boards nailed to the foundation and also to the blocks. The joints were filled with gravel, rammed, then a composition of pitch and tar was poured in until the joints were completely filled, when the surface was also covered with tar, gravel, and sharp sand." This foundation was somewhat elastic and maintained the even surface of the pavement as long as it was in shape, but when the pavement became pervious to water it settled and became rough and uneven. This was probably the first use of the tar and gravel joint for pavements of any description.

In 1872 a cement-concrete foundation was first used for a wood pavement. The concrete was 4 inches thick and was laid by the Ligno Mineral Co. The blocks were of beech, mineralized by a special process, 3 inches wide, 4 inches deep, and 71⁄2 long, with

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