Work of Maintenance Broken-Stone Road

Rolling.

In the spring after the frost goes out, the road bed is soft and porous; and a thorough rolling with a steam roller at this time, before the subgrade is dry, is one of the best and cheapest methods of keeping a stone road in good condition. Just before this rolling is the time to add a little fresh surface material. here and there, as may be needed to fill up slight depressions. For precautions to be taken in filling these depressions, see § 385.

Sprinkling.

While water in excess is an enemy of crushed stone roads, moisture in a moderate quantity is a great benefit. Moisture is necessary to preserve the cementing power of the binding material, and also to prevent an excessive removal of dust by the wind; and therefore sprinkling to the measure required to prevent these injuries is an advantage. The water should be applied in a fine spray, and not be allowed to run in streams on the road; that is, several light sprinklings are better than a single flooding. If sprinkled too heavily or too often, the road is softened and breaks up easily.

Sprinkling is usually employed on park drives and city streets. where it is generally conceded to be true economy, without taking into consideration the prevention of dust; but on account of the expense, it is likely to be many years before this refinement is adopted for rural roads. The cost of sprinkling will vary greatly with the cost of water and the length of haul. It has been esti mated that the annual expense of sprinkling country roads would be $75.00 per mile.* In some localities, particularly in California and at the seaside summer resorts in New Jersey, broken-stone roads have been sprinkled with crude petroleum to prevent dust. The oil is applied hot, with a sprinkler, when the road is dry, and only in such quantities as will be readily absorbed. An elastic cushion is thus produced, which is practically impervious to water, and which holds the dust and screenings from blowing and washing from the surface and reduces the wear due to travel. From 50 to 60 barrels per mile are required for the first treatment, and about 20 for each subsequent application. Two or three applications are made per year.

Removal of Mud.

Considerable material must be re moved from the road surface. Traffic grinds the road metal into dust, mud is brought in from the unpaved side-roads, and the horses drop a large amount of dung. All superfluous dust should

be removed for the comfort of both travelers and adjacent prop erty owners. However, to prevent the surface stones from work ing loose, it is customary to keep the surface of the road damp by sprinkling, and therefore the detritus to be removed is chiefly in the form of mud. The removal of the mud prevents the formation of tracks, and therefore greatly decreases the tendency to produce ruts. An accumulation of mud retains water, which softens the road and increases the wear.

The more sticky mud is removed with a shovel or a special mud scraper; and the more fluid mass is removed with brooms. A laborer by hand can ordinarily clean 700 to 1,000 square yards per day. The sweeping should not be so thorough as to remove the binding material from between the surface stones.

Mud-scraping machines are upon the market which consist of a series of narrow spring scrapers, and which will clean 5,000 to 6,000 square yards per hour at a less cost than can be done by very cheap hand labor. It is necessary to use them with great care, to avoid loosening the surface stones. Machine brooms are usually employed for this work where the road is cleaned at frequent intervals. The ordinary form consists of a cylindrical brush or broom about 16 inches in diameter and 7 feet long, attached beneath the axle and connected by suitable gearing with the wheels of a vehicle drawn by one or two horses. The axis of the broom is set horizontally at an angle of about 40 degrees with the axle of the vehicle. When working, the broom rests firmly on the surface of the 1 'avement or road-covering and revolves in a direction oppo site to that of the wheels, sweeping the dust sidewise from a strip about 5i feet wide and leaving it in a ridge behind the rear end of the broom. In using this machine upon a broken-stone road, the precaution should be taken to see that the brush is not too stiff. What would be entirely suitable and in all respects well adaptetl for sweeping pavements of stone blocks, wood, or asphalt, might injure the surface of a broken-stone road by penetrating too deeply, thereby loosening the stones at the surface and destroying the bond. The detritus is deposited on the side of the road, and subsequently removed in carts or wagons.