| OCR Text |
Show HOW. DRAGS MAINTAIN ROADS Simple and Inexpensive Device Well Adapted for Producing Smooth and Uniform Surface. (Prepared by the United States Department Depart-ment of Agriculture. The drag is a simple and inexpensive inexpen-sive device for maintaining certain types of roads which when wet become rutted under traffic and which become firm on drying out. It Is also well adapted for producing a smooth and uniform surface on newly constructed roads in which the material used for surfacing Is earth, earthy gravel or some similar material. It is essentially essential-ly a maintenance implement and Its use In construction Is distinctly secondary. sec-ondary. Roads which are very rocky or very sandy cannot be materially improved im-proved by Its use. Properly used at the right time the road drag performs four distinct offices. of-fices. First, by moving at an angle to the traveled way it tends to produce or preserve a crowned cross section. Second, Sec-ond, if used when the material of the surface is not compact and hard, it tends to reduce ruts and otner irregularities irregu-larities in the road by moving material from points which are relatively high to those which are relatively low. Third, when used after a rain it accelerates ac-celerates the drying out of the road by spreading out puddles of water and thus increasing the surfaces exposed to evaporation. Fourth, if the surface material is in a slightly plastic state, dragging Nsmears over and partially seals the so-called pores which naturally nat-urally occur In earthy material, and thus makes the road surface more or less impervious to water. The advantage advan-tage of this smearing action of the drag will be more readily understood if a sample of ordinary earth Is examined ex-amined under a magnifying glass. Such an examination will show that the earth closely resembles a sponge or honeycomb in structure, and the desirability de-sirability of closing the open pores will be readily apparent. If used improperly or at the wrong time, the drag may do actual Injury to a road. Dragging a very dry road, for example, serves to increase the quantity quan-tity of dust and may do additional Drag is Essentially Maintenance Implement. damage by destroying the seal produced pro-duced during previous dragging. If, on the other hand, the road is very wet and muddy, the irregularities in the surface are likely to be increased rather than diminished by dragging. |
