EARTH, SAND-CLAY, AND GRAVEL ROADS. 65 



cut is more than 500 feet from the center of gravity of the corresponding fill, 

 overhaul will be allowed for the entire amount of material in the cut for the 

 actual distance in excess of 500 feet. 



Drainage structures. — [Insert specifications for necessary drainage structures.] 



SPECIFICATION FOR SAND-CLAY ROAD. 



Subgrade. — The graded roadway shall be brought to the elevation, alignment, 

 and cross section indicated for subgrade on the plans, and shall be maintained 

 free from ruts and other depressions until covered with the surfacing material. 



Natural sand-clay surfacing. — The engineer will designate suitable places for 

 obtaining natural sand-clay mixtures for surfacing. 



All unsuitable material that may overlie the acceptable material shall be 

 stripped off and removed, and this work will be paid for at the unit-price bid for 

 stripping, measured in excavation. 



The natural sand-clay mixture shall then be excavated, hauled to the road, 

 and spread. All excavation shall be so conducted that the pits will be left in 

 good and sightly condition, and that, where possible, provision will be made for 

 draining the pits without additional excavation beyond their limits. 



Hauling.. — The hauling shall be done in wagons of approximately uniform 

 capacity, and the loads shall be dumped at such a distance apart as will give 

 the amount of material required to construct the surface according to the 

 proposed cross section. 



Spreading.— -The surfacing material shall be immediately spread on the pre- 

 pared subgrade to such depth that the surface, when compacted, will conform 

 accurately with the profile, alignment, and cross section, as shown on the 

 drawings. All subsequent loads may then be hauled over the surface thus 

 formed. 



The construction of the surface shall begin at that point on the road nearest 

 the source of material and be continued from such point. In hauling over the 

 material as deposited, wagons will be required to use the entire width of sur- 

 faced roadway so as to compact the whole section as nearly to a uniform 

 density as possible. The teams will not be permitted to follow a single track 

 or to form ruts. 



Finishing. — After 500 or 600 feet of roadway have been thus roughly con- 

 structed the surface shall be cut up and pulverized to a depth of 2 or 3 inches 

 with a plow or harrow and at the same time the shoulders on each side of 

 the surfaced portion of the road shall, if necessary, be sufficiently loosened to 

 permit of a smooth regular crown being constructed from shoulder to center 

 of road. 



When the roadway has been loosened sufficiently, the surface shall be worked 

 with a road grader or drag to the true cross section required by the plans. This 

 operation shall be repeated daily until the entire surface becomes smooth and 

 firm. 



Mixing sand clay. — In case the natural sand-clay mixture, as found, does not 

 contain a sufficient percentage of either sand or clay to give a durable surface 

 there shall be spread as much of the deficient material as the engineer may 

 direct, and this shall be thoroughly mixed and incorporated with the material 

 previously spread. In places where a natural mixture is not available suitable 

 amounts of clay or sand shall be hauled, spread, and mixed as directed by the 

 engineer. 



The process of mixing may require plowing to a depth of 6 or 8 inches and 

 harrowing with a disk or tooth harrow, and this work may be required in wet 

 weather. 



61531°— Bull. 463—17—5 



