3 28 



FARM DEVELOPMENT 



wearing surface of a road is evenness. The materials 

 should be so mixed that the wheel tracks will wear 

 evenly. To accomplish this result requires that a uniform 

 mixture be made and that it be spread evenly and thor- 

 oughly compacted. Thus, 

 in making a mixture of 

 coarse gravel, sand and 

 clay, which should be 6 

 to 12 inches deep accord- 

 ing to the quality of the 

 substructure and to the re- 

 Figure 215. Heavy telford road surface. A, niiirpmpnt^ nf trnt7-p>1 fVi 

 large rock; B, 2 to 3-inch rock; C, 1 to 2- M u 'tS OI travel, trie 



different . materials can be 



put on in layers. The first layer can be put on the sub- 

 structure which has been carefully smoothed with the 

 road machine ; after having been 

 dumped from the wagon or 

 scrapers, this layer may be 

 smoothed off and made uniform 

 in thickness by the blade of the 

 road machine. Another layer 

 may then be placed in a similar 

 manner, and finally the third Figure 216. section of telford road 



,_, , iii surface. A, large stones laid by hand 



layer. Ihe plOW Or disk liarrOW at bottom of road; B, 2 to 3-inch 



rock laid over the large stones; C, 1 



may now be used to thoroughly part^KVS 8Urfacing of sma11 

 mix together all of the layers. 



After each plowing or disking, the common field harrow 

 should be used to level down the surface. By repeating 



the plowing or disking 

 several times, an even mix- 

 Transverse section of telford ture may be produced. If 

 desired, a thin layer of 

 gravel may then be placed on the surface. Only very 

 general directions can be given, since different materials 

 must be mixed in different proportions and each mixture 

 may require special treatment. In many cases it will 



Figure 217. 



road with macadam surface. 



