ROADS AND STREETS 



ROADS AND STREETS 



miles of road had been constructed and over 

 $7,000,000 invested. Again, about 1830, the 

 United States was in the midst of a road-build- 

 ing period. During these years the Federal 

 government was building the only great high- 

 way it ever undertook, the Cumberland Road 

 (which see), also called the "great national 

 pike." 



In the meantime, during the first half of the 



nineteenth century, the United States had 



vastly increased its area, until it extended 



from ocean to ocean. As the flood of immi- 



ion spread over the Mississippi Valley and 



West, there was an immediate necessity for 



roads. They were needed on such a vast scale 



that there was neither time, labor, nor money 

 to build improved roads. This period of ex- 

 pansion was followed by an area of railroad 

 construction, which opened up a still vaster ter- 

 ritory. For a generation or two the population 

 of any newly-settled region is too busy wrest- 

 ing a livelihood from the soil to give its atten- 

 tion to such secondary matters as road building. 

 This was true in the United States and to some 

 extent it is true in Canada at the present time. 

 It is only when a community has, in a sense, 

 grown up and reached some degree of stability 

 that it begins to consider the advantages of 

 good roads, and to bring these advantages 

 within reach of its citizens. 



Improved Roads and Pavements 



An improved road is one that has been prop- 

 erly graded and drained, and has been given a 

 surface covering of some material which makes 

 it reasonably firm and durable. Such a cover- 

 ing is called pavement, a word derived from the 

 Latin pavire, meaning to beat or tread down. 

 The ancient city of Babylon had paved streets, 

 and the pavement probably consisted of beaten 

 clay, laid to a considerable depth to present a 

 hard and even surface. The old Roman cities 

 of Pompeii and Herculaneum were paved with 

 stones and volcanic matter thrown from the 

 crater of Vesuvius. 



Stone. Stone blocks, preferably of granite, 

 form the most durable pavement, but they 

 have great disadvantages. The noise of heavy 

 vehicles drawn over stone pavements is very 

 trying, and the uneven stones severely test the 

 wearing qualities of wagons. Granite pavement 

 is very expensive, but when properly laid will 

 last for years without repair. It is used largely 

 in cities and areas carrying much heavy traffic. 



Macadam and Concrete. Pavements made 

 of small, crushed stone, instead of large block-. 

 have been in general use since the beginning 

 of the nineteenth century. This form is called 

 macadam, from the name of the Scotch engi- 

 neer, John L. MacAdam (1756-1836), who in- 

 troduced it. Formerly all macadam was water- 

 bound; that is, the stones were held together 

 by a natural cement of dust and moisture. 

 Macadam marked a great advance in paving 

 methods, but it does not wear well under heavy 

 or fast traffic. Water-bound macadam, more- 

 over, is dusty in dry weather and hard to clean. 

 Its place is gradually being taken by bitumi- 

 nous-bound macadam, which is made in the 

 same way except that a special cement of a- 



phalt or tar is used. The binder may be mixed 

 with the stones before the pavement is laid, or 

 may be sprinkled on it afterward. Bituminous- 

 bound pavement which is mixed before laying 

 is usually called bituminous-concrete, or merely 

 concrete. 



Asphalt. This form of pavement consists of 

 two parts, a binder and a wearing surface, laid 

 on a solid foundation. The foundation is usu- 

 ally of concrete, and the binder, which serves 

 to unite the foundation and the wearing sur- 

 face, is of small, broken stones mixed with an 

 asphaltic cement. The wearing surface is a 

 mixture of sand, Portland cement (or carbonate 

 of lime) and asphalt, mixed together at a high 

 temperature and then spread on the roadway. 

 Asphalt pavement is sometimes laid in blocks, 

 the mixture being first molded by machine, and 

 then when cold laid like bricks. It is noiseless 

 and easily cleaned, but is not suitable for heavy 

 traffic (see ASPHALT). 



Brick. In recent years the use of brick for 

 paving has greatly increased. The bricks in- 

 tended for such use are specially prepared and 

 are so hard-burned that thrv have a glassy ap- 

 pearance. When laid on a foundation of con- 

 crete, brick will sometimes outwear every other 

 kind of pavement except stone blocks. It is 

 easy to clean, but it has the disadvantage of 

 being very noisy for horses and metal-tired 

 wagons. It is an excellent pavement for roads 

 on which automobile traffic is heavy and other 

 forms of traffic are light. 



Wood. Wood pavement is made of round or 

 brick-shaped blocks of wood with the spaces 

 between them filled with tar or a mixture of 

 tar and sand. Round blocks were formerly in 

 common use, but have now been almost en- 



