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Roads

the Science and technics
 
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Many basic elements of modern road building have been developed still by Romans who were famous for the engineering art and constructed roads with the reliable basis, a good drainage and a smooth surface.

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The High system of Romans has been carefully planned, and on mainstreams stopping points, like modern servicing deports on motorways have been equipped. After a decline of Roman empire roads have practically ceased to watch, and they have gradually collapsed. However many lines which Romans used, make today a basis of a considerable part of the European network of highways. In England the science of road building has reached blossoming in the beginning of XIX century thanks to efforts of the Scottish engineers Thomas Telforda and John Makadama. Telford supervised over building more than 1600 km of roads and about 1200 bridges. And Makadam, besides making of roads, published works on their building and has invented the road covering known as termakadam, or degtebeton.

Expansion of a network of railways has interrupted development of road building in England, but interest to it has renewed with the invention of the car in the end of XIX century


Planning

If necessary to connect a highway two areas, it is necessary to plan a route precisely. It is not necessary to lay a line through the centers of cities, agricultural grounds, unique landscapes and industrial platforms. As a rule, engineers-schedulers spend preliminary shooting of district and plot some possible routes. Having analysed all advantages and lacks of each of them, they stop on one variant and spend more detailed studying. Then design drawings become. People and the organisations through which earths will take place a highway route, have the right to state the objections. In many cases official examination of the project is spent, and by its results changes are often made to it.

After the project statement hundreds working drawings are carried out. Besides a highway route, on them crossroads, entrances on a motorway and congresses from it, bridges, underground transitions and prodrivings, and also other constructions are in details presented. Complexity of the organisation of all works demands use by engineers of special computer programs.


the Roadwork

Roadwork On some sites at first it is required to take down buildings and other constructions interfering building. Then start one of the main processes - to dredging and moving of huge volumes of soil and breed, to tens millions tons.

That the line lay on a horizontal surface, the big weights of a ground from raised territories pour on the lowered sites. This method is called working out with a bookmark. Withdrawn at a line lining the top layer of earth is used for a covering of roadsides, embankments and the central dividing strips, and then planted with a grass and other vegetation.

For a water drain to roadsides the roadbed has the convex form (curvature of a profile). At the very beginning of building for water gathering the powerful drainage system is put.

Allocate three basic components of road clothes: the spreading surface, the basis and a covering, - which all together define rigidity of a covering. The rigid covering is made of concrete plates seams between which are filled plastic germetikoj, providing elasticity at fluctuation of loadings on a line. As a nonrigid covering serves "ёхЁэ№щ Ёхсхэі" - a mix of rubble or sand with coal tar or oil bitumen. Such coverings are called "=хЁьрърфрьш" or "ьрърфрьш with bitumen яЁюяш=ъющ". The bitumen road covering also is known as asphalt, and its both versions (with degtevoj and bitumen impregnation) name asfaltobetonom.

At both kinds of coverings the spreading surface consists of the condensed rubble or gravel. At roads with a firm covering the basis, as a rule, concrete, and with unsteady - from "ёхЁэюую Ёхсэ ".


Finishing touches

Before highway input in operation it is necessary to make a marking and to establish traffic signs, traffic lights and GAI posts. Along the central dividing strip and on some other difficult sites construct protections. To service life prolongation it is expensive it is necessary to support them in proper condition.