History of roads and highways. Part I
I. Reading materials.
Text A.
Introduction.
Modern highways are complex engineering structures. They are intended for high-speed motor traffic. Therefore, hey must be designed and constructed in such a way that the performance characteristics of vehicles may be effectively realized under normal conditions of engine operation. Their design should provide for the comfort and safety of transportation.
Road jobs are essentially labour-consuming, demanding the extensive transportation of large quantities of materials. Thus, for the construction of 1 km of a motor road with asphalt-macadam surfacing on a gravel base, in flat country, it is necessary to transport about 7,500 tons of sand and gravel and excavate up to 12,000 cum of soil, transporting it for a distance of perhaps several hundred metres. Stone aggregates used in the road pavement often have to be hauled from afar.
The road-building operations are very complicated because of the extensive length of the construction site - often tens and hundreds' of kilometres. This requires the introduction of special techniques end methods of work organization.
As in other fields of construction, road building requires the application of industrialization techniques on a wide scale -the use of prefabricated reinforced concrete structures. Because of this, road construction and the building of artificial structures form complementary part of the same constructional programme.
The mechanization of read construction has grown immensely, especially in such operations as earthworks, sand and gravel quarrying, atone crushing and completion of asphalt macadam and cement concrete surfacing.
The solutions of road construction problems are closely connected with those of reduction of cost and the improvement of the quality of the work.
To ensure the nest economical design of the road it is necessary to assimilate the experience gained in the carrying out of similar projects. It is very important to apply the latest techniques developed in the fields of science and engineering to the construction and analysis of road projects.
Text B.
History of roads and highways. Part I.
The first roads. Roads are so old that we are not sure of the origin of the word road Most experts think it came from the Middle English word rode, meaning a mounted journey. This may have come from the old English road, from the word ridan, meaning to ride.
In England, hundreds of years ago, certain main roads were higher than the surrounding ground. This was because earth was thrown from the side ditches toward the center. Because they were higher, they were called highways. These roads were under protection of the king's men and were open to all travelers. Private roads were known as byways.
The first roads in the world probably followed trails and paths made by animals. These trails and paths led from feeding grounds to watering places. People followed these trails to hunt for animals. People also made their own trails and paths in searching for water, food, and fuel. Explorers followed these trails as they investigated new lands.
Early roads were built in the Near East soon after the wheel was invented. This was about 3000 B.C. As trade developed between villages, towns, and cities, other paths, or trade routes, were made. One such early system of roads was the Old Silk Trade Route which ran over 6,000 miles (9,700 kilometers), connecting China with Rome and pre-Christian Europe. Merchants used this ancient route to carry Chinese silk across Turkestan, India, and Persia.
The first road markers were piles of stones at intervals. Trails through forests were marked by blazing trees, or cutting a piece from the bark of the tree.
The Egyptians, Carthaginians, and Etruscans all built roads. But the first really great road builders were the Romans. They knew how to lay a solid base and how to give the road a pavement of flat stones. The Romans knew that the road must slope slightly from the center toward both sides to drain off water. This gave the road a crown. The Roman road builders knew also that there must be ditches along the sides of the road to carry water away. Roman roads were built mainly to get soldiers from one part of the empire to another. These roads ran in almost straight lines and passed over hills instead of cutting around them. The Romans built more than 50,000 miles (80,000 kilometers) of roads in their empire and some of them still are in use.
From the 500's to the 1800's, most roads in Europe were merely clearings in the forests. Cobblestone paving was used in some urban areas. There was little reason to build good roads, because most of the travel was on horseback. The cleared way was sometimes quite wide, so that robbers hiding in the woods could not leap out suddenly upon unsuspecting travelers. Later, when more wheeled vehicles, such as wagons, came into use, the roads of Europe still remained in poor condition. Usually the roads were made up of one mudhole after another. Roads with smooth surfaces were rare in England until the 1600's.
In South America, from the 1200's to the 1500, the Inca Indians built a network of 10,000 miles (16,000 kilometers) of roads. The roads connected their cities.
The first highway department was established in France in 1716. This department built Europe's finest gravel and stone roads of the 1700's using methods developed by Pierre M.J. Tresaguet, an engineer.
In the early 1800's, the person who did more for European roadbuilding than anyone else up to that time was John Loudon McAdam, a Scottish engineer. McAdam is remembered for the surface he developed for roads. This kind of surface, called macadam is still used today. McAdam also stressed the importance of proper drainage to keep roads on a solid foundation See McAdam, John Loudon; Industrial Revolution (Roads).
Text C.