The history of road development can be studied under the following headings:
History of Road Development
1. Early Development
The oldest mode of travel was on the footpath.
Animals were widely used to transport men & materials.
Later the invention of wheels resulted in the development of vehicles run with the help of animals.
This type of vehicle became the most popular mode of transportation for a very long period.
2. Roman Roads
~These roads are developed by the Roman Civilization among which some are still in existence.
~ Roman roads were built with stone blocks of considerable thickness.
The main features of the Roman road are:
~ They were built straight ( with minimal slope or without slope).
~ They were built after soft soil is removed and a hard status was reached.
~ The total thickness of the construction was as high as 0.75 m to 1.2 m.
3. Tresaguet Construction
~ After the fall of the Roman Empire, their technique of road construction didn’t gain popularity in other countries.
~ Pierre Trezeguet (1716 – 1796 AD) developed several methods of road construction which were considered to be quite advantageous and meritorious.
~ The main feature of his proposal was that the thickness of construction needs to be only 30 cm.
~ Side drainage was also provided on these roads.
4. Metcalf Construction
~ John Metcalf (1717-1810 AD) was engaged in road construction in England during the period when Trezeguet was working in France.
~ He followed the recommendations made by Robert Phillips.
~ Metcalf was responsible for the construction of 290 km of road in northern England.
5. Telford Construction
~ Thomas Telford (1751 – 1834 AD), the founder of the institution of civil engineers in London began road construction in the early 19th century.
~ He believed in using a heavy foundation above the soil subgrade to keep the road foundation formed and also insisted on providing a definite cross slope for the top surface of the pavement by varying the thickness of the foundation on stones.
~ He proposed to provide cross drains at an interval of almost 90m which were usually laid below the foundation level.
6. Macadam Construction
~ There are different stages of road development. But among all of them, Macadam road is the most successful type of road. Some detailed features about macadam road are:
~ John Macadam (1756 -1836 AD) ; the surveyor-general of the road in England put forward an entirely new method of road construction.
~ The macadam method is the first method based on scientific thinking.
~ It realized that the stresses due to wheel load get decrease at the lower layers & so it is not necessary to provide large layer pavement.
~ The importance of subgrade drainage and compaction was recognized. So the subgrade was compacted and was prepared with across slope (1 in 36 ).
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There are four types of Macadam roads and they are:
In this type, broken stones are bounded with the help of stone dust and water during the construction process.
b.Traffic Bound Macadam
Broken stones or gravels are generally used as a wearing. Multi-layers of stones and gravels are provided in this type.
Bitumen is used as a binding material to bind stone chips and also to bind base and sub-base courses.
d. Cement Macadam
Cement macadam is quite similar to bitumen macadam. Cement is used as a binding material instead of bitumen.
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