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We all know that road is a chief means of transport that helps in developing the nations in all aspects. Roads help the nations to unite with each other. Earlier, travelling from one nation to another by roadways is quite problematic for the people but as the world is developing technologically, different modernised equipments are discovered to make the roads smooth so that travel becomes easy. Highway construction is basically a part of the civil engineering course that comprises of planning, design, construction, operation and preservation of roads, flyovers, and subways to provide safe and time-saving travel to the people. The highway engineer planned and design highways keeping in the mind the augmenting problem of traffic. There are many methods in constructing highways.

Various Designs of Highway Construction

The location, configuration and the shape of the highways are decided in the designing phase by the engineers. The engineers design the highway after completing the phase of planning and development. The designs of the highways depend on three features that are human, vehicular and roadway. It is the duty of the highway engineers to design the road properly so that the number of the accident cases reduced a little bit. There are many designs involved in highway construction that are as follows:

• Lane width
• Alignment, super elevation and grades
• Level of Service (LOS)
• Design traffic volume
• Design speed
• Number of lanes
• Sight distance
• Cross section
• Horizontal and vertical clearance

Other than these there is a kind of design that is known as flexible pavement design. This design comprises of three or four layers and the longevity of this type of designed highways is 15 to 20 years. The speciality of this design is that the pavement is made up of hot mix asphalt.  Rigid pavement design is another important genus of highway construction design. This design is chiefly employed in building airports and foremost highways. Portland Cement Concrete is the most common substance that is used in this design. The longevity of this sort of design is more than 30 years and is constructed in three layers.

Methods of highway construction

• Subbase course construction is a technique of highway construction that is positioned between the subgrade and base course of the path. The width of the subbase usually comes in the range of 4 to 16 inches and it is planned to support the structure of the pavement. The different materials used in this method are gravel, crushed stone, fly ash, cement or lime.
• Base course construction is another kind of highway construction mode that is placed directly under the surface course. The usual thickness of this base course varies from 4 to 6 inches. When the heavy loads are put on the surface of the pavement, this base course becomes powerful to handle that load. The materials utilised in base course construction are often applied with cement, calcium chloride, sodium chloride, fly ash or lime. This amalgamation helps the base course to carry the heavy load of the pavement properly.