Historical Development Of Road Construction

                          

        Historical Development Of Road Construction

• The first road is constructed at that time of Assyrian empire at 1900 B.C
• According to our historical record ,At different periods different  type of roads were constructed.

       Now we discussed

1.   Roman Roads

• During the period of Roman civilization ,many roads were built of stone blocks.
• They were built straight of gradients.

             Steps of construction:-

• First they remove the soft soil,and built after a hard stratum was reached.
• One or two layers of large foundation stones were laid in lime mortar at the bottom and the thickness of this layer from 10 to 20 cm.
• At the edge vertical kerb stones were placed.
• A second layer lime concrete(large size broken stones and lime mortar) was laid over bottom course up to thickness 25 to 40 cm
• Then the top layer,lime concrete was laid over this with small broken stones up to thickness 25 to 40 cm or more, if necessary.
• At last the wearing course was dressed with large stone blocks set in lime mortar and the thickness varied from 10 to 15 cm.
• The total thickness of the road was 0.75 to 1.2 meters 

2. Tresaguet  Construction

• pierre Tresaguet developed improved the method of construction in France.
• At that time he developed different methods which was quite innovate.

          Steps of construction:-

•  At first subgrade was prepared and a layer of large foundation stones were laid.
• Kerbs were provided two edges.
• At corners heavy foundation stones were hammered and in gap filled with smaller stones.
• Broken stones were packed up to 8 cm thickness and well compacted.
• Then the top wearing course was made with smaller stones up to 5 cm thickness at edge and gradually increased towards the centre .
• The cross-section  having the slope of 1 in 45 to the surface,to provide surface drainage.
• The shoulders were also provided cross slope to drain the surface water to the side drain
• The total thickness of the road was 30 centimeter

3. Telford Construction

• In 19th century,Thomas Telford began the construction.
• He was the founder of the Institution of Civil Engineers at London.

             Steps of construction:-

• A level of subgrade was prepared to designed width of about 9 meters.
• At bottom,large foundation stones of thickness 17 to 22 cm were laid.
• Lesser thickness of stone  (17cm) placed at edge and increasing thickness towards centre.
• At centre largest stone thickness provide.
• Small stones are filled between the largest foundation and well compacted.
• The central portion of about 5.5 meter width has covered with two layers of angular broken stones to compacted thickness of 10 and 5 cm.
• These layers are initially rammed and later it allowed to be compacted under traffic and consolidated by the rains.
• A certain width of the pavement towards the edges was constructed by compacted broken stones,sometimes lime mortar used in kerb portion for lateral stability.
• A wearing course about 4 cm thickness was constructed on the top using gravel.
• The cross-section  having the slope of 1 in 45 to the surface,to provide surface drainage.
• He provides the cross drain at interval of about 90 meters.

4. Macadam Construction

• The method was constructed by John Macadam.
• Macadam was the surveyor General of Roads in England.
• He mainly emphasize the compaction and drainage of water.

             Steps of construction:-

• Subgrade is compacted and prepared with a cross slope of 1 in 36 up to 9 meter width.
• At bottom,l stones were placed ,which size 5 cm was compacted and thickness of 10 cm.
• The second layer of strong broken stones of size 3.75 cm was compacted to thickness of 10 cm.
• The top layer consisted of stones of size 2 cm compacted to thickness of 5 cm and finished,
• The cross-section  having the slope of 1 in 36 at top surface.
• This method was widely used at that time.