History of Highway Engineering | Engineer Ji

In this article I am going to discuss the history of development of modern highways in India for JE Civil Exam (point of view). 
Because, we have already learnt about Highway & Airport Engineering so, there is no need to read again, read these important points only. 

1. Chronological order of Road development:

• Roman Roads
• Tresaguet Roads
• Metcalf Roads
• Telford Roads
• Macadam Roads 

i). Roman Roads:

• Main Features of Roman Roads:

i) They were built straight regardless of gradient.

ii) Used heavy foundation stones at the bottom. 

iii) Crete was a major Roman Road making innovation.

iv) They mixed lime & volcanic pazzolona to make mortar & they added gravel to this mortar to make crete. 

• Construction Process: 

i) Excavation of the surface till they find hard strata. 

ii) Sometimes, depth of excavation may be 0.75m to 1.2m

iii) Bottom most layer of the road was of large stone. 

iv) Second layer made of broken stones.

v) 3rd layer lime crete.

vi) last layer or topmost layer - paving stones

ii). Tresaguet/Metcalf/Telford Roads:

• Features of these roads:

i) Thickness of road was around 30cm. 

ii) Gave important to soil subgrade (moisture content).

iii) Replace top surface large stones with broken stones.

iv) To counteracted drainage problem provided "camber" to the surface along with deep side ditches.

iii) Macadam Roads:

• Macadam is a type of road construction, pioneered by Scottish engineer John Loudon McAdam around 1820, in which single-sized crushed stone layers of small angular stones are placed in shallow lifts and compacted thoroughly.

• He realized "stresses due to wheel loads of traffic gets reduced to the lower layer of pavement."

Difference