History of Road Development

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 that run with the help of animals.

~ This vehicle became the most popular mode of transportation for a very long period.

  2. Roman Roads  

Ancient Roman Roads were developed during the Roman Civilization, among which some still exist.

~ Roman roads were built with thick lime concrete and stone blocks.

Examples: Via Popillia, Via Appia, etc

1. Features of Ancient Roman Roads  

The main features of the Roman road are:

~ They were built straight ( with minimal slope or without slope).

~ They were constructed after soft soil was removed and a hard status was reached.

~ The total thickness of the construction was as high as 0.75 m to 1.2 m.

2. Construction of Ancient Roman Roads  

Construction of ancient roman roads was done in the following steps:

a. Excavation of road was carried out until hard status was reached.

b. Subgrade having the thickness of 10-20 cm was prepared.

c. Above subgrade, large foundation stones were laid, which were bonded together with the help of lime mortar.

d. At corners, kerbstones were provided.

e. Above the stone foundation, stone chips along with lime mortar were provided.

f. Then, a layer of pure lime concrete was provided.

g. At the top, large stone slabs of 10-15 cm were provided.

h. The thickness of such constructed road was as high as 0.75 m to 1.2 m, and the width was between 2.2-2.5 m.

3. Disadvantages of Ancient Roman Roads  

Some disadvantages of ancient roman roads were:

a. There was no provision for a cross slope.

b. No provision for a drainage system.

c. Use of large foundation stones.

  3. Tresaguet Construction  

After the fall of the Roman Empire, their road construction technique didn’t gain popularity in other countries.

Pierre-Marie-Jérôme Trésaguet (1716 – 1796 AD) developed an improved method of road construction in France in 1764 AD, which was considered quite advantageous and meritorious. 

i. Features of Tresaguet Road Construction  

The main features of Tresaguet Road Construction were:

a. The thickness of the construction was only 30 cm.

b. Side drainage was also provided on these roads.

c. There was a provision of camber with slope 1 in 45.

d. There was a provision for a side drain.

ii. Construction of Tresaguet Road  

Construction of Tresaguet Road was done in the following steps:

a. At first, the soil was excavated, and then large stones having a thickness of 17 cm were laid.

b. Kerbstones were utilized at the corners.

c. Above stones, broken stones of about 8 cm thick were used.

d. At the top, a sloping wearing surface of 5 cm thick was provided. Stone powder or lime was generally utilized on the wearing surface.

e. The thickness of such constructed road was 30 cm, and the width was 2.7 m.

f. Shoulders having a slope of 1 in 20 were also provided on this road.

g. There was also a provision for a side drain.

  4. Metcalf Construction  

~ John Metcalf (1717-1810 AD) was engaged in road construction in England when Trezeguet worked in France.

~ He followed the recommendations made by Robert Phillips.

~ Metcalf was responsible for constructing 290 km of road in northern England.

~ This road was quite similar to Tresaguet Road.

  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 insisted on providing a definite cross slope for the top surface of the pavement by varying the thickness of the foundation stones.

~ He proposed to offer cross drains at an interval of almost 90m, usually laid below the foundation level.

i. Features of Telford Road Construction  

a. Stones of varying sizes (17 – 22 cm ) were utilized to make the road foundation.

b. Above this layer, angular broken stones of 7 cm size and 10 cm thickness were used in the central area, and broken stones along with lime mortar were used at the sides.

c. Generally, a wearing surface with a slope of 1 in 45 and thickness of 4 cm was constructed.

d. Cross drains were provided at an interval of almost 90m which were usually laid below the foundation level.

  6. Macadam Construction   

There are different stages of road development.  Among them, Macadam Road is the most successful type.

 John Loudon Macadam (1756 -1836 AD) was the surveyor-general of the road in England who put forward an entirely new method of road construction called the macadam road. This road was the first road based on scientific thinking.

The importance of subgrade, drainage, and compaction was also recognized. So the subgrade was compacted and was prepared with a slope of (1 in 36 ).

i. How was Macadam Road constructed?  

~ The standard size of the road was taken as 4.5 m.

~ The total thickness of the base, sub-base, and surface course was taken as 25 cm.

~ The construction of the macadam road consists of the following steps:

a. Sub Grade Preparation

Compacted subgrade having cross-slope 1 in 36 was prepared.

b. Sub Base Preparation

The layer above the subgrade was constructed using stones passing through a 5 cm sieve.

Its thickness was 10cm.

c. Base Course Preparation

The base course was prepared from broken stones passing through a 3.75 cm sieve.

Its thickness was 10 cm.

d. Surface Course Preparation

It was prepared using broken stones passing through a 1.9 cm sieve.

Its thickness was 5 cm.

Note:

It was the process of road construction when John Macadam introduced it. 

ii. What are the types of Macadam Road?  

Over time, different modified macadam roads were developed.

Using binding materials in macadam roads has become more popular because of the increased durability and life of the road.

Macadam road can be classified into the following four types.

a. Water Bound Macadam  

Over time, different road building technology was applied to macadam road by several engineers. One of them was Richard Edgeworth.

He filled the gaps between the surface stones using a mixture of stone dust and water to make the surface more smooth. This method of construction is named water-bound macadam.

The macadam road’s wearing coarse is constructed with clean crushed aggregates, which are mechanically interlocked by rolling and bounded together with the mixture of filler material(sand or clay) and water laid on a prepared base course.

Water Bound Macadam Road is abbreviated as WBM road.

Advantages

a. Made from local materials and labour.

b. It is economical to construct.

c. No skilled workforce is required.

Disadvantages

a. They are permeable.

b. Short life.

c. Production of dust during service.

b. Traffic Bound Macadam  

In this macadam, broken stones or gravels are generally used at a wearing course. Multi-layers of stones and gravels are provided in this type.

It is used in rural as well as urban areas.

The compacted thickness of each layer may vary from 2.5 to 5.0 cm.

c. Bituminous Macadam  

In bituminous macadam, bitumen is used as a binding material to bind stone chips and also to bind base and sub-base courses.

It is also called Tar Bound Macadam.

The dust became a serious problem on macadam roads, so bituminous macadam was introduced.

Flexible pavement is a modified type of Bituminous Macadam.

d. Cement Macadam  

Cement macadam is quite similar to bitumen macadam. Cement is used as a binding material instead of bitumen.

Rigid Pavement is a modified type of Cement Macadam.