c3010 highway engineering unit1

Introduction of Highway Highway Engineering C3010 / UNIT 1/

INTRODUCTION OF HIGHWAY ENGINEERING

OBJECTIVES

General Objective

To understand the development and transportation system in Malaysia.

Specific Objectives

At the end of the unit you should be able to :-• state the construction structure used in transportation system.• identify the related profession in the road construction development.• describe the history of road development.• describe the road category.• identify the related agencies involved in road construction.

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UNIT 1


1.0Introduction

For rapid economic, industrial and cultural growth of any country, a good

system of transportation is very essential. Transportation system comprises of

good network of roads, railways, well developed water ways and airways.

Airways and water ways although help to some extent in transportation within the

country, but they are the modes of transport mainly with foreign country.

Railways and highways also to some extent help in transport with foreign

countries but their main concern is within the country itself.

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INPUT

CONSTRUCTION STRUCTURE FOR TRANSPORTATION


1.0.1 Different modes of transportation

Man has always been curious for new inventions. In the early days

of civilization it was thought that the movement of any human being can

be on the earth only. No one thought of flying in air or cruising in large-

oceans.

Modes of transportation can be classified as follows :

a. roadways or highways

b. railways

c. water ways

d. airways

The science which covers designing, maintenance and operation of

the roads, for convenience of the road traffic, is called highway

engineering. The science dealing with planning, designing, operation and

maintenance of railway track, wagons, coaches, locomotives, is called

railway engineering.

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Seeing birds flying, man must have

thought of flying and that may probably be

the starting point of modern aeronautics.

Similarly, seeing fishes cruising in the sea

or river, man must have thought of rowing

in water, and that may probably be a

starting point in the development of water

ways and designing of ships and boats.


Similarly planning, designing, operation, control and maintenance

of water ways, airways and their connected machinery are respectively

called harbour engineering and airport engineering.

Besides the above stated four major modes of transportation, fluids

are mainly transported through pipes. Belt conveyors, cable cars,

monorails are some other minor systems of transportation, but they are

used for specific purposes. Looking to the transport characteristic of each

type of transportation system, it can easily be appreciated that roads and

railways are economical and easy for internal transportation, while airways

and waterways are main economical for transportation with foreign

countries. Airways are gaining importance even in internal movement

these days, because they cause saving in time of travel.

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1.0.2 Road transport characteristics

While going to railway station, harbour or airport, roads is the first

mode which is going to lead you to these places. Hence it can be said that

out of all types of transport systems, road is the nearest to the man.

Characteristics of road transport are given as follows :

a. Roads can be used by all sorts of vehicles like bullock

carts, carriages, bicycles, scooters, cars, buses and

lorries, etc. They are equally useful for pedestrians also.

b. Roads can lead to any remote place.

c. Investment on road transport by government is

comparatively small. Maintenance of roads is also

cheaper than rail-track, docks, harbours and airports.

d. There is complete freedom to road users to transfer the

vehicles from one lane to another, or from one road to

another according to the requirements.

e. Local communication among villages, villages and towns

is only possible through roads.

f. Movements on roads are not time bound, as in case of

railways or airways.

g. Road transport is the only mode of transport that offers

itself for the service of whole community alike.

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1.1 HISTORY OF HIGHWAY ENGINEERING

Traces of early roads have been found since the recorded history of the

man kind. The first and oldest mode of travel obviously was foot path. Before

invention of wheel, people used to move on foot, thus creating foot paths. Men

and material must have been transported either on backs of men or animals.

The historical road development can be divided in to the following era :

• Early/ Basic roads

• Roman roads

• Modern roads

1.1.1 Early roads

After invention of wheel, animal drawn bullock carts continued to be

the popular mode of transport for quite a long time. This necessitated in

providing hard surface for wheeled carts. The first hard surface was

discovered in Mesopotamia at about 3500 B.C. Archeological findings

street were paved in Mohanjodaro at about 3500 B.C.

There are signs of pucca roads were used during the construction

of Illahun pyramids in Egypt between 3000 - 2500 B.C. This would be due

to the transportation of huge limestone blocks.

1.1.2 Roman roads

In the ancient Rome era, more intensive system of roads was

developed. The road radiating in many directions from Rome. Some of

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those roads are said to be a very elaborate construction. Many of the

Roman roads are still in existence even after 2000 years. Romans were

considered to be the pioneers in road construction. With the fall of Roman

Empire, the road building technique became a lost art.

1.1.3 Modern roads

In eighteenth century, improved construction methods for roads

again began to develop. Mr. Pierre Tresaquet developed an improved

method of construction in 1764 in France. At the time when Mr. Pierre

Tresaquet was busy in developing his road construction method, Mr. John

Metcalf was engaged in his development in England. Metcalf constructed

about 290 Km road in northern region of England. Since Metcalf was blind,

his work was not recorded and thus got lost.

Telford and Macadam were the pioneers in road development in

England. Telford believed in using heavy foundation stones over the soil

sub-grade, while Macadam advocated the use of compacted crushed

aggregate layer at the bottom. Macadam’s method of road construction is

still in used and is named after his name.

1.2 CHARACTERISTIC OF SOME IMPORTANT EARLY ROADS

Important early roads include:

a. Roman roads construction

b. Tresequet roads construction

c. Metcalf’s roads construction

d. Telford’s roads construction

e. Macadam roads construction

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1.2.1 Roman roads

Roman’s developed very elaborate system of roads mainly for the

purpose of military movement. They constructed in all about one lakh

kilometers of road, extending in whole of their empire. An Important road

constructed by Romans in 312 B.C called Appian way is still in existence

in Rome.

The main characteristics of Roman roads were as follows:

1. They weary very thick. Total thickness of the road varied

from about 0.7 m to as much as 1.2 m.

2. They were straight, without any regard for gradient. Probable

reason for straightness may be their main use for army.

3. Roads were not built on soft soil formations but on hard

stratum reached after excavation.

Method of construction for Roman roads

First of all loose soil was used to be removed from the site of the

road and a trench, equal to width of carriage way excavated to depth so

that hard stratum is reached. At the bottom of the trench one or two layers

of large stones were laid in lime mortar. The thickness of this foundation

layer ranged from 10 – 20 cm. Over this, 25 – 40 cm thick layer of lime

concrete with large size broken stone aggregate was laid. Another layer

again 25 to 40 cm of lime concrete but using comparatively small size

broken stone aggregate was laid over the previously laid layer. Lastly 10

to 15 cm thick dressed large stone blocks, set in lime mortar were used as

wearing course. Seeing thickness of the road, it is obvious that these

roads must be very strong, but they cannot prove economical, when

compared with modern design methods.

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1.2.2 Tresaquet’s roads

Mr. Pierre Tresaquet was inspector general of roads in France from

1775 to 1785. He developed an improved method of road construction.

The main feature of his work was that the thickness of the road was about

30 cm. He also made consideration of sub-grade moisture and drainage

from the surface. He also emphasized the need for continuous

maintenance of road to keep it in good shape. At the time of Napoleon,

quite elaborate road system was developed in France mainly for use of

military adventures.

Method of construction for Tresaquet’s roads

On the prepared sub-grade a layer of large foundation stones was

laid, keeping all the stones on edge. At the edges of the road, a large size

stone was laid length wise to give lateral support to the foundation layer.

The interstices of the foundation stone layer were filled with stone

aggregate of smaller size. Compacted thickness of this layer was about 8

cm. Lastly the top wearing course was laid of walnut sized stones and

compacted to a thickness of about 5 cm. A cross slope of about 1 in 45

was used to be developed in the road surfaced by adjusting thickness

mainly in top and intermediate layers. Lastly, shoulders were also given

suitable cross slope, away from the edges of carriage way.

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1.2.4 John Metcalf roads (1717-1810)

He was working in England at the time when Tresaquet was busy in

France. He experimented road construction with a graded mixture of earth

and gravel. Since Mr. Metcalf was blind, his work could not be recorded.

But it is believed that he was following the procedure outlined by Robert

Philips in 1737. Robert Philips method consisted of laying gravel layer

upon a well drained and dried sub-grade. Gravel layer was used to be

compacted in due course of time, by the action of the traffic using road.

Metcalf constructed about 290 Km of road in northern parts of England.

Telford roads (1757-1834)

Thomas Telford was Scottish road engineer and founder of the

institution of civil engineers. He used big size stones in foundation wearing

from 17 – 22 cm to develop a firm base. He also provided cross drains

under foundation layer to keep the sub-grade in dry condition. He

proposed provision of cross drains at intervals of about 90 m. Total

thickness of road advocated by him was about 38 cm.

Construction Method for Telford roads

A level sub-grade which may be on embankment or cutting was

prepared in the required width. Telford adopted 9 mm width of the road.

On the prepared sub-grade a layer of large size stone boulders, varying in

size from 17 cm near the edges to a maximum size of about 22 cm at the

centre of the width of the road was laid. Laying of the stones was done by

packing. By using smaller size stone near the edges and larger size near

centre, a cross slope, of 1 in 45 in road surface was developed. The

interstices in this boulder foundation layer were filled with smaller stones

and chippings and properly compacted.

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Now central width of about 5.5 m ( 18’ ) of road was covered with

intermediate coating consisting of two layers. The compacted thickness of

first layer was about 10 cm and consisted of 6.5 cm size stone aggregate.

The compacted thickness of second layer was about 5 cm and consisted

of about 4 cm size stone. These layers were used to be rammed initially,

but allowed to be compacted under traffic. No water was sprinkled during

compaction. Only rain water was used to help compaction and

consolidation of these layers.

Over the intermediate coat, 4 cm thick gravel layer was used to act

as blinding and wearing layer. The finished surface used to have a cross

slope of 1 in 45. The remaining width of the foundation left untreated by

intermediate coats (two layers), on either side, was treated by lime

concrete. Lime was mixed with broken stone aggregate about 10-15 cm

size to prepare lime concrete, to be laid on either side of the road. This

treatment provided lateral stability to the road structure.

1.2.5 Macadam Roads ( 1756-1838 )

He, for the first time put forward entirely new concept of road

construction in 1827. He was a Scottish engineer and was surveyor

general of roads in England. Important characteristic of his concept are as

follows:

• It was he who for the first time recognized the importance of sub-

grade compaction and drainage. To affect speedy surface drainage

he recommended suitable cross slope for the sub-grade.

• It was he who realized for the first time that heavy foundation

stones are not at all necessary. If sub-grade is prepared properly

and kept well drained it can be very well bear the traffic load

transmitted to it through foundation layer, having smaller

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compacted thickness of small size broken stones. He was of the

opinion that a broken stone layer of few centimeter thickness can

sustain mush heavier load than a thick layer of big size stones.

• Size of the aggregate to be used in wearing course was decided

according to requirements of stability under the effect of vehicles.

Method of Construction for Macadam roads

Sub-grade was prepared and compacted to the required

width of the road. Prepared sub-grade was given the same camber,

as to given to the finished road surface. Construction of road

according to Macadam method consists of three layers, namely,

foundation layer, intermediate layer and wearing surface layer.

Foundation layer was 10 cm thick (compacted) and was made from

5 cm size aggregate. Intermediate layer was also 10 cm thick

(compacted) but made from aggregate passing 40 mm sieve.

Lastly, wearing surface was made 5 cm thick (compacted) using

aggregate passing 20 mm sieve. Cross slope of finished surface

was kept as 1 in 36.

In those days, there were no rollers to affect thorough

compaction and interlocking, and hence, this action was used to be

achieved by means of traffic. This was the reason that next layer

could not only be laid once the previously laid layer gets thoroughly

compacted. Macadam method was first scientific method based on

modern concepts and hence is still in use in most parts of the

world, though with certain modifications.

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1.3 Comparison Between Macadam and Telford Roads

a. Telford roads are costlier than Macadam roads.

b. In the case of Telford construction, sub-grade was kept horizontal due

to which drainage of sub-grade was not proper. In the case of

Macadam construction sub-grade was given 1 in 36 cross slope. This

aspect helped in better sub-grade drainage.

c. Large size stones were adopted by Telford for foundation. Size of

stone varied from 17 cm near edges to 22 cm at the centre of the road.

In the case of Macadam roads 5 cm was the maximum size of the

aggregate used for foundation layer.

d. Cross slope in Telford using smaller size stones at the edges and large

size stones at the centre of the width-developed roads. Thicknesses of

subsequent intermediate and surfacing layers, is kept constant for the

full width of the road. In Macadam roads, required camber was given to

the sub-grade itself and all the subsequent layers of aggregate

including foundation layer of uniform thickness for the whole of the

width of the road.

e. Telford construction is carried out in four layers namely foundation

layer, two layers of intermediate coat and 4 cm thick wearing top layer.

Macadam construction is done in three layers. Two layers each of 13

cm compacted thickness as foundation layers and 5 cm thick surfacing

layer.

f. In Telford roads, camber given was 1 in 45 while in Macadam it was 1

in 36.

g. Telford’s foundation layer, being of larger sized stones, behaved like

semi flexible road but Macadam’s base was yielding type and hence

Macadam roads behaved like fully flexible roads.

h. Total thickness of road structure was about 40 cm in case of Telford

but only about 25 cm in case of Macadam.

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TEST YOUR UNDERSTANDING BEFORE YOU CONTINUE WITH THE NEXT

INPUT….!

1. Describe briefly the contribution of Tresaquet , Metcalf, Telford and

Macadam to road improvement of a scientific nature.

2. Write short notes on the history of:

a. Early basic roads

b. Romans roads

c. Moderns roads

3. Discuss the comparative specifications of Telford and Macadam road

crust construction.

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ACTIVITY 1

GOOD LUCK….


1. Pioneers contributions are :

a. Tresaquet

• Developed an improvement method of road construction

which feature of his work was that the thickness of the road

was about 30 cm.

• The interstices of the foundation stone layer were filled with

stone aggregate of smaller size and compacted thickness

of this layer was about 8 cm.

• Top wearing course was laid of walnut sized stones and

compacted to a thickness of about 5 cm.

• A cross slope of about 1 in 45 was used to be developed in

the road surfaced by adjusting thickness mainly in top and

intermediate layers.

b. Metcalf

• Experimented road construction with a graded mixture of

earth and gravel.

• Method consisted of laying gravel upon a well drained and

dried sub-grade. It used to be compacted in due course of

time, by the action of the traffic using road.

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FEEDBACK ON ACTIVITY 1


c. Telford

• Used big sized stones in foundation wearing from 17-22 cm

to develop a firm base

• Provided cross drains under foundation layer to keep the

sub-grade in dry condition

• Level sub-grade on embankment or cutting was prepared in

the required width.

d. Macadam

• Using entirely new concept of road construction.

• Recognized the importance of sub-grade compaction and

drainage

• Using a broken stone layer of few centimeter thickness can

sustain much heavier load than a thick layer of big size

stones

• Size of the aggregate to be used in wearing course was

decided according to requirements of stability under the

effect of vehicles.

2.

a. Early roads.

After invention of wheel, animal drawn bullock carts continued to be

popular mode of transport for quite a long time. This necessitated

providing hard surface for wheeled carts. The first hard surface was

discovered in Mesopotamia at about 3500 B.C. Archeological

findings in Mohanjodaro indicate that about 3500 B.C Street was

paved.

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b. Romans roads.

In the ancient Rome era, more intensive system of roads was

developed. The roads radiating in many directions from Rome.

Some of those roads are said to be a very elaborate construction.

Many of the Roman roads are still in existence even after 2000

years. Romans were considered to be the pioneers in road

construction. With the fall of Roman Empire, the road building

technique became a lost art.

c. Modern roads.

In eighteenth century, improved construction methods for roads

again began to develop. Mr. Pierre Tresaquet developed an

improved method of construction in 1764 in France. At the time

when Mr. Pierre Tresaquet was busy in developing his road

construction method, Mr. John Metcalf was engaged in his

development in England. Metcalf constructed about 290 Km road in

northern region of England. Telford and Macadam were the

pioneers in road development in England. Telford believed in using

heavy foundation stones over the soil sub-grade, while Macadam

advocated the use of compacted crushed aggregate layer at the

bottom. Macadam’s method of road construction is still in use and

is named after his name.

3. Comparison between Telford roads and Macadams roads are :

a. Telford roads are costlier than Macadam roads.

b. In the case of Telford construction, sub-grade was kept horizontal

due to which drainage of sub-grade was not proper. In the case of

Macadam construction sub-grade was given 1 in 36 cross slope.

This aspect helped in better sub-grade drainage.

c. Large size stones were adopted by Telford for foundation. Size of

stone varied from 17 cm near edges to 22 cm at the centre of the

17


road. In the case of Macadam roads 5 cm was the maximum size of

the aggregate used for foundation layer.

d. Cross slope in Telford roads was developed by using smaller size

stones at the edges and large size stones at the centre of the width.

Thicknesses of subsequent intermediate and surfacing layers, is

kept constant for the full width of the road. In Macadam roads,

required camber was given to the sub-grade itself and all the

subsequent layers of aggregate including foundation layer of

uniform thickness for the whole of the width of the road.

e. Telford construction is carried out in four layers namely foundation

layer, two layers of intermediate coat and 4 cm thick wearing top

layer. Macadam construction is done in three layers. Two layers

each of 13 cm compacted thickness as foundation layers and 5 cm

thick surfacing layer.

f. In Telford roads, camber given was 1 in 45 while in Macadam it

was 1 in 36.

g. Telford’s foundation layer, being of larger sized stones, behaved

like semi flexible road but Macadam’s base was yielding type and

hence Macadam roads behaved like fully flexible roads.

h. Total thickness of road structure was about 40 cm in case of

Telford but only about 25 cm in case of Macadam.

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1. Describe brie the characteristic of road transport..

2. Describe the method of construction for Macadam roads.

3. Classify the modes of transportation used in Malaysia.

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Question


1. The characteristics of road transport are as follows :

i. Roads can be used by all sorts of vehicles like bullock carts,

carriages, bicycles, scooters, cars, buses and lorries, etc.

They are equally useful for pedestrians also.

ii. Roads can lead to any remote place.

iii. Investment on road transport by government is

comparatively small. Maintenance of roads is also cheaper

than rail-track, docks, harbors and airports.

iv. There is complete freedom to road users to transfer the

vehicles from one lane to another, or from one road to

another according to the requirements.

v. Local communication among villages, villages and towns is

only possible through roads.

vi. Movements on roads are not time bound, as in case of

railways or airways.

vii. Road transport is the only mode of transport that offers itself

for the service of whole community alike.

2. Method of Construction for Macadam roads

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Answer


Sub-grade was prepared and compacted to the required

width of the road. Prepared sub-grade was given the same camber,

as to given to the finished road surface. Construction of road

according to Macadam method consists of three layers, namely,

foundation layer, intermediate layer and wearing surface layer.

Foundation layer was 10 cm thick (compacted) and was made from

5 cm size aggregate. Intermediate layer was also 10 cm thick

(compacted) but made from aggregate passing 40 mm sieve.

Lastly, wearing surface was made 5 cm thick (compacted) using

aggregate passing 20 mm sieve. Cross slope of finished surface

was kept as 1 in 36.

In those days, there were no rollers to affect thorough

compaction and interlocking, and hence, this action was used to be

achieved by means of traffic. This was the reason that next layer

could not only be laid once the previously laid layer gets thoroughly

compacted. Macadam method was first scientific method based on

modern concepts and hence is still in use in most parts of the

world, though with certain modifications.

3. Modes of transportation can be classified as follows:

a. roadways or highways

b. railways

c. water ways

d. airways

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