There are two main types of roads: flexible and rigid. Flexible roads have asphalt surfaces and are composed of several layers including the pavement, base, sub-base, and sub-grade. Rigid roads have concrete surfaces and also have multiple layers providing structural support. Both road types aim to distribute vehicle loads across layers while allowing for drainage. Proper construction and material selection influence how long roads last before needing repair or rehabilitation.

2. ROADS/PAVEMENT
&
TYPES OF ROAD

3. • NAMESNAMES
ROLL #ROLL #
• SAAD UllaH
26
• MUHAMMAD KAMRAN 40
• HZMZA ANWAR 33
• SHEHZAD KHAN
35
• ARSALAN KHAN
25
• WASEEM AHMAD
R27

4. What is Road ?
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Introduction
 An open, generally
public way for the
passage of vehicles,
people, and animals.
Purpose :
Many rely on paved roads
to move themselves and their
products rapidly and reliably
Finish with a hard smooth
surface (pavement) helped
make them durable and
able to withstand traffic
and the environment.
Road pavements
deteriorate over time
due to the impact of
traffic, particularly
heavy vehicles, and
environmental factors.
Roads have a life
expectancy of
between 20 - 30 years.

5. Functions :
 One of the primary functions of a pavement is
load distribution which can be characterized by
the tire loads; tire configurations; repetition of
loads; distribution of traffic across the pavement;
and vehicle speed.
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6.  Several elements
make up the
roadway.
 Each layer
represents one of the
elements of the
pavement system.
 All these elements
work together to
provide a quality
durable pavement.
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Typical Components

7. Embankment
 When roads are built higher than the surrounding
ground, a structure of compacted earth called an
embankment is built.
 The embankment is built to support the other three
layers of the pavement system.
 Embankments can be made from almost any common
type of deposit except topsoil.
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8. Sub-grade
 The sub-grade is made of soils that have been specially
prepared to meet the requirements to support the other
two layers.
 The sub-grade is a selected soil material that is
carefully compacted to provide uniform support to the
pavement.
 The sub-grade lies directly on either the embankment or
the native soil.
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9. Base
 The base is a mixture of crushed rock.
 The base layer provides uniform support to the
pavement and allows water that penetrates any joints
or cracks in the pavement to move quickly to the sub-
drain without saturating and softening the sub-grade.
 The base layer lies directly on top of the sub-grade and
is built of clean sand or rock.
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10. Pavement
The top layer is the pavement.
The pavement materials can either be
Hot Mix Asphalt (HMA) and Portland
Cement Concrete (PCC).
The pavement itself resists bending, and
distributes vehicle weights over a large
area.
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11. Sub-Drain
 The sub-drain collects water from the base and the sub-grade and
drains that water.
 The sub-drain is basically a perforated pipe near the bottom,
surrounded by clean coarse-size rock which allows
rapid transportation of water.
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12. TYPES OF ROAD/PAVEMENT:
1. Flexible road/pavement
2. Rigid road/pavement

13.  Flexible pavements are those which are
surfaced with bituminous (or asphalt)
materials.
 Its "flexible" since the total pavement structure
"bends" or "deflects" due to traffic loads.
 Generally this type of pavement requires some
sort of maintenance or rehabilitation every 10
to 15 years.
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14. QSM 602
Each layer receives the
loads from the above
layer, spreads them out,
and then passes on these
loads to the next layer
below.
LOAD DISTRIBUTION

15. QSM 602
Material layers are usually arranged in
order of descending load bearing
capacity with the highest load bearing
capacity material (and most expensive)
on the top and the lowest load bearing
capacity material (and least expensive)
on the bottom…….

16. This is the layer (or layers) under the base
layer.
A sub-base is not always needed.
A proper sub-base consists of various sizes
of crushed stone aggregate, commonly
known as “crusher run”.
Depending on the sub soils on your site
you may need 8-12 inches of various sizes
of sub-base.
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Sub-base Course

17.  It functions primarily as structural support but it can also
help:
a) Minimize the intrusion of fines from the sub-grade
into the pavement structure.
b) Improve drainage.
c) Minimize frost action damage.
d) Provide a working platform for construction.
 The subbase generally consists of lower quality materials
than the base course but better than the sub-grade soils.
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Sub-base Course (CONTINUE)…..

18.  The first coat to be placed, on top of your
proper sub-base, is the base course .
 It provides additional load distribution and
contributes to drainage and frost resistance.
 The base is built of clean sand or rock.
 The base layer provides uniform support to the
pavement and allows water that
penetrates any joints .
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Base Course

19.  After the binder is put into place with paver, it is compacted with a
vibratory roller for tighter density and added strength.
 Base courses are usually constructed out of:
i) Aggregate: Base courses are most typically constructed
from durable aggregates that will not be damaged by
moisture or frost action.
ii) HMA: In certain situations where high base stiffness is
desired, base courses can be constructed using a
variety of HMA mixes.
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Base Course (Cont)

20.  This is the top layer which comes in contact with traffic.
 It normally contains the highest quality materials.
 It serves to prevent the entrance of excessive quantities of
surface water into the underlying base & sub-grade.
 It is sometimes subdivided into two layers:
i) Wearing Course: A layer in direct contact with traffic
loads. It is meant to take the impact of traffic wear and
can be removed and replaced as it becomes worn.
ii) Intermediate/Binder Course: It's main purpose is to
distribute load. It may compose of one or several HMA
sublayers.
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Surface Course

21.  Hot mix asphalt (HMA) is "the black stuff" used
as a pavement material.
 Its a combination of aggregate and asphalt
binder mixed together at elevated temperatures
that forms a hard, strong construction material
when cooled to suitable temperatures.
 Also known as "asphalt concrete" (AC), "asphalt",
"blacktop" or "bitumin“.
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Surface Course

22.  when it is well mixed, it is laid down on the roadway as
pavement.
 The pavement must then be compacted to achieve
uniform density.
 If this is not done properly, it can reduce the life time of
the pavement and increase the costs of maintaining the
road.
 It usually costs less.
 The life expectancy of an asphalt pavement is between
15 to 20 years.
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Surface Course

23. 2. RIGID PAVEMENT…
TYPE OF ROAD/PAVEMENT

24.  Rigid pavement composed of a PCC surface course.
 Such pavements are "stiffer" than flexible pavements
due to the high modulus of elasticity of the PCC
material.
 Further, these pavements can have reinforcing steel,
which is generally used to reduce or eliminate joints.
 Because of its relative rigidity, the pavement structure
distributes loads over a wide area with only one, or at
most two, structural layers.
 This type of pavement can serve 20 to 40 years with
little or no maintenance or rehabilitation and often used
in urban and high traffic areas.
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25.  This is the layer (or layers) under the base layer.
 The properties and function of this layer are
similar to as in flexible roads/pavements.
 A sub-base is not always needed and therefore
may often be omitted (OPTIONAL DEPENDING
ON SUBGRAGE OR SOIL).
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Sub-base Course

26.  This is the layer directly below the PCC layer and generally
consists of aggregate or stabilized sub-grade.
 It provides additional load distribution, contributes to
drainage, uniform support to the pavement and a stable
platform for construction equipment.
 Base courses are usually constructed out of:
a) Aggregate base.
b) Stabilized aggregate or soil.
c) Dense-graded HMA.
d) Lean concrete
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Base Course

27.  The surface course is the layer in contact with
traffic loads.
It consists of the PCC slab which is the stiffest
layer and provides the majority of strength.
 The surface course can vary in thickness but is
usually between 150 mm (for light loading) and
300mm (for heavy loads and high traffic).
 Portland cement concrete is used as pavement
material.
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Surface Course

28. Portland cement concrete is made by
mixing portland cement with water, and
coarse- and fine-size rocks.
It initially can be more expensive.
The life expectancy of portland cement
pavement varies, as little as 20 years or more
than 40 years.
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Surface Course

29. There are several factors that affect
pavement life:
Traffic volume
Quality of materials used
Construction practices, and
How well the other layers of the road
perform.
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30. Hard Shoulder
 Continuous strips alongside pavements, which vehicles
may drive during emergencies.
 Normally 3 m wide to fulfilled the functions of the slow
lane.
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31. Kerbs
 To define the limits of
carriageway.
 It is the dividing line
between
carriageway and
footpath.
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32. Drainage- Surface and Subsurface
 Road Chamber – Cross falls.
 To cope with heavy water run-off during a storm.
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33. Street lamps:
 Street lamps are
designed to
illuminate the
surrounding area at
night, not only as a
deterrent to criminals
but also to allow
people to see where
they're going.
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34. Road Markings:
 This furniture is any kind of
device or material that is
used on a road surface in
order to convey official
information.
 They provide guidance and
information to drivers and
pedestrians.
 They can be used to
delineate traffic lanes or serve
as noise generators when run
across a road.
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35. traffic Signs:
 They warn drivers of upcoming road
conditions such as a "blind curve",
speed limits, etc.
 Direction signs tell the reader the way
to a location.
 Direction signs are usually mounted on
poles.
 Illumination is added in order to aid
nighttime users.
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