A Road is a thoroughfare, route, or way on land
between two places, which has been paved or
otherwise improved to allow travel by
some conveyance, including a horse, cart, or motor
vehicle. Roads consist of one, or sometimes
two, roadways) each with one or more lanes and also
any associated sidewalks and road verges. Roads that
are available for use by the public may be referred to
as public roads or highways.
WATER BOUND MACADAM
• Macadam is a type of road construction pioneered by
Scottish engineer John Loudon McAdam around 1820.
• The method includes single-sized aggregate layers of
small stones, with a coating of binder as a cementing
agent, mixed in an open-structured roadway.
• McAdam's road building technology was applied to
roads by other engineers. One of these engineers was
Richard Edgeworth, who filled the gaps between the
surface stones with a mixture of stone dust and water,
providing a smoother surface for the increased traffic
using the roads.
• This basic method of construction is sometimes known
as water-bound macadam. Although this method
required a great deal of manual labour, it resulted in a
strong and free-draining pavement.
• Roads constructed in this manner were described as
TAR BITUMEN ROADS
• The term bituminous materials is generally taken to include all materials
consisting of aggregate bound with either bitumen or tar. Materials of this
kind are used almost exclusively in road construction.
• The generation of dust from McAdam’s roads lead to the use tar as a
dressing to bind the surface
• Tar was most suitable for this purpose as it could be made into a fluid on
heating and stiffened on cooling.
• Tar also protects the road from the effects of water.
• Bitumen was found to be less temperature susceptible than tar thus more
harder and stiffer than tar
• It was resistant to deformation at high temperatures and softer than tar at
• Asphalt also known as is a sticky, black and
highly viscous liquid or semi-solid form of petroleum.
• It may be found in natural deposits or may be a refined
• The primary use (70%) of asphalt/bitumen is in road
construction, where it is used as the glue or binder mixed
with aggregate particles to create asphalt concrete.
• Asphalt concrete is a composite material commonly used
to surface roads, parking lots, and airports. It consists
of mineral aggregate bound together with asphalt, laid in
layers, and compacted.
• Asphalts rely on their dense, stiff mortar for strength and
• An asphalt concrete surface will generally be
constructed for high-volume primary highways having an
average annual daily traffic load greater than 1200
vehicles per day.
• Advantages of asphalt roadways include relatively low
noise, relatively low cost compared with other paving
methods, and perceived ease of repair.
• Disadvantages include less durability than other paving
methods, less tensile strength than concrete, the
tendency to become slick and soft in hot weather and a
certain amount of hydrocarbon pollution to soil
and groundwater or waterways.
CEMENT CONCRETE ROAD
• Concrete surfaces (specifically,
Portland cement concrete) are
created using a concrete mix
of Portland cement, coarse
aggregate, sand and water .
• Concrete (cement) is produced
from abundantly available
• Concrete roads have a long service
life of forty years and during this
service life concrete road do not
require frequent repair or patching
• A vehicle, when run over a
concrete road, consumes 15-20%
less fuel than that on asphalt roads.
• This is because of the fact that a
concrete road does not get
deflected under the wheels of
• Soil stabilization is a way of improving the weight bearing capabilities and performance
of in-situ sub-soils, sands, and other waste materials in order to strengthen road surfaces.
• The prime objective of soil stabilization is to improve of in-situ soils by 4 to 6 times.
• The other prime objective of soil stabilization is to improve on-site materials to create a
solid and strong sub-base and base courses.
• In certain regions of the world, typically developing countries, soil stabilization is being used
to construct the entire road.
• In the past, soil stabilization was done by utilizing the binding properties of clay soils,
cement-based products, and/or utilizing the "rammed earth" technique and lime.
• As technology evolved, there have now emerged new types of soil stabilization techniques,
many of which are classified as "green technologies".
• Traditionally and widely accepted types of soil stabilization techniques use products such as
bitumen emulsions which can be used as a binding agents for producing a road base.
• However, bitumen is not environmentally friendly and becomes brittle when it dries out.
• Portland cement has been used as an alternative to soil stabilization.
A Pavement in construction is an outdoor floor or superficial
surface covering. Paving materials include asphalt, concrete,
stone such as flagstone, cobblestone, and setts, artificial
stone, bricks, tiles, and sometimes wood.
In landscape architecture pavements are part of
the hardscape and are used on sidewalks, road
surfaces, patios, courtyards, etc.
• Laterite, also called as murram, varies considerably in the proportion of
stones (which are usually very small) to earth and sand.
• It ranges from a hard gravel to a softer earth embedded with small stones.
They may be referred to as 'dirt roads' in common speech, but that term is
used more for unimproved roads with no surface material added.
• Compared to sealed roads, which require large machinery to work and
pour concrete or to lay and smooth a bitumen-based surface, Murram
roads are easy and cheap to build.
• Murram which contains a significant proportion of clay becomes very
slippery when wet, and in the rainy season, it may be difficult even
for four-wheel drive vehicles to avoid slipping off very cambered roads
into the drainage ditches at the side of the road.
• As it dries out, such laterite can become very hard, like sun-dried bricks
• Block paving also known as brick paving is a
commonly used decorative method of creating
a hard standing.
• The main benefit over other materials to create a
hard surface are that the individual bricks that go
together to make up the block paved surface are
able to be lifted up and then replaced.
• This allows for remedial work to be carried out
under the surface of the paving without any visible
notice to the surface once the paving bricks have
• This kind of brick paving is said to be flexible
• Typical areas of use would be for
driveways, pavement, patios, town centre's, precin
cts and more commonly in road surfacing.
• There are two common makes of block paving
brick, concrete and clay. Although other composite
materials do exist to make up an individual
brick. There are many different laying patterns that
can be achieved using block paving.
• The most common of these is
the herringbone pattern. This pattern is the
strongest of the block paving bonds as it offers the
most interlock, therefore making it a good choice
for driveways and road surfacing.
• Stone fulfills all the conditions of a good
• It is the most durable material for
• It is comfortable for travelling, clean, dirt
free, noise free and does not require
• It is cheap
• The nature of stone prevents its ever
becoming smooth or polished by use and
hence it presents as good and firm a foot
• Being uniform in its texture or hardness,
it wears equally
• The closeness of the joints prevent little
or no water penetration and it is never
affected by frost and it never get into
• Usually granites are used for the purpose
of paving but stones which are hard and
fine grained, containing very little mica,
and which is very similar in texture, color
and hardness are also used.
Water on or under the roadway is the single most
significant cause of damage to the roadway. Problems
related to water include rutting, cracking, potholes,
erosion, washouts, heaving, flooding, and premature
failure of the roadway.
To prevent these problems and help ensure a roadway
achieves its designed service life, a drainage system is
A good drainage system includes several elements, all of
which must function properly and be well maintained:
• Surface drainage
• Subsurface drainage
• Culverts ,ditches and gutters.
• Road surface drainage deals with the drainage of storm water runoff from
the road surface and the surfaces adjacent to the road formation.
• Several elements can be used to intercept or capture this runoff and
facilitate its safe discharge to an appropriate receiving location.
• After falling onto road surfaces, rainfall runoff drains to the lowest point
and in moving across the road surface forms a layer of water of varying
• This water can be a hazard to the motorist. Splash and heavy spray are
thrown up by moving vehicles reducing visibility, whilst the water on the
pavement reduces friction between the tires and road surface.
• Design of the elements for this runoff must adequately cater for the safety
and convenience of road users, including pedestrians and protect adjacent
properties and the road pavement from damage.
• A road’s crown should have
sufficient slope from the
pavement centerline to the
edge to make water
effectively drain off the
• When the slope is too flat,
water can pond on the
surface and migrate through
joints and cracks into the
pavement or under the
• This can lead to pavement
cracking and potholes. Water
that doesn’t drain off the
roadway can also present a
safety hazard to motorists
To aid in drainage, shoulders should be flush with the adjacent
roadway, slope slightly away from the roadway, and have no erosion
problems or secondary ditches. Earth shoulders should be mowed
every now and then.
Slopes are normally referred to by the ratio of the run to the rise The
degree of foreslope and backslope is determined by design
standards and local conditions(e.g., cohesive soils, or rights of way).
Local conditions may require that slopes be designed and
constructed steeper or flatter than the design
• A subsurface drainage system carries water from beneath the pavement to appropriate
drainage features, like ditches or storm drains.
• The purpose of subsurface (or subsoil) drainage is to control the moisture content of the
pavement and the surrounding material in order to maintain pavement strength and
serviceability throughout the design life.
• The design and installation of subsurface or subsoil drains beneath / adjacent to road
pavements is essential where groundwater or seepage is known or considered to be present.
• Subsurface or subsoil drains are provided in order to avoid the following types of premature
• Loss of sub grade strength and shape due to an increase in moisture content in moisture
• Overload of the sub grade due to hydrostatic transmission of live load through a saturated
• Layer separation and pothole formation in the pavement.
• Subsurface drainage systems are generally installed in a road either to remove water from the
sub grade and pavement materials or to intercept water before it reaches the road structure.
• The elements of subsurface drainage include sub drains (under drains and edge drains).
Under Drains/Edge Drains
• A well-maintained system of transverse and
longitudinal drainage pipes effectively
intercepts and carries water out of the granular
layer. Under drains carry water from the
granular drainage layer to edge drains. Edge
drains are installed under shoulders,
longitudinally adjacent to the pavement.
• Edge drains are constructed during roadway
construction where a perforated pipe is
installed in a trench parallel to the roadway,
which is then backfilled with an open-graded
1. Caps of impervious soil are placed on top of
edge drains to prevent surface water from
draining into them.
2. Filters may be used to prevent fine-grained
soil from clogging the open-graded aggregate
or the pipe itself.
3. Water from the under drains is collected in a
non-perforated edge drain pipe that
discharges into a roadside ditch or a storm
All sub drains should maintain the flow lines and
the design slopes. The outlet water flow
should be clear and uniform, indicating that
erosion is not occurring and the system is not
• Culverts provide drainage
under driveways, roads,
slopes, and adjacent areas.
• Their grade and direction
should conform as closely
as possible to that of the
water they are carrying.
• Culverts are well
maintained when the flow
line and the design slope
from inlet to outlet still
• No sections have settled,
and all joints are tight and
• The curtain walls are not
exposed, and the
downstream channel has
not started to erode.
• Ditches collect runoff from
the road surface. A well-
flowing ditch will be free of
heavy vegetation (tall grass,
trees, cattails, etc.) and
standing water, with
enough grade to ensure
• Ditches with flat percent-of-
grade allow residue or
debris to settle and fill in
the ditch. If sediment
accumulates, water may
erode a new path outside
of the ditch area.
• A gutter is a depression running
parallel to a road designed to collect
rainwater flowing along the street and
divert it into a storm drain.
• A gutter alleviates water buildup on a
street, allowing pedestrians to pass
without walking through puddles and
reducing the risk of hydroplaning by
• When a curbstone is present, a gutter
may be formed by the convergence of
the road surface and the vertical face
of the sidewalk; otherwise, a
dedicated gutter surface made of
concrete may be present.