ROAD CONSTUCTION METHODs

Presented by

Group –5

Himgiri Yadav

Kamal nabh tripathi

Mohd. Sharique Pervez

Mamta

Supriya Pal

What is a road?

Road is a pathway used by the people to travel from one place to other in a shortest possible way with maximum riding comfort.

Why we needs roads?

It contribute in the following ways:-

It contribute to the economic development.

It contribute to the industrial development.

It help in the social and cultural development.

It interconnect all area and thus facilitate us to travel from one place to other.

why we needs good transportation system?We need because of the:Demand for transport infrastructure is rising by

around 10% a year. India has 1% of traffic and about 8% of worlds

fatalities.Average bus speed in metro cities is about 10-

12km/hr.Automobile sector area increases from 6.3

million in 2002-2003 to 11.2 million in 2008-2009.

Mumbai

Traffic is increasing very fast

OLD ROAD

Road construction methods:-

Various method under this heading are:- Earth road method. Gravel road method. Water Bound Macadam method. Bituminous method. Concrete Cement road method.

Earth road methodIt mainly consist of mainly earth as raw

material which is to be compacted.It is the cheapest type of road prepared

from natural soil.It has high camber and cross slope to

avoid erosion due to water in rainy season.

Construction Procedure

It consist of :-

Clearing of site .

Excavation and construction of fills to bring the road to a desired grade.

Shaping the subgrade.

Then the borrowed soil (it consist of mixture of two or more near soil) is dump on the subgrade and well compacted ,depth not exceed 10 cm .

Make the soil upto O.M.C level.

After this it is allowed to dry for few days before opening to traffic.

MeritsIt has following merits:-It is cheap.It has easy construction.It can be build with less skill.

Demerits of Earth Road

Its demerits contains:- It has low bearing capacity . Mainly for poor places. It get eroded vary quickly. It become slippery when wet.

Gravel road methodIt mainly consist of crushed stone as their

raw material.It is superior to earth road .It consist of two method:

A. Feather edge type:- In this the subgrade is uneven and the construction is done over it to obtain the desired cross slope.

B. Trench type:- In this subgrade is prepared by excavating a shallow trench.

Procedure for construction

It consist of the :- Clean the area. Make the subgrade upto desired cross slope. Crushed gravel aggregates are placed

carefully in the trench so as to avoid segregation .

Provide proper camber. Some water may be used to make there

compaction effective. Left for few days before opening.

Demerits

Its demerits are:- It does not provide comfortable ride. It become detereoted very soon. It can not hold very heavy traffic. It can not hold rain.

Merits

Its merits are:- It is superior to earth road. It does not become slippery when wet. It maintenance coast is low. It can hold medium traffic. It is easily constructed. It is cheap.

Water Bound Macadam Road Method

It was develop by the John Macadam(1756-1836)and was first person to suggest that heavy foundation stones are not at all necessary to be placed at the bottom layer of construction .

He uses water as the binding material.He uses different grades of stone for different layer.

Important Introduction sub grade drainage Good compaction. It uses scientific knowledge which says that in flexible

pavement stress is transfer by grain to grain or layer to layer method.

Construction ProcedureIt consist of the following procedure: Preparation of foundation for receiving the

WBM coarse.Spreading of coarse aggregates.Rolling and compaction.Sprinkling and Grouting .Binding material’s application.Setting and Drying.Checking of surface evenness and Rectification

of defects.

Merits It has following merits: It provide base coarse for top surface. It can be used with little care. It is a cheap method. It introduce the concept of sub-base drainage.

DemeritsIt has following demerits:- It detereoted very easily. It can not be used without surface covering. It aggregates get loose when water loose from

them.

Bituminous Road Method

It is the most common type of road construction. It main purpose is to protect the sub-base coarse

from wearing and tearing and to provide a smooth riding comfort.

It has no. of method. They are:-

1. Bituminous surface dressing:- It is provided over an existing surface to serve as thin wearing coat. It serve as water proof pavement. Dust proof in wet season and mud proof in wet season.

2 . Penetration Macadam: It is used as a base or binder coarse. In this bitumen is used as a cementing material to bind the aggregates and as a filler to fill the void.

3. Built –up spray grout: It consist of two layer composite construction of compacted crushed aggregates with application of bituminous binder after each layer for bonding and finished with key aggregates at the top to provide a total compacted thickness of 75mm.

4. Bituminous Macadam: it is premixed construction method consisting of one or more coarse of compacted crushed aggregates premixed with bituminous binder . It consist of thickness of 75mm. It should be cover with suitable cover.

5. Bituminous Premixed carpet: It consist of coarse aggregates of 12.5 and 10mm size premixed with bitumen and composed to a thickness of about 20mm. It should be covered by a suitable seal coat. It aggregates consist of size between 20mm to 6.3mm.

6. Bituminous Concrete: it is a dense graded premixed bituminous mixture which is well compacted to form a high quality pavement surface course. Thickness ranges from 90 to 75mm. IRC has provided specification for 40mm thick bituminous concrete surface coarse for highway construction.

Construction ProcedureAll method has nearly same construction procedure.

Common steps to all the methods are:- Preparation of existing surface . Spreading of coarse aggregates. Rolling . Seal coat / Track coat. Surfacing finishing . Opening of traffic.

MeritsIt has following merits:- It is cheap. It provide good riding comfort. It hold the aggregates well. It prevent the wearing of sub-base.

DemeritsIt has following demerits:- It get detereoted. It design life in not long. It require frequent maintenance for heavy

traffic.

• It mainly consist of concrete & cement in its construction.

• It has nearly same concept of laying road slab as in the building slab.

• CC construction can be divided into :-

1. Construction of pavement slab:- In this we are concern about the construction of the road slab.

2. Construction of joints:- In this we are concern about the construction of the joints between the road the slab.

Concrete and cement road method

CC has two modes of construction which are:-

1. Alternate bay method :- In this we make alternate block of CC on the both lane in the same time , leaving gaps between them. It is usually not prefer today's.

2. Continuous bay method :- In this we make a lane upto certain length and the next lane is completed afterward. This is now days in practice.

Construction ProcedureIt has the following steps:- Preparation of subgrade & sub-base . It include-

1. Moist the sub-base in advance of placing concrete.

2. Sub-base should be well compacted and does not contain any soft spot.

3. It should have proper drained facility. Placing of forms- Steel and wooden forms

should be properly connected to the slab. Batching of materials in this the aggregates

are

graded to calculate the amount of cement require. Placing of concrete in this the concrete is properly

placed over the sub-base. Compacting and Finishing in this concrete is

compacted with the help of vibrator. It has two method-

A. Floating and Straight edges.

B. Belting, Brooming and Edging.Curing in this concrete is kept moist for about 28

days. It has two types:-

A. Initial curing.

B. Final curing

Cement-concrete road

Colure full cement Plain concrete

MeritsIt give best riding comfort.It is long design life.Further all the characteristic of road can be

easily predicted.It can bear any type of load.It does not get easily detereoted.It has sufficient friction both in wet and dry

condition.

DemeritsIt has high initial cost.It maintenance coast is high.It require time for completion.It require great skill.It maintenance time is also large.

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