ContentsIntroduction

Classification of Highway

Materials Used In Highway Construction

Machinery Used In Highway Construction

Maintenance And Rehabilitation

IntroductionA line of communication (travelled way) using a

stabilized base open to public traffic, primarily for theuse of road motor vehicles including "bridges, tunnels,supporting structures junctions, crossings and tollroads.

The first research dedicated to highway engineeringwas initiated in the United Kingdom with theintroduction of the Transport Research Laboratory(TRL), in 1930.In the USA, highway engineering becamean important discipline with the passing of the Federal-Aid High,way Act of 1944

Classification Of Highway National Highways

Important roads &connect state capitals, ports andforeign highways. They also include roads of militaryimportance. They are financed by the. centralgovernment

State Highways

Connect important cities and district head quarters inthe state, national highways & state highways ofneighbouring states. Financed by state governmentroads and buildings department.

District Roads

These are the roads within a district.

i) Major District Roads

ii) Minor District Roads

Village Roads

They connect villages with each other and to thenearest district road.

Highway StructureRoads Road Structure Depends Upon the key What is

it for! There are two main types of pavement (road structure)

i) Flexible Roads ii) Rigid

Flexible Carriageway Construction

When a road is built, the surface is dug-out down to the designed depth of the intended road. The sub-grade is the ground below the road layers which is exposed once the ground has been dug out ready to build the road.

--------------------------------------Surface Course

--------------------------------------Binder Course

--------------------------------------Base

--------------------------------------Sub - Base

--------------------------------------Capping

- - - - - - - - - - - - - - - -Sub – Grade

Rigid Highway Construction

Rigid pavement is the technical term for any roadsurface made of concrete.

The largest advantages to using concrete pavementare in its durability and ability to hold a shape.

A surface layer, made up of slabs of Portland cementconcrete (PCC), sits on top of a handful of sub-layers.

The layer directly under the PCC is more flexible thanthe concrete, but still quite rigid.

Materials Used In Highway Construction1.Asphalt

Asphalt also known as bitumen is a sticky, black andhighly viscous liquid or semi-solid form of petroleum.

Asphalt is used in road construction, where it is usedas the glue or binder mixed with aggregate particlesto create asphalt concrete.

It is use to prepare asphalt emulsion, Hot mix asphaltconcrete, cold mix asphalt concrete.

Aggregates1.Granite aggregates are crushed hard rock of

granular structure, being the most common on Earth.

Fractions of Aggregates

0-5mm the smallest granite aggregates fractions areused, besides the road construction, for decorationand paving paths, for covering sports grounds.

5-10mm fraction, is used for road construction andproduction of concrete.

10-40mm a road sub base also used for roadmaintenance operations.

2.Gravel aggregates are aggregates acquired as the result ofsifting quarried rock and by crushing natural stonerock.

3. Limestone aggregates are a product of the crushing ofsedimentary rock - limestone, which is composedmainly of calcite (calcium carbonate ).

4.Slag Aggregates are obtained by crushing of smelter slagor by special treatment of fire-liquid slag melt(molten slag aggregates).

Machinery used in Highway ConstructionMachinery used in road constructions are used for

rough grading, fine grading, surfacing, paving,compaction and to control moisture level.

AIR-TRACK DRILLA drilling machine for quarry or opencast blasting

equipped with tracks and operated by independentair motors.

AIR-TRACK DRILL

CHIP SPREADERA chip spreader lays down the aggregate on top of a

bituminous binder which is then rolled by acompactor.

COLD PLANERSA cold planer (also known as a pavement planer,

pavement recycler, mill or asphalt milling machine) isa machine used to remove bituminous pavement orasphalt concrete from roadways.

CompactorsUsed for compactions

Vibratory Steel Drum compactorVibratory roller compactor is used to compact soil,

gravel, concrete, or asphalt in the construction ofroads and foundations.

Pneumatic tired rollerPneumatic tire compactors are used on small to

medium size compaction jobs, primarily on bladed,granular base materials.

Padded Drum CompactorPadded drum compactors are usually applied to

compact soil, gravel, concrete, or asphalt in theconstruction of roads and foundations.

OIL DISTRIBUTORSAsphalt distributors are used to apply prime or tack

coats on a surface in preparation for paving.

PAVERA paver is a machine used to lay asphalt on roadways.

It is normally fed by a dump truck which brings hotasphalt.

Maintenance and Rehabilitation

Roads are exposed to tremendous loads that willsooner or later leave their marks on them. A time willcome when every road will be in need of a generaloverhaul. Following methods are used.

Replacing the PavementBy removing only those layers of a road structurethat are actually damaged.

Additional conditions frequently stipulate that theflow of traffic must be maintained in spite ofextensive reconstruction measures.

Replacing the Pavement

Paving thin Layer HotPaving thin layers in hot application is a viable option

for rehabilitating of Limited damaged roads.

At first surface deformations are removed by coldmilling machines fitted with fine milling drums tocreate an even, slightly roughened road surface.

When using a paver with integrated spray module,the paver seals the base by spraying a tack coat ofpolymer-modified bitumen emulsion with a minimumbitumen content of 60% .

Paving thin layers Cold

Fast and economically efficient alternative to replacing the entire road pavement.

Traffic safety is hazarded when the road surface getsslippery, when wheel ruts have dug into thepavement, or when the road is covered with bumpsand deformations.

Cold milling machines fitted with fine milling drumsprepare the road surface for application of the thin,cold pavement layer.

It works at a maximum milling depth of 50 mm,reprofiling the pavement by means of modernlevelling technology to produce a level surface. Theslightly roughened surface texture produced by finemilling offers.