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In order to fulfill growing population, India needs to develop

quality, reliable, sustainable and resilient infrastructure,

including regional and trans-border infrastructure to

support economic development and human well-being,

with a focus on affordable and equitable access for all.

India is currently ranked 70 out of 140 countries for

infrastructure quality in the Global Competitiveness Index.

Similarly on the quality of road infrastructure (rank 48),

adoption of standards in the coming years will deliver better

results.

Sustainable road construction: current practices and future

concepts

The road sector produces the highest level of greenhouse

gas, directly, through fossil energy used in mining,

transportation, paving works...

Besides, huge challenges await the road construction sector

such as a cheaper and better production, construction and of

course maintenance, all the more as raw materials are

becoming scarce and the environmental laws are getting

stricter regarding air pollution and noise disturbances. Like

the rest of the sectors, the road construction sector needs to

face the challenge of sustainability.

Role of Geosynthetics for building Sustainable roads

Conventional construction material like aggregates is

becoming progressively scarce on account of environmental

concerns as well as legal restrictions on quarrying while the

construction activity has expanded phenomenally. This has

shifted focus from large scale use of conventional aggregates

to use of local, recycled and engineered marginal aggregates

in construction.

Geosynthetics can enhance the properties of such recycled

and engineered marginal aggregates in construction.

Enhancing performance and reducing maintenance and

thereby increasing comfort and minimizing interruptions to

smooth flow of traffic.

Use of Geosynthetics for various applications in road

pavements optimizes the total cost of project as these

materials reduce the use of natural aggregates significantly.

This in turn reduces the construction period and impact of

carbon footprint on the environment.

To summarize, with the use of geosynthetics, apart from

technical and environmental benefit the direct cost benefit

of 10% to 30% can be achieved based on the site condition

and availability of natural aggregates.

Applications of Geosynthetics for Road ConstructionImportant applications of geosynthetics in developing good

transportation infrastructure include: Ÿ Use of Biaxial Geogrids and Geotextiles for subgrade

separation and stabilization Ÿ Use of Biaxial Geogrids and Geocells for the

reinforcement/stabilization of granular base and sub-

base courses of pavements Ÿ Use of Paving fabrics, and Asphalt Interlayer Composite

in asphalt pavements Ÿ Use of Drainage Geocomposites for behind the retaining

structures & subsurface drainage of pavementsŸ Use of uniaxial Geogrids and Geostraps for

reinforcement of fills for the construction of reinforced

soil walls and steep slopes Ÿ Use of Gabions and Geocells for retaining structures and

slope protection and stabilization Ÿ Use of high strength polyester Woven Geotextiles,

Geogrids, Geocells and PVD's for ground improvement

for embankments and reclamation fills on soft ground

Use of geosynthetics in Roads and Provisions in Indian

Codes

The new IRC SP 59: 2019 emphasizes on detailed design

methodology, specifications, construction guidelines,

standard test methods, handling and storage of all the

geosynthetics for road pavement applications.

IRC 37: 2018 “Design of Flexible Pavements” also advises for

usage of Geosynthetics in cost optimization, complex site

conditions and minimization of natural aggregates.

Indian Infrastructure andRole of Geosynthetics

August - 202072CONSTRUCTION TECHNOLOGY TODAY

PAVEMENT STABILISATION WORKS IN

AMARAVATI, ANDHRA PRADESH

Project : Construction of E10, E14 and

N16 roads in AP new capital city, Amravati Client : Amravati Development Corporation Ltd.Product and Quantities : Techgrid PP Biaxial 30/30

Geogrid – 2,50,000 Sqm and

Techgeo PN 25 Non-Woven

Geotextile – 2,50,00 SqmProblem : The major challenge was to

develop a ring road on the

agr icultural f ie lds which

contain black cotton soils

having more than 200%

s we l l i n g i n d ex . S o, t h e

government is taking all

necessary measures to adopt

the global technology to

strengthen the road network

a n d m a k e t h e r o a d

infrastructure more durable.Solution proposed:

After a careful evaluation of the project requirements and site

conditions, it was decided to reinforce the pavement section with

Techgrid PP biaxial 30/30 Geogrid + Techgeo PN25 Non-Woven

Geotextile at the subgrade level.

Specific to the roads developed in the Amaravati capital region of

Andhra Pradesh, the subgrade soil is purely black cotton with high

free swell index, wherein the current solution to counter the effect

of free swell index proposed is to prepare a subgrade of 0.5m with

sand before laying the pavement layers (Base and Sub base).

Figure 3: Typical Section of Reinforced Pavement with PP Biaxial

Geogrid and Non Woven Geotextile at the subgrade level

In this scenario addition of PP biaxial geogrid will further

improve the elastic modulus of the prepared subgrade by the

mechanism of lateral restraint and tension membrane effect.

This improvement in elastic modulus will minimise the strains

developed due to high expansiveness of existing subgrade.

Considering the effect of shallow ground water table, a non-

woven geotextile layer is provided below the geogrid. The

function of Non-Woven geotextile is to act as separation layer

between the subgrade layer and the granular base and sub

base layers.

Author by :Namrata Bichewar (Design Engineer)Manish Barot (Business Development Head)TechFeb India Industries

Figure 1: Shrinkage cracks in the existing subgrade soilFigure 1: Shrinkage cracks in the existing subgrade soilFigure 1: Shrinkage cracks in the existing subgrade soil

Rolls of Techgrid PP biaxialRolls of Techgrid PP biaxialGeogrid and Techgeo Non-WovenGeogrid and Techgeo Non-WovenGeotextile ready to be laidGeotextile ready to be laid

Rolls of Techgrid PP biaxialGeogrid and Techgeo Non-WovenGeotextile ready to be laid

Unrolling of Geogrid & GeotextileUnrolling of Geogrid & Geotextileand Inspection for any wrinkles and Inspection for any wrinkles Unrolling of Geogrid & Geotextileand Inspection for any wrinkles

Geogrid Overlaps of 150mm at the side edges

Spreading and compaction ofSpreading and compaction ofGSB material on the geogridGSB material on the geogrid+ geotextile layer + geotextile layer

Spreading and compaction ofGSB material on the geogrid+ geotextile layer

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August - 2020 73 CONSTRUCTION TECHNOLOGY TODAY

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