Geotextile in pavement

GEOTEXTILE IN PAVEMENT
REPORT
of the Seminar (CE4092) carried out for partial fulfilment of the award of the degree
in Bachelor of Technology in Civil Engineering
by
BHAG CHAND MEENA (B120915CE)
Department of Civil Engineering
NATIONAL INSTITUTE OF TECHNOLOGY CALICUT
August 2015

CERTIFICATE
This is to certify that this seminar entitled “GEOTEXTILE IN PAVEMENT” is a bona fide
record of the work carried out by
BHAG CHAND MEENA (B120915CE)
during Monsoon 2015-2016 in partial fulfillment of the credit requirements of CE4092 -
Seminar
Mr. Harikrishna M
(Seminar i/c)
Date:
i

ACKNOWLEDGEMENTS
I would like to thank god almighty, parents, teachers and friends who gave all their support
in completion of this report.
I would like to acknowledge the support of Mr. Harikrishna M., Course coordinator &
Assistance Professor, Department of Civil engineering National Institute of Technology,
Calicut, Who gave crucial advices and suggestions that are needed to complete this report.
I would like to express my deepest appreciation to all those who provided me the possibility
to complete this report.
ii

TABLE OF CONTENTS
Cover page 0
Certificate i
Acknowledgements ii
List of figures and tables iii
Abstract 1
1. Introduction 2
2. Types of geo-textiles 2
2.1 Woven type 2
2.2 Non woven type 3
2.3 Knitted type 3
3. Geo-textiles manufacture 4
3.1 Material required 4
3.2 Manufacture 4
3.21 Woven construction 4
3.2.2 Non-woven construction 5
3.2.2.1 Needle punching 6
3.2.2.2 Heat bonding 6
3.2.2.3 Resin bonding 6
3.2.2.4 Combination bonding 6
4. Placing of geo-textiles in pavement 7
5. Functions and application of geo-textiles in pavement 9
5.1 Separation 9
5.1.1 Cost saving 11
5.2 Filtration 12
5.3 Reinforcement 14
5.4 Drainage 15
5.5 Errosion control 16
6. Conclusion 17
7.References 17

LIST OF FIGURES AND TABLES
1. FIGURES-
1. Direction and dimension of woven geo-textiles
2. View of different types of geo-textiles
3. position of geotextile
4.placing of geotextiles
5.geotextile as separation layer
6.placing of separation layer
7.comparision between cost of geotextile and aggregate
8.geo-textiles in filteration
9.geotextile as reinforcement
10. geotextile in drainage
11.geotextile in erosion control
iii

1
ABSTRACT
A geotextile is a class of industrial-grade textile that is composed of polypropylene and/or
polyester resin (products of the oil refining process) that have yarns.Yarns have property of
chemical and thermal bonding to make a flat permeable sheet.Other types of textiles are also
available. Mainly geotextiles have four functions in pavement-separation, drainage, filtration
and reinforcement. Pavements typically consist of a bituminous or concrete surface,
aggregate base layer, or support layer and then the natural soil subgrade. Geotextiles prevent
the mixing of the fine subgrade soils with the aggregate support layer. By preventing this
mixing, geotextiles prevent early deterioration of roadways.
To quantify the improvements in geosynthetically-stabilized pavement two tests are to carried
out. From both experiments, it can be analysed that how the geosynthetically-stabilized
pavement is different from pavement without geotextiles.
These are 2 tests on pavement-1.falling weight deflometer(FWD)
2. surface rutting of the pavement

2
1. INRODUCTION-
Geo-textiles are defined as a permeable geo-synthetic material or we can say these are the
permeable fabric which has ability to separate,filter,reinforce and protect,when used with
soil.These are generally made up of polypropylene or polyester,but other ingradients are also
there they are-polyamide (nylon), polyvinylidene chloride, and fiberglass.There are many
forms available of geo-textiles in its producing companies.Among the different geo-
synthetics geo-textile is present in a wide range with respect to its properties,that’s the reason
it is used in various forms. Geo-textiles are probably one of the first textile products in human
history,and now it has become the need of every highway construction.It has been using from
last 30 years successfully but now the numbers and types ofgeo-textiles manufactured with
aspecific focus in roadway design has increased dramatically. This increase has resulted in
many new performance-enhancing and cost-saving design alternatives for roadways.
Water has lot of effect on pavement surface. In fact, moisture damage in asphalt pavements is
global concern. In situation when rainwater is not properly drained off the pavement surface,
it will penetrate into the pavement thereby deteriorating the pavement layers. Geo-textiles
when used for drainage purpose. Key characteristics of drainage geo-textile are the AOS
(Apparent Opening Size), which indicates the size of openings in the material, and flow rate,
which indicates how much water, can pass through the geo-textile. And this function of geo-
textiles comes first in the list.
Geo-textiles basically comes in 3 forms, based on that geo-textiles are classified-
2.TYPES OF GEOTEXTILES-
1. Woven fabrics
2. Non woven
3. Knitted fabric
2.1 WOVEN FABRIC-
As per The Great Soviet Encyclopedia(1979), article produced by weaving should be
interlocked by perpendicular threads- warp in longitudinal and weft in transverse direction. In
certain cases to form a nap or patterns some other additional systems of threads can also be
adopted. Wovenfabricsarethe mostcommontextiles;theymay be produced as cloth or

3
finishedgoods,such as kerchiefs or tablecloths. Woven fabrics are thin(usually less than
5mm), wide(generally up to 1.5m and sometimes up to 12m) and of varying length.
Example of woven fabric-Linen, denim, cotton twill, satin, chiffon, corduroy, tweed and
canvas.
2.2 NON WOVEN-
When it is asked to some average person, it seems to be very new term, because It is not like
traditional woven fabric.It is something modern and advanced term is somewhat clearer to the
experts.
Nonwoven fabrics are not based on yarn, these are based on webs of individual fibers. Or we
can define it as sheet or web structures (long fibers) bonded together by entangling fiber or
filaments (and by perforating films) mechanically, thermally, or chemically. They are flat,
porous sheets that are made directly from separate fibers or from molten plastic or plastic.
Some nonwoven materials lack sufficient strength unless densified or reinforced by a
backing. In recent years, nonwovens have become an alternative to polyurethane.
Non woven geo-synthetics can be manufactured from either short staple fiber or continuous
filament yarn.
Uses of nonwoven fabrics-isolation gowns, surgical gowns, surgical drapes and covers,
surgical scrub suits, caps, sterilization, gloves, shoe covers.
2.3KNITTED FABRIC-
Knitted geo-synthetics are manufactured using another processwhichis adopted from the
clothing textiles industry, namely that of knitting. In this process interlocking a series of
loops of yarn together is made. All of the knitted geo-synthetics are formed by using the
knitting technique in conjunction with some other method of geo-synthetics manufacture,
such as weaving.

4
Fashion designers prefer this type of fabrics for its comfort, texture, wrinkle resistance, and
elasticity. Additionally, knit fabric is easy to sew with the right machine and stitching
technique. It has characteristics that endear it to crafters and wearers alike.
These fabric have different properties then woven type. These are flexible than woven type
and can be constructed into more small pieces than that type, making it ideal for socks and
hats.
Its properties are different from nonwoven fabric with respect to its durability, that it is more
durable but takes more resources to create, making it suitable for multiple uses.
3 GEO-TEXTILES MANUFACTURE-
3.1 MATERIAL REQUIRED-
As earlier stated geo-textiles are made of polypropylene, polyester, polyethylene, polyamide
(nylon), polyvinylidene chloride, and fiberglass,In which polypropylene and polyethylene are
most ingradients. A thread is required for geo-textiles that is made of Kevlar or any of these
materials above. By changing the processing methods used to form the molten material into
filaments and by the use of additives in the composition, the properties of these polymers can
be changed. Bundled and twisted fibres are used to form yarns, by the process known as
spinning. Yarn maybe used as a long fibre (filaments) or short pieces cut from cut from
filaments (staple fibers).
3.2 MANUFACTURE-
There are 2 types of construction of geo-textiles-1. Woven construction
2. Non-woven construction
3.2.1 WOVEN CONSTRUCTION-
Weaving methods is traditional and old method from which woven geo-textiles can be
manufactured, that isplain weave, basket weave, twill weave, and satin weave. Geotextile has
equal or different strengths in the warp and fill directions because of the variation in
construction. Multifilament woven construction produces highest strength and modulus of all
the construction, but costs also highest.

5
Ref.-3
Fig.1-Direction and dimension of woven geo-textiles
3.2.2 NON-WOVEN CONSTRUCTION-
These are thicker than woven. These can be made of either continuous filament or from staple
fibres. These fibres lies in geo-textile oriented randomaly, but can be given a preferable
orientation. In spun-bonding process the filament are to be laid directly on moving belt to
form mat, which is then can be bonded by using of any of these processes-
1. Needle punching.
2. Heat bonding
3. Resin bonding
4. Combination bonding.
3.2.2.1 NEEDLE PUNCHING-
It is the process of pushing many needles into the one or more layers of the fibre normal to
the geo-textiles plane. The process causes mechanical effect and results in geo-textiles has an
appearance of felt mat.
3.2.2.2 HEAT BONDING-

6
This is done by fibre having same polymer type but different melting point in the mat, known
as incorporating fibres or by using hetrofilaments, that is fibre composed of one type will be
inside and fibre having low melting point will be covered all around.
3.2.2.3 RESIN BONDING-
Resin is used into the fibre mat for coating the fibre and for good bonding between fibres.
3.2.2.4 COMBINATION BONDING-
Used sometimes to get desirable properties.
Ref.2
Fig.2- View of different types of geo-textiles
4. PLACING OF GEO-TEXTILES IN PAVEMENT-
Pavements typically consist of a bituminous or concrete surface, an engineered aggregate
base, or support layer and then the natural soil subgrade. Geo-textile is used as a support layer
that has many advantages. It is to be placed just above the subgrade and below the base
course.

7
Ref.2
Fig.3- position of geotextile

8
Ref.1
Fig.4-placing of geotextiles

9
5.FUNCTIONS AND APPLICATIONS OF GEO-TEXTILES IN
PAVEMENTS-
Every textile product used in soil is geo-textile, it is used in reinforcement of streets,
embankments, ponds, pipelines, and similar applications. Depending on the required
function, they are used in open-mesh versions, such as a woven or, rarely, warp-knitted
structure, or with a closed fabric surface, such as a non-woven. Mode of geo-textile in
pavement is defined by these functions-
1. Separation
2. Filtration
3. Reinforcement
4. Drainage
5. Erosion control
5.1 SEPARATION-
Geo-textile layer as a separation layer tends to prevent the mixing of two dissimilar material
so that they can perform effectively, and life of structure can be improved or better use of
material provided.
For example, a major cause of failure of roadways constructed over soft foundations is
contamination of the aggregate base course with the underlying soft subtotttgrade soil. So a
geo-textile is provided between aggregate layer and subgrade that acts as separator,
minimizing the contamination of aggregate base by subgrade.
The roads are classified into two categories- 1. Paved
2. unpaved
Separation is mainly used in unpaved type that allows the vertical deflection of 25mm and
constructed with a poor subgrade.

10
Ref.2
Fig.5-geotextile as separation layer
• Use of geo-textile separator prevents the mixing of base and sub-base.
• When this is used a greater densities can be achieved in filled materials.
• Reduces pore water pressure that results in increasing consolidation in subgrade.

11
• To reduce fines pumping, thick geo-textiles are preferred.
• In initial stages of construction geo-textiles provides a better platform to work, so it is
easy to handle.
Nowadays this is being used in low cost paved road also.
Conclusively this is a function of geo-textiles to prevent the ingress of fines into the sub-base
and to allow the transverse drainage of excess porewater, which permits a reduction in
layerwork thickness. Maintenance which would otherwise be incurred is also reduced.
Ref.1
Fig.6-placing of separation layer
5.1.1COST SAVINGS-
As per Chair, Flintsch, Trani.,“Effectivness of using geotextitles in flexible pavements: life-
cycle cost analysis”Feb 27, 2006. Cost of provided separation layer is less than the cost of
1inch of bas course layer, and it prevents the whole base/sub-base, therefore the benefit
significantly over-weigths the cost of its construction.
As early as 1994, a joint American Association of State Highway and Transportation
Officials (AASHTO) industry task force identified “quantifying life cycle cost-benefit of
pavements incorporating geotextile separators”

12
Ref.1
fig.7-comparision between cost of geotextile and aggregate
5.2 FILTRATION-
This is the oldest function of geo-textiles, most widely known and most used.
It is defined as the equilibrium of a geotextile-soil system that allows for adequate liquid flow
with limited soil loss across the plane of the geo-textile over a service lifetime compatible
with the application under consideration.
In filtration fabric can be woven or non-woven for passes the water and retaining the soil
particles. Porosity and permeability are the major properties of geo-textile that are to
consider in filtration. This system should achieve an equilibrium that permits for adequate
liquid flow under conditions of consideration. If the flow of liquid is perpendicular to the
plane of geo-textile, filtration known as cross plane hydraulic conductivity or permittivity,
that is given by
Where is the permittivity, is the cross-plane hydraulic conductivity, and is the
geotextile thickness at a specified normal pressure.

13
Apparent opening size (AOS) is also important relevant property of geo-textiles in filteration.
the opening size larger than 95% of the geo-textile’s pores which is compared to soil particle
size characteristics.
Ref 1&2
Fig8.-geo-textiles in filteration

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5.3 REINFORCEMENT-
It is a significance increase in strength of pavement, created by the introduction of geo-
textiles into pavement layer. In US this function is fulfilled by using geo-grids instead of geo-
textiles. In most cases Geo-textiles interacts with soil to resist frictional and adhesive force.
This is condition for reinforcement that A geo-textile must have a sufficient strength and
embedment length to resist the developed tensile force, and strength must be developed at
small strains to prevent excessive movement of reinforced structure.
Mechanism-
• Lateral restraint through friction between soil/aggregate and geo-textile. When
transportation moves on a road it try to move laterally, unless it is restrained by geo-
synthetic reinforcement or subgrade. soft and week soil allows more movement so
rutting develops and that become a problem by the movement of aggregate, and that
can be prevent by geo-textile having a good resistant capability.
• Increased bearing capacity i.e., by forcing the potential bearing surface failure plane
to
develop at alternate higher shear strength surface.
• Membrane type of supportof the wheel loads.
Ref.1
Fig.9-geotextile as reinforcement
5.4 DRAIANGE- According to Sharma, Kanaungo, Khatri.,2014,“Application
ofGeotextilesinPavementDrainageSystems,International Journal of Civil Engineering
Research.volume” 5(4),385-390, Geo-textiles acts as the a conduit for the movement of liquid

15
or gases in the plane of geo-textiles, while functioning for drain. Examples are geotextiles
used as wick drains and blanket drains. The relatively thick nonwoven geotextiles are the
products most commonly used. Selection should be based on transmissivity, which is the
capacity for in-plane flow.
Ref.1
Fig.10-geotextile in drainage
5.6 EROSION CONTROL-
In erosion control the geotextile protects soil surfaces from the tractive forces of moving
water or wind and rainfall erosion. Geotextiles can be used in ditch linings to protect erodible
fine sands or cohesionless silts. The geotextile is placed in the ditch and is secured in place by
stakes or is covered with rock or gravel to secure the geotextile, shield it from ultraviolet
light, and dissipate the energy of the flowing water. Geotextiles are also used for temporary
protection against erosion on newly seeded slopes. After the slope has been seeded, the
geotextile is anchored to the slope holding the soil and seed in-place until the seeds germinate
and vegetative cover is established. The erosion control function can be thought of as a
special case of the combination of the filtration and separation functions.

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Ref.1
Fig.11-geotextile in erosion control
6 .CONCLUSION-
• Geotextiles are very important part of pavement construction regarding its strength,
durability, and working performance.
• Very useful in case of silt and clay
7. REFERENCES-
1. Sharma, Kanaungo, Khatri.,2014,“Application
ofGeotextilesinPavementDrainageSystems,International Journal of Civil Engineering
Research.volume” 5(4),385-390
2.Chair, Flintsch, Trani.,“Effectivness of using geotextitles in flexible pavements: life-cycle
cost analysis”Feb 27, 2006.
3. Guyer, Pe, Ra. 2009, “An introduction to geotextile in pavement and drainage
application”, C02-019

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