Geotextiles and their applications in road construction, maintenance, and erosion control were discussed. Jute geotextiles, which are low-cost, renewable, and eco-friendly, are increasingly being used. Field experiments showed jute geotextiles can improve pavement performance when used as separators between subgrade and sub-base layers. They also helped improve ground conditions and reduced settlements for road embankments built on soft soil. Jute geogrids effectively controlled erosion on denuded slopes. Non-woven jute geotextiles also worked well for drainage and filtration applications in a hill road project. A case study described how a jute geotextile successfully controlled bank erosion along a

1. Geotextiles in Road Construction, Maintenance and Erosion Control
Geotextile applications are changing rapidly as research shows results and manufacturing processes improve.
Geotextile and their application in road construction, maintenance and erosion control were discussed in detail.
Fundamental considerations in design and installation were also discussed. India is a large producer of jute. Jute
is a low cost, renewable, biodegradable and eco friendly natural product. Jute-based geosynthetics is finding
increasing acceptability among geotechnical engineers primarily because of its eco concordance, facility of
production of tailor-made fabrics and price competitiveness. However civil engineers are still apprehensive
about its long- term effectiveness on account of its bio-degradability .Applications of Jute geotextiles in ground
improvement, Improvement in Pavement Performance, Erosion Control of Denuded Slopes and in Drainage and
Filtration Application presents an interesting picture. The paper also discusses the mechanism of erosion control
on surface and in the riverbanks followed by a case study in a river in West Bengal. In another case study on
strengthening of sub-grade in a road also in West Bengal the mechanism of functioning of Jute Geotextile has
been discussed.
A geotextile is any permeable textile material used with foundation, soil, rock, earth, etc. that is an integral part
of a constructed project,structure or system. It may be made of synthetic or natural fibers. In contrast; a
geomembrane is a continuous membrane-type liner or barrier. It must have sufficiently low permeability to
control migration of fluid in a constructed project, structure or system. A geotextile is designed to be permeable
to allow the flow of fluids through it or in it, and a geomembrane is designed to restrict the fluid flow.
Geotextile related materials are fabrics formed into mats, webs, nets, grids, or formed plastic sheets (Figure 1).
They are considered to be different from geotextiles.
History of Geotextile Applications
Textiles were first applied to roadways in the days of the Pharaohs. Even they struggled with unstable soils
which rutted or washed away. They found that natural fibers, fabrics or vegetation improved road quality when
mixed with soils, particularly unstable soils. Only recently, however, have textiles been used and evaluated for
modern road construction. This fact sheet clarifies the confusion over terms and definitions of geotextiles, and
discusses their common roadway and erosion control applications. In the 1920’s the state of South Carolina
used a cotton textile to reinforce the underlying materials on a road with poor quality soils. Evaluation several
years later found the textile in good workable condition. They continued their work in the area of reinforcement
and subsequently concluded that combining cotton and asphalt materials during construction reduced cracking,
raveling, and failure of the pavement and the base course. When synthetic fibers became more available in the
1960’s, textiles were considered more seriously for roadway construction and maintenance. As these new
synthetic fabrics evolved, there was confusion over terms and definitions. Textiles and membranes now have
reasonably well-accepted definitions in the construction industry, due mostly to the work of Dr. Jean Pierre
Giroud. Giroud created the original terms geotextile and geomembrane, using the Latin prefix “geo” meaning

2. “soil”. Later the term geosynthetic came into popular use, and the three terms were used interchangeably,
creating confusion.
Geotextiles and their application
Modern geotextiles are usually made from synthetic polymers – polypropylenes, polyesters, polyethylenes, and
polymides – which do not decay under biological and chemical processes. This makes them useful in road
construction and maintenance. Geotextiles made of materials are most commonly used. The makeup of these
fabrics determines their best application, so it is important to understand their characteristics. Geotextiles can be
produced as a non-woven, a knitted, or a woven fabric. We will focus on the non-woven and woven fabrics
since knitted fabric is rarely used. Whether the fabric is woven or non-woven is an important characteristic in
choosing a geotextile for a particular use. The non-woven fabric, which looks like a felt fabric, is an
arrangement of fibers either oriented or randomly patterned in a sheet. Materials commonly made of non-woven
fabric include upholstered furniture coverings and cloth interiors of automobiles. These fabrics can be
manufactured in a variety of ways, bonding fibers together using chemical, thermal or mechanical processes
(Figure 2). The bonding methods do not significantly change the function of the fabric. Non-woven geotextile
fabric is more likely to stretch than woven geotextile. It has the ability to let water flow along the plane of the
geotextile.
The woven geotextile, which looks like burlap,is a sheet made of two sets of parallel strands systematically
interlaced to form a thin, flat fabric. The strands may be slit film which are flat, or monofilaments which are
round (Figure 3). The way these two sets of yarns are interlaced determines the weave pattern which in turn
determines the best application for that woven fabric.Weave patterns come in a virtually unlimited variety
which do affect some properties of the fabric. However, a buyer will specify properties of the fabric such as
porosity, strength and elongation, not weave pattern. In general a woven geotextile is less likely to stretch, and
does not let water flow as freely as non-woven geotextiles.
In the road industry there are four primary uses for geotextiles: separation, drainage, filtration and
reinforcement. In separation, inserting a properly designed geotextile will keep layers of different sized particles
separated from one another. In drainage, water is allowed to pass either downward through the geotextile into
the subsoil, or laterally within the geotextile which functions as a drain. How it is used depends on the drainage
requirements of the application. In filtration, the fabric allows water to move through the soil while restricting
the movement of soil particles. In reinforcement,the geotextile can actually strengthen the earth or it can
increase apparent soil support. For example, when placed on sand it distributes the load evenly to reduce rutting.
Geotextiles now are most widely used for stabilizing roads through separation and drainage.When the native
soil beneath a road is very silty, or constantly wet and mucky, for example, its natural strength may be too low
to support common traffic loads, and it has a tendency to shift under those loads. Although the subgrade may be
reinforced with a base course of gravel, water moving upward carries soil fines or silt particles into the gravel,
reducing its strength. Geotextiles keep the layers of subgrade and base materials separate and manage water

3. movement through or off the roadbed. However, a layer of geotextile cannot be used as a substitute for using an
adequate thickness of free draining soils (like clean sand) to reduce frost heaving.
Geotextiles for separation
In separation functions geotextiles keep fines in the subgrade from migrating into the base course. Tests show
that it takes only about 20% by weight of subgrade soil mixed into the base course to reduce its bearing capacity
to that of the subgrade.This problem usually is due to the movement of large amounts of water. When large
loads cross the surface of the roadway they set up a pumping action which accelerates this water movement and
soil particle migration, and speeds up the failure of the road. (Figure 4).
Two important criteria for selecting a geotextile for separation are permeability and strength. The geotextile
used for separation must allow water to move through it while retaining the soil fines or sand particles. It should
let water pass through it at the same rate or slightly faster than the adjacent soil. It must also retain the smallest
soil particle size without clogging or plugging. Figure 4 is a diagram of the application of a geotextile as a
separator. To select a geotextile, you will need to know the grain size distribution of the subgrade and the
subbase as well as the permeability of the geotextile.
In selecting a specific geotextile for separation we must consider its basic strength properties. Be sure to take
into account how its physical properties will survive the construction process as well as how it will survive the
pressures of traffic on the gravel cover and enhance the life of the road. These strength properties are described
in manufacturers’ literature and design manuals in a variety of terms including burst and abrasion resistance,
and puncture, grab, and tearing strength (Figure 5).
Be sure when we use fabric for separation that you do not assume in the pavement design that it will also
provide structural support. It will not.
Design considerations for using geotextiles in separation.
When using geotextiles, consider the following.
1. What has been the past performance of geotextiles in similar types of soil?
2. You will need to know solid characteristics and the permeability of the subgrade, and match them to the
permeability criteria of the geotextile.
3. Select the fabric strength requirements on the basis of constructability. More specifically, it must withstand
placement and survive the construction period without puncturing, tearing,bursting, abrading, etc. Is the fabric
sufficiently workable for the specific application? That is, can the geotextile support the workers and equipment
during gravel placement.
4. Use standard load guidelines for designing pavement strength with no allowance for the geotextile.
5. In an existing roadway, check to see if additional subbase was added previously for extra structural support
to counter the soil weakness and reduce rutting under construction equipment to three inches. If so, reduce that

4. subbase by 39%-50% and include a geotextile in the design between the subgrade and subbase.
6. Select the cover carefully. If you will be applying a surface course, you may use a cleaner aggregate with
less than 15% fines. If this will be a gravel road and traffic will travel directly on the aggregate, then you must
provide more fines (at least 15%) or the aggregate will whip off the fabric.
Geotextiles for erosion control
Geotextiles can be used many ways for erosion control. One of these is with riprap along stream banks, lake
shores, and other bodies of water to keep finer soils beneath the riprap from eroding.(Figure 8). Geotextiles
recommended for erosion control should have permeability, resistance to abrasion, and high resistance to
ultraviolet rays as primary considerations.
Erosion control covers a variety of conditions from high velocity stream flow to heavy wave action, to less
severe conditions.
All conditions should be considered before selecting a fabric.The following instructions describe how to install
geotextiles on stream banks and similar steep slopes. These may be modified for applying geotextiles in less
severe conditions such as rip rapping in ditches. Geotextile/riprap installations may also be used in specifically
designed systems to protect against scouring around bridge piers and abutments,and in other water
installations.To install geotextiles for any riprap system:
– Before starting, review such design considerations as wave action, bank steepness, etc.
– Identify soils by particle size and permeability as these will determine certain geotextile specifications.
– Identify the size of riprap planned for this application.
– Review past weather and climate conditions for such information as levels of ice, wave action, and amount
of sunlight for their effect on riprap/geotextile installations.Ultraviolet rays in sunlight deteriorate most
synthetic materials. If exposure to ultraviolet rays is anticipated, select a geotextile with high resistance to
ultraviolet rays.
– Depending on the type of installation and the care it will need, you may have to consider abrasion to ensure
that the geotextile will survive installation.
Use of Jute Geotextiles in Road Construction
India is a large producer of jute. Jute is a low cost, renewable, biodegradable and eco-friendly natural product.
Jute geotextiles are used in many geotechnical applications. A series of field experiments were carried out by
CRRI using jute geotextiles for different functions, are described as follows: –
Jute Geotextiles as Separator to Improve Pavement Performance

5. The performance of pavements constructed on soft soils can be improved using jute geotextiles. Jute fabric
when used as separator prevents the penetration of subgrade material into voids of granular base course. The
permeability characteristic of the fabric also aids in faster dissipation of pore pressures and ensures better
drainage which results in better long term performance of the pavement. Provision of fabric enables subgrade
develops its full bearing capacity and thus controls rutting. Jute geotextile was used as a separator between
subgrade and sub-base layers. Results showed negligible settlements of the pavement after six months under
traffic and no signs of surface distress observed in the treated test section.
Jute Geotextiles for Ground Improvement
The field subsoil was soft silty clay and the water table was 0.5 m below the ground level, the whole area gets
submerged during high tide. The highway constructed earlier faced problems of subsidence of the fill during
construction, excessive post construction settlements and lateral spreading of fill material, etc. On the basis of
settlement calculations, it was estimated that as much as 30 per cent of the fill sinks into the soft subsoil during
construction itself, necessitating large quantities of costly fill material,thereby, pushing up the cost of
construction. The problem was solved through the use of jute geotextiles. Monitoring of completed
embankment i.e. both treated and control stretch showed better performance of road embankment constructed
using jute geotextile.
Jute Geogrid for Erosion Control of Denuded Slopes
On the basis of field studies, conducted in the past by CRRI, it has been concluded that shallow sacrificial slides
constitute a significant proportion of landslides in areas with moderate rainfall intensity and where soil cover is
medium cohesive in nature. Surfacial slides extend to only a couple of metres below the slope surface and
originate as a result of erosion from down flowing water over the denuded slopes. If erosion is allowed to
proceed unchecked, there is every possibility that the damage may spread laterally thus increasing the depth of
erosion, eventually resulting in a much larger damaged slope area. Vegetative turfing represents one of the most
important corrective measures. In the case of freshly exposed cutting made for road construction, vegetative
turfing is important, even as a preventive measure. In the case of deep-seated slides, however, vegetative turfing
is only one of the techniques among available corrective measures and as such it can prove to be effective only
when conjointly implemented with other corrective measures. Based on several field trials carried out by the
Institute, the use of jute geogrid technique has been developed for treatment of erodible slopes as a part of
landslide correction works.
Jute Geotextile for Drainage and Filtration Application
The field conditions were the stretch of hill road was located on debris slide area and debris consists of
micacious sandy silt. A number of seepage points exist on the uphi ll as well as on downhill slopes. The road
stretch was experiencing subsidence during the monsoon every year, including damages to the restraining
structures. Breast walls constructed earlier had been damaged due to slip. To arrest the sinking of road

6. pavement, a systematic network of roadside trench drains and cross trench drains were constructed using non-
woven jute geotextiles. The trench drains were made of rubbles encapsulated in non-woven jute geotextiles to
stop the finer particle entering into the voids of encapsulated rubbles, thereby preventing clogging the trench
drains. About 1000 sq.m of non-woven jute fabric having 750 gsm has been used for drainage application on
about 100 m length of road stretch. The monitoring of field experiments on this particular stretch of treated road
has shown very encouraging and satisfactory results.There has been no further sinking and subsidence of the
road at this location after three years.
Case Study with JGT for Erosion Control
Location of the Site
Left bank of the river Phulahar in the district of Malda, West Bengal, up stream of Sankharitala Ghat near
Mathurapur (35 km from Malda town).
Problem
Flood during the monsoon as a result of high precipitation caused rise in water level both in the Ganga and the
Phulahar connected with it. There was a heave-up of the excess water at the mouth of the narrower Phulahar
that takes a bend at a distance of one and a half kilometers from its outfall in the Ganga. The concave bank was
understandably subjected to heavy erosion that was accentuated due to strong protective measures undertaken
on the opposite end for the stability of a big land-form (Bhutni Diara) that has emerged within the Ganga.On
earlier occasions of flood also, the same stretch was subjected to similar erosion.Irrigation & Waterways
Department, Govt. of West Bengal constructed earlier an apron of loose boulders to control of the bank. The
apron could not stand the erosive forces and gave in.The problem is unabated erosion at the eastern stretch
during the flood, engulfing chunks of land every year.
Object
The object is to control erosion in the vulnerable stretch of 750 meters (approximately) of the river Phulahar by
use of Jute Geotextile and/or other measures.
Remedial concept
Erosion at the toe of the bank can be controlled by construction of submerged repelling spurs or by construction
of a toe wall. Irrigation & Waterways Department adopted the second option, presumably for avoiding flow
repulsion to the opposite end that could destabilize the protective work around Bhutni Diara. The bank slope
measuring 12 meters in length was given a ‘break’ after 5 meters from the bank top, forming a berm of a 1
meter.

7. Some features of relevance
The bank soil was made up of fine sand (average particle size – 0.175 mm). Co-efficient of soil permeability
was of the order of 10-4 per sec. The monsoon discharge veers around 9330 cumec while the maximum velocity
of the current was of the order of 2 meters per second.
Implementation
Implementation of the remedial concept was done in 2004 after the monsoon. A toe wall with crated boulders
(900 X 1200 in size) was constructed. The bank slope behind the toe wall was prepared and dressed to 2:1 slope
and bitumen-treated woven Jute Geotextile was laid over it. An armour of loose granite boulders (Rajmahal
trap) in two layers having a thickness of 450 mm was placed over the fabric.
Feature of Jute Geotextile used
The JGT used had the following features—
– Weight per unit area –760 gsm (1200 gsm after treatment with bitumen)
– Tensile Strength (MDXCD) –minm. 20 kN/m x 20 kN/m when grey 21 kN/m X 21 kN/m after treatment
– Elongation at break (MDX CD) –maxm.10% X 10%
– Porometry –150 micron ± 10%
– Flow Rate at 50 mm constant water head—14 litres/ m2/second
– Permittivity at 50 mm constant water head—350 x 10 –5 per sec.
– Puncture Resistance –400 kN
Performance Evaluation
The treated stretch of the affected bank is in a fine shape two years after remedial measured were taken with
Jute Geotextile. The letter of the Executive Engineer, Malda Irrigation Division is confirmatory. The toe wall
also played its desired role in controlling erosion at the toe.
Mechanism of Strengthening of Road Sub-grade
One of the underlying principles for separation and reinforcement function to be effective by use of
geosynthetics is not only to ensure segregation and withstanding dynamic stresses respectively, but also to help
generate membrane effect that exerts an upward thrust against the imposed loads. Initial tensile strength of JGT
and its low extensibility certainly helps in this respect. But more important are the functions of filtration and
drainage of geosynthetics that ensure natural consolidation of a road subgrade.Permittivity (flow across the
geosynthetics) and transmittivity (flow along the plane of geosynthetics) are two critical parameters that help
maximize soil consolidation only when soil in the sub-grade is not allowed to migrate. Roadside drainage and
lateral restraint of the pavement are two other technical necessities. All the requirements as indicated could be

8. achieved if the fabric porometry is rightly decided. Decision on pore size of JGT or, for that matter, any
geosynthetic is critical.Consolidation of soil, as already mentioned, is a time-dependent process and may
continue for a protracted period. In one of the field applications on roads done in Kakinada Port in Andhra
Pradesh, an increase of CBR by about 3 times were observed after a lapse of 6 years of laying of woven JGT on
a severely damaged road! (Rao et al 1993, Sreerama Rao 2003) This is again a pointer that long term durability
of JGT is not a technical indispensability in all cases.One of the difficulties faced in placement of JGT under
granular base/sub-base is the probability of puncturing. The fabric may be punctured by the sharp edges of
coarse aggregates. The difficulty can be obviated by spread of a thin cushion of sand above or under the fabric
as necessary. In one of the field studies, JGT was overlain by WBM comprising sharp-edged brick metal.
Thickness of WBM was reduced and part of it was replaced by brick flat soling for prevention of puncturing.
Admittedly there were chances of inhibition of permittivity in such an arrangement. The difficulty was
overcome by keeping a gap of 10 mm in each joint. In reality the extent of transitivity exceeds the magnitude of
permittivity, the arrangement worked and the performance of the treated pavement was satisfactory.
Case Study in Road Construction
Location of the Site
Andulia-Boyratola Road is a 3.5 km long rural road located under Haroa block of the North 24 Parganas, West
Bengal. It passes through three unconnected habitations and is close to agricultural fields, fishing ponds and
small scale industries. The area in future is expected to show up due to developmental programmes being
envisaged in the area. The proposed road is likely to take on a larger traffic in future. It rests on a ground higher
than the ambient ground level by 725 mm.The average annual rainfall in the area is 1500 mm.
Soil
The soil is basically organic silty clay (IS Soil classification- OL), Average L.L. is 46% while average P.L. is
27.5% (PI is 18.5%). OMC was found to be 23.5% while MDD was observed to be 1.72 gm/cc. The average
soaked CBR value of the sub-grade was found to be 3.22 % (4 days).
Traffic
Traffic census was carried out at the nearest all weather road (AWR) for the purpose of design , CVPD
(Commercial Vehicles per day) has been taken as 22, considering 10% of the traffic in the nearest all-weather
road (AWR).
Salient Features of the Project
The DPR was drawn up in accordance with IRC SP 20:2002. Woven Jute Geotextile (JGT) was laid on the sub-
grade to improve its CBR. Pavement was designed with an enhanced CBR value of 4.93% (1.5 times the exiting

9. CBR of the subgrade -rounded off to 5%). The total cost of the project worked out to Rs. 1.48 crores. The
financial component of JGT was 4.34% of the total project cost. The thickness of the sub base,the base and the
wearing coarse was 200 mm, 150 mm and 26 mm respectively. (as per the relevant curve corresponding to the
assumed CBR, CVPD & average annual rainfall).
Installation of Woven JGT
Woven untreated JGT (specifications given below) was laid on the sub-grade after raising the road level to 1200
mm from G.L. (the level of the sub-grade). The top width of the road was finished to 7500 mm with 1:1.5 side
slope while the actual carriage way measured 3750 mm.After the sub-grade was rolled to OMC, the specified
JGT was laid in taut condition on the prepared sub-grade, taking care to ensure that there was no gap between
the subgrade and the fabric. Overlaps at sides (150 mm) and ends (300 mm) were provided duly stapled at an
interval of 300 mm with broad- headed nails. A cushion of a thin layer of local sand was provided on JGT to
avoid puncturing during rolling the subbase and the base of the pavement.On laying the fabric, the pavement
was finished as per specifications stated in the approved DPR which was vetted by the Civil engineering
Department, Bengal Engineering & Science University, Sibpur,West Bengal.
Specifications of Woven JGT
The specifications adopted for the woven untreated JGT were as under—
– Weight—– 810 gsm (untreated)
– Thickness–2 mm
– Width—— 76 cm
– Tensile Strength—minm. 30 kN/meter (both in machine & cross directions)
– Elongation at break—max. 10 % (both in MD & CD)
– Porometry— 150 micron + 10%
– Permittivity at 50 mm constant water head—350 x 10-5 per second
– Puncture Resistance —0.600 kN
Inference
Field CBR was ascertained by the Civil Engineering Department of Bengal Engineering & Science University
(also the accredited State Technical Agency for the PMGSY Programme). CBR was found to be 10%-a figure
double the enhanced design value of the sub-grade CBR estimated after laying of JGT.The case study is a
pointer that i) with JGT, the sub-grade CBR could be improved by around three times the control value even
after one and half years and ii) thickness of the pavement, reduced by 45 mm, almost compensated the cost on
JGT. Evidently the design was conservative and that further reduction in thickness would have been possible
entailing further cost reduction.
Conclusion

10. – Certain fundamental considerations are necessary for success in any application of Geotextiles . We must
know the soils to select the proper geotextile in road construction and maintenance. In many installations,
permeability may override concern for durability and resistance to bursting, puncturing and tearing.In other
installations, such as a separator in a road where the geotextile will be subjected to severe loads, durability is of
concern.
– Permeability should also always be considered in separation uses to allow moisture to move freely through
the system. This avoids excessive hydrostatic pressures which cause soil failure.
– Most geotextile system failures result from improper installation, improper selection of fabrics, a change of
conditions from the original design, or a combination of these factors.
– In the present realm of growing global emphasis on adoption of bio-technical measures,Jute Geotextile
deserves encouragement due to its several striking attributes. Of all the ingredients of natural geosynthetics, jute
happens to be the best spinnable fibre that ensures making of customized fabric to meet site-specific
requirements.
– JGT is also the most drapable of all geosynthetics—a property essential for control of surficial soil erosion.
Its low extensibility and high initial strength helps in enhancing the bearing capacity of soil.
– Its environmental concordance is by far its most attractive feature along with its cost-competitiveness. When
we consider the environmental price of JGT, it matches with its man-made counterpart both in respect of price
and technical suitability in most of the geotechnical applications. This is because long durability of
geosynthetics is not a technical necessity in majority of applications.
References
– Chaudhury, Goswami & Sanyal–Application Of Jute Geotextile In Rural Road Construction Under
PMGSY—A Case Study In West Bengal (Indian Geotechnical Conference at Ahmedabad, India,2005)
– International Trade Centre UNCTAD/GAATT, Geneva –Jute Geotextiles-A Survey of Marketing &
Distribution Systems in Selected European Countries (Prepared for IJO in 1991)
– Ramaswami & Aziz –Jute Geotextile For Roads (Intl. Workshop on Geotextiles at Bangalore, India,1989).
– Sanyal–Control Of Bank Erosion Naturally- A Pilot Project in Nayachara Island in the River Hugli
(National Workshop on Role of Geosynthetics in Water Resources Projects at New Delhi,1992)— Sanyal &
Chaudhury–Appraisal Of Performance (All India Seminar on Applications of Jute Geotextiles in Civil
Engineering at Kolkata,India 2002)
– Sanyal & Chakravarty –Application Of Jute Mattress in the Bank Protection In The Hugli Estuary
(Geotextiles & Geomembranes, U K.1993)
– Sreerama Rao –Jute Geotextile Application In Kakinada Port Area (National Seminar on Jute Geotextiles &
Innovative Jute Products at New Delhi, India, 2003.