Revised Draft Report Prepared by

CENTRAL ROAD RESEARCH INSTITUTE

New Delhi – 110 025

Submitted to

Indian Roads Congress

New Delhi

April 2011

Report Preparation

Sudhir Mathur

Head, Geotechnical Engg Division, Central Road Research Institute

U.K.Guru Vittal Scientist F, Central Road Research Institute

T.Sanyal Geotech Advisor, Jute Manufactures Development Council

P.K.Choudhary In-charge, Geotech Cell, Indian Jute Industries Research Association

CONTENTS

Page No

1 Introduction 1

2 Composition and Characteristics of Jute Fibre 1

3 Structure of Jute 6

4 Properties of Jute fabric 6

5 Manufacturing Process of Jute Geotextile (JGT) 8

6 Functions of JGT 10

7 Transportation, Storage and Handling of JGT 13

8 Properties of JGT & Important Test methods 15

9 Durability of JGT 20

10 Environmental aspects of JGT 21

11 Civil Engineering applications of JGT 22

12 Cost of Jute geotextile and Commercialisation 36

13 Laboratory Studies on Jute Geotextiles 37

14 Some Case Histories / Field Demonstrations 48

15 International Usage of Jute Geotextiles 71

Appendix – I (JGT Manufacturing Photographs) 78

Appendix – II (Equipment for JGT Testing) 84

Appendix – III (List of Important Application Projects) 93

Appendix – IV (Standards for Testing) 96

Appendix – V (References) 98

Terms & Definitions

1. Bast: Belonging to group of strong, woody fibers, such as flax, hemp, or jute, obtained

from phloem tissue and used in the manufacture of woven goods and cordage

2. Denier: A measure of the fineness or size of a yarn expressed in terms of mass per unit

length; numerically equal to number of grams per 9,000 metres length of fibre

3. Tenacity of Fibre: Capability of fibre to keep a firm hold on objects without slippage

4. Separation: Segregation of two layers of materials by preventing their intermixing

5. Filtration: Process of retaining soil particles while allowing water to pass through

6. Erosion: Detachment of soil particles from a soil surface and the transportation of the

detached particles to new location

7. Geotextile: Textile materials which are permeable, made by either woven or non woven

process, used along with soil or backfill material for improving the performance of civil

engineering structures

8. JGT: Jute geotextile – Textiles made by using Jute fibres by adopting either woven or non

woven techniques

9. Woven geotextile: Manufactured by weaving weft threads through warp threads, usually

(but not necessarily) having stronger warp threads than weft threads. A textile structure

comprising of two or more sets of filaments or yarns interlaced in such a way that the

elements pass each other essentially at right angles and one set of elements is parallel to

fabric axis.

10. Non woven geotextiles: Geotextiles produces from randomly distributed continuous

filaments or staple fibres, which are bonded together chemically, thermally or mechanically

or a combination of such processes

11. Jute netting: A type of open weave jute geotextile, having large openings between

successive warp and weft threads, mainly used for erosion control applications

12. Percent Open Area (POA): The net area of a fabric that is not occupied by fabric filaments,

normally determinable only for woven and non woven fabrics having distinct visible and

measurable openings that continue directly through the fabric

13. Drapability: Bending ability of geotextile for making full contact with the soil and taking the

shape of the contour of the soil surface.

14. Typical value: Refers to average value of the geotextile sample property, which should be

determined by testing statistically sufficient number of samples

15. Minimum average roll value (MARV): Derived statistically as the average value minus two

standard deviations

16. Pore size: The size of the opening between fabric fibres

17. Apparent Opening Size (AOS) or Equivalent Opening Size (EOS): AOS is a measure of

the largest effective opening in a geotextile. AOS is determined by sieving glass beads of

successively bigger size until 5 per cent or less pass through the fabric.

18. Clogging: The plugging of a fabric by deposition of particles within the fabric pores

19. Filter cake: A thin layer of fine soil particles accumulated in the soil adjacent to the fabric

as a result of smaller soil particles being washed through the soil pores and the geotextile

20. Permeability, Longitudinal or in plane: The fabric property which permits a fluid, normally

water, to flow in the plane of the fabric, also known as ‘Transmissivity’

21. Permeability, Transverse: The fabric property which allows a fluid, normally water, to flow

through a fabric perpendicular to the plane of the fabric, also known as ‘Permittivity’

22. Coefficient of Permeability (Coefficient of Permittivity): A measure of the permeability of a

porous media such as soil or geotextile to water. It is the ratio of discharge velocity to the

hydraulic gradient under laminar flow conditions

23. Trench drains: Covered type of drains constructed in the sub-soil for lowering the water

table or for effective drainage of sub-soil water

24. Puncture resistance: Resistance to failure of a fabric from a blunt object applying a load

over a relatively small area

1. Introduction 1.1 India is the largest producer of Jute and allied fibres. It produces more than 60 per cent of the

total jute produced all over the world. India and Bangladesh are the two major players in this

field. In India major production of the jute goods are consumed domestically, whereas

Bangladesh exports majority of its products to other countries. In India jute cultivation is confined

to West Bengal, Eastern Bihar, Assam, Orissa, Tripura, Uttar Pradesh and to some extent in

Meghalaya. Out of these states, West Bengal, Bihar and Assam contribute about 80 per cent of

the total production. Figure 1, shows the picture of jute plant, jute fibre and jute bales.

1.2 Jute is a textile fibre, which when converted into fabric possesses many of the desired

properties required for geotechnical engineering works and termed as Jute Geotextile (JGT).

Textile materials in woven, non-woven or other forms, when applied to soils (geo) for improving

its engineering characteristics are termed as Geotextiles. Use of synthetic geotextiles made up of

polymeric materials like polypropylene, polyester etc, to address soil related problems in civil

engineering is a well tried and accepted concept all over the world. Application of Jute

Geotextiles (JGT) in this field, however, is a recent phenomenon. Natural fibres of jute can be

processed as fine yarns which, in turn, can either be woven into permeable and drapable fabrics

by appropriate weaving machineries (woven fabric) or can be matted together in a random

manner (non-woven fabric). Different type of jute geotextiles are shown in Figure 2, 3, 4 and 5.

1.3 Both woven and non-woven fabrics have been used in many road projects successfully to

facilitate construction, ensure better performance of the structure and reduce maintenance cost.

The jute geotextiles have also been used in protection of river banks, in managing slopes

including hill slopes, control of surface soil erosion, stabilisation of embankments, prevention of

reflection cracks in bituminous pavements and consolidation of soft soils, etc. The enormous

potential of jute geotextile is being increasingly appreciated by end-users because of its low price

and technical feasibility.

2. Composition and Characteristics of Jute Fibre

2.1 Jute is a natural ligno-cellulosic bast fibre. Bast refers to a group of strong, woody fibers,

such as flax, hemp, or jute, obtained from phloem tissue which are used in the manufacture of

woven goods and cordage. Jute is highly hygroscopic and can absorb water upto about 5 times

its own dry weight. This property introduces in jute an element of variance in weight under

different relative humidity. Jute is a very good insulator of heat and electricity. This property also

varies with the change in moisture content. The strand of jute fibre consists of numerous

individual filaments, which form a meshy structure. These fibres have varying length, fineness,

strength, extensibility, tenacity, stiffness and toughness. The matured jute plant with a height of

about three metre is cut and sun dried in the field. The plants with shaded leaves are tied in

bundles and immersed in mild flow water for about two weeks for retting. The fibres are extracted

from the plant, washed in clean water and sun dried to make it ready for use. The constituents of

jute fibre are mainly Cellulose, Hemicellulose and Lignin. They are distributed in the fibre as

shown in Table 1.

Table 1: Composition of Jute Fibre.

Constituents Percentage

– Cellulose 60 – 62

Hemi Cellulose 22 – 24

Lignin 12 – 14

Others (Wax, Ash, Nitrogen etc.) 1 – 2

Figure 1: Photographs of Jute Plant, Jute Fibre and Jute Bale

Jute Bale

Jute Fibre

Jute Plant

Figure 2: Jute geotextiles for control of surface soil erosion

Figure 3: Jute geotextiles for filtration and drainage

Figure 4: Jute geotextiles for separation and filtration

Figure 5: Prefabricated jute drains for accelerated consolidation of soft soil

2.2 Tenacity of jute is usually high and remains stable over a range of 30 per cent – 80 per cent

of relative humidity. Under very wet or very dry conditions, tenacity of jute decreases. Stiffness is

a measure of resistance to bending (breaking stress/breaking strain). Stiffness of jute is high at

normal moisture content but decreases with increase in moisture content above the normal.

Torsional rigidity of jute is also affected at higher moisture content. Toughness of jute is low on

account of its low extensibility. Toughness is defined as the area under stress-strain curve for the

fibre under test. Some salient physical properties of jute are given below:

Density – 1.47gm/cc

Average Fineness – 20 denier (i.e., weight in gm of 9000 metres of filament)

Tenacity – 4.2 gm/denier

Average Extension at break – 1.2 per cent

Average Stiffness – 330 gm/denier

Average Toughness Index – 0.02

Hygroscopicity (average regain at 65 per cent relative humidity) – 13 per cent

2.3 Jute fibres as already mentioned are natural fibres, comprising approximately 83 per cent to

87 per cent natural cellulose and 12 to 14 per cent Lignin. The fabric made of jute yarns

biodegrades, leaving a fibrous residue. The other important feature of jute is that it does not

draw upon the valuable nitrogenous reserves and ultimately decomposes, as is usually the case

with other natural fibres. Jute geotextile acts like a straw or peat mulch aided by its degrading

fibres, which help to retain the moisture and improve the soil-permeability. JGT possesses better

drapability

and also wettability, compared to all other geotextiles. JGT being the most

hygroscopic among widely used fibres and is also more wettable than other fibres. This has been

reported after a study was undertaken in this regard by Dr.T.S.Ingold and Mr.J.Thompson. The

comparative physical properties of jute and other fibres are shown in Table 2. A brief description

of the physical properties of jute fibre has also been given below Table 2.

Table 2: Comparative physical properties of Jute and Other Fibres.

Fibre Density (gm/cc)

Fineness (denier)

Tenacity (gm/denier)

Elongation At break (per cent)

Initial Modulus

(gm/denier)

Moisture Content

(per cent) at 65 % RH

Jute 1.47 20 4.2 1.0 to 1.8 380 13

Cotton 1.55 2 3.5 8.0 50 8.5

Flax 1.50 12 5.0 2.2 250 –

Kenaf 1.46 27 3.7 1.1 330 12.5

Nylon 1.14 1.5 – 3.0 5.0 15.0 40 4.0

Coir 1.40 – 10.0 30.0 – 10.5

a) Tenacity

It depends on thickness of the filament. It remains almost constant at 30-85 per cent RH

but decreases at very dry or wet condition. For conducting tenacity test on jute fibre, the

fibre length is kept as 10 mm and time to break is kept as 10 seconds.

b) Elongation

The elongation at break varies from 1.0 per cent to 1.2 per cent under normal

atmospheric condition while in wet condition it increases marginally.

c) Flexural Rigidity and Torsional Rigidity

It is a measure of resistance to bending. This is quite high at normal moisture content.

Flexural rigidity of jute ranges from 3.0 to 6.0 dynes cm2. Torsional rigidity of jute reduces

with increased moisture content. Modulus of Torsional rigidity (in x 1010

dynes cm2) is of

the order of 0.25 to 1.30. These are measures of resistance of jute fibres (single fibre)

against bending and torsion.

d) Hygroscopicity

Jute is highly hygroscopic in nature. Jute being the most hygroscopic among widely used

fibres, is also more wettable than other fibres. The moisture retention capacity

accelerates its spinnability and subsequent manufacturing processes.

e) Thermal behaviour

Like many other textile fibres, jute is a good insulator of heat. The transference of heat

through the fabric is not only dependent on conductivity of fibre but also to a large extent

on the volume of entrapped air in the fabric.

3. Structure of Jute

3.1 Strand of jute fibre consists of numerous individual filaments which are entangled at different

places to form a meshy structure. Prior to spinning, entanglement of fibre mesh is mechanically

broken into individual fibres. The fineness and length of an individual fibre may vary from 8

denier to 30 denier (gm/9000 m) and from a few mm to 300 mm respectively.

4. Properties of Jute Fabric

Jute fabric is a tailor made product. The fabric is designed in such a manner that it possesses all

the required properties suitable for specific geotechnical applications. Indian Jute Industries‟

Research association (IJIRA) in collaboration with Jute Manufactures development Council

(JMDC) have developed various types of woven, nonwoven, open weave JGTs for different end

use applications in geotechnical engineering. Specifications of some typical JGTs are given in

Table 2, 3, 4 and 5. Detailed explanation of the properties of jute fabric is given in section 8. As

already stated, JGT is biodegradable. Hence available residual strength of JGT at the end of

specified period would depend on the ambient conditions (e.g., type and properties of

surrounding soil, temperature and moisture content, etc). Several case studies in fields showed

that the strength of JGT typically gets reduced by about 60 to 70 per cent after lying embedded in

estuarine soil for around 18 months. Exhumed samples of JGT from different projects often

showed that integrity of the fabric remains unaffected despite strength reduction. Further R&D

work is under progress in this regard.

Table 3: Properties of some typical Jute Geotextiles

Parameters Woven Open mesh ASTM Test

Methods

Mass per Unit Area (gm/m

2)

760 300 500 D 5261

Construction D.W.Twill Plain Plain

Warp Count (lbs) 10 36 120

Weft Count (lbs) 28 36 120

Ends/dm 102 12 6.5

Picks/dm 39 12 4.5

Cover Factor 98 40 50

Porometry (Apparent Opening size-AOS in mm)

0.10

–

–

D 4751

Aperture size-mm – 8 x 8 13 x 11

Tensile Strength (kN/m) Warp Weft

20 20

10 7.5

17.5 5.5

D 4595

Roll width Available (cm) 76 122 122

Minimum Length (m) (cut length)

100 70 70

Maximum Length (m) (packing length/bale)

Upto 457 (IS : 2873)

Upto 820 Mill Practice

Upto 550 Mill Practice

Treatment Available Rot resistant and Bitumen

Nil Nil

Estimated lifetime 4 Years 2 Years 2 Years

Water Holding Capacity-(Grey) Dripping Squeezed Normal

400% 80 – 100% 8 – 20%

500% NA

8 – 20%

500% NA

8 – 20%

Recommended Use Separation and Filtration Road construction River/ Canal Bank Protection

Erosion Control of Slopes Afforestation in Semi-arid Zone Road Surfacing

Erosion control of Slopes Mine Spoil Stabilisation Landscaping

Table 4: Open mesh woven jute geotextiles (IS Specifications)

Properties Type 1* Type 2 Type 3 ASTM Test

Mass per Unit Area (gm/m2) 292 500 730 D 5261

Threads/dm (MD X CD) 12 x 12 6.5 x 4.5 7 x 7

Thickness (mm) 3 5 7

Width (cm) 1122 122 122

Open Area (%) 60 50 40

Strength (kN/metre) (MD X CD) 10 x 10 10 x 7.5 12 x 12 D 4595

Water holding capacity on dry weight (%)

400 500 500

Typical Durability (Minimum years) 1 1 1

*Note: Type 1 open mesh JGT has now been removed from the IS Specifications

Table 5: Woven Jute Geotextiles

Properties Grey (untreated)

Rot proof Rot-resistant and bitumen

treated

ASTM Test Methods

Mass per Unit Area (gm/m2) 760 760 and above 1200 D 5261

Threads/dm (MD x CD)

102 x 39 102 x 39 102 x 39

Thickness (mm) 1.75 1.75 2 D 5199

Width (cm) 76 76 76

Strength (kN/metre) (MD x CD) 20 x 20 20 x 20 21 x 21 D 4595

Elongation at break (%) (MD x CD)

10 x 10 10 x 10 10 x 10

Porometry (O90) micron 300 300 150 D 4751

Flow rate at 10 cm water head (litre/m

2/sec)

50 50 20 D 4491

Puncture Resistance (N/cm2) 380 380 400 D 4833

Typical Durability (Minimum years)

1 2 4

Table 6: Nonwoven Jute Geotextiles (Indicative Specifications)

Properties Type 1 Type 2 ASTM Test Methods

Mass per Unit Area (gm/sq.m) 500 1000 D 5261

Thickness (mm) 4 8 D 5199

Width (cm) 150 150

Strength (kN/metre) MD x CD 4 x 5 6 x 7 D 4595

Elongation at break (%) MD x CD

20 x 20 25 x 25

Permeability Coefficient (metre/sec)

3.4 x 10–3

3.4 x 10–4

D 4491

Durability (Years) 1 1

Recommended Use Construction of JGT – encapsulated concealed rubble drains by the side of road and railways

Drainage of water from cohesive fills

Table 5: Properties of Pre-Fabricated Jute Drain with Coir Wicks

Properties (Unit) PVD ASTM Test Methods

Material Composition Sheath Core

Jute Fabric Coir Yarn

Width (mm) 92 – 93

Thickness at 20 kPa( mm ) 9.0 D 5199

Weight of material/ linear m (gm) 140 D 5261

Material Tensile strength (kN) 4.5 D 4595

Elongation at break during tensile test (%)

4 – 5

AOS of jute sheath (O90) Micron 0.425 – 0.6 D 4751

Durability (Years) Minimum 1

5. Manufacturing process of Jute Geotextiles (JGT)

5.1. The coarse jute fibre is initially softened and made pliable by passing through the softener

machine followed by application of emulsion (oil in water) and kept in pile form for about 24 hrs.

After cutting out the hard root portion from the bottom end, the fibre is mechanically processed

through 2 to 3 carding passages when meshy (entangled fibres) structure is broken and

delivered in form sliver. The sliver is thinned and made parallel by passing through 2 to 3 drawing

passages. Sliver is then spun into yarn of different counts through slip draft or rove (for open

mesh fabric) spinning frames. The spun yarn is then wound in spool in spool winding machine &

ultimately to beam in beaming machine as warp thread and also in cop in cop winding machine

as weft thread. In the weaving process, the warp and weft threads are interlaced with each other

in the loom to manufacture woven jute geotextiles. For weaving open wave (mesh) fabric,

bobbins are directly placed in the creel behind the loom as warp thread.

5.2 The non - woven jute geotextile is manufactured in different process. The waste jute sliver is

fed into garneting cum cross lapping machine where the fibres are split out and randomly

distributed over the conveyor and delivered in lap form with desired thickness. Generally one

layer of jute scrim cloth is placed in between two layers of lapped sheets to add strength to the

material. The lapped sheet is punched by needles in the needle punching machine for bonding

the fibres mechanically to produce non-woven jute geotextile. Jute being a natural fibre, it

degrades within a year when laid in contact with soil. Its durability can be enhanced by 2 to 3

years by treatment with rot-resistant chemical and also by bitumen treatment. Some photographs

of manufacturing process are shown at Appendix I. The process flow of JGT manufacturing

process is given as follows:

Jute Fibre

Softening

Carding

(Woven JGT) (Nonwoven JGT)

Drawing Garneting cum Cross lapping Spinning Needle Punching Winding Packing Beaming

Weaving Rot resistant & Bitumen treatment

Packing

6. FUNCTIONS OF JGT

6.1 JGT, like the synthetic variety, improves the geo-technical properties of the soil on which it

is applied. JGT, being permeable, allows the water retained within the soil to permeate across

it and also along its plane. The extent of cross permeability (termed as permittivity) and in-

plane permeability (termed as Transmissivity) depends on the pore size of JGT (termed as

porometry). The porometry of JGT determines the extent of soil particle retention on which it is

laid. Properly designed JGT (in most cases, in relation to the mean diameter of the soil-grains

i.e., d50) arrests migration of the soil particles and imparts strength to the soil body. Properly

designed JGT would perform the following functions:

Separation

Filtration and drainage

Initial reinforcement

Control of surface soil detachment

Promoting vegetation growth or biotechnical support

6.2 Separation

6.2.1 Separation function implies segregation of two layers of materials by preventing their

intermixing, i.e., intrusion of one layer into the other comprising either dissimilar materials or

similar materials with different grading. The phenomenon causes reduction in thickness of a

particular pavement layer making the overlying structure susceptible to failure.

6.2.2 In road construction, separation is needed to segregate the sub-base from the subgrade for

prevention of the excessive pavement deflection under axle loads of moving vehicles.

Intermixing of two layers causes reduction in the thickness of a pavement to lower than the

desired thickness. Load carrying capacity and the pavement life are consequently reduced.

6.2.3 Separation of two layers for at least one season cycle helps for gradual riddance of water

from the base soil by use of JGT through concurrent functions of filtration and drainage.

Experiments have proved that once this phenomenon takes place, chances of subsidence of a

part of any road or structure due to intermixing become substantially less. Biodegradability of

JGT therefore does not normally pose any technical impairment after a season cycle (about 12

months) of their application.

6.3 Filtration

6.3.1 As already indicated in previous sections, JGT is supposed to perform two contrasting

functions; soil retention and ensuring permeability of water through and along them. JGT

provides a technically superior solution to traditional granular graded filters. JGT can be

manufactured with pore sizes commensurate with the median grain size of the base-soil to

ensure their retention. At the same time the requisite quantity of water is allowed to pass across

and along JGT without causing to develop any differential pore water pressure. The functions of

permittivity and Transmissivity are therefore important. With a tailor made JGT, differential water

over pressures across it can be effectively dissipated, preventing migration of soil particles

concurrently.

6.3.2 JGT, like its synthetic counterpart, first retains the coarser particles of the soil. These

coarse particles block smaller ones in the soil, which in turn prevents migration of even smaller

grains. This phenomenon, which is known, as „filter cake formation‟ is in fact an indication of

formation of natural filter within the soil. The situation can develop only if it is ensured that JGT

has made full contact with the base soil (i.e. if drapability of the JGT is ensured). For ensuring

full drapability, JGT requires to be suitable ballasted. This load on top of a JGT not only prevents

its uplift under certain condition, but also protects the fabric from continuous exposure to

weather.

6.3.3 Soil properly overlain by JGT is seen to develop „filter cakes‟ usually within a period of 3 to

4 months from the date of application according to laboratory tests carried out in Research

Institutes. Development of „filter cakes‟ is a sure indication of the base-soil having attained

natural stability. Once the soil attains natural stability, function of any separating fabric, be it

synthetic or natural, becomes redundant. Though laboratory experiments by some researchers

have shown formation of „filter cakes‟ within about 3 to 4 months from the date of application of

JGT, it is advisable to ensure durability of JGT for at least one season cycle. Bio-degradation of a

JGT therefore does not normally pose any deficiency in its expected performance for drainage or

filtration.

6.3.4 Clogging is generally accumulation of particles on and into the openings of JGT. Soil

particles at the base or particles in suspension of flowing water tend to block the pores of JGT by

deposition on its surface or within its layer. Chemicals in water are sometimes responsible for

chemical clogging of JGT. Performance of JGT is consequently adversely affected leading to

progressive clogging. Such clogging may be allowed if the rate of deposition is very slow or for a

limited duration.

6.4 Drainage

6.4.1 JGT performs drainage function by conducting water. Proper drainage of soil accelerates

its consolidation. The cohesion of the soil, as a result, is increased which, in turn, accentuates

the separation effect of the JGT.

6.4.2 JGT possesses a high degree of Transmissivity, i.e., it can drain water effectively along

their plane. JGT is also capable of holding water to about five times their own weight. In roads,

lateral drainage of water from sub-base and subgrade is critical. JGT used as a separator may

facilitate the lateral evacuation of water from the road-structure and prevent water accumulation

at the subgrade level.

6.5 Initial Reinforcement

6.5.1 JGT can reinforce soils, whose shear strength is low at the initial stages. Once the

consolidation process takes place, there will be increase in the shear/ tensile strength of sub-soil

and hence there may no longer be need for JGT reinforcing layer. By facilitating consolidation of

weak sub-soil when initial reinforcement is being provided by JGT, increase in tensile/shear

strength of soil can be ensured after the consolidation process. Any large soil body e.g., an

embankment, undergoes failure by vertical subsidence, lateral dispersion and rotational slides.

When used in appropriate layers, especially across vulnerable planes of failure and distress, JGT

can effectively control such failures. Soil movement is curbed by its confining action. JGT also

absorb a part of the stress that could cause a shear-failure. Stability of such soil-structures is

thus substantially enhanced enabling faster construction without removal of weak soil layers.

6.5.2 As has already been pointed out, any soil mass tends to stabilize naturally if proper

separation, filtration and drainage and soil retention can be ensured. JGT can be manufactured

upto 30 kN/m tensile strength in both warp and weft directions and can impart sufficient strength

to soil body in the initial performing phase. Once consolidation has been achieved, stability

improves, it has been established that the technical function of a geotextile – natural or synthetic,

becomes redundant.

6.6 Control of Surface Soil detachment

6.6.1 Surface soils get eroded due to detachment of the particles by raindrops, splash and

surface run-off during and after the rainfall and their transportation elsewhere. Such detachment

may also be caused due to strong wind.

6.6.2 JGT (in fabric form) control erosion of any surface soil basically in two ways. First, they

give a protective cover (partial or full) to the exposed soil surface. Secondly, they control

migration of a portion of the soil particles by reducing the flow of surface run-off. The finer

particles are mainly transported leaving the coarser grains to remain in position. This

phenomenon reduces the erodability coefficient of the soil. JGT absorb a large part of the kinetic

energy of raindrops and control rain splash detachment. To promote vegetation growth and

thereby to arrest soil erosion open weave JGT (instead of fabric form) can be used. Open weave

JGT acts as miniature check-dams or a sort of micro-terraces which prevent, to a large extent,

the detachment of soil particles, help in precipitation and reduce the velocity of surface flow.

6.6.3 JGT holds many advantages over other types of getoextiles in controlling surface soil-

detachment and consequent erosion. JGT, as already stated, can retain almost 5 times their

own weight of moisture, can attenuate extremes of temperature, can provide protection to

seedlings from the direct sunrays, can prevent dehydration of soil, allow air and light through

their open structures and provide nutrients to the soil after their biodegradation.

6.7 Bio-technical Support

6.7.1 JGT facilitates, quickens and supports growth of vegetative cover on them. Once

vegetation is grown, the function of JGT virtually ceases. Vegetation so grown, besides

dissipating substantially the kinetic energy of rain-drops, serves as a receptor of moisture with

the help of the leaves and the stems. The wind effects are also attenuated by vegetation. The

velocity of surface run-off is also reduced by virtue of the surface rugosity (roughness) of the

vegetation. The root system ensures soil-attachment and imparts strength to the soil-body. Soil-

porosity and permeability are also improved, helping to control erosion. And finally, vegetation

provides a sustainable solution to the problems of erosion control. JGT, a natural product,

enhance vegetation-growth and together they provide a bio-technical solution to the problem of

soil-erosion.

6.7.2 The choice of species of vegetation depends on the nature and composition of the nature

and composition of the soil, which vary from place to place. Live sods of perennial turf-forming

grass may be laid on embankment slopes, verges (earthen shoulders) and in other location.

Proper preparation of the soil bed, application of manure and lying of JGT are basic prerequisites

for growth of a good vegetative cover.

6.7.3 To ensure quick growth of vegetation, selection of the right type of vegetation species is

extremely important. Studies have revealed that JGT enhance micro-climatic conditions (like

temperature, soil-moisture) and organic matter-levels in soil, which are conducive to quick and

sustainable growth of vegetation.

6.7.4 Laboratory and analytical studies have been carried out at CRRI concerning the role of

vegetation in improving the stability of slopes. It has been established by laboratory testing that

the binding effect of roots imparts to the soil a cohesive strength equivalent to a minimum of 2.0

to 2.5 ton/m2. Assuming an effective depth of penetration of 0.5 m and increase in cohesive

strength of 2.0 ton/m2, analysis has shown that under certain conditions of slope geometry, a

significant increase in the factor of safety is estimated up to a depth of about 6 m. Thus, by

providing a vegetative cover, not only the erosion of the slope is checked, but also the possibility

of shallow failure averted, due to the strengthening of the top 0.5 m of the hill slope.

7. TRANSPORTATION, STORAGE & HANDLING OF JGT

7.1 JGT can be easily handled and transported. Jute yarns are basically robust provided care is

taken to keep them free from moisture (being hygroscopic) and fire. JGT can be shipped in rolls

or bales either as a bulk or a break-bulk cargo. A bale weighs around 340 kg. (680 m2) and may

consist of a number of lengths (8 to 10) depending on the required individual roll length.

7.2 Storage

7.2.1 Prolonged storage of JGT in warehouse is to be discouraged, as JGT is susceptible to

microbial action and loss of strength. JGT should be provided with a water-proof cover for

protection against rains. Direct contact with soil during storage should also be avoided. Jute

should not be stored in a wet condition. Humidity, temperature variation, lack of air-circulation

and abnormal moisture absorption affect the quality of JGT. Storage of JGT therefore calls for

attention. The main thrust should be on safe transportation and storage of JGT at site without

damaging and unduly exposing the material to adverse climatic conditions.

7.3 Site unloading

7.3.1 A fork lift or front end loader fitted with a long tapered pole (carpet pole/stinger) is

recommended for unloading JGT rolls. The carpet pole is inserted into the core of the JGT roll,

which is then unloaded from the truck. Nylon straps/ropes/roll pullers may also be used. Not

more than three JGT rolls should be lifted /unloaded at a time. Use of chains & cables for

unloading purposes is to be discouraged. A tarpaulin, a sheet of plastic or the like should be

placed on ground for initial storage of JGT.

7.4 Site Handling

7.4.1 As already stated, JGT rolls should be provided with a protective wrapping. It should be

kept above the ground and should be covered with a tarpaulin or an opaque plastic sheet.

Exposure of JGT to moisture/water may pose handling problems. As JGT can absorb water upto

5 times its own dry weight, handling wet JGT becomes more difficult than handling a moisture-

free JGT. The cores of JGT-rolls usually made of laminated paper are susceptible to damages

on being exposed to moisture/water and should therefore be kept dry. JGT should not normally

be stored for a long period. Protracted storage of JGT may reduce their strength to some extent.

7.5 Installation

7.5.1 The soil surface on which JGT is decided to be laid should be made free from sharp

aggregates, stones etc. Undulations should be levelled. JGT should normally be laid by

unrolling the JGT from top towards the bottom where there is vertical difference in ground levels

e.g. in slopes, banks of waterways etc. care should be taken to ensure that the fabric touches all

points of the base-soil and is in intimate contact with it.

7.5.2 The next step should be to secure the JGT so laid with U-shaped staples made of 11

gauge wire at an interval of 150 mm normal to the slope unless otherwise recommended. It is

advisable to use suitable wooden pegs as iron staples may get rusted on exposure. The length of

staples to be used depends on the softness of the soil. If a soil is soft, i.e., easily penetrable,

longer staples should be used for a greater pull-out resistance. A manual test for pull out should

be made before finally hammering the staple down. Suitable non-metallic staples fabricated from

biodegradable plastics may also be used. In addition to split bamboo pegs, steel staples (U

shaped) of dimension 50/150 mm may also be used as per Guidelines issued for JGT application

in Railway Embankments.

7.5.3 A wet JGT shrinks on drying. When JGT is to be laid in a wet condition, it should not be

laid fully taut as the shrinkage sustained by JGT may pull it out of its initially placed position. The

two ends of JGT roll should be properly anchored in a trench at least 500 mm deep and a spade-

width wide (for digging convenience) unless specified otherwise. The trench is to be backfilled

with heavy stones/boulders in addition to stapling on the vertical and horizontal faces of the

trench at an interval of not less than 150 mm.

7.5.4 Longitudinal edges should be provided with an overlapping of 100 to 150 mm and stapled

at 100 mm c/c. unless otherwise recommended. Overlapping between the end of the upslope roll

and top of the next downslope roll (i.e. the width-wise overlapping) should be at least 200 mm

secured by stapling at an interval of 100 mm c/c. unless otherwise recommended. Plantation of

seedlings can be made after laying of the JGT through openings made as desired. Seeds may

be spread on the prepared base-soil both before and after laying of JGT.

8. PROPERTIES OF JGT AND IMPORTANT TEST METHODS

8.1 In view of absence of code of practice for all varieties of JGT, the selection of the right type of

JGT for specific application is of vital importance. Reliance on the available standards in the

synthetic geotextiles is therefore unavoidable. Even the test standards of synthetic Geotextiles

are not uniform across the world. Reference has been made to the American Standards (ASTM

standards) for the sake of uniformity, wherever necessary Bureau of Indian Standards (IS) codes

of practice have also been given. The properties of JGT have also been drawn from „Jute

Geotextiles – A Survey‟ made by International Trade Centre, UNCTAD/GATT where deemed

applicable. The section is subdivided into three categories.

Physical Properties

Mechanical Properties

Hydraulic Properties

8.2 Physical Properties

Physical properties mentioned in this subsection refer to JGT as manufactured. They are

indicative only, and not the critical design properties of the product.

8.2.1 Mass per unit area

The weight of the fabric is mass per unit area and it is expressed in gram per square metre

(gsm). This is an important property having a direct impact on the cost and mechanical

properties. After 24 hours of conditioning at standard ambient conditions of 210C ± 2

0C, relative

humidity 65 per cent ± 5 per cent, the following nomenclatures for civil engineering application

may be adopted in case of untreated JGT in respect of mass per unit area.

i) Light weight – 290 to 300 gm/m2 (usually referred to as „gsm‟).

ii) Medium weight – 400 to 500 gm/m2.

iii) Heavy weight – 700 to 1000 gm/m2

Note: i) International Trade Centre recommends 500 mm x 500 mm sample sizes for tests.

ii) The weight should be measured to the nearest 0.01 per cent of the weight of total

specimen.

iii) Mass, length and width should be measured without tension.

iv) The current test procedure for this property is ASTM D 5261.

8.2.2 Thickness

This is an important property in connection with Transmissivity of JGT. It is measured between

the upper and lower surfaces of the JGT at a specified pressure (2 kPa). ASTM D 5199/IS-

13162 Part-3 stipulate that the accuracy should be at least 0.02 mm under a pressure of 2 kPa.

Thickness of commonly used JGT ranges from 1.5 mm to 5 mm. Thickness of JGT influences the

Transmissivity of fabric.

8.2.3 Porometry (AOS)

Porometry is the size of the pores present in a woven fabric and is a critical property for

permittivity and soil retention. JGT can be manufactured with an open mesh (“Soil saver” –

usually with the pore size of 2.84 cm2 for medium weight JGT) or with closely woven mesh with a

pore size upto a fineness OAR (Open Area Ratio) reducing permittivity and inducing clogging.

Based on the soil particle size distribution pore size of the fabric can be designed as fine as 100

micron. Pore sizes can be measured by three different techniques

By Microscope

By using a calibrated microscope in the case of rectangular pores, the smaller dimension is taken

as the pore size. A grading curve for the pore size distribution can then be represented on a

semi-logarithmic graph, which is similar to a particle size distribution graph for a soil.

By Reverse Dry Sieving Technique

Special glass beads (ballotini) of known size are vibrated on the JGT-fabric having unconfirmed

mesh-size or porometry. The percentage of the glass beads passing through it is recorded and

the test is repeated for successive smaller grades of glass beads. The pore size vs. grading

curve may be drawn on the basis of the findings. However, It may be noted that the weight of

glass beads and the extent and nature of vibration applied for this test are yet to receive

universal acceptance.

By Wet Sieving

The standards for this test vary widely and is therefore not stated.

8.2.4 Drapability

It is the bending ability of fabric in making full contact with the soil and taking the shape of the

contour of the soil surface. Drapability of wet jute fabric is more when compared to its dry state.

JGT should have the ability to shape itself in keeping with the soil surface contours and to

establish full contact with the surface. The extent of drapability is assessed by measuring the

sag (D) in mm of the JGT in between two points (S) also in mm. Drapability of jute is more when

it is wet. Drapability can be a measure of JGT‟s flexural stiffness, i.e., bending of JGT under its

own weight between two points (vide test method in ASTM D 1388). Open weave JGT

possesses a better drapability than its synthetic counterpart. A study on drapability of JGT and

synthetic geotextiles was taken up by Dr.T.S.Ingold and Mr.J.Thompson. They tested drapability

of JGT and synthetic geotextile by placing the samples (of equal unit weight) over an open span

and measuring the sag during dry state as well as wet state of the fabric. It was noted by them

that sagging of JGT (in both dry as well as wet state) was much more than synthetic geotextiles.

In other words, JGT hugs the ground in a much better manner than synthetic geotextiles.

8.3 Mechanical Properties

Mechanical properties of JGT are basically indicative of the product‟s resistance to mechanical

stresses developed as a result of application of loads and/or installation conditions. The tests

that may be used for determining mechanical properties of a JGT are tensile strength, puncture

strength, burst strength and tear strength. Test for friction resistance (soil-JGT friction) is also

considered to be important.

8.3.1 Tensile Strength

The test for Tensile Strength should be in keeping with ASTM D 4632. In case of woven JGT,

either ASTM D 4632 or IS 1969 can be followed. The test specimen size of JGT normally taken

for testing is 20 cm x 10 cm. The JGT specimen is stretched by gripping it at two ends till its

failure. When extending the sample, both load and deformation are to be measured and noted.

Other tensile test methods are Narrow Strip Test (ASTM D 751) and Wide Width test (ASTM D

4595/BIS – 13162 Part 5). A sample of 20 mm and 500 mm width respectively serve the

purposes for the aforesaid tests. Maximum tensile stress is often referred to ultimate strength.

Woven JGT (heavy type) can be manufactured to an ultimate strength of 30 kN/metre under

normal manufacturing process. Commonly used woven JGT have the tensile strength in the

range of 20 kN/m to 30 kN/m. The stress-strain curve of JGT sample indicates the following:

Maximum tensile stress

Strain at failure (i.e., elongation at break)

Modulus of deformation (i.e., the slope of the initial portion of the stress-strain curve)

Toughness (usually the area under the stress-strain curve)

8.3.2 Puncture Strength

This is the resistance to puncture of JGT. A puncture rod is pushed through the JGT sample

clamped to an empty cylinder. Resistance to puncture is measured in N. Woven JGT (heavy

type) may be manufactured to possess puncture strength of 400 N.

8.3.3 Burst Strength

This test is also known as Mullen Burst Test and is described in ASTM D 3786. The JGT is given

a shape of a hemisphere by inflating it by a rubber membrane. The sample bursts when no

further deformation is possible. This is an index test and is used basically as a quality control

test. The unit is kilo Pascal (kPa).

8.3.4 Tear Strength

This test is performed in tensile strength testing machine. JGT should be inserted into a tensile

testing machine with an initial 15 mm cut. The load stretches the fabric before it tears. The test

is described in ASTM D 4533/IS 14293. The unit is kilo Newton (kN).

8.3.5 Frictional Resistance

This property can be determined either by the direct Shear Test using a shear box or the Pull out

Test. The sample is placed between two parts of a shear box with its lower half fixed. The upper

half filled with soil is moved horizontally relative to the lower half at a constant rate of

displacement. The maximum horizontal force required to move the top half is used to calculate

maximum horizontal shear stress by dividing it by the specimen area. In the pull out test, the

JGT sample sandwiched between two halves of the box fitted with the soil is pulled by the jaws at

a constant rate of displacement. The pull-out forces is a function of JGT-extensibility, length of

embedment, redrawal stress etc.

It may be noted that determination of values for different test indicated above depends largely on

the testing procedures like the method of gripping the sample, slippage of the sample, rate of

deformation, sample-size etc. Hence following standard procedure is extremely important for

repeatability of test results.

8.4 Hydraulic Properties

The major hydraulic properties of a JGT are permittivity and Transmissivity. These properties act

in conjunction with their soil-retention capacity. JGT help stabilize the adjacent soil-structure by

developing „filter cakes‟ under unidirectional flow conditions and together they control the ultimate

flow-capacity of the system. In unidirectional flow conditions, initially there is loss of fine soil

particles through the pores of JGT leaving gaps in its soil-structure immediately contiguous to it.

Larger particles bridge over these gaps as in arches as well as over the pores in JGT. Once

larger particles rush to form the so-called „bridges‟, passage of smaller particles are blocked and

a graded filter naturally develops in contact with the JGT.

Research in this field has confirmed that even fairly uniform sands can bridge a regular mesh-

opening of two to three times the mean particle size (d50). In reversing flow condition (two-

directional flow) such graded filters within the soil zones adjacent to JGT may also develop

provided there is sufficient cycle time. In such cases of reversal of flow, a combination of JGT

and granular filter is often considered necessary.

Formation of filter-cakes depends on compatibility of distribution of pore-sizes in JGT vis-à-vis

grain size distribution of the contiguous soil. If the pore sizes in a JGT are too large, there may

be substantial initial loss of soil particles in range of sizes. This is in effect a phenomenon of

“internal erosion”. When voids created by „internal erosion‟ are large, the soil-body as a whole

becomes vulnerable. Suffusion is also a type of internal erosion, confined to finer particles in a

soil-matrix without shift of position of larger particles. Suffusion is less damaging than internal

erosion as it does not contribute to destabilisation of the soil-matrix as such.

Pore size of JGT is important and should be judiciously chosen. Larger than the optimum pore

size may lead to internal erosion while lower than the optimum pore size may cause clogging. As

already stated, permittivity and porometry of JGT are two contrasting functions. Permittivity of

JGT depends on permeability of the soil. Soil retention is obviously more effective with smaller

pore-size, which however, reduces its permittivity. A judicious compromise is therefore called for

in for selecting a JGT with proper porometry. IRC SP 59 provides guidelines for selection of

polymeric geotextiles based on in-situ soil characteristics and Permittivity and AOS properties of

geotextiles. These may be referred to while using JGT also. However producing JGT with AOS

lesser than 100 microns may not always be feasible. In such situations, a sand cushion of 25 to

50 mm can be laid below and above JGT.

8.4.1 Soil Permeability (ks)

Permeability of the soil can be measured in a laboratory. This property is indicative of soil flow

capacity under a given hydraulic gradient and flow-area as per Darcy‟s Law.

q = ks x is x A

Where q = unit flow rate, ks = coefficient of permeability of soil

is = hydraulic gradient. A = total cross-section of flow.

The equation can be expressed as

q = Ks x Δhs /L x A or Ks = q x L/ Δhs x A

Where Δhs = change in hydraulic head or head loss across soil

L = length of flow path or soil thickness over which Δhs occurs

Ks = is expressed in cm/sec.

8.4.2 Permittivity of JGT

One of the major functions that geotextiles perform is filtration. In filtration, the liquid flows

perpendicular to the geotextile into crushed stone, a perforated pipe, or some other drainage

system. It is important that geotextile allow this flow to occur without being impeded. Hence the

geotextile‟s cross permeability must be quantified. The fabrics deform under load. Thus a new

term, permittivity, has been introduced to express the permeability of geotextiles. It is expressed

as amount of water moving across a geotextile in unit time through unit area and at unit head. It

is usually referred to as Kn/t, where Kn is permeability normal to the geotextile (metre /sec) and t

is thickness in metre. If permittivty of JGT is known, the flow capacity of JGT can be assessed for

any giver hydraulic gradient and flow area. It is expressed in reciprocal of time (sec -1)

and

is

deriver from Darcy‟s Law.

q = Kg x ig x A

= Kg x Δhg/tgxA

where kg stands for coefficient of permittivity of JGT,

hg = hydraulic gradient (Δhg/tg)

Δhg = headloss across JGT

A = JGT cross-section

The ratio kg/tg is termed as the permittivity of JGT and is therefore equal to a/ΔhgxA

8.4.3 Transmissivity

For the flow of water within the plane of geotextile (e.g., in the utilization of drainage function),

the variation in geotextile thickness (its compressibility under load) is again a major issue.

Therefore the word Transmissivity was introduced. The in-plane permeability along the

geotextile plane is referred as Transmissivity. It is expressed as Kp.t (Kp is expressed in

meter/sec, t is thickness in meter and Transmissivity is expressed in m2/sec).

8.4.4 Determination of clogging potential of JGT

There are two test methods available to evaluate clogging potential of JGT – Gradient Ratio test

and Hydraulic Conductivity Ratio (HCR) test. The first method does not simulate the field

conditions in respect of compaction and confinement, which the latter method does. ASTM D

5567 describes methods for the HCR test. ASTM D 5101 mentions about the Gradient Ratio

method in which water is allowed to flow downwards through a vertical column of the soil placed

over the candidate JGT. The hydraulic gradient is measured at two locations above the JGT. If

the ratio of the flow exceeds a prescribed limit, it indicates the vulnerability of the JGT to

clogging. The intention of either of these two methods is to ensure a long term flow compatibility

between soil and JGT. Clogging-proneness of a JGT is low when the flow rate test decreases

with time and then attains a stable value over a time. Clogging potential is high when the flow

rate continues to decrease with time and does not stabilize. Piping failure is indicated when the

flow rate goes on increasing with time.

Some of the testing equipment available in India to test jute geotextiles are shown in

Appendix II.

9. DURABILITY OF JGT

9.1 It has been established after several laboratory tests on samples of JGT with varying linear

density that its biodegradation depends on environmental factors. It has also been observed that

jute degrades faster in an acidic ambience having pH value less than 5.2. The rate of

degradation of JGT is generally fast in the initial stages, but slows down subsequently. On the

other hand, when pH is in a higher range (above 7) i.e. in an alkaline environment, the laboratory

tests conducted by IIT, Delhi have initially revealed that higher the linear density of yarns in a

JGT, quicker is its degradation, though more elaborate studies are needed for this purpose to

come to a definite conclusion. As already stated in section 4, several case studies in fields

showed that the strength of JGT typically gets reduced by about 60 to 70 per cent after lying

embedded in estuarine soil for around 18 months.

9.2 Bacteria and fungi are two main groups of micro-organisms responsible for the microbial

decomposition of any natural geotextile. Moisture plays a key role in this respect. It has been

reported that the minimum moisture requirements for the growth of bacteria and fungi in JGT are

20 per cent and 17 per cent respectively. Jute attains the aforesaid moisture contents when the

relative humidity in the atmosphere is above 80 per cent.

9.3 Temperature is also instrumental for bacterial and fungal attacks on the jute. A temperature

of 370

C is the optimum temperature for bacterial growth and 300

C for growth of fungi in JGT.

Both sunlight and rain causes quick degradation of JGT. The organic content accelerates the

decay of jute fibre. The degradation studies on jute so far conducted indicate that the mechanism

of its biodegradation is complex, being dependent on interaction of a number of influencing

factors.

9.4 In order to increase the life of jute geotextiles, jute geotextiles have been successfully treated

with bitumen, copper based chemicals, phenol and some other patented chemical compounds.

However, few environmentalist expressed a view that chemicals should be so selected that may

not pollute the ground soil and water. The jute mills have therefore after several deliberations

have decided to treat jute geotextile with COMPSOL (trade name) which is a Copper Ammonium

Carbonate solution prepared to meet the U.S. and Canadian WHMIS (Workplace Hazardous

Materials Identification System) standards. It is an aqueous solution containing Copper as

Copper Ammonium Carbonate (5-10 per cent ml/Litre and Ammonium Hydroxide 6-15 per cent

ml/Litre). The remaining ingredient is water and other components, present in less than 1 per

cent concentration. It is claimed that these component have no significant additional hazards.

The compound is stable, does not cause hazardous polymerization, and is not compatible with

strong acids. No toxicological data is available on Copper Ammonium Carbonate, though

Ammonium Hydroxide is mildly toxic. There is no cancer causing agent in the compound. It is

not irritating to contaminated tissues. It does not produce mutagenicity (change in genetic

material), embryo toxicity, teratogenicity (damage to developing foetus) and reproductive toxicity.

Other properties of COMPSOL are given below:

Specific Gravity – 1.20 at 150°C

Solubility – Completely soluble in water

pH – 9.9 at 15°C

Evaporation rate – Similar to water

Freezing point – Minus 50 C

9.5 Bitumen as water-repellent

Normally 90/15 Grade Industrial bitumen is used. Modified bitumen and polymerized bitumen

have not been tried. As a result of the application of rot resistant chemical or bitumen, the life of

a JGT can be prolonged to about 2 to 5 years, subject to the specific subsoil environment. As

already stated in section 4, several case studies in fields showed that the strength of JGT

typically gets reduced by about 60 to 70 per cent after lying embedded in estuarine soil for

around 18 months.

10. ENVIRONMENTAL ASPECTS OF JGT

10.1 Jute, being an agricultural produce, poses no adverse environment impact. Besides its

cultivation, its processing and manufacture are essentially pollution free. A study by Dundee

University reveals that jute processing has not caused any illness to workers engaged in the job

for as long as twenty years. Quantities of chemical pesticides/fungicides and fertilizers that are

usually necessary for jute cultivation are far less than those required for cotton cultivation. Jute

cultivation facilitates multiple cropping pattern, enabling farmers to increase their field outputs.

Jute cultivation precedes paddy and pulse cultivation in that sequence. Leaves of jute plants

enrich the soil fertility.

10.2 As already mentioned fibres are extracted from jute plants by retting. Water in retting tanks

does not affect natural drainage nor does it pollute ground water. In fact, the retted water can be

used for irrigation for watering crop fields. Testing of jute fibres reveals that proportions of

pesticide/fungicide and fertiliser-residues are insignificant. Studies conducted by Indian Jute

Industries Research Association (IJIRA) and Central Pollution Control Board show no adverse

environmental impact of the effluent released from jute mills.

10.3 Hydrocarbon emission from jute batching oil (JBO) has also been rigorously studied by

IJIRA. The waste batching oil emulsion is mostly recycled for processing of jute without posing

any environmental threat. An alternative batching oil (rice bran oil) has recently been developed

by IJIRA which is a non-polluting lubricant. During manufacture of jute yarns, other ingredients

used like starch, natural gum are found to have no adverse environmental impact.

10.4 Environmental Protection Encouragement Agency (EPEA), Hamburg in Germany, a

research and consultancy body, and the FAO Secretariat have made a comparative study

between jute and polypropylene (PP) in respect of waste generation, water requirement, energy

consumption and CO2 emission in their production. The Table 8 below indicate the same.

Table 8: Comparison of environmental effects of Jute & PP fibres per ton basis

Parameter Jute PP Ratio (PP/Jute)

Waste produced (tons of Waste/ton of product)

0.9 5.5 6.1

Water Consumption per ton of product (m

3)

54 to 81 1.3 0.016 to 0.02

Energy Consumption per ton of product (GJ/t)

5.4 to 14.35 84.3 5.9 to 15.6

CO2 emission (tons of CO2/ton of product)

-1.2 to 0 3.7 to 7.5 –

10.5 Jute geotextiles (JGT) evidently pose no environmental threat. Being biodegradable JGT

ultimately coalesce with the soil on which it is laid, adding nutrients to it and retaining water for

quicker growth of vegetation. Unlike synthetic geotextiles which are not biodegradable, JGT

have no disposal problems.

11. CIVIL ENGINEERING APPLICATION OF JUTE GEOTEXTILE (JGT)

There are several areas of application of JGT in Civil engineering which have proved effective

after field trials. These are listed below:

- Surface Erosion Control in Slopes

- Bank Protection in Rivers and Waterways.

- Erosion Control in Slopes

- Stability of Embankments for Highways.

- Strengthening of a Road-structure.

- Shoulder Drainage

- Consolidation of Soft Soil.

- Prevention of reflection cracks

Design approach, installation-method, and suitability of the type of JGT for the intended use are

indicated separately for each application hereinafter.

11.1 Surface Erosion Control

11.1.1 The most popular use of JGT has been for erosion control purposes. It has been in use

since 1950s when it was developed and exported to Europe and USA in the name of Soil Saver

of Geo-jute. Geo-jute is a structure made of jute fibres woven into a heavy open mesh. It was

mainly used for protecting newly cut slopes from erosion through growth of vegetation. Geo-jute

has good tensile strength, is flexible, easy to install and biodegradable and is thus environment

friendly. Geo-jute is normally available in rolls of 1.22m width and 70m length. The open mesh

size of geo-jute net may be 16mm x 22mm or as per the requirement of the application site.

11.1.2 The purpose of natural geotextile is to protect and support the natural environment for a

limited time span. The task is complete when nature, through soil and vegetation, eventually

provides adequate protection. The natural geotextile, therefore, provides temporary aid for the

establishment of natural vegetation. Once the vegetation cover is established, the shrubs and

plants themselves act as cover to the surface to prevent erosion in the long run. Thus JGT acts

as bio-engineering or engineered agronomic system for erosion control i.e. engineering and

vegetative measures used in conjunction with each other to fulfil the ultimate goal of erosion

control. Ingold and Thomson (1990) carried out studies on the erosion control characteristics of

different geo-textiles in sandy loam soil on 1 V:2 H slope and found that geo-jute reduced the soil

loss to about 1.3 gm/mm from control. The mean erodibility for synthetic mat was found to be

about 5 gm/mm. Rickman (1988) reported the soil loss in geo-jute as 14 per cent of the control.

With a growth of good grass cover the protection efficiency of geo-Jute can be in the range of

99.0 to 99.9 per cent with a crop factor of 0.00 to 0.01 (Ingold and Thomson, 1990). Tests

carried out by them further showed that natural fibre net such as geo-jute significantly reduces

the splash erosion by rain drop impact. Geo-jute strands absorb much of the runoff and ponded

water within the miniature check dams which the JGT strands provide. Water absorption capacity

of open weave JGT is about 4-5 times its dry weight. The good absorbency of geo-jute has

much to do with its runoff control ability. Once jute absorbs water to capacity, its flexibility is

increased approximately, 25 per cent thereby improving its drapability, i.e. its ability to maintain

intimate contact with soil, which further helps in reducing erosion. Ingold and Thomson (1990)

reported that the runoff with application of jute net is reduced to about 15 per cent compared to

42 per cent in the control.

11.1.3 It is obvious that when the rainfall intensity exceeds the permeability of the base-soil,

surface run-off results in transporting the detached soil particles. Rain-drop impact is the prime

agent in detachment of soil-particles while the surface run-off is the main transporting agent. It

may be noted that the extent of surface soil-erosion depends on other factors as well namely, the

nature and extent of vegetative cover, inclination of the surface, length of flow etc. Table 9 below

shows a correlation between rainfall form and kinetic energy.

Table 9: Correlation between rainfall intensity and kinetic energy

Rainfall form Intensity (mm/hour)

Diameter of rain drops (mm)

Kinetic Energy (j/me/hour)

Drizzle <1 0.9 2

Light 1 1.2 10

Moderate 4 1.6 50

Heavy 15 2.1 350

Excessive 40 2.4 1000

Cloudburst 100 2.9 to 6.0 3000-4500

11.1.4 The netting structure of the geo-jute provides innumerable miniature check dams in the

flow or runoff which trap fine soil particles and a part of runoff, thereby improving soil moisture

status. The heavy strands of jute absorb the impact of falling rain drops and check splash

erosion. The open mesh provides protection to seeds and plants sown from washing away by

runoff. The jute mat also functions as a mulch to maintain humidity and regulates temperature

for proper seed germination. Thus, geo-jute creates improved micro-environment for the growth

of vegetation and biodegrades in due course (which may take place in about two years) adding

additional organic matter to the soil.

11.1.5 JGT have to perform usually two contrasting functions namely, soil retention and

permittivity. It is always advisable to develop a vegetative cover over the affected soil surface.

JGT‟s function ceases once the vegetation is fully grown and reinforces the soil. Untreated JGT

have a useful life of one season (generally) by which time the vegetation has to grow.

Decomposition of JGT adds nutrients to the soil, besides acting as a water receptor. It is

recommended that the laying of JGT along with seeding are so timed as to take advantage of the

increased moisture content of the soil from the monsoon showers. JGT possess the highest

moisture absorption capacity of all fibres – natural or synthetic – about 500 per cent of its own

dry weight and much higher than that of two other natural fibres in use as natural geotextiles

namely, Sisal (175 per cent) and Coir (150 per cent).

11.1.6 Design Approach The porometry and the strength of JGT are the basic criteria for design. Soil loss by detachment

and transportation is prevented initially by JGT, which will be subsequently be done by the

vegetative cover. The vegetative cover controls erosion naturally after degradation of JGT.

Kinetic energy of rain-splash is dissipated by JGT before vegetation takes over the function.

Slope, composition of soil and rainfall are guiding factors for choice of the type of JGT. The

design-approach may be three pronged:

Agronomic (biological)

Land/soil management

Mechanical

JGT is useful tool for agronomic control by helping in rapid growth of vegetation. Land/soil

management also needs JGT. Mechanical methods are, in fact, manipulation of the surface

topography by construction of terraces/benches or silt fences. JGT maybe used as a component

of the slit-fence. Each or a suitable combination of the three methods is necessary for surface

erosion control.

The types of JGT useful for the purpose are indicated below:

Type I – Weight 750 gm/m2

May be used where

Aperture size – 20x20 mm - Soil type is mixture of coarse to very

Thickness – 7 mm coarse aggregates like rock-particles.

Thread/m (warp x weft) – 70x70 - Steep slopes up to 450

Tensile strength – 30 x 20 kN/M - Annual rainfall upto 3000 mm

(warp x weft)

Type II – Weight 500 gm/m2

May be used where

Aperture size – 25x25 mm - Soil is mixture of silt and sand or

Thickness – 5 mm clay

Thread/m (warp x weft) – 65x45 - Moderate slopes (450 to 30

0)

Tensile strength – 25x 20 kN/M - Annual rainfall upto 3000 mm

(warp x weft)

Type III – Weight 300 gm/m2 May be used where

Aperture size – 25x25 mm - Soil is sandy clay

Thickness – 3 mm - Gentle slopes < 300

Threads/m (warp x weft) – 100x120 - Annual rainfall upto 2000 mm

Tensile strength – 20 X 15 kN/M

(warp x weft)

11.1.7 Application Method

The soil-surface is to be levelled without any sharp aggregate protruding over it. if

necessary, the slope may be re-graded to the angel of internal friction of the soil prior to

levelling.

Broadcasting of seeds of appropriate vegetation.

Unrolling of JGT from top of the slope to the bottom or along the direction of surface run-

off.

Anchoring of JGT by steel staples/wooden pegs within a trench at the two ends.

Care should be taken ensure drapability of JGT i.e., the fabric must touch the ground at

all points.

Overlaps should be 10 cm at the sides and 15 cm at the ends.

Second dose of seed broadcasting should be done over the laid JGT along with dibbling

of locally available grass.

Note: Selection of the type of vegetation is very important. Sowing/planting procedures are not

uniform and depend on the types of species, soil-composition, rainfall etc. Local

experience should be the guide. Taking help of botanists, agronomists, local Forest

Departments for selection of species, timing of sowing/planting, planting/broadcasting

procedures, procedure of their nurture and maintenance etc, are strongly advised.

11.1.8 Monitoring

Close monitoring should be carried out for at least one season cycle. Displacement of JGT, of

any, is to be noted and watched without disturbing it initially. Torn portions of JGT may be over

lapped by fresh JGT pieces duly stapled on all sides. Watering/maintenance of the plant-saplings

may be done as per procedures suggested by the botanists/agronomists/forest department, as

the case may be.

11.2 Bank Protection of Rivers and Waterways

11.2.1 The main causes of bank erosion are as follows:

i) Weak bank soil which is easily erodable.

ii) Strong current and eddies near the bank.

iii) Waves induced by wind and moving vessels.

iv) Large fluctuations in water-level

v) Uplift pressures due to alternating hydraulic gradients.

11.2.2 Bank erosion may be controlled effectively either by repulsion of flow away from the

affected banks or by providing a durable protection to the affected banks or by a combination of

both these measures. Repulsion of flow is a task of the concerned engineers and can be

achieved by construction of suitable regulatory measures at appropriate locations. Protection to

the banks can be done by a combination of conventional granular filter /armour and JGT. The top

of the bank protection work should have a cover of vegetation (e.g., quick growing local grass,

„vetiver‟ grass, mangroves in saline inter-tidal zones).

11.2.3 The basic function of JGT in bank-protection in rivers and waterways is filtration as a more

precise alternative to conventional granular filters. Filter design for erosion-control in banks of

rivers, canals and waterways should address three basic criteria:

i) Design of JGT

ii) Survivability of JGT

iii) Durability of JGT

11.2.4 The design basically involves selection of a Jute Geotextile (JGT) which will ensure soil

tightness and proper permittivity of water to prevent differential over-pressures from developing

across it. It has already been stated that soil tightness i.e. retention of fines and permittivity are

two contrasting functions. A judicious compromise has to be made in respect of selection of JGT

so that both the functional demands are met. Survivability of JGT is important and therefore

fabric should possess sufficient strength against installation stresses.

11.2.5 Design Approach

a) Retention

The basic relation is On (usually O90 or O95) < dn (usually d90 or d50), where On is the Apparent

Opening size. If On is increased then there is a possibility of piping i.e. sub-surface erosion. On

the other hand, if On is decreased, clogging may take place, causing differential over pressures

across the JGT. The following recommendations may be followed in case of JGT as adopted by

AASHTO (1990) in respect of synthetic geotextiles. AOS (apparent opening size i.e. O95 ) should

be less than 600 micron if d50 is larger than 0.075 mm. and AOS should be less than 300

microns if d50 is less than 0.075 mm.

b) Permittivity

Permittivity is the ratio of co-efficient of permeability of JGT (kg) and its thickness (tg). It should

be ensured that the coefficient of permittivity of JGT (kg) should be more than the coefficient of

permeability of the soil (ks). In other words, (kg) >(ks). In rivers having reversing flows, Kg should

be at least 100 times Ks. As already mentioned, chances of both mechanical and chemical

clogging of JGT cannot be ruled out. Clogging potential of JGT should be tested as per ASTM D

5101 (Gradient Ratio test), or any other suitable method (Hydraulic Conductivity Ratio test). A

JGT is expected to function with a low probability of clogging when the flow rate initially

decreases with time and then stabilizes to a certain value over a time period.

Normally the Permittivity should be greater than 5 x 103 ks x is where ks is the co-efficient of

permeability of the base soil and is is hydraulic gradient of soil. There is however a cautionary

note : If there is a possibility of down slope migration of soil in the bank, JGT should be laid on a

granular sub-base. Alternatively, JGT should be thicker than the normal design thickness either

in a single layer or by combination (multiple layers).

11.2.6 Installation :

The bank should first be cut to a stable slope preferably at the angle of internal friction of

the bank soil. The surface should be levelled and made free from angular projections,

undulation, soil-slurry or mud.

Anchoring trench (usually rectangular) should be excavated at the top of the slope.

Recommended dimensions of the trench – 500 mm deep and at least 250 mm wide at

the bottom. The trench should be free from foreign material, mud etc.

JGT should then be unrolled across the trench and along the slope from top down to the

lowest water-level. JGT should be stapled with U-shaped nails (usually 11 gauge) within

the anchoring trench both at the sides and bottom at an interval of 150 mm along the

length of the trench. There should be at least two staples both depth-wise and width-

wise in each cross section.

JGT should be laid with the overlapping in the direction of water flow. Care should

always be taken to ensure that JGT does not suffer damage due to puncture, tear and

similar operational stresses. The recommended overlap is 150 mm (minimum). The

overlapped portion should be stapled at an interval of 75 mm.

The anchoring trench should then be filled with stones/boulders for securing and

protecting the JGT. Care should be taken to ensure that JGT touches the bank slope at

all points (proper drapability).

Armour overlay of stone/boulder should then be placed on the JGT carefully. It should

be ensured that armour stones/boulders are not dropped on the JGT, but are carefully

placed and properly arranged. A thin layer of sand as a cushion on top of the JGT is

recommended to avoid puncture of the fabric by granular overlay.

Similar care in laying should be taken when a combination of granular filter and JGT is

used under reversing flow-conditions.

There must be a beam at the toe of slope. This can be done by folding the JGT as per

dimensions (usually 500mm diameter) with sand filling and duly stapled on the other side

preferably at an interval of 75 mm. Alternatively, an angular trench may be dug at the toe

and the JGT placed on it ensuring full contact with the soil, duly stapled at a spacing of

75 mm and ballasted. Care should be taken to see that the overlapping layer is not

displaced during installation.

Suitable grass seeds should then be spread on the treated bank. Alternatively, saplings

of suitable plants may be planted at close intervals through the interstices of the overlay,

taking care to place them into the bank soil.

Installation should be completed preferably just before the monsoon to take advantage o

the rains for quick germination of seeds.

11.2.7 Monitoring and Maintenance

The treated bank should be kept under watch for at least one full season cycle. Frequent visits

to sites during and after the rains or any natural calamity are necessary. Siltation is expected to

take place after about a month which should cover up the granular overlay gradually.

Maintenance involves, besides monitoring, re-arrangement, of the overlay, if displaced, in

position. No part of JGT should be allowed atmospheric exposure due to displacement of the

overlay. In all bank erosion control works, it is imperative that the longevity of JGT should be at

least 4 to 5 years. The purpose is two-fold. First, to allow sufficient time for stable formation of

filter cake. Secondly, to ensure growth of a dense vegetative cover for holding the base soil

naturally. The selected JGT should therefore be smeared with suitable rot-resistant chemicals or

industrial grade bitumen. Care may be taken to ensure that such application of rot resistant

chemical/bitumen does not affect the porometry of JGT beyond a tolerance limit of 25 per cent.

Considering that there may be reduction in Open Area Ratio (OAR) as a result of application of

rot resistant chemical/bitumen, it is recommended that pore size of any selected untreated JGT

should be decided keeping in view the possible reduction in OAR after treatment. The JGT

strength may be ascertained after one season cycle and the overall performance should be

analysed.

11.3 Stability of Embankments for Highways

11.3.1 Stability of embankments concerns stability of the soil-body as a whole, apart from the

stability of the exposed slopes. Road and railway embankments are subjected to moving traffic,

which develop dynamic stresses within them. Flood-control embankments are supposed to

withstand lateral thrusts of rising water which may seep into the embankment body and enhance

the moisture content within it. It is worthwhile noting that soil derive stability from their shear

strength. The safe slope of an embankment depends on the shear strength of the fill. Non-

cohesive granular soil possesses high internal frictional resistance which helps develop

increasing shear strength with the addition of load.

11.3.2 Soil in general hardly possesses any tensile strength. It behaves differently according to

its composition, structure and other geo-technical properties. As a result, embankment

constructed with soils prone to volumetric variations, suffer failure in the shape of vertical

subsidence, lateral dispersion, down-slope migration, rotational slides, etc. The use of JGT for

reinforcing the soil in the body of the embankment shall be based on the evaluation of

improvement expected in regard to its stability because of such use. The improvement is a

function not only of the fill-properties, but also of the JGT.

11.3.3 Design Approach

Reference may be made to Koerner (1990) for a suitable method of analysis or other text-books

on geo-synthetics, dealing with reinforced embankments. Generally, stability of the embankment

subjected to moving loads may be ensured by JGT, which can perform the following functions

effectively:

11.3.3.1 Initial Reinforcement

An earthen embankment when subjected to moving loads, develops stresses and strains which

may lead to its failure if the permissible limits are exceeded. JGT when placed at appropriate

levels within an earthen embankment can absorb these stresses and strains to a substantial

extent at the initial stages and control failure of the embankment. Soil-JGT friction acts as

medium of transference of stresses and strain JGT, when put to tension, strengthen the soil-

body. JGT can directly reinforce an embankment only during its useful life-span (not more than 4

to 5 years after rot-resistant treatment). In fact, JGT may not serve the purpose of reinforcing an

embankment fully or a long period, but can certainly perform the functions of filtration, separation

and drainage which, in turn, induce strength and stability to the embankment-structure as a

whole.

11.3.3.2 Separation

JGT separates the natural ground from the fill materials of an embankment and thus prevent their

intermixing. If the base-soil is weak and compressible, the first embankment layer can retain its

geo-technical characteristics better as a result of the separation.

11.3.3.3 Filtration

When the first embankment layer is made of freely draining materials, JGT can ensure soil-

tightness while allowing passage of water.

11.3.3.4 Drainage

JGT may serve as a draining layer (Transmissivity), as a drainage layer by itself, within its own

thickness when there is no localised out-flow of water. Functions of separation, filtration and

drainage in combination accelerate consolidation of the fill of the embankment by gradual

riddance of water. The basic design criteria are similar to what has been stated under Section on

Bank Protection in Rivers and Waterways, in so far as porometry and permittivity are concerned,

it is imperative that both the grain size distribution and coefficient of permeability of the fill and

also of the base soil are determined for choice of an appropriate JGT. Before construction of any

new embankment, JGT treated with bitumen of suitable grade should be laid on the base soil.

The will prevent intermixing of the base soil and the fill material. If the soil material has a high

Plasticity Index (i.e., high consistency and hence, high order of compressibility), it is

recommended that two to three layers of JGT treated with suitable rot resistant chemicals should

be laid in successive layers above the prepared ground. There should be provisions for side-

restraint if the soil material has low internal friction. When permeability of the fill material is less

than 10-5

metre/sec, a combination of woven and non woven JGT is recommended. In addition,

design measures for slope stability are also to be taken care off.

11.3.3.5 Installation

The following sequence of construction is recommended:

The surface of the base should be levelled and cleared of any foreign materials

Treated JGT should be placed at the interface of the base-soil and bottom of the

proposed embankment with the fill material and folded up to ⅛th of the base width of the

proposed embankment

More fill materials should be laid at the edge

The central portion is to be filled next

The height of the embankments is to be raised

Complete filling the central portion in stages

The slopes should be protected as already indicated under the relevant section.

Note: - The fill-material should not be an organic soil or have

- Plasticity index (P) not more than 20 and Liquid Limit (LL) more than 40 when

tested according to IS 2720 (Part 5).

- Filling behind abutments and wing wall of all structures should conform to IRC /

MoRTH Specifications

- The fill materials shall be laid in horizontal layers and compacted as per IRC/

MoRTH Specifications.

- Backfilling should not be done in water. Water should be bailed out, mud scooped

out and JGT laid on the prepared ground. It is recommended that granular material

of maximum particle size of 75 mm and uniformity co-efficient (d60/d10) above 10

should be used in such cases as fill material.

- Sufficient settlement period should be allowed to the new embankment before any

construction is undertaken. Alternatively, methodology of pre-loading the new

embankment maybe considered.

- In case of very high embankments, treated JGT may interposted at appropriate

layers within the embankment body; however, a separate design should be

obtained from an expert.

11.3.3.6 Monitoring

Any newly constructed embankment should be monitored for two season cycles for settlement

and other distresses. The basic principles for a trouble free stable embankment is to avoid

ingress of water into it and to draw out water if there be any entrapped water/moisture within it.

11.4 Strengthening of Pavement Structure in Roads

11.4.1 Poor subgrade often causes pavement-failures as strains accumulate under repeated

dynamic loads of traffic. It often happens that the materials in the base course of the pavement

get intermixed with the subgrade, reducing the required depth of the pavement decided on the

basis of class of loading vis-à-vis CBR (California Bearing Ratio). A poor subgrade may also

cause lateral displacement of the subgrade and the base-materials under loads. Insufficient

drainage of the surface water and also the entrapped moisture/water within the sub-surface

layers along with the seepage of water from the sides often lead to road-failures. JGT can tackle

all these problems effectively by segregating different layers of a road pavement, preventing

movement of the subgrade soil (soil tightness) and facilitating filtration through them.

11.4.2 Design Approach

11.4.2.1 JGT when placed over the subgrade help stabilize it in a number of ways. Besides

preventing intermixing of the subgrade and the sub-base, JGT also check the upward movement

of the fine particles in the subgrade, provide frictional resistance against lateral dispersion and

act as a support membrane.

11.4.2.2 It is always advisable to segregate the soft subgrade from the pavement layers by

selecting a proper JGT-fabric with the right strength, porometry and permittivity. JGT to be used

in road should have a Puncture Strength of 400 N and a tensile strength of at least 15 – 25

kN/metre. Normally the available woven geotextile meet the above strength requirement.

Porometry of the JGT may be decided on the basis of mean grain size of the subgrade as

already indicated in preceding sections. Permittivity of the JGT depends on the permeability of

the subgrade and may be determined as per recommendations given. Subgrade has to be

compacted to optimum moisture content (OMC) prior to laying of the selected JGT.

11.4.3 Installation

The subgrade is to be excavated to the required level, cleared of all foreign materials and

compacted to the OMC (Optimum Moisture Content). The subgrade should be done up

with the specified profile. Vegetation, if any, should be uprooted and the area levelled

with earth and rolled.

JGT as selected should be laid by unrolling, ensuring proper drapability (i.e., JGT should

touch the subgrade surface at all points) and stapled at an interval of 300 mm with

overlaps of 150 mm. Staples should be preferably U-shaped nails (11 gauge). It is

preferable to avoid overlaps to the extent possible.

A thin cushion of local sand (minimum 15 mm thick) may be spread over the JGT to

prevent puncture/damage due to rolling of the upper sub-base/base-layer.

The first layer of aggregates in the Sub-base layer (conforming to IRC/ MoRTH

specifications) should then be spread. No traffic should be allowed on an un-compacted

base with less than 200 mm (150 mm for CBR>3) thickness laid over JGT.

Any rut that may develop during construction should be filled in.

Parallel rolls of JGT should be overlapped and stapled.

For application in curves, JGT should be folded or cut and overlapped in the direction of

the turn. Folds in JGT should be stapled at an interval of 300 mm.

Before covering up the JGT, its condition should be assessed for any

constructional/installation damage. Torn/damaged portions may be covered by pieces of

JGT and duly stapled on all sides preferably at an interval of 75 mm. The extent of

overlap will be such as to fully cover the damaged/torn portion fully plus at least 75 mm

beyond, on all sides.

Usually filling is carried upto a height of 1.5 m after placing of JGT as first stage during

stage wise construction of road embankment. Sufficient waiting period as per design

needs to be provided for consolidation process to take place.

11.4.4 Shoulder Drainage

Often the sub-surface water is drained through the JGT-medium to the shoulders of a carriage

way. In such cases, shoulder drains are required to be constructed either beneath the edge of

the shoulder or immediately adjacent to its edge (In USA, such drains are called „under-drains‟).

In the event of existence of black cotton soil or expansive clay, porous drain pipes are also

inserted within the shoulder drain to augment drainage efficiency.

11.4.5 Monitoring and Maintenance

The performance of the pavement with JGT should be monitored closely, especially with regard

to development of pot holes, subsidence, road side drainage, dispersion of subgrade and the

like. Frequency and extent of surface treatment and also re-sectioning needed are also to be

noted. Special attention is necessary during and after the rains. Pot holes should be

immediately restored. Surface drainage over the pavement should not be allowed to hinder due

to malfunctioning of road side and shoulder drains. Close monitoring should be done at least for

two season cycles by noting the type and extent of subsidence of tracks. Clogging of the

drainage outlet requires surveillance. Review of design (depth and spacing of JGT fibre drains)

may have to be done in case erosion pumping failure persists.

11.5 Consolidation of Soft Soil

11.5.1 Compressible soils pose problems for any type of construction on it due to their volume

variation with change in water-content. Consolidation of soil can be achieved if the water in the

sub-surface layers can be drained out. In order to drain out water quickly from the saturated

subsoil, sand/band drains/sand-wicks are conventionally being used. Band drains are made up of

synthetic fibres. Instead of synthetic fibres, jute fibres can also be used to manufacture band

drains. The Indian Jute Industries Research Association has developed prefabricated JGT

drains. JGT fibre drains have been successfully used to accelerate consolidation of subsoil.

Pre-fabricated JGT fibre drains can act as an extremely effective draining medium. Sand-wicks

are essentially porous „stockings‟ filled with sand. JGT fibre drains have been developed with

jute-wicks inside instead of sand.

11.5.2 Specification of prefabricated JGT drain

11.5.2.1 The specifications of Prefabricated JGT drains developed by IJIRA (with the guidance

of Prof. Ramaswamy) are indicated below.

The properties are :

Weight/metre – 140 gm

Tensile strength – 4.5 kN

Extension – 4 to 5 per cent

Permeability at 50 mm water head – 0.41 mm/sec

Discharge capability at 50 kPa under unit hydraulic gradient – 13.1 ml/sec.

11.5.3 Design approach

11.5.3.1 The design approach is similar to what is normally being used for geosynthetic drains.

The general steps in designing band drains is indicated below. However, it is suggested that an

expert opinion be taken for designing and installation of jute geotextile band drains for

consolidation of soft subsoils.

11.5.4 Installation of prefabricated Jute drains

11.5.4.1 Special drilling equipments are needed for digging deep holes and removing the loose

spoils. JGT fibre drain should be „guided‟ into the drilled holes by mechanical or suitable

contrivances and the annular spaces filled up with sand. Indian Institute of Technology (IIT),

Delhi has developed a special machine for this purpose. The details of the same are available at

Textile Engineering and Civil Engineering Department of IIT, Delhi. Some general steps of

installation are indicated below.

Drilling of holes (diameter 150 mm for 100 mm wide prefabricated jute drains) with

augers usually 2 metres below the bottom ballast level.

Taking out of all loose materials from the holes.

Insertion of JGT prefab drains inside the holes with help of split bamboo sticks, taking

care to place it centrally.

Filling the side-space with sand/non-cohesive fine aggregates.

The top of the JGT drains should be kept slightly above the bottom ballast level of the

track. If there is a sand blanket under the ballast, the top of the fibre drains can be kept

under the sand blanket.

In case of JGT-wrapped porous pipes to be laid laterally, horizontal drilling may have to

be done, loose materials removed and the pipe inserted keeping their outfall end laid on

to the exposed surface of the embankment slope for ultimate drainage of the entrapped

water.

11.5.5 Monitoring

11.5.5.1 Monitoring should be done at regular intervals for noting the rate of consolidation and

settlement. One season-cycle is usually adequate for full consolidation.

11.6 Jute Geotextile for Controlling Reflection Cracks in Roads 11.6.1 Life of a flexible pavement depends basically on its flexural strength. Usually, except in

cases of subgrade failure, flexural fatigue and also natural ageing may cause cracks to develop

and propagate within a flexible pavement. Crack propagation can be stalled by interposing a

fabric in combination within the existing pavement. Jute Geotextile (JGT) has been used to act as

the interposing fabric to prevent cracks from getting propagated in the upper layer of a

bituminous pavement.

11.6.2 Reflection cracks occur after re-surfacing of a cracked road. Thermal changes usually

tend to induce a tensile force in the horizontal direction. Repetitive vehicular loads induce vertical

shear. Combination of the two causes parallel shear to develop. Understandably, the crack(s) on

the pavement-base are the line(s) of weakness on either side of which there is interplay of

fluctuating stresses. Crack(s) once formed want to move up and result in a line of cleavage in the

riding surface.

11.6.3 Synthetic Geotextiles have been successfully used in some parts of the world to delay the

propagation of reflection cracks in both bituminous as well as rigid pavements. Jute Geotextile

(JGT) instead of synthetic one, is also one of the viable options for use as a reflection crack

arresting layer. JGT is to be laid on an old bituminous pavement after sealing the existing cracks

with neat bitumen. JGT may be laid with a tack coat of bitumen followed by a premixed sheet of

bitumen–stone chip–stone dust mix. The grade of bitumen should be decided on the basis of site

conditions and ambient temperature. Modified rubberised bitumen may also be tried. Jute and

bitumen have excellent thermal compatibility. Bitumen heated up to 190oC may be safely used.

The quantity of tack coat should depend on the nature of surface of the pavement base.

Normally, bitumen at the rate of 0.3 kg/m2 may be used as tack coat overlain by another coat of

bitumen of the same quantity. Woven JGT to be used should be capable of withstanding tensile

stress to the extent of 30 kN/metre initially in both machine and cross-directions. JGT having a

porometry of 70 per cent coverage (open area of about 30per cent) should serve the purpose.

The specifications are provisional and are subject to alteration in accordance with the site

conditions.

11.7 New Areas of Application of JGT

Besides the areas mentioned in the preceding chapters, several new areas of application

deserve consideration for laboratory investigation and field trial. The following areas may open

up new end-uses of JGT.

11.7.1 In bituminous overlays

Bituminous overlays are used as wearing course over exiting black top pavements. Bitumen

impregnated geotextile may be laid between the top bituminous macadam layer and the

bituminous wearing overlay. This may enhance the service life of the wearing course. Bitumen

and jute have excellent thermal compatibility. JGT may also help in prevention of reflective

cracking.

11.7.2 In temporary haul roads

JGT can provide the desired reinforcing effects in temporary haul roads which are required to be

constructed for access to sites for a limited period. Its initial stiffness and low extensibility may

be effective in temporary high-duty roads.

11.7.3 As fabriforms

Fabriforms are used to mould wet concrete in a desired shape. JGT may be cut and stitched in

accordance with the desired shape of concrete before being filled up with wet concrete.

Fabriforms made of jute geotextiles may be put to use for making revetment mattresses and

remedial works for concrete structure. The function of JGT is to give and retain the desired

shape of the concrete and its function ceases once the concrete hardens. Biodegradability of

JGT is an advantage in such cases.

11.7.4 Jute Geo Cell

Use of jute geocells in low cost embankments and pavements construction on soft soil has been

advocated by Mandal and Mhaiskar (1994). For design of low cost embankments with jute

geocells, Mandal et al have recommended use of slip line theory (by H. Hency – 1923) and for

designing pavement on soft soils, the method proposed by AASHO (American Association of

State Highway Officials). Jute Geocells are innovative forms of JGT and are worth trying in the

aforesaid areas.

12. Cost of Jute Geotextiles and Commercialisation

12.1 The comparative cost of natural jute geotextiles and synthetic geotextiles is shown in Table

10. It is observed that open mesh JGT is around four times cheaper than similar SGT while the

woven JGT is about half the cost of SGT. The non woven JGT is more than five times cheaper

than the synthetic non woven. The cost data provided in the Table 10 is based on a survey

carried out by the authors in the year 2006. The costs are only indicative and subject price

variation and escalation. The readers are advised to contact the manufacturers whose addresses

are provided in the document.

Table 10: Comparative cost of Jute Geotextiles (JGT) & Synthetic geotextiles(SGT)

A.

Open mesh JGT (exfactory) Open mesh SGT

Rs.7.00 to Rs.14.00 per m

2

Rs.30.00 per m2 (not usually used)

B.

Woven JGT (ex-factory) Woven SGT

Rs.22.00 to Rs.45.00 per m

2

Rs.90.00 to Rs.110.00 per m2

C.

Non woven JGT (ex-factory) Non woven SGT

Rs.9.00 to Rs.18.00 per m

2

Rs.50.00 to Rs.60.00 per m2

12.2 Since mid eighties large scale experimental trials followed by commercialisation of JGT in

different application areas have established the efficacy of the product. It has also been

established that biodegradability of jute has got no detrimental effects on its demand. Table 11

shows the domestic consumption of JGT during the year 2000 and 2001.

Table 11: Comparative Consumption of JGT during 2000 and 2001 in India

Sector 2000 – 2001 2001 – 2002

Area (m

2)

Weight (MT)

Area (m

2)

Weight (MT)

Irrigation & Waterways (760 gsm treated)

20,000

15.2

2,15,000

163.4

PWD (Roads) (760 gsm grey & 300 gsm grey)

28,500

18.9

29,000

16.7

Mines (500 gsm)

-

-

1,30,000

39.0

Railways (760 gsm treated , 500 gsm grey & 500 gsm non woven)

15,000

7.5

10,000 +

6.3

Total

63,500

41.6

3,84,000

225.4

Note: Export figures have not been shown

13. Laboratories Studies on Jute Geotextiles

13.1 Several laboratory investigations were carried out to assess the Feasibility of using jute

geotextiles for different applications in the laboratory scale. Some of the laboratory investigations

carried out on the jute applications are given below.

13.2 Jute Geotextiles for Roads – Laboratory Investigations

13.2.1 Objectives of the study

i) To assess the feasibility of using jute geotextiles for application in road construction

ii) To observe whether the biodegradability of jute fabric is a deterrent factor for its use as a

separator in road construction

13.2.2 Laboratory Investigations

Extensive studies were carried out to evaluate behaviour of jute fabric under different types of

loading conditions.

13.2.3 Dynamic Load Test

Dynamic load test was conducted with clayey subgrade at 40 per cent moisture content. A

dynamic load of 8 kN and a simulated contact pressure of 255 kN/m2 was applied. Upto 1000

load applications were made. The results of the dynamic load test are presented in Fig 6 and

also in Table 12.

Table 12: Results of Dynamic Load test on Jute geotextile

Thickness of

aggregate layer (mm)

Rut Depth (mm) Remarks

Without JGT With JGT

100 22 10 With the use of JGT, more than 50 per

cent reduction in rut depth in both cases 200 18 7

The results of the dynamic load tests on jute fabric correlate very well with those of Lai and

Robnett who carried out similar tests on a synthetic geotextile (Ref: Lai, J.A.S and Robnett, Q.L

(1980), „Designing and use of geotextiles in road construction‟, Proceedings of third Conference

of Road Engineering Association of Asia and Australia, Taipei)

13.2.4 Static Load Tests

Static load test was conducted on clay in layers of 100 mm. Jute fabric was placed with back

filling of 100 mm thick moist sand (Moisture content – 6 per cent) and pavement pressure of 2.4

kN/m2 was simulated. Short time rutting tests were performed under a series of loading

pressures from simulated wheel loads of 350 N, 900 N and 1350 N, while long term (6 weeks)

loading tests were performed under simulated wheel loads of about 1000 N on bearing plate of

200 mm diameter. Results of short term static load tests and long term sustained loading tests

were found satisfactory and are presented in Fig 7 and 8.

13.2.5 Unconfined Compressive Strength and CBR Test

Unconfined compressive strength and CBR tests were carried out to assess the influence of jute

geotextile on the strength of clayey subgrade at different moisture contents. The findings are

presented in Table 13 and 14.

Table 13: Effect of Jute Geotextile on Unconfined Compressive Strength

Water

Content (%)

Unconfined Compressive Strength (kN/m2) Strain at failure (%)

Without Fabric With Fabric Without Fabric With Fabric

25 110 300 8 26

30 45 115 10 30

35 36 65 22 42

Table 14: Effect of Jute Geotextile on Laboratory CBR Values

Water Content (%) 20 25 30 35

CBR Value (%) Without Fabric 5.0 4.7 3.5 2.6

With Fabric 8.0 6.8 5.2 4.5

13.2.6 In-situ Trials

Plate load test was conducted to evaluate the in-situ behaviour of the subgrade soils provided

with JGT. The subgrade soil used was soft to medium silty clay having natural moisture content

equal to 35 per cent and Vane shear strength (in-situ) equal to 20 kN/m2. Plates of 300 mm

diameter were used. The results are similar to tests reported with man made geotextiles (Ref:

Jerret, P.M., et al (1997), „The use of Fabrics in Road Construction on Peat‟, International

Conference on Soil Textiles, Paris, France, pp 19 – 22)

13.2.7 Durability Tests

The test specimens consisted of JGT treated with 40 per cent, 50 per cent and 60 per cent

bitumen and samples were preserved with 3.5 per cent, 6 per cent and 12 per cent preservative.

They were kept in different environment like acidic solution (pH = 3), alkaline solution (pH = 12)

or buried under clay in a separate container and the grab tensile strength test was performed

after every month upto one year. Durability studies confirmed that the JGT retains sufficient

strength for about one year.

13.2.8 Conclusion

Jute geotextiles function in a manner similar to their synthetic counterpart. The laboratory tests

confirmed that application of JGT significantly improves bearing capacity and settlement

behaviour of reinforced with JGT. JGT were found durable upto one year when treated with

bitumen and other preservatives.

Fig 6: Typical surface rut depth vs number of load application for dynamic load test using jute geotextile

Fig 7: Load settlement relationship with and without jute geotextile

Fig 8: Rut time relationship for sustained seven weeks loading test

13.3 Comparative study of Synthetic and Jute Geotextile for Erosion Control

13.3.1 This laboratory study was taken up to evaluate performance of JGT for surfacial erosion

control and to assess the comparative performance of such systems made with synthetic

geotextiles vis-à-vis JGT. An artificial embankment slope constructed beneath a rainfall simulator

was used for the experiment. The embankment slope modelled by battered face of the soil was

inclined at 260 to the horizontal to represent a 1V:2H slope. The slope width of 5 m was divided

into 6 trial bays, each 500 m wide to allow space between adjacent bays. To conduct the

experiment,

Simulated rainfall was generated using a series of nozzles fixed to an oscillating bar above

the slope.

Rainfall drop size was kept equal to 1.3 mm

Kinetic energy of rainfall was 14 joules/ m2 / mm

Eight storms were simulated, each having return period of 100 years for Eastern England

region

First five storms had rainfall intensity of 40 mm/hour with one hour duration. The first storm

was on a pre-wetted slope. The remaining four storms at this intensity were run in pairs at

three day intervals such that the first storm of each pair fall on a dry slope. Two hours

duration was allowed for drainage before starting the second cycle on a wet slope. After a

three day drying the same cycle was repeated.

A different approach was adopted for the last three storms. Rainfall intensity was increased

to 75 mm/hour and the storm duration was decreased to 20 minutes. The first cycle

comprised one storm falling on a dry slope and after two hours, a second storm was applied

on a wet slope. After three day period, the slope was pre-wetted and a single storm was

applied to the wet slope.

Each of the five samples were installed on 500 mm x 1.8 m trial plot in accordance with the

supplier‟s instructions

The sixth plot was top seeded in a usual manner and used as a control plot. All the six plots

were seeded to assess the ability of each product to resist washout of the un-germinated

seed. The control plot and other five plots were covered with 200 mm top soil comprising of

12 per cent clay, 29 per cent silt, 33 per cent sand and 26 per cent gravel. Seeding was

done by hand using commercially available grass seeds at the rate of 28 gm/m2.

Table 15: Type and Characteristics of Fabrics Selected for Trials

Geotextile Composition Properties

Weight

(gm/ m2)

Thickness

(mm)

Tensile

Strength

(kN/m)

Opening

Size (mm x

mm))

Durability

(Years)

JGT Jute 500 - 7.5 11 x 18 2

Commercial

synthetic mat 1

(CSM 1)

Wood / Wool

mulch contained

in PP strand

mesh

360 - 25 x 37 1.5

Commercial

synthetic mat 2

(CSM 2)

Polyamide 260 9 0.8 - -

Commercial

synthetic mat 3

(CSM 3)

Polyethylene 450 18 4.4 6 x 8 -

Commercial

synthetic mat 4

(CSM 4)

HDPE 1740 - - - -

13.3.2 Results

Some inconsistent and very low run-off values were obtained for the initial application of 40

mm/hour intensity storm to the pre-wetted slope due to high initial rates of filtration. Similar

problems were encountered for dry slope at the higher intensity of rainfall. These results were

disregarded when calculating mean run-off values, there by leaving reliable data for wet slopes

only at 75 mm/hour rainfall intensity. The run-off values obtained are presented in Table 16.

Table 16: Run-off (in cc) in Different Test Beds

System Dry Slope,

Rainfall – 40 mm/Hr

Wet Slope,

Rainfall – 40 mm/Hr

Wet Slope,

Rainfall – 75 mm/Hr

Control Section 25 33 50

JGT 2 9 11

CSM 1 3 16 31

CSM 2 19 41 34

CSM 3 28 37 23

CSM 4 16 33 23

Storm Duration One Hour One Hour 20 Mins

The relative effect of different rainfall intensities, where sediment loss is expressed in grams are

shown in Table 17. During this test, storm duration was normalised in all the three cases to one

hour.

Table 17: Sediment Loss (in Grams) in Different Test Beds

System Dry Slope,

Rainfall – 40 mm/Hr

Wet Slope,

Rainfall – 40 mm/Hr

Wet Slope,

Rainfall – 75 mm/Hr

Control Section 70 92 263

JGT 6 25 57

CSM 1 4 23 84

CSM 2 56 121 189

CSM 3 81 106 124

CSM 4 51 104 136

Mean values of soil erodibility (gm/mm) are given in Table 18.

Table 18: Soil Erodibility (in gm/mm) in Different Test Beds

System Dry Slope,

Rainfall – 40

mm/Hr

Wet Slope,

Rainfall – 40

mm/Hr

Wet Slope,

Rainfall – 75

mm/Hr

Overall

Average

Control Section 7.1 8.0 5.8 7.0

JGT 16.4 1.7 2.1 6.9

CSM 1 7.5 1.1 1.0 3.5

CSM 2 10.4 6.4 3.3 7.4

CSM 3 9.0 7.8 3.3 7.2

CSM 4 12.3 8.6 6.2 7.9

Storm Duration One Hour One Hour 20 Mins

Moisture absorption of different systems expressed in percentage of original dry weight is given

below in Table 19.

Table 19: Moisture Absorption (as percentage of dry weight) in Different Test Beds

System Absorbed Moisture

JGT 485

CSM 1 Not Measured

CSM 2 118

CSM 3 40

CSM 4 9

The results clearly showed that JGT is very effective in reducing erosion of the soil beds. All the

products tested reduced erosion, where as JGT proved to be most effective at higher intensity of

rainfall. JGT reduced erosion under lower rainfall unprotected soil (initially dry condition) and to

27 per cent of unprotected soil (initially wet condition). JGT seems to operate mainly through

considerable reduction in run-off. JGT is the most effective product for containing erosion due to

higher intensity rain and also showed a tendency to become more effective with time. This is due

to better drapability of JGT when it is wet which helps to maintain close contact between JGT

and the soil surface.

13.4 Use of Jute Geotextiles for Construction of Roads for Light Traffic – A laboratory

Experiment

This experimental study was taken up to ascertain improvement in load bearing capacity of

subgrade soil with the introduction of JGT and two layers of bricks. Six sets of plate load tests

were conducted with mm thick steel plate of 30cm X 30cm deep. The plate was placed centrally

into the test pit of size 150cm X 150cm and 30 cm deep. The conventional method was followed

for the plate load test. The schedules of the tests are given below in Table 20.

Table 20: Test Details for Use of JGT in Light Traffic Roads

Test Set

The Test Pit Layers of brick laid over the final level

(a) 30cms No brick Layer

(b) 60cm; made 30cms by filling with same virgin soil One layer of brick

(c) 60cm; made 30cms by filling with same virgin soil over JGT (60cms x 60cms)

No brick layer

(d) Same as in set (c) One layer of brick

(e) Same as in set (b) Two layer of brick

(f) JGT(60cms x 60cms) was placed at 60 cms depth and 30cms depth was made by placing virgin soil over JGT

Two layer of brick

(The experimental study was made by Dr. Amalendu Ghosh, Prof.,Civil Engineering Deptt, B.E college, West Bengal, India; Published in All India Seminar on “Application of Jute Geotextile in Civil Engineering: (March 07,2002)

13.4.1 Characteristics of Soil Used

The soil used on the test was silty clay having properties given in Table 21.

Table 21: Properties of Soil Used in the Experiment

Property Value

Liquid Limit 78 Per Cent

Plastic Limit 40 Per Cent

Natural Moisture Content 30 Per Cent

Unconfined Compressive strength 4.7 t /m2

Procter Test - OMC 21 Per cent

Procter Test - Max Dry density 1.57 gm/ cc

13.4.2 Result of Plate Load Tests

The yield stresses and corresponding settlements for different cases are given below in Table

22.

Table 22: Results of the Plate Load Tests

Type of test medium Yield stress, t/m2 Settlement, mm

Virgin soil (set a) 12.11 30.00

Compacted soil* underlain by single Layer of brick (set b)

27.90 58.70

Compacted soil underlain by one layer of jute-textile (set c)

19.40 70.00

Compacted soil overlain by By single layer of bricks and underlain By a layer of jute geo-textile (set d)

35.50 27.00

Compacted soil overlain by two layers of brick (set e)

21.20 26.00

Compacted soil overlain by two layers of bricks and underlain by a layer of jute geo-textile (set f)

19.30 12.70

*compacted soil was obtained in the pit near OMC at the unconfined compressive strength of the

compacted fill of 6.6 t/m2.

13.4.3 Characteristics of Jute Geotextile Used

Weight 418 gm/m2

Thickness 2.305 mm

Tensile strength 0.0704 Kg/cm

In-plane permeability 6.428 x 10-3

cm/sec

Cross plane permeability 1.358x 10-3

cm/sec

13.4.4 Conclusions

Placement on the layer of bricks on the top of the surface of compacted soil set (b) helps for

increasing the load Carrying capacity quite significantly compared to virgin soil, set (a) or

simple a jute geo-textile layer overlain by compacted soil set (c)

The response of two layers of bricks over compacted soil (set e) has been better. But when

one brick layer along with a jute geo textile layer (set d), the load carrying capacity is

improved and is higher than that in the case when only two layers of bricks are used (set e).

The best results is obtained when two layers of bricks are used in addition to layer of jute

geo-textile (set f) but (set d) appears to be most effective both from performance and

economic point of view in case of two low volume rural road construction.

Repeated Load Tests on Jute Geotextile and Bamboo Reinforcement

Repeated (Cyclic) load tests were conducted to compare the behaviour of unreinforced and jute

geotextile and bamboo reinforced unpaved roads. These tests were aimed to ascertain the

effectiveness of reinforcement in increasing the fatigue resistance of the pavement structure. The

cyclic test was carried out on a 16 cm thick gravel sub-base layer loaded directly over soft

subgrades; Gravel subbase layer with jute geotextile at the subbase-subgrade interface and

Gravel subbase layer with jute geotextile and a bamboo grid at subbase-subgrade interface.

Test Set up

The loading frame procedure for compacting the subgrade (Bombay marine clay) and subbase

(Byhatti gravely soil) was the same as that in the static loading test. The hydraulic jack was

replaced by a pneumatic cylinder which had a 75 mm ram movement. The ram movement the

period and the applied force was controlled by a specially designed setup consisting of a

pressure regulator, Solenoid values, etc.

Testing Procedure

Three repetitive loading tests were performed on unpaved road model. Since, this was an

unpaved road, the number of load applications were limited to 10,000 cycles. The pavement was

subjected to a cyclic pressure of 197 k Pa (maximum) application. Seven cycles were applied in

a minute to simulate the traffic condition on an unpaved road.

Resutls and Discussions

Fig. 9 to 12 shows the fatigue behaviour of un-reinforced and reinforced subgrade upto 10,000

cycles of load application. It is observed from Fig 9 to 12, that with increase in number of cycles

of load application, the fatigue resistance decreases as a result of which deformations of the

pavement increase. This is particularly observed when the pavement is subjected to large

number of load application. The effectiveness of the reinforcement in reducing the fatigue is

measured by considering the cumulative deformation of the pavement after 10,000 cycles of load

applications (Table 23).

It was found that jute geotextile and bamboo grid at the subbase-subgrade interface was the

most effective of arrangement of reinforcement for reduction in pavement deformation. Providing

only a jute geotextile as a reinforcement also increased the fatigue resistance type of test.

Table 23: Reduction in the Pavement Deformation due to Reinforcement

Type of Test Cumulative Deformation of the pavement (mm)

Per cent Reduction in Deformation of the pavement

Unreinforced pavement 59.00 -

Jute geotextile reinforced 38.5 34.75

Jute and Bamboo grid reinforced pavement

21.05 64.41

Fig. 9: Cumulative Deformation Vs. No. of cycles for unreinforced and reinforced pavements

Fig. 10: Cumulative Deformation Vs. No. of cycles for unreinforced and reinforced pavements

Fig. 11: Cumulative deformation Vs. No. of cycles for unreinforced and reinforced pavements

Fig. 12: Cumulative deformation Vs. No. of cycles for unreinforced and reinforced pavements

14. Some Case Histories/ Field demonstration

To promote use of jute geotextiles in civil engineering applications, a series of field experiments

were carried out using jute geotextiles for different functions. Application of jute geotextiles for

different functions at different locations are described in the following sections.

14.1 Jute Geotextiles as Separator

14.1.1 Roads around Kandla Port

In Kandla port area, authorities were facing the problem of road construction on soft soil. The

road network in the Kandla port trust area was to be improved to facilitate better movement of

vehicular traffic. The soil in the port area is very soft and has very low bearing capacity,

premature failure of road pavements were a common occurrence in the area. In order to improve

the pavement performance, it was suggested that a layer of geotextile be provided over the soft

subgrade to prevent the intermixing of subgrade and subbase soil. In the broad spectrum of

geotextiles, natural geotextiles made of jute are very helpful. They are eco-friendly, economical

and at the same time serve the desired function. It was proposed to use jute geotextile as a

separator between pavement layers. The performance of pavements constructed on soft soils

can be improved using jute geotextiles. The jute fabric as separator was provided with a view to

prevent the penetration of subgrade material into voids of granular base course, for faster

dissipation of pore pressures and ensures better drainage, which result in long term performance

of the pavement. It was also expected that provision of fabric would reduce rutting and subgrade

would develop its full bearing capacity. The properties of jute geotextile used in the experimental

trial are given in Table 25.

Table 25: Properties of jute geotextile used as a separator at Kandla Port

Sl. No.

Description of Property Value

1 Type Woven

2 Tensile strength 10.81 kN/m

3 Thickness 6.91 mm

4 CBR push through load 0.5 kN

5 Index puncture resistance 0.077 kN

6 Inplane permeability 9.2 x 10-4

m/s

7 Falling cone test No clear hole formed

8 Failure strain 30 per cent

The table shows that the fabric has low tensile strength but fails at a large strain of the order of

30 per cent. In particular, in falling cone test, no clear depression or punching was observed

under the fall of the cone indicating the resistance of fabric for puncturing with aggregate or the

material used in base layers.

Design

The geotextile can provide restraint and acts as reinforcement and prevent localized bearing

capacity failures, which result from individual stones being forced into the subgrade. The

pressure at the stone/geotextile interface is related to the burst pressure for a given aggregate

size. A design guide for separator function indicating the requirement of burst resistance was

developed for the field application.

Construction Details

Site was cleaned properly from its rough surface. Spreading and compaction of moorum cushion

was carried out subsequently. The area was instrumented by installation of settlement gauges.

Fig 13: Treated stretch of embankment (Kandla Port)

Fig 14: Untreated stretch of embankment damaged after cyclone at Kandla

The subgrade was compacted to the optimum water content and maximum dry density of the

subgrade material. The jute geotextile was spread over the compacted subgrade. This

corresponds to the requirement of the low bursting strength of geotextile and also helps in

reducing the impact of large sized aggregates. A thin layer of morum with average thickness of

about 10 mm was provided at the interface to prevent punching of jute geotextile by large size

aggregates. It was followed by the base course consisting of two WBM layers of 300 mm

thickness of 60-125 mm size aggregates followed by a 200 mm thick WBM constructed using 40

to 60 mm size aggregates.

Monitoring of the completed section

The engineers of Kandla Port Trust monitored the completed section for its performance in terms

of rut depth and other visible signs of distress. Settlements of the test section in relation to

conventional pavement section were being monitored. Settlement of the test section in relation to

conventional pavement section was recorded with the increase of pavement loads from 0.5

MT/sq. m to 2.0 MT/sq. m. Loads were increased in increments of 0.5 MT/sq. m each month from

February 1997 to May 1997. Results of the settlements recorded from February 97 to May 97

sent by Kandla port trust, shows almost negligible settlements after six months and no signs of

distress in the treated test section. During the cyclone of Oct. 1996, the untreated stretch got

badly damaged, however, the treated stretch was not affected. This encouraging result had

prompted the Kandla port trust to purchase another consignment of 15,000 sq. m of Jute

geotextiles from IJMA, which has been used for road and embankment construction in creep

area in Kandla port. Some photographs showing the site and laying of geotextile is shown in Fig

13 and 14.

14.1.2 Guptipara Station Road in the district of Hooghly, West Bengal

Construction of pavement of Guptipara Station Road using JGT was taken up as a

demonstration project since it was having a good volume of traffic. The objective was to reduce

the designed thickness of the pavement by introducing jute Geotextiles. The 300 GSM 200 SD

jute non woven was selected to conduct the field trial. The original designed thickness of

pavement was 450 mm but in the trial the pavement thickness was reduced to 400 mm.

Horizontal drainage system was introduced by laying 50 cm wide jute non woven at both sides of

the road at a depth of 4000mm under compacted soil and broken brick bats. The work was

conducted during May-June, 1998. The work was kept under continuous observation and

performances were monitored.

The performance of the stretch of the road treated with JGT was good for a considerable period

whereas the stretch without JGT showed signs of deterioration in the form of ruts, potholes and

cracking on the surface though the thickness of the untreated pavement was 50 mm more than

the JGT laid stretch. Hence it can be inferred that the JGT has performed significantly to

contribute better towards durability of the road.

14.1.3 Widening and Strengthening of Munshirhat Pero-Khila Rajapur Road in the district

of Howrah, West Bengal

The road was taken up for improvement and widening under RIDF-IV Scheme. The original road

pavement was 3 m wide and there were proposals for widening it to 5.5m. The total length of the

road was 11.3 km, out of which widening portion of 2km was selected for treatment with JGT for

strengthening. The road passes through low-lying area with high water table and poor soil belt.

The JGT installed on the extended portion of the road on both sides after compaction of the

subgrade. Over the JGT brick bats, Jhama metal and stone metal consolidation were done. The

B.M with premixed carpet and seal coat was extended throughout 5.5 m width of the road. The

properties of JGT used in this road are given in Table 25.

Table 25: Properties of JGT (Rot Proof) Used at Munshirhat Pero-Khila Rajapur Road

Property Value

Weight (gm/m2) at 20 per cent moisture content 760

Threads / dm (MD x CD) 102 x 39

Thickness (mm) 2

Width (mm) 76

Strength (kN/m) (MD x CD) 20 x 20

Elongation at break (%) (MD x CD) 10 x 10

Pore sixe (O90) micron 300

Water permittivity at 10 cm water head (litre/m2/sec) 50

Puncture resistance (N/cm2) 380

The road was constructed in the year 2000 and was kept under constant observations under the

offices of Howrah Highway Division, PW (Roads) Department. They evaluated the performances

of the portion treated with JGT and compared with untreated stretches. The widening portion

without having JGT showed signs of distress and formed depressions and pot holes whereas the

portion treated with JGT is much better and showed very little or negligible distress even after a

lapse of three monsoons.

14.1.4 Rehabilitation of Roads

The following roads under Serampore Municipality, West Bengal were rehabilitated using jute

geotextiles.

a. Road in front of Serampore Municipality and Railway level Crossing (Medium traffic)

b. Netaji Subhas Avenue (High traffic volume)

c. Thakur Das Babu lane, in front of Bandav Samity (Low traffic volume)

All the above roads had continuously suffered from early distresses and required frequent repairs

and rehabilitation. To solve the perpetual problem rehabilitation work was done applying Jute-

Geotextiles and their performance have been kept under rigid monitoring and regular inspection.

The work was completed before the advent of monsoon in the year 2002. Almost couple of

monsoons have already been elapsed there is practically no appreciable signs of distress was

observed. The riding quality of the above roads surfaces is good. This indicates the

improvement of performance level due to use of JGT in repairing work.

14.2. Jute Geotextiles as Initial Reinforcement

14.2.1 To Support Embankments at Kakinada

A deep-water port was under construction at Kakinada in Andhra Pradesh and within the port

area a number of highway embankments were under construction for transporting cargo from the

ships to the storage godowns. At some locations, the subsoil was soft silty clay and the water

table was at 0.5m below the ground level. The whole area was getting submerged during high

tide (Fig 23). The highway constructed earlier faced many problems during and after construction

such as 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 would sink into the soft subsoil during spreading of the fill itself,

necessitating extra quantities of costly granular fill material, thereby, pushing up the cost of

construction.

In order to mitigate the above problems, various alternatives were examined, among which

geotextile was found to be the promising one. The use of jute geotextile to improve

embankments over soft subsoil was proposed as it is an effective method for reinforced soil

construction. Geotextiles was proposed be used to improve i) the embankment stability against

bearing capacity failure, ii) stability against slope failure through the foundation, iii) allow a more

controlled construction over very soft or difficult foundation soils, iv) ensure more uniform

settlement of the embankment and v) to also act as separator between the embankment material

and soft sub soil. They also performed as drainage blanket for draining pore water during

consolidation. Embankment stability usually needs to be improved only during the short period in

which the foundation consolidates, and in such cases the long-term durability of the geotextile

reinforcement is of secondary concern.

Reinforcement in an embankment on soft soil is very effective when placed at or close to the

foundation surface. If the reinforcement were absent, the factor of safety at the end of

construction would fall to a value below unity. In other words, the desired cross section cannot be

built without the reinforcement. Again the factor of safety starts increasing, as the strength of the

foundation soil improves due to consolidation and the foundation soil attains the required

strength. Thus the reinforcement is needed only to improve the stability during construction and

in that period of consolidation during which the soil attains the required strength. Fig 15 and 16

show the construction of embankment using JGT as initial reinforcement at Kakinada.

Fig 15: Embankment Construction Using Jute Geotextiles – Kakinada

Fig 16:Jute Geotextiles as Initial Reinforcement – Kakinada

The main loading from an embankment is due to the vertical self-weight of the embankment fill,

which causes horizontal stress in the fill, which in turn produces lateral forces (outward shear

stress). The resulting outward shear stress, which acts on the foundation surface, reduces the

foundation bearing capacity. So the primary role of reinforcement is to support the outward shear

stress and relieve the foundation from the lateral forces, thereby, increasing the allowable height

of the embankment that can be supported by the foundation soil. A layer of reinforcement placed

in the embankment may resist lateral displacement by exerting an inward shear stress on the

foundation surface thus reducing the lateral spreading of the foundation. Since the geotextile was

placed between the embankment fill and the subsoil, it also performed the function of separator,

thereby, eliminating the mixing of costly granular fill material with the subsoil. The geotextile

along with the sand cushion will also act as a drainage layer for the escape of the pore water

during consolidation.

A woven jute geotextile was used for reinforcement and also as a separator between the

embankment and the soft subsoil. From the experiment it was found that the required strength of

the subsoil developed within the short life of the jute geotextile, which is biodegradable and

degrades in about 2 years and is economical as well as safe to use geotextile in such projects.

Design aspects

While considering an embankment placed upon very soft soil foundation and supported by

geotextile the following design elements were checked for arriving at the required properties of

the geotextile.

Bearing capacity: In order to check for bearing capacity failure and to check the geometry of

embankment can be arrived at using the following considerations.

qall = C Nc /FS

qall = Y.Hall

where

qall = Allowable bearing capacity

Ý = Unit weight of the embankment soil

Hall = Allowable height of the embankment

Nc = Bearing capacity factor

C = Undrained shear strength of the foundation soil

FS = Factor of safety

From the above equations we can calculate the allowable height of the fill.

Global stability: It is necessary to check the stability against slope failure passing through the

foundation cutting across the geotextile, thereby, arriving at the required strength design of

geotextile in major and minor principal stress direction.

Elastic deformation: The amount of elastic deformation allowed by the geotextile will govern the

deformation of the embankment. The maximum strain at the required stress is assumed to be

approximately 10 per cent. This enables us to find the required modulus and failure strain in

major principal stress direction and in minor principal stress direction for the geotextile.

E = Treqd /εf

E = modulus of elasticity

Treqd = tension in the geotextile

εf = strain in the geotextile

Pull out and anchorage: With the mobilization of all, or part of the fabric reinforcement‟s

strength, the essential requirement is that the soil behind the slip zone resists pullout. Sufficient

anchorage distance behind slip plane should be available to mobilize the required strength.

Lreqd. = Tact / 2(Ca + σv tan )

where

Tact = Actual stress in geosynthetic

Ca = Adhesion of soil geosynthetic

tan = Friction coefficient of the soil to geosynthetic

Lreqd = Required anchorage length behind the slip plane

Lateral spreading: It is necessary to arrive at the frictional properties of geosynthetic by

considering the tension cracks developed in the embankment and active earth pressure exerted

on the side. Assuming the fill material above the geosynthetic to be granular, the following criteria

must be satisfied.

Tan = HKa /L

where

L = length of the zone involved in spreading

Properties of materials

The topsoil up to a depth of 2 m from the ground level is mainly silty sand and clay mixture. The

soil below this depth is highly plastic clay. This soil in general found to have a natural moisture

content ranging from 70 per cent to 85 per cent with bulk density varying from 1.3 g/cc to 1.45

g/cc. Undrained shear strength of the soil as determined from vane shear tests was found to be

4.6 kN/sq.m to 6.0 kN/sq.m. Compression index (Cc) varied from 0.15 to 0.29 and coefficient of

consolidation (Cv) ranges between 1.l X 10-3

to 3.0 X10-3

.

Construction procedure

The geotextile was available in width of 75 cm., so, 10 pieces of geotextile were stitched at the

site to make the width to 7 m and 26 m long geotextile (base width of embankment is 23 m and

anchorage length at both ends is 3 m) and were carried to the site. Before spreading the

geotextile the site was cleared off all debris and any tree roots. Any rough surfaces which could

not be cleared, were covered with sand to eliminate the damage to geotextile. The geotextile was

laid with its warp direction (strong direction) parallel to the width of the embankment. A trench of

size 0.5 m X 0.5 m X 0.5 m was dug in the soil on either side along the embankment length, for

anchoring the geotextile. The geotextile was then placed in the trench and sand filling was done

for proper anchorage. Ten pieces of geotextiles were stitched to bring the width to 7.0 m and

length to 26.0 m. Base width of embankment was 23.0 m and anchorage length at both ends was

3.0 m. An overlap of 30 cm was given between two rolls of geotextiles. The geotextile was

stretched manually, so that no wrinkles were there while spreading, this would also build a small

amount of initial tension in the geotextile. After spreading the geotextile and anchoring it at the

two ends, a sand cushion of minimum 30 cm thick was laid, to take care of the damage due to

moving trucks or any other vehicles. Soil filling in the embankment was continued in the usual

manner. Settlement gauges were installed to monitor the settlement in the embankment. The

jute geotextile was used for 110m length of the road stretch. Approximately a total of 3000 sq. m

of jute was used in this project.

Woven jute geotextiles with properties given in Table 26 was used at the experimental stretch at

Kakinada Port area for reinforcement and also as a separator between the embankment and the

soft subsoil. Monitoring of completed embankment i.e. both treated and control stretch, was

carried out by JNTU College of Engineering, Kakinada.

Table 26: Properties of Woven Jute geotextiles used at Kakinada Port

S. No. Property Test value

1. Thickness 5 mm

2. Weight 750 gsm

3. Tensile strength 15 kN/m

4. Elongation 10 per cent

5. Puncture resistance 350 N

6. Overlap length 300 mm

7. Type of fabric Woven

Results and Discussion

At the end of seven months, the increase in shear strength of sub-soil ensured the required

factor of safety for the embankment. The strength of fabric was no longer required to provide

reinforcing effect. Brief details of some of the tests on sub-soil are given in Tables 27 to 29.

Table 27: Water content of Soil before and after Laying of JGT

Location Water content (%)

before laying JGT

Water content (%) after laying JGT at elapsed months of

3 7 21 30

1 97.4 76.3 68.7 55.0 50.0

2 72.7 69.1 56.3 45.4 35.3

3 76.4 69.1 68.7 59.0 53.4

Table 28: Dry Density of Soil before and after Laying of JGT

Location Dry Density (gm/cc)

before laying JGT

Dry Density (gm/cc) after laying JGT at elapsed months of

3 7 21 30

1 0.70 0.85 0.89 0.95 1.05

2 0.82 0.87 1.01 1.25 1.35

3 0.84 0.92 0.89 0.94 1.07

Table 29: Void Ratio and Compression Index of Soil at Different Elapsed Time

Location Void Ratio Compression Index

Before

Laying

Following Laying at Elapsed

Months of

Before

Laying

Following Laying at Elapsed

Months of

3 7 21 30 3 7 21 30

1 2.63 2.10 2.00 1.70 1.60 0.65 0.52 0.51 0.50 0.45

2 2.10 1.80 1.75 1.30 1.10 0.61 0.56 0.50 0.40 0.38

3 2.10 1.90 1.80 1.60 1.40 0.61 0.60 0.50 0.44 0.40

Conclusions

Water content, void ratio and compression index decreased while insitu density increased by the

use of jute geotextiles. Jute geotextiles appears to be very effective even in weak subgrade soils

in reducing their compressibility and increasing their strengths as reflected from good

performance even after a lapse of seven years.

14.2.2 PMGSY Pilot Project Using Jute Geotextile

Jute Manufactures Development Council (JMDC), a national promotional body under Ministry of

Textiles, Government of India, has embarked upon a Pilot Project under PMGSY with the support

of Ministry of Rural Development/ National Rural Roads Development Agency. Central Road

Research Institute (CRRI) has been appointed as Technical Consultant by JMDC. This project

has been taken up in five states (Assam, Chattisgarh, Madhya Pradesh, Orissa and West

Bengal). Ten roads, two in each state will have JGT as integral component of the road structure

to study its usage as separator, filter, drainage medium and reinforcing material. The main

objectives of this Pilot Project is to evaluate the beneficial effects of the use of JGT and

standardise different types of JGT for different applications in road construction. The following

aspects will be considered in the Pilot Project:

1. Benefit of woven/ non woven JGT as a separation layer, segregating and preventing inter-

penetration of material overlying and underlying the fabric

2. Benefit of non woven JGT as a drainage layer, facilitating in plane discharge of water that

percolates through the upper layer of the pavement

3. Benefit of woven JGT as an initial basal supporting system for embankments on soft ground

(slushy soil, marshy area, etc)

4. Benefit of open weave JGT as a bioengineering protective measure by facilitating growth of

vegetation on the embankment slopes and earthen shoulders

5. Benefit of woven JGT as an agent of improvement in the load bearing capacity of subgrade

The total length of ten selected roads is 47.84 km and total estimated cost of construction is

Rs.17.83 Crores. Brief details of the ten selected roads are given in Table 29.

Table – 29 Details of Ten Selected Roads for Pilot Project Using JGT

State Name of the Road Road Length (km)

Orissa Jadupur to Mahanangal, Kendrapara District 5.50

Orissa MDR 14 to Chatumary, Jajpur District 4.00

Madhya Pradesh Berasia to Semrakalan Approach Road, Bhopal District

5.10

Madhya Pradesh Gehlawan village to PMGSY road, Raisen District 3.14

Chattisgarh Kodavabani to Khursi Road, Bilaspur District 4.80

Chattisgarh Kherajiti to Ghirghosa road, Kawardha District 5.50

West Bengal Notuk to Dingal Road, West Midnapore District 4.80

West Bengal Nandanpur to Marokhana High School Road, Hooghly District

6.20

Assam Rampur Satra to Dumdumia, Nagaon District 4.20

Assam UT Road to Jorabari, Darang District 4.60

Total Length 47.84

Detailed Project Report (DPR) for each of these roads was prepared by CRRI. The project roads

are being constructed by respective state agencies through established tendering process being

followed in case of any other PMGSY road. CRRI has been entrusted the job of quality

management and third party random quality checking.

Types of JGT in Use in the Project

Different types of JGT which were developed by IJIRA have been chosen on the basis of soil

survey carried out by CRRI in these project roads and the specific end use of JGT. Woven JGT

to be used for separation function shall be having three different values of tensile strength – 15

kN/m, 20 kN/m and 30 kN/m. Of all the three varieties of woven JGT, about 50 per cent of the

material to be laid would be treated with a branded rot resistant textile friendly chemical

(COMPSOL – A blend of Copper Ammonium Carbonate solution and Ammonium Hydroxide

conforming to specifications of WHMIS – Workplace Hazardous Materials Identification

Standards of USA and Canada). The remaining 50 per cent will be laid as untreated. This will

enable carrying out a comparative study on the necessity of rot resistant treatment of JGT as a

separator, filter and drainage medium above subgrade soil.

Non woven JGT of 500 gsm has been used for facilitating drainage. Non woven JGT possesses

low tensile strength but is an efficient drainage medium. In fact transmissivity criterion is more

dominant than permittivity for geotextiles for efficient water dispersion from soil.

Open weave JGT of 500 gsm will be used on the side slopes of road embankments and in

shoulder areas of selected stretches for surfacial soil erosion control. This is a bio-engineering

measure intended to improve slope stability and embankment integrity. Laying of open weave

JGT would be followed by sowing the seeds of grass/ leguminous plants which will have deep

roots and thrive under the local climatic conditions.

In areas prone to water logging, woven JGT of 20 kN/m tensile strength will be treated with

bitumen to prevent its early degradation due to prolonged contact of the fabric with water.

Bitumen to be used for coating woven JGT shall conform to IS 702 (Industrial grade bitumen of

grade 90/15). Bitumen absorption by the untreated JGT shall not be less than 60 per cent of its

weight. Work could not be taken up in two of the above roads due to frequent floods and other

local problems. Construction work has been completed in six roads. Performance monitoring is in

progress in five of these completed roads.

14.3 Jute Geotextile for Drainage and Filtration Function 14.3.1 Design and Construction of Filter using Jute Geotextile Behind Retaining Wall,

New Delhi

The drainage filter should adequately satisfy its performance during and after construction of the

structures. In case of high embankments constructed using fly ash (pond ash) as fill material, the

drainage aspects of the fill material is of critical importance during construction period because of

high permeability or fly ash. In the case of Road Over Bridge, such as Hanuman Setu, the filter

criteria was critical during the construction, as the water percolation into the back fill was more

during construction particularly in monsoon season. After construction of ROB, the percolation of

water was negligible as the road pavement material was almost impermeable and camber of 1 in

30 also facilitates a faster run-off. Thus, the filter thickness requirement was more during

construction than after construction. To facilitate quick drainage, jute geotextile was chosen as

filter it can be effectively and economically used. A non woven jute geotextile would satisfy the

filter criteria.

Design criteria

Fly ash was used as a backfill material in the said project. Because of lower specific gravity and

finer‟ gradation of the material, design requirement was more critical than the conventional

backfill material. 750 gsm non woven jute geotextile was substituted for 30 cm thick conventional

filter. Conventional filter was designed based on normal practice of IRC.

The filter was designed according to the following criteria: D15 of filter material < 4 to 5 D85 of base material D15 of filter material = 5 to 20 D15 of base material D15 of filter material = 2 to 4 Maximum opening size of pipe Grain size curve of filter material may be parallel to the base material. Gradation characteristics of different materials in this project are given below:

i. Pond Ash D15 = 0.075 mm D85 = 0.09 mm

ii. Gradation type 1 (medium to course sand) D15 = 0.45 mm D85 = 3.0 mm

iii. Gradation type 2 ( fine gravel, uniformly graded) D15 = 15 mm D85 = 20 mm

Construction

Fly ash was compacted in layers of 20 cm thickness up to the edge of the facing panel. Once the

height reached up to the next geogrid level, trench of width 0.6m was excavated in the

compacted fly ash. Jute geotextile was cut to the required size and placed vertically in the trench.

Sand and coarse aggregates were filled in the trench and compacted. At the time when the

construction of the embankment was just completed and only paving was left, about 100mm of

rainfall occurred. From the visual inspection after the rainfall, it was found that jute geotextile

retained the fine fly ash effectively and water drained through the jute geotextile.

14.3.2 JGT for Trench Drains at Joshimath – Malari Road

The stretch of Joshimath – Malari Road at km 3.5 in Uttrakhand, had been experiencing

subsidence and sinking for the last many years. The stretch is located on debris slide area and

debris consists of micacious sandy silt. A number of seepage points were observed on the uphill

as well as downhill slopes. The road was experiencing subsidence during the monsoon every

year, inducing damages to the restraining structures. Breast walls constructed earlier had got

damaged due to slip. During rainy season, the whole slope mass gets saturated and surfacial

and sub-surfacial water flows down the slope. The subsurface water was flowing downhill side

saturating the subgrade completely. The pavement thus experiences continuous gradual

subsidence under repeated loading at many locations in the stretch.

As a measure to arrest the sinking of road pavement, a systematic network of roadside trench

drains and cross trench drains was proposed using non woven jute geotextiles (Fig 17 to 20).

Conventional roadside trench drains consists of a shallow trench filled with graded aggregate

filter material with or without a perforated pipe. Such a drain is difficult to construct as the

procuring and placing of graded filter pose problems. Such drains even if constructed would lose

its efficiency due to clogging as the fine materials enter the filter material and fill the voids. The

trench drains were made of rubbles encapsulated in non woven jute geotextiles to prevent the

finer particle entering into the voids of rubbles, thereby 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 on Joshimath-Malari road during June, 1996.

The monitoring of field experiments on this particular stretch of treated road was carried out in

June, 1997 and has shown very encouraging and satisfactory results. There has been no further

sinking and subsidence of the road at this location.

Fig 17: Plan View and Cross Section sub-surface drain Constructed Using JGT at Joshimath – Malari Road

Fig 18: Construction of Road Side and Cross Trench Drains Using JGT at Joshimath – Malari Road

Fig 19: Construction of Road Side Trench Drain Using JGT

Fig 20: Satisfactory Performance of the Road after one year

14.4 Jute Geotextile for Erosion Control of Hill Slopes

On the basis of field studies, CRRI has come to the conclusion that at number of locations,

shallow surfacial slides constitute a significant proportion of landslides in areas with moderate

rainfall intensity and where soil cover is medium cohesive in nature. Most surfacial landslides

occur as a result of denudation of vegetation on soil slopes consequent upon a cut being made

for road construction purposes. Surfacial slides extend to only a couple of meters below the

slope surface and originate as a result of erosion from flowing water. If erosion is allowed to

proceed unchecked, there is the possibility that the damage may spread laterally or the depth of

erosion may increase, eventually resulting in a much larger damaged slope area. Vegetative

turfing represents one of the most important corrective measures in either case. 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 ingredients of the total mix of corrective measures and as such it can prove to be effective

only when conjointly implemented with other corrective measures. Vegetative turfing has proved

to be, by and large, the most economical and simple means of protecting slopes of hills and

embankments against erosion.

Based on several field trials carried out by the Institute, technique has been developed for

treatment of erodible slopes as a part of landslide correction works either singly or in combination

with other techniques. Brief details of the technique are given below;

The barren slopes are initially demarcated, graded and fertilized. The levelling of the area must

be ensured so that when netting is laid it would cover the entire area flush to the ground resulting

in run-off water flowing over the netting/geogrids. First a dose of seed broad casting of locally

available perennial grasses is done. Thereafter, jute netting/geogrid of 1.25 cm to 2.50 cm

openings size and having roll width of 1.0 m to 1.25 m, is laid on the prepared slope surface

firmly in the direction of water-flow. The widths of netting are secured against displacement by an

overlapping of 5 cm to 8 cm and stitched or pegged down with 15 cm long steel nails about 1.0 m

apart. The top and bottom ends of the fully stretched jute netting are fixed/ anchored in trenches

of 30 cm depth. Afterwards, another dose of seed broadcasting and dibbling of locally available

grasses 15 to 20 cm apart, row to row is carried out.

The jute net provides innumerable miniature check dams thus absorbing the impact and kinetic

energy of the falling rain drops and surface runoff, thereby, reducing its erosion potential. The

soil, seed, grass root slips are kept in situ without being dislodged, thereby, getting full benefit of

moisture. After the first rainy season, the seeded and sprigged vegetation soon envelops the

entire surface thus protecting the slopes permanently. Jute geogrid have been observed to have

a life of about 2 to 3 years in the field, which is sufficient in fully promoting the growth of

vegetative cover over the denuded slope. Once vegetative growth is established within two

monsoon seasons, the mission is accomplished for the jute geogrid. At the end of jute geogrid‟s

life, the geogrid decomposes and in the process adds nutrients to the soil. The method proved

particularly successful if it is so timed that advantage is taken of the increased moisture content

of the soil resulting from the first couple of monsoon showers.

14.4.1 Hill Slopes on Kaliasaur Landslide

A study was taken up by CRRI to assess the causes of landslide both on Kaliasur. A number of

causative factors were determined to analyze the slopes on to suggest the remedial measures.

Kaliasaur landslide is very old which is operative since 1920. Since then it has repeated itself a

number of times. Records show that this landslide reactivates almost every few years. The

landslide is situated at the bank of meandering Alaknanda at km.147 on Haridwar-Badrinath

road. Disastrous occurrence of the landslide event happened in September 1989 when it blocked

about one fourth of the river Alaknanda, which flows about 100 m below the road level.

Geology of Slide Area

The main rock types in the slided area are represented by pink quartzite, maroon slates,

dolomitic limestone and metabasic. The rock in the area is faulted and jointed. These rocks are

show effect of cataclasis and mylonitisation. The rocks are marked by a number of mesoscopic

shears. The rock in the upper portion of the slide was found to be in weak state, weathered and

fractured. Quartzite has developed bedding joints, opening out on the free face towards the road,

where as the slate bands are highly fractured. There are a number of scree zones. Scree

deposits and fractured quartzite occupy the lower part of the slide. The length of the road

affected by the slide area is approximately 300 m. The slope angle ranged from 40 degree to 50

degree. The height of the crown above the road level about 165 m. The slide was multitier slide

having combination of surfacial and deep seated movements. The area around the slide is thickly

forested.

Mechanism of Slide

The crown portion of the slide appeared nearly vertical with a height of about 15 m concaving

towards the road and was in unstable condition. Village Chatikhal is situated less than a

kilometer away from the crown of the slide. A series of tension cracks existed in the area

between the crown and the village. The slided portion was found in denuded state both uphill

side as well as down hillside of the road. The concave portion of the crown had become a shelter

house for wild animals like deers and wild goats. The rock pieces break under the impact of the

foot of the running animals and start falling down the steep slope. The upper portion of the slope

was quite steep, of the order of 600 to 70

0. And the falling pieces attain high speed. A falling

stone hits another stone resting on the slope, which also starts falling down. In this way, a chain

reaction was created setting into motion a number of stones and movement of the loose debris

material. This sustained movement of the debris prevented vegetation growth and thus the slided

portion remained in denuded condition for the last about 50 years.

Installation of Jute Geogextile

It was proposed to install jute geogrid on the denuded debris mass. The main object of the

installation of jute geogrid at this site was to stop the sustained movement of the slope debris

and need for plantation to be carried out. The uphill site slope material consists of gravel with fine

soil, existing in a heterogeneous state. One thousand square meter of jute geogrid was used to

protect an area on the denuded slope. The jute geogrid was in the form of rolls of width 1.2 m

and of continuous length. The total area or the slide debris is approximately 5000 sq.m. So, with

1000 sq.m. only a part or the slope area could be covered. Top length of about 60 m of the slide

consists of partially weathered rock. The area covering a length of about 50 m below this was

selected for installation of jute geogrid. Geogrid pieces of 60m length were cut and a layer was

laid. The top and lower ends of the geogrid were buried into trenches of about 50 cm. depth.

Next length was similarly placed alongside of first length and the two lengths were stitched

together. In this way, the entire fabric was laid to cover 1000sq.m. of the area. Steel nails of

about 6 mm diameter and of 40 to 50 cm in length were also used to anchor JGT at various

selected locations in the entire covered area. The fabric was laid in the month of June 1996. The

executing authority was requested to identify locally available bushes and shrubs and carry out

the plantation work during the coming monsoon. It was also advised to periodically spread the

seeds of these plants. Some photographs showing the laying of geotextile is shown in Fig 21.

In this manner by promoting the vegetation growth, the landslide activity at Kaliasaur has been

contained to a large extent.

Fig 21: Stabilisation of Hill Slope – Kaliasaur Landslide

14.4. 2 Field Experiments for Erosion Control in Himachal Pradesh

A denuded slide area was selected in Himachal Pradesh in April 1997, where only jute geogrid

was needed to be used for erosion control. The slide area is located at km 31.20 at Sataun near

Poanta Sahib on SH -1 in H.P (Fig 22 and 23). The width of the slide area is about 30 m and the

height of the crown of the slide above the road level is about 120 m. In order to prevent the

movement of debris and promote the growth of vegetation on slopes, which are in the denuded

condition, about two thousand square metres of jute, geogrid was installed in June,1997. The

specifications of jute geogrid are given in Table 27. Locally available plants and grasses were

dibbled subsequent to the installation of jute geogrid over the slope. The treated experimental

stretch was monitored for its performances for a couple of years. Monitoring showed very good

performance of JGT in promoting vegetation growth and containing surfacial slides.

Table 27: Specifications of Jute Geotextile installed at Sataun (H.P)

Description Properties

Material 100 per cent Jute

Type Open Weave with square grids

Grid size 2.5 cm x 2.5 cm

Mass 750 gsm

Form Continuous rolls of 1.2m width

Fig 22: Laying of Jute Geotextile at Sataun

Fig 23:Slope at Sataun Covered with vegetation after JGT Application 14.4.3 Rehabilitation of Mine spoils at Sahasradhara

The CSWCRTI, Dehradun selected a highly degraded abandoned limestone mined watershed

near Sahasradhara in Doon valley in the outer Himalayas for rehabilitation by integrated soil and

water conservation measures on watershed basis. Geo-jute was used to rehabilitate the highly

erodible mine spoil slopes as described below.

Description of the watershed

Sahastradhara Limestone quarry watershed area measuring 64 hectares, is situated in the lesser

Himalayan zone of Doon valley at an altitude from 820 m – 1310 m above msI. Surface mining

operations results in a huge quantity of over burden. The over burden to mineral ratio being as

high as 5:1. Mineral rejects and overburden piled up at several places in the watershed were

highly erodable and difficult to vegetate due to absence of top soil and poor fertility. The area

receives an annual rainfall of about 3000 mm, 80 per cent of which is received during monsoon

months (June to September). The area is characterised by Krol belt comprising limestone,

gypsum, marble, slates and dolomite, etc. The mine spoil is sandy loam in texture with high

gravel content. (60 per cent of the material is greater than 16 mm size), alkaline (pH – 8.0),

calcareous (CaCO³ – 61 per cent) and poor in fertility status (Organic carbon – 0.13 per cent,

Nitrogen – 0.02 per cent and available P2O5 – 0.4 kg per hectare) and poor water holding

capacity (Dadhwal et al. 1992). The poor fertility of the mine spoil inhibits the growth of

vegetation. The watershed is having an average slope of 50 per cent, at some points the slopes

are exceeding even over 100 per cent.

The unscientific mining operations destroyed almost all the vegetation cover of the area

comprising of mixed deciduous forest species of subtropical type. This along with high rainfall

and steep slopes caused heavy debris movement from the watershed, leading to frequent

vehicular disruption, entailing a huge recurring maintenance cost annually. The siltation of the

river downstream led to frequent floods in monsoon destroying agricultural and other forest

lands.

Geo-jute for mine spoil rehabilitation

Geo-jute was tried to give temporary protection to these slopes and help protect the vegetation

till it establishes. The specifications of the geo-jute used were: Weight – 500 g/m2, strand

thickness – 5 mm and open area – 65 per cent. Different slopes (30 – 70 per cent) covering an

area of 0.86 hectare were treated. Besides geo-jute, synthetic geo-textiles were also

experimented for their performance.

Application technique

Seeds of suitable tree species (Acacia catechu, Leucaenaleucocephala etc.), were spread on the

area and scarified. Grass mulch locally available was spread at the rate of 2 – 3 ton per hectare.

Geo-jute was spread on the area loosely. The two adjoining widths were overlapped by about 10

cm and fastened with jute threads. Wooden sticks were driven to hold the mesh at place.

Rooted slips of grasses like Saccharum spontaneum (Kans) and Thysanolaena mixima (broom

grass) and cuttings/root slips/rhizomes of ipomoea carnea, cites negundo, Arundo donax and

hybrid napier were planted in openings between strands at close spacings. The technique for

application of geo-jute is shown in Fig.3.

Vegetation Growth

In the geo-jute area there was good growth of grasses compared to control section.

Thysanolaena maxima grass recorded an yield of 3052 kg per hectare (oven dry) compared to

640 kg per hectare in control after 3 years of plantation. Hybrid napier when planted in contour

trenches filled with good soil mixed with farm yard manure (FYM) recorded an excellent yield of

9850 kg per hectare compared to 1960 kg per hectare in control, Saccharum spontaneum also

showed good performance. The grass roots provided good anchorage to the soil in the second

year of plantation itself. Survival of tree species was observed to be poor. The geo-jute

biodegraded in about two years, by then the vegetation cover had established itself. The

vegetation cover in the geo-jute applied area was better than the vegetation cover in the

synthetic geo-textiles applied area.

Moisture improvement

The geo-jute helped in moisture conservation by upto 50 per cent. It was observed that in the

geo-jute area the moisture content reached below wilting point in 7 days compared to 3 days only

in control after a rainfall of 20 mm (in the top 15 cm layer). In seven days period, the seeds can

germinate and moisture in deeper layers can sustain the tender plants. There was still good

amount of moisture below 30 cm depth after one month from the day of occurrence of 20 mm

rainfall event.

14.4.4 Slope Protection of Eastern Approach Embankment of Ishwar Gupta Setu over

Hooghly River at Kalyani, West Bengal

Eastern Approach Embankment of the bridge 8 m high without any sub-bank was eroded due to

heavy rains during consecutive monsoons, the stability of the slope of the high embankment was

at stake. A programme for application of Jute Geotextiles on the slope was chalked out in

collaboration with Jute Research Laboratory in 1991-92. Open mesh JGT was applied on the

slope after mending the damages and depression on the slope. The JGT mesh was anchored

with iron hooks at suitable interval. Seeds of suitable grass were spread on mesh. The grass

had grown rapidly resulting in dense grass carpet on the slopes of the embankment. This

prevented any further erosion of soil from the slopes of the embankment, which was kept under

constant observation. Even after a lapse of a decade no additional provisions like construction of

sub-bank was needed for protection of the embankment.

14.5 Jute Geotextile to Prevent Reflection Cracks

The Jute Geotextile was tried in a portion of a busy road (Garia Station Road) at the outskirts of

Kolkata in February 2002 in association with 24 Paraganas Highways Division under Public

Works (Roads) Department, Government of West Bengal. This road takes off from Raja S C

Mullik Road near Garia junction in the southern fringe of Kolkata passes through a fast

developing urban cluster and is subject to heavy traffic. Consequently this road had suffered

extensive distress in the form of cracks and potholes. The State PWD was resorting to routine

upkeep measures. The road had poor lateral drainage in a particular stretch of 1 km and under

review due to encroaching structures on its either side. Even modest showers resulted in water

stagnation on the road which, under the effect of vehicular loading resulted in loosening of

aggregates in the wearing course leading to formation of potholes. When JGT application was

taken up, about 500 metres of the road length was heavily distressed. The wearing course was

virtually non-existent. Signs of subgrade settlement were also evident.

The affected stretch was initially levelled with aggregates and rolled. The prepared surface was

applied with a bitumen tack coat at the rate of 3 kg/10m2. Jute Geotextile as per the

specifications given in Table 33, was laid and lightly rolled (Fig 24). Another coat of bitumen was

applied over JGT at the rate of 5 kg/10m2 followed by a layer of pre-mix carpet and seal coat.

Thickness of the overlay was kept as 20 mm. The width of paved area treated was 7 m.

Table – 33 Properties of JGT Used as Crack Arresting Layer

Geotextile Characteristics Typical Properties

Type of Geotextile Open mesh woven jute geotextile

Weight (g/m2) 292

Threads/dm (MD x CD) 12 x 12

Thickness (mm) 3

Width (cm) 122

Open area (per cent) 60

Strength (kN/m) (MD x CD) 10 x 10

JGT laid in wearing Course followed by Premix carpeting

Cracks on Garia Station Road

Finished Road with JGT on wearing course

Fig 24: Laying of Jute Geotextile in prevention of reflection cracks

Condition of the road after three years of treatment with JGT

The treated stretch was inspected in December, 2002 after it was subjected to one full monsoon

season. Table 34 will reveal the conditions prevailing before and after the treatment.

Table – 34 Condition Survey of the Road

Potholes Cracks Pothole area / Depth

Condition before laying JGT

No. per cent Area per cent

770

11 1239m2 17.7 5per cent

(Average Depth – 75mm)

Condition after laying JGT

84 1.2 257.25m2 3.67 Nil

Evidently the road was found to be in a better shape after the treatment compared to the

adjoining stretches where JGT was not applied with the overlay. The trial brought out the fact that

JGT may help in reinforcing the bituminous overlay.

List of some important field trials using jute geotextile are given in Appendix III, available

standards at Appendix IV and list of manufacturers are given in Appendix V.

15. International Usage of Jute Geotextiles

Though there has been persistent demand of Jute Geotextiles in the overseas market especially

in the USA, Australia and several European countries. JGT has been used for erosion control

related applications in these countries since many decades. In the early 1940s, the British

established a Jute Mill in Calcutta (The Ludlow Jute Mills), one unit of which was only producing

jute mesh (now known as soil saver). Since the beginning it was an export item, probably to U.K.

and now there are a quite a few mills in Calcutta which continue to produce this product and

supply overseas. In recent times, jute is being used for erosion control in the United States,

where soil conservationists have taken a modified form of the jute mesh used to warp bales of

cotton and laid it on slopes to prevent wash-off from newly seeded ground. Even earlier, jute

fabrics were reportedly used in the construction of Kingsway Road in Dundee, Scotland for

erosion control in cutting slopes (ITC, 1991) on the same road. Few erosion control materials

have been around as long as jute. Perhaps the best reason to use jute mesh is that its

performance has been proven for nearly 3 decades, not only in the U.S. but in Europe, Asia and

Canada as well. The table 35 below shows the quantum of Jute Geotextiles (open weave and

non woven variety) exported from India since 1999. The figures, however, do not include Woven

Jute Geotextiles which are included in the category of „hessian‟, the largest exportable jute

product.

Table – 35 Quantity of Jute Geotextiles exported from India

Year

Soil Saver (Open

Weave JGT)

‘000 MT

Non-woven JGT

‘000 MT

1999-2000 4.0 0.07

2000-2001 6.0 0.09

2001-2002 4.0 0.08

2002-2003 9.3 0.0032

2003-2004 10.5 0.03

2004-2005 6.5 0.01

2005-2006 4.9 0.01

2006-2007 4.7 0.06

2007-2008 5.9 0.11

2008-2009 3.77 0.13

Source-DGCI & S, Kolkata

There are references aplenty on the studies conducted in the foreign universities on Jute

Geotextiles. The pioneering research on road application of Jute Geotextiles was done by Prof.

S. D. Ramaswamy and Prof. M. A. Aziz of National University of Singapore in 1989. Outdoor

field tests conducted in Parker, Colorado by Fifield and Malnor (1989) assessed the erosion

control effectiveness of 32 different products, including blankets, hydromulches, tackifiers and

geotextiles. Data was collected for three years, 1987 – 1989. Numerous parameters of erosion

were evaluated including the C Factor, sediment production (soil loss), runoff (water leaving plots

and vegetative production. The C Factor for the 32 products ranged from 0.001-0.033. Jute

showed a C Factor of 0.004 (the smaller the number, the better the performance) for a 3:1 slope

and 0.005 for a 1:5:1 slope. This means that jute retained 99.6% (3:1 slope) and 99.5% (1.5:1

slope) of the sediment expected to be lost from bare ground. From these tests, it is apparent that

jute is one of today‟s top performing erosion control products. Extensive research has also been

carried out in Cranfield University, UK (Silsoe College) by Prof. Jane Rickson on open weave

Jute Geotextiles used for erosion control in road embankments. A significant study on Jute

Geotextiles was made by Dr. T. S. Ingold and Mr J Thomson who, as consultants to the

International Trade Centre, UNCTAD/GATT, Geneva, submitted several reports on applications

and marketability of Jute Geotextiles in European countries to the Common Fund for

Commodities and the International Jute Organization (now International Jute Study Group). Brief

details of some of the specific international case studies of JGT usage are given below:

15.1 Erosion Control Using JGT at Vail Pass, Colorado, USA

During the mid 1970‟s, a 22 km stretch of Interstate No 70 in Colorado, USA was constructed

over mountainous terrain in central Colorado. This project, known as Vail Pass, involved one of

the most intensively researched and planned Interstate Projects to-date, utilising a cooperative

effort of Federal/State Highway and USDA forest service administrators, Colorado Division of

Wildlife personnel, private consultants and other state and local agencies. Crossing the

continental divide at an elevation of 10,500 feet the project had to address numerous

environmental factors relating to erosion control, wildlife habitat, revegetation and preservation of

a fragile and scenic alpine landscape.

Jute mesh was selected as the primary erosion control material for all slopes steeper than 3:1.

More than 200 acres were covered with jute, demonstrating the confidence which the project

designers had in the ability of jute to perform as needed for this environmentally sensitive project.

Placed over straw or hay mulch, the jute “effectively stopped rill and gully erosion common on

highway slopes at this altitude.” To create a more natural appearance, slope preparation included

the placement of large boulders, tree stumps and shrub/tree plantings. The jute proved easy to

place over and around these landscape components and could also be planted through, where

smaller woody material was used.

Project evaluations of the treatments used to control water quality and erosion were conducted

by the USDA Forest service. Their evaluations stated that the use of jute over hay/straw mulch

“proved to be highly successful, providing immediate erosion control protection during

establishment of vegetation cover.” the slopes of Vail Pass were protected from erosion and

revegetated, quickly transforming a difficult construction project into an aesthetically pleasing and

ecologically functional landscape.

15.2 JGT Use for Road Project in Meridian, Mississippi, USA

This case study, completed in 1987, incorporated the use of jute and soil bioengineering

techniques. The site is a logging road cut slope located on the boundary of the meridian Naval

Air Station in central Mississippi. The section of cut slope treated was approximately 3 m high by

22 m long, very steep (1.25:1) and it had been severely eroded. The top bank had been steadily

undercut, gullying and shallow mass wasting were well defined and almost no vegetation existed

on the slope. Most of the erosion had been caused by rainfall, with ground water seepage also

contributing to the slope deterioration. The project design included the use of a soil

bioengineering system called live fascines (live branches tied together in sausage-like bundles)

combined with jute mesh. The jute served two important functions. It was used to line trenches

within which the fascines were placed and was applied over the critical crown and foot sections

of the slope.

The site was evaluated twice in 1987, once at 12 weeks and again at 20 weeks after installation,

which took place in February, 1987. Both inspections found the “soil stability of the cut bank had

greatly increased overall” and where shallow mass wasting was occurring before installation, no

further loss of soil had occurred. No gullies or rills had developed where the jute mesh fabrics

systems were in place.” In less than six months the slope had been stabilised and was

supporting vigorous plant growth. Erosion had been effectively controlled. Jute ensured success

of this difficult site.

15.3 Erosion Control using JGT in Mine Areas, Southeastern Ohio, USA

This case study refers to usage of JGT for erosion control in coal mine areas. A coal mine in

Muskingum County of southeastern Ohio has been using jute to revegetate ditches and swales.

Use of jute has helped the mine agencies to meet stringent reclamation regulations for erosion

control. The mine uses jute mesh primarily for revegetation of drainage channels where slopes of

12 per cent to 18 per cent occur. These areas are seeded, mulched with hay or straw then

covered with jute. Over the years, performance of jute has been consistent, stabilising soil and

promoting a vegetative cover within as little as 6 weeks. Jute has allowed the environmental

team at the mine to use less rip-rap for the gentler ditches and swales, helping the mine to save

money. For a given budget, JGT can control erosion over a larger area than more expensive

erosion control products. Applications of 5,000 – 10,000 sq. m of jute per year are common in

this project. Ease of installation and erosion control protection for up to two growing seasons are

additional seasons why jute is used year after year. With 15 years of performance at this site it

was obvious that jute meets this mine‟s erosion control needs.

15.4 Application of JGT on Rural Roads of Bangladesh for Slope Protection

JGT was successfully used for slope protection work on Pakulla-Lauhati Road of Delduar

Upazilla, under District Tangail about 80 km north of Dhaka, Bangladesh. In this study, treated

JGT was used. JGT resembling PVD (Band Drains) were installed in the embankment area

adjoining a river. Sandy soil was used for construction of embankment and JGT was used to

provide cover to this embankment slope and also to promote vegetation growth on this slope.

In a similar manner, successful application of JGT for erosion control and prevention of

landslides have been reported from hilly areas of Chittagong in Bangladesh.

15.5 Use of JGT in road projects in UK

Rickson (2000) has reported several case studies in UK wherein JGT has been used

successfully. Rickson has reported that due to better water holding capacity, geotextile induced

roughness to the flow of run-off water, ponding of flow by geotextile, etc, JGT performed better

than other types of geotextiles when used in erosion control applications. Geotextiles can be

used to enhance soil‟s bearing capacity. She has reported that by tensile strength of JGT is on

the lower side compared to present day specifications, which have been obviously evolved

keeping in view polymeric geotextiles.

Some photographs collected from various sources on application of Jute Geotextiles in foreign

countries are also appended herewith (Fig 25 to 27).

Slope stabilization of slope of road embankment with JGT

Slope stabilization of slope of road embankment with JGT

Stabilized slope of railway embankment with JGT

Fig – 25 APPLICATIONS OF JGT IN EUROPE

Sprouting of vegetation through JGT

Laying of JGT on slope of road embankment

Installation of JGT on the prepared road sub-grade

Fig – 26 APPLICATIONS OF JGT IN EUROPE

Laying of JGT (RECP) on slope of road embankment

Installation of JGT for slope stabilization

Fig – 27 APPLICATIONS OF JGT IN AUSTRALIA

APPENDIX I JGT Manufacturing Process Photographs

Softening

Piling Softener

Emulsion Application

Carding

SPINNING

DRAWING

WINDING

BEAMING

WEAVING

PACKING

(Typical Jute Bale)

NON - WOVEN JGT FABRIC

500 gsm 1000 gsm

APPENDIX II

EQUIPMENTS AVAILABLE IN INDIA FOR TESTING JUTE GEOTEXTILES

THICKNESS GAUGE TESTER THICKNESS GAUGE TESTER

WITH JGT SAMPLEWITH JGT SAMPLE

PUNCTURE RESISTANCE APPARATUSPUNCTURE RESISTANCE APPARATUS

UNIVERSAL TENSILE TESTING MACHINE (U.T.M)

CALIFORNIA BEARING RATIO TESTCALIFORNIA BEARING RATIO TEST

APPARATUSAPPARATUS

DIRECT SHEAR TEST APPARATUSDIRECT SHEAR TEST APPARATUS

CONE DROP TESTING CONE DROP TESTING

EQUIPMENTEQUIPMENTAFTER TESTING WITH AFTER TESTING WITH

JGT SAMPLE JGT SAMPLE

APPEARENT OPENING SIZE TESTING MACHINEAPPEARENT OPENING SIZE TESTING MACHINE

–– WHEN READY WITH JGT SAMPLEWHEN READY WITH JGT SAMPLE

SIEVE BRASS FRAME OF SIEVE BRASS FRAME OF

DIFFERENT SIZESDIFFERENT SIZES

WET SEIVE TEST APPARATUS with JGT SampleWET SEIVE TEST APPARATUS with JGT Sample

TESTING APPARATUS WITH JGT SAMPLE

FLOW RATE ,PERMEABILITY & PERMITTIVITY

BTRA – – PERMITTIVITY TESTER

TEST APPARATUS PERMEABILITY PLANE IN -

PERMEABILITY

FOR SOIL

TESTING APPRATUS

GRADIENT RATIO TEST APPARATUS

LONG TERM FLOW TEST APPARATUSLONG TERM FLOW TEST APPARATUS

APPENDIX III

LIST OF IMPORTANT FILED TRIALS WITH JGT

A. EROSION CONTROL

Application Quantity Supplied

Site & user Date of application

Result

1. Mine Spoil Stabilisation

10000m2 Sahashradhara, Uttar

Pradesh, Central Soil & Water Conservation Research & Tr. Institute

1987 By 1990 erosion checked & water pollution decreased

2. Hill slope protection

5000 m2 Chunbhati & Kalijhora,

Darjeeling, Deptt. Of Forest, Govt. of West Bengal

1988 Treated areas produced double vegetation density than the untreated areas after 6 months

3. Sand dune 5000m2 Digha Sea Beach,

Midnapore, Forest Deptt. Govt. of West Bengal

1988 80per cent covered by vegetation after 6 months

4. Control of top soil erosion

5000m2 Arcuttipur, T.E. Cachar,

Assam, July „95 97per cent

reduction in soil loss

5000m2 -do- -do- 93per cent

reduction in soil loss

5. –do- 3000m2 Rosekandy TE

Cachar, Assam, July „95 95per cent

reduction in soil loss

6. Erosion Control in embankment

100 m2 Valuka, Malda, Irrigation

Deptt., Govt. of West Bengal August „96

No damage by rains in ‟96 & „97

7. Land slide repair

-5000m2 Kaliasour, U.P. CRRI & PWD

of U.P. Govt. 1996 60per cent growth

of vegetation observed in 1997

8. Road side slope protection

-do- Ponta Sahib, Himachal Pradesh, CRRI & P.W.D. Govt. of H.P.

1997 Report not available

9. Afforestation & Erosion control

1000m2

each Hijli & Porapara, Midnapore Forest Deptt., Govt. of West Bengal

Aug. „97

Growth of the trees in the treat-darea significantly higher. No. sign of erosion

10. Hill slope protection

4000m2 Lamding, Assam (Chief

Engineer, N.F. Rly. Assam) April „97

-Report not available

11. Railway Track slope protection

4000m2 Keonjhar, S.E. Rly. Orissa April,

„98 -do-

12. –do- 15000m2 Jammu Tawai Links, N. Rly. Sept.

2000 -do-

13. Mine spoil stabilisation

44, 000 m

2

Bilaspur, Western Coal Fields Ltd.

Expected in May, 2001

Appendix – III (continued)

LIST OF IMPORTANT FILED TRIALS WITH JGT – OTHER CIVIL ENGINEERING

APPLICATION

Application Quantity Supplied

Site & user Date of application

Result

1. River bank

protection

33,

000m2

Nayachar, on the river Hugli Midnapore, Calcutta Port Trust

May

1992

Bank is still in a

good shape

2. River bank

protection

1000m2 Hasanpur, Murshidabad

Irrigation Dept. Govt. of West Bengal

June

1995

Behaved better than granular filter in terms of performance

3. River bank

protection

10,000

m2

Ramayanpur, Malda, Irrigation Deptt., Govt. of West Bengal

August

1996

-do-

4. Protection of

slopes of the

road connecting

a jetty

500m2 Kedarpur, Sunderban,

Sundarban Devt. Board Govt. of West Bengal

August,

1996

-do-

5. Repairing of a bathing ghat

500m2 Barrackpore, 24 pgs. (N)

Irrigation Deptt. Govt. of West Bengal

March 1997

Report not available

6. Protection Bank

500m2 Majuli, Assam, on the

Brahmaputra SDO, Majuli & AVARD (NE)

April 1997

-do-

7. Protection of canal banks

30, 400m

2

Jalpaiguri, Teesta Barrage Project, Govt. of West Bengal

June 1997

A portion was damaged; reasons are under investigation

8. River bank protection

500m2 Una, Irrigation & Public

Helath Deptt., Govt. of Himachal Pradesh

Sept. 1997

Report not available

Appendix – III (continued)

Application Quantity Supplied

Site & user Date of application

Result

9. Road pavement construction

25, 000m

2

Kankinada, A.P, (CRRI & Kankinada Municipality)

1996 No damage of the treated portion while the untreated road was damaged severely

10. –do- 15, 000m

2

Kankinada, A.P, (CRRI & Kandla Port Trust)

1997 Report not available

11. Drainage and filtration of trench drain for roads

1000m2 Joshimath – Manali Road

U.P., (CRRI & PWD of U.P. Govt.)

1996 No damage of the stretch after one year

12. Filtration & drainage during construction of roads

-do- Hanuman Setu and Okhla Fly Over Delhi, (CRRI & DDA)

1996 & 97

Report not available

13. River bank protection

9000m2 Ganga Anti-erosion Division

Murshidabad 1998 Report not

available

14. –do- 2000m2 Mahananda Embankment

Division Malda Govt. West Bangal

1998 -do-

15. –do- 2000m2 -do- 1999

-do- -do-

16. –do- 11,000m2 Balurghat Irrign. Divn. Govt.

of West Bengal 2000 Reports awaited

17. Road Constrn

7500 m2 Howrah Highway Divn. Govt.

of West Bengal

2000

-do-

18. Road Surfacing

6000 m2 Alipore & Kalyani Divn. Govt.

of West Bengal P.W.D. 2000

-do-

19. Road construction

15000 m2 Kandla Port Gujarat 1984-

2000 -do-

20. River bank 14,300 m

2

Balurghat Irrign. Divn. Govt. of West Bengal

Work yet to start

APPENDIX IV

LIST OF STANDARDS

Though mostly references of various test methods have been drawn from American Standards,

some Indian standards for jute and allied products are available which may be consulted for

ensuring quality control of JGT. The following references will serve as a guide.

2 Weight - IS : 2387 – 1969

3 Width - IS : 1954 – 1969

4 Thickness - IS : 7702 – 1975

5 Threads/Metre - IS : 1963 – 1981

6 Bitumen - IS : 702 – 1988

7 Application - IS : 8477 – 1985

8 Rot-proofing - IS : 1623 – 1991

9 Strength - IS : 1969 – 1985 and also BIS 13162

(Part 2) 1992 read with ASTM-D5035

Regarding permittivity and porometry, reference may be made to ASTM D4491-35 and D 4716 –

87.

In addition, a further list of American and Indian Standards is given below for consultation:

1. ASTM D 4595 “Test method for Tensile Properties of Geotextiles by the Wide Width Strip

Method” Annual Book of ASTM Standard Vol. 4.08 American Society for Testing and

Materials, Philadelphia, P, 1992 pp 880-890.

2. ASTM D 4632 “Test method of Determining Apparent Opening Size for a Geotextile”

Annual Book of ASTM Standard Vol. 4.08 American Society for Testing and Materials,

Philadelphia, P 1992 pp 339-342.

3. ASTM D 4751 “A Test Method for Determining Apparent Opening Size for a Geotextile”

Annual Book of ASTM Standard Vol. 4.08 American Society for Testing and Materials,

Philadelphia.

4. ASTM D 4533 “Test Method for Trapezoid Tearing Strength of Geotextile” Annual Book

of ASTM Standard Vol. 4.08 American Society for Testing and Material, Philadelphia.

5. ASTM D 276 “Test Method for Identification of Fibres in Textiles” Annual Book of ASTM

Standard Vol. 4.08 American Society for Testing and Materials, Philadelphia.

6. ASTM D 5101 “Standard Test Method for Measuring the soil Geotextile System Clogging

Potential by the Gradient Ratio Method” Annual Book of ASTM Standard Vol. 4.08

American Society for Testing and Materials Philadelphia, P, 1992 pp 1190-1196.

7. IS 13162 – 1992, Glossary of Terms for Geo-synthetics, Part I : Terms used in Materials

and Properties.

8. IS 13162 – 1992 (1996) Geotextiles – Methods of Test – Part 5 “Determination of Tensile

Properties using Wide Width Strip Method.

9. IS 14293 – 1995 Geotextiles – Methods of Test – Determination of Trapezoid Tearing

Strength.

10. IS 14294– 1995 Geotextiles – Methods of Test – Determination of Apparent Opening

Size (AOS).

11. IS 14324 – 1995 Geotextiles – Methods of Test – Determination of Water Permeability –

Permittivity.

12. IS 14715 : 2000 – Woven Jute Geotextiles-Specifications

13. IRC : 56-1974 (reprinted 1991) – Recommended Practice for Treatment of Embankment Slopes for Erosion Control (The Indian Roads Congress Publication)

REFERENCES

1. Abdul Jabbar Khan (2008), Quality Control of Jute Geotextiles and development of Testing

facilities, International workshop on Jute geotextiles, Kolkata

2. Akhter.F., Ahmed,Z., Banu,H., Haque,M.S (2003) Utilisation & feasibility of retting effluent

as fertilizer in vegetable crops production, Pakistan Journal of Biological Sciences Vol 6/4

3. Amalendu Ghosh (1997), Geojute in unpaved Roads – Efficacy and cost effectiveness,

Proceedings of Workshop on Jute geotextiles, Kolkata

4. Banerjee, P.K., Ghosh, M., (2008) Studies on jute-asphalt composites. Journal of Applied

Polymer Science, 109/5

5. CFC/IJO (1995) Technical specification and market study of potentially important jute

geotextiles, Project completion report by Silsoe College, Cranfield University, U.K

6. CFC (1998), Jute geotextiles – Techno Economic manual, Technical paper No. 1, CFC,

Amsterdam, The Netherlands

7. Chakrabarty.S., Bhandari.G.N and Adak.N (1997), Performance of a model footing on

compacted PFA, geojute reinforcement overlying soft clay, Proceedings of Workshop on

Jute geotextiles, Kolkata

8. Chattopadhaya.B.C (1996), Report on Test results of Geojute, BE College, Howrah

9. Datye.K.R and V.N.Gore (1994), Application of Natural Geotextiles and Related Products,

Geotextiles and Geomembranes, Vol 13, No. 67, Elsevier Applied Sciences, Oxford

10. Dvorscak P., (2004) Použitie Protieróznych Prírodných Materiálov Rohoží A Sietí Na

Svahoch Ciest, Technicka univerzita vo Zvolene, Slovakia – Intl. Symposium on Jute,

May,Liberec, Czech Republic

11. Ellis H (1993), Natural Erosion Control Materials Solve Problems on Manchester Airport‟s

New Rail Link, Geosynthetics World, London

12. Gary.D.H and Sotir.R.B (1996), Biotechnical and soil engineering slope stabilisation – A

Practical guide for erosion control, John Wiley & Sons Inc., New York

13. Ghatak.S (2002), Construction of Bituminous road overlay using Jute Geotextile, All India

Seminar on applications of Jute Geotextiles in Civil Engineering, Kolkata

14. Ghosh.S.N., Chatterjee.P.K., S.Palit (1993), Controlling soil erosion by Geojute

application, Textile trends

15. http://www.naturalfibres2009.org/en/iynf/sustainable.html

16. Junno Marjut, (2004) Application of Natural fibres in Erosion Control, Environment

Designer, AMK, Finland - Intl. Symposium on Jute, May, Liberec, Czech Republic

17. Juyal.P, Sastry.G and MSRM Rao (1994), Rehabilitation of a Mined area in Himalayas by

Geojute and other measures, Proc of 5th International Conference on Geotextiles,

Geomembranes and related products, Vol 2, Singapore

18. Jute Geotextiles – A survey of marketing and distribution systems in selected European

Countries (1991) - International Trade Centre, UNCTAD/GATT, Geneva

19. Kaniraj.S.R and G.V.Rao (1994), Trends in use of geotextiles in India, Geotextiles and

Geomembranes, Vol 13, Nos 6-7, Elsevier Applied Sciences, Oxford

20. Lee.S.L., Karunaratne.G.P, Ramaswamy.S.D, Aziz.M.A and N.C.Dasgupta (1994), Natural

geosynthetic drain for soil improvement, Geotextiles and Geomembranes, Vol 13, Nos 6-7,

Elsevier Applied Sciences, Oxford

21. Majumdar.A.K, Bhattacharya.S.K., S.Ghatak, K.Goswami and D.Sanyal (2006), Case

studies on field trials for road construction with jute based geotextiles, Proceedings of

International Seminar on Geosynthetics in India – Present and Future, New Delhi

22. Rao.P.J., et al (1996) Report on evaluation of Jute Geotextiles in civil engineering

applications, CRRI, New Delhi

23. Rao.P.J. et al (1996), Design and construction of drainage filter using jute geotextile at

Hanuman Setu, Proceedings of national Seminar on Jute based Geotextiles, New Delhi

24. Ranganathan.S.R (1994), Development of potential jute geotextiles, Geotextiles and

Geomembranes, Vol 13, Nos 6-7, Elsevier Applied Sciences, Oxford

25. Ramaswamy.S.D, Karunaratne.G.P and S.Palit (1992), Application of Biodegradable Jute

geotextile filters, Proceedings of International Conference on Filters and Filtration

phenomena in Geotechnical and hydraulic engineering, Karlsruhe, germany

26. Ramaswamy.S.D, and M.A.Aziz (1982), Jute fabric in road construction, Proceedings of

2nd

International Conference on geotextiles, Las Vegas

27. Ramaswamy S.D. and Aziz M.A., Singapore State University (1989), - Discussion of Jute

Geotextiles for Roads, Proc. Int. Workshops on Geotextiles, CBIP, Nov., Bangalore, Vol.2

28. Ramaswamy S.D. and Aziz M.A., Singapore State University (1989) - Jute Geotextiles for

Roads, Geotextiles Vol.1, Tata Mc.Graw-Hill Publishing Co. Ltd., New Delhi

29. Ramaswamy S.D., Singapore State University (1991) - Appraisal Highlights and

Recommendation on Jute Geotextiles, UNIDO Report, Vienna

30. Ray.P, Ghosh.S.K and A.Mukherjee (2008), A Critical review on quality control and testing

of jute geotextiles, International workshop on Jute geotextiles, Kolkata

31. Report on Erosion Control Trials – ski piste, San Sicario, Italy (1986), Civil Engineering,

June – London, U. K.

32. Report on Geo-Jute Erosion Control System (1985) – Jute Market Promotion Project

I.T.C., UNCTAD/GATT, Geneva

33. Report on Geo-Jute Trials for Erosion Control on River Severn in U.K. (1985) – New about

Jute, I.T.C., UNCTAD/GATT, Geneva

34. Report on Jute Products for Geotechnical & Biotechnical Applications, March (1987) –

prepared by Mr. James Thomson & Dr. T. S. Ingold for International Jute Organisation

35. Results of Current Research of Synthetic and Natural Fibre Erosion Control Systems –

International Trade Centre, UNCTAD/GATT, Geneva – prepared by Dr. T. S. Ingold & Mr.

James Thomson

36. Sarsby R.W., (2007) - Use of „Limited Life Geotextiles (LLGs)‟ for basal reinforcement of

embankments built on soft clay. Geotextiles and Geomembranes Journal, Elsevier

Science, UK- vol. – 25 (4/5)

37. Rickson, R.J. et al (1996) Technical Specifications and Market Study of Potentially

important jute geotextile products, IJO Jute geotextile Conference, Dhaka

38. Sanyal T (1992) Control of Bank erosion naturally, Proceedings of National Workshop on

Role of Geosynthetics in Water Resources Projects, New Delhi

39. Sanyal.T and Chakraborty.K, (1993), Application of Jute mattresses in the bank protection

works of Hoogly Estuary, Geotextiles and Geomembranes, Elsevier Science, UK

40. Shahid.A.S.M, (1994), „Geojute provides long lasting erosion control, Proceedings of fifth

international conference on geotextiles, geomembranes and related products, Vol 2,

Singapore

41. Shukla.M.K, Sunil Bose, A.Dhawan and P.K.Sikdar (2004), Investigation on use of

Geosynthetics / Jute fabric for retardation of reflective cracking in bituminous overlays,

Proceedings of ICGGE-2004, IIT-Bombay, Mumbai

42. Sikdar.D, Chattopadhyay.K.K and Chattopadhyay.B.C (1997), Characteristics of geojute

as filter medium for bank protection, Indian geotechnical Conference, Baroda

43. Sivaramakrishnan R (1994) Jute geotextile as revetment filter for river bank protection,

Proceedings of 5th International Conference on geotextiles, geomembranes and related

products, Vol 2, Singapore

44. Sudhir Mathur and U.K.Guru Vittal (2008), Jute Geotextile – Potential and applications in

road works, International workshop on Jute geotextiles, Kolkata

45. Tan S.A.; Muhammed M., Karunaratne G.P. and Lee S. L., (1994) - Use of Jute

Geotextiles in Layered Clay Sand Reclamation Scheme, Proc. 5th Int. Conf. On

Geotextiles, Geomembranes and Related Products, Vol. 2, Singapore

46. Use of Jute Fabrics in Erosion Control (1986) - International Trade Centre,

UNCTAD/GATT, Geneva – Mr. James Thomson & Dr. T. S. Ingold (Jason Consultancy

SA)

47. www.jmdcindia.com

48. www.jute.com

49. www.jute.org

50. Zahid Hossain Prodhan (2008), Application of Jute Geotextile on rural roads of

Bangladesh for slope protection, International workshop on Jute geotextiles, Kolkata

51. Zlatuska K., (2004) Utilization of Geo Textiles made from Natural materials in Civil

Engineering, A.KTI, Int. Symposium on Jute, May, Liberec, Czech Republic