JGT Presentation by Mr. P. K. Choudhury, IJIRA

Report
Development & Application of Potentially
Important Jute Geotextiles (CFC/IJSG/21)
A Presentation by
P K Choudhury & Koushik Das
Indian Jute Industries’ Research Association
(IJIRA)
Kolkata
ASSIGNED ACTIVITIES FOR IJIRA AS A
FACILATATING AGENCY FOR THE PROJECT
NATIONAL JUTE BOARD ( NJB), THE PROJECT IMPLEMENTATION AGENCY
ENTRUSTED IJIRA AS A FACILITATING AGENCY ( FA ) FOR THE FOLLOWING
ACTIVITIES : • To design and develop potentially important JGTs
optimally to meet specific technical requirements for the
three specified end uses like rural road construction,
river bank erosion control and hill slope stabilization
• To provide installation guidance to the end users for all
the above three types of field applications
ACTIVITIES UNDERTAKEN

Identification of Potentially important JGT on the basis of previous
performance evaluation jointly by NJB / BESUS / BUET / PwC / IJIRA
•
Types of JGT primarily chosen were –
20, 25 & 30 kN/m woven, 500 gsm non-woven & 500 gsm open weave.
•
Additionally, 5 new varieties of woven DW plain weave JGT
(627,665,724,760 & 810 gsm) & 4 new varieties of open weave JGT
(365,500,600 &700 gsm) were also planned to design and develop
TYPES OF WOVEN JGT AVAILABLE OFF THE SHELF
woven JGT s are used for road construction and river bank erosion
control while for slope protection works open weave JGTs are used.
In the past DW Twill weave JGTs with varied tensile strengths & weight
like, 15kN- 643 gsm,20kN-760 gsm,30kN - 810gsm & 40 kN/m -900 gsm
were developed by IJIRA having two specific widths like, 76 cm and 200
cm.
These fabrics were being popularly used so long in river bank, road
construction & railway works
Deficiencies observed in the exhisting fabrics:a) 76 cm wide fabric is too narrow as it entails wastages on overlaps
and leaves planes of weakness on laps
b) 200 cm wide fabric are manufactured by a very few jute mills because
of non availability of wider looms ( 90 inches). Moreover, heavier unit
weight ( gsm) of the fabric leads to higher cost of product
FABRIC ENGINEERING :
Need base development of Potentially Important JGTs was mooted
for the project.
Procedure for development of the targeted fabric was based on “design by
experience” followed by “design by approach” to ensure a) Effectiveness in performing the basic geotechnical functions like,
separation, filtration, drainage and initial reinforcement
b) Facility of manufacturing new varieties of JGT by any jute mills
c) Economy & ease of availability
d) Selection of the appropriate cost effective jute batch for meeting the
tensile strength requirements
Careful assessment of tensile strength & porometry requirements for the
3 specified end-uses was carried out. And the fabric design was optimized
meeting the technical needs as well as economy
DEVELOPMENT OF POTENTIALLY IMPORTANT JGTs
FACTORS CONSIDERED FOR DEVELOPMENT OF THE FABRICS –
A)
B)
C)
D)
TENSILE STRENGTH
POROMETRY
WEIGHT OF FABRIC / COST OF PRODUCT / BATCH COMPOSITION
TYPE OF WEAVE & EASE OF MANUFACTURE BY ANY JUTE MILLS
FOLLOWING EMPERICAL RELATIONSHIP WERE ADOPTED FOR CALCULATING
WEIGHT AND TENSILE STRENGTH OF FABRICS –
•Weight of Fabric ( gsm) = 1.425 ( N1 G1 + N2G2),
where, N1 = Ends /inch & N2 = Picks / inch and G1= Warp count in lbs & G2=Weft count in lbs.
•Tensile strength ( MD ), FS ( kgf) = C x QR x N’1 X U%
2.204
where FS is Tensile Strength of Fabric in warp way (MD), C is warp count, N1 for ends / inch & QR is a factor
derived by dividing tensile strength with warp count of yarn & expressed in percentage & U stands for
utilization %,
•Tensile strength ( CD ), F’S ( kgf) = C’ x QR x N’2 X U%
2.204
Where F’S is Tensile Strength of Fabric in weft way (CD),C’ is weft count, N2 for picks / inch & QR is a factor
derived by dividing tensile strength with weft count of yarn & expressed in percentage & U stands for
utilization
Determination of porometry of woven JGT –
Calculation of pore size and pore diameter of JGT ; Method 1:
Particulars of Warp and Weft
Method of calculation
Warp/dm
102
Weft/dm
39
Count of warp in ld/spyndle
9.75
Count of weft
28
Diameter of yarn in inch
0.035
Diameter of yarn in inch
0.059
Diameter of yarn in cm
0.088
Diameter of yarn in cm
0.149
Distance covered by the warp
yarns in one dm (cm) (L1)
8.988
Distance covered by the
weft yarns per dm (cm)
5.824
L1 = (Threads/dm) X
diameter of the yarn
(cm)
Gap (Open area) left by the
warp yarns in one dm (cm) (L2)
1.011
Open distance left by the
weft yarns per dm (cm)
4.176
L2 = 10 – L1
Open distance between the
warp yarns (mm)
0.100
Open distance between
the weft yarns (mm)
1.099
L3 = L2 X 10 / (no of
threads – 1)
Area of each open space (pore)
in the fabric (Sq mm) (L3)
(√ count)/90
0.110
L3 of warp X L3 of Weft
Diameter of the pore (mm)
0.332
Assuming shape of the
pore as square, the side
of the square will be the
pore diameter.
Diameter of the pore (micron)
332
Calculation of pore size and pore diameter of JGT ; Method 2 :
Established equations for calculation of cover factors of Jute fabric are :
•Warp cover : K1 = No of warp / inch X √ (Count of warp in ld/spyndle)
•Weft cover : K2 = No of weft / inch X √ (Count of weft in ld/spyndle)
•Fabric Cover : Kc = K1 + K2 – (K1 K2 / 120)
Diam
Open
No of
Pic
Count
Fabric Ope
area in
Warp Weft
mesh
ks
threads
cover
n
one
cover cover
in one
/ (Warp X Weft)
(Kc) area
square
(K1)
(K2)
squar
dm (lb/spindle)
(%)
(%)
dm
e dm
(sq mm)
Open eter Diam
eter
area/
of
of
mesh one
one
(sq pore pore
mm ) (mm) (micr
*
(A)
on)
102
39
10 X 27
81.93 51.47
98.26
1.74
3978
174.11
0.044 0.209
209.2
11
94
39
10 X 27
75.50 51.47
94.59
5.41
3666
541.06
0.148 0.384
384.1
73
End
s /
dm
(√ A)
.
Indicative batch composition of raw jute used to prepare
yarns for developing the targeted fabric
20/627
Tensile strength (KN/m) /
Weight (gsm)
25/724
Warp
Weft
Warp
Weft
10 / 345
28 / 965
10 / 345
27 / 930
TD4
3 6 .5
--
36.5
--
TD5
63.5
10
63.5
20
Yarn count in lbs/ tex
TD6
46
46
Rope & Habijaby
10
10
Cuttings
22
15
Thread Waste
10
9
Gunny cuttings
1
-
Caddies
1
-
Total
100
100
100
100
NB: Presently, due to non availability of good quality raw jute, batch
composition of weft yarn for 25 kN/m fabric has marginally been
modified to achieve desired tensile strength.
Based on the above concept five varieties of DW Plain weave JGT of 100 cm width having varied tensile
strength with a porometric range from 150 to 400 micron were developed, tested and evaluated
Construction
Double Warp Plain Weave (DW
Plain) for application in rural road
and river bank
Width (cm) Min
100 cm
20 - 30
Tensile
strength
20 - 30
(kN/m)
MDx
MD
Fabric weight (gsm) 62 665
724
760
810
7
Ends X Picks / dm
Thickness (mm)
Elongation
break(%)Min
MD x CD
A.O.S.Micron O
85
X
32
77 X
35
94 X
39
102 X
39
2-4
at
8 - 12
150 - 400
102 X
41
Open weave jute geotextile (
soil saver) for hill slope
management
122 cm
600
365 (with
500
thicker
(with
weft /
thicker
thinner
wft &
warp
thinner
yarn)
wp
yarn)
5X4
6.5 X
7X
4.5
6
700
7X7
The fabrics developed were tested at IJFT & IJIRA geotextile
testing laboratory and the results were found technically
suitable for application under the project
However, PIA has zeroed in on 2 types of woven JGT (20 kN/m627 gsm & 25 kN/m - 724 gsm and 3 types of open weave JGT
(500, 600 & 700 gsm) for meeting end-use requirements, ease of
manufacture and economizing cost of production
Specifications of two newly developed DW Plain Weave Jute Geotextiles.
Nomenclature
Woven JGT 20 kN/m Woven JGT 25 kN/m
Construction
1/1 DW Plain Weave
1/1 DW Plain Weave
Weight (gsm)
627
724
Width (cm)
100
100
85 x 32
94 x 39
1.7
1.85
20 x 20
25 x 25
Elongation at break (%), MDx CD
8x8
10 x 10
Puncture Resistance(kN)
0.400
0.500
Burst Strength (KPa)
3100
3500
Permittivity at 50mm constant head (/sec)
350 x 10-3
350 x 10-3
A O S ( micron ) O95
150 - 400
150 - 400
Ends x Picks / dm
Thickness, (mm at 2 kPa)
Tensile Strength (kN/m) , MD x CD
Cost Benefit factor of Newly Designed Woven JGT
 Cost of JGT is mainly governed by its weight.
 Hence, 627 gsm ( 20 kN/m) JGT is
17.5 % cheaper as compared to earlier 760 gsm JGT.
&
 724 gsm ( 25kN/m) is about 5.0 % cheaper than its
earlier variety.
TWILL or PLAIN WEAVE ?
Woven JGT of DW Twill construction as
developed earlier are now being widely used in road
construction, river bank protection and also in railway
track improvement.
Incidentally, the type of construction i.e. twill or plain
practically is hardly of significance. On the other hand
jute looms
of 46.5"(118cm) R.S. are basically
designed for plain weave construction and set
with 2 leaf wyper ( tappet ). Further, plain
weave is more convenient than twill weave
from operational point of view. Hence, the
manufacturers are in favor of plain weave
construction which is also acceptable to the
end users.
Methodology followed to produce desired JGT
• To develop the targeted fabric, conventional
46.5"(118cm) R.S. loom was utilized
• Modifications/adjustment in shedding , raising the back
rest as well as use of single denting in place double.
• Appropriate & standard batch composition of jute fibre
were chosen to minimize the cost and to achieve desired
tensile strength.
• Targeted porometry was achieved by judicial selection
of yarn count ( dia) and yarn density in the fabric
DEVELOPMENT OF OPEN WEAVE JGTs
• 292 gsm,500 gsm & 730 gsm Open Weave ( OW ) JGT available
off the shelf are being widely used world wide mainly for
stabilizing the slopes of earthen embankment.
• CSWCRTI, who is one of the PEUs recommended to develop three
new varieties of OW JGTs viz, 500 gsm,600 gsm & 700 gsm for
use in hill slope stabiliztion.
• Accordingly, the products were developed by IJIRA.
• In designing the newer variety of 500 gsm fabric 170 lbs weft
yarn was used instead of conventional 124 lbs for higher yarn dia.
in anticipation of getting better effect in controlling surface runoff. As there is no significant role of warp yarn in entrapping the
soil particles as well as to keep the weight of the fabric at lower
side lighter warp count of 70 lbs was used which also controlled
the cost
• The fabrics were tested at IJFT & IJIRA laboratories prior to put
them to use in hill slope stabilization works by CSWCRTI at three
different hill sites.
SPECIFICATIONS OF NEWLY DEVELOPED OW JGTs
TYPE
1
2
3
500
600
700
6.5 x 4.5
8x7
8x8
Thickness (mm)
4.5
5.25
5.5
Width (cm)
122
122
122
55
48
40
6.5 x 6
12 x 6
14 x 7
500
500
600
PROPERTIES
Weight (g/m2) at 20% M.R.
Threads/dm (MD x CD)
Open area (%)
Strength (kN/m) [MD x CD]
Water holding capacity (%) on
dry weight
CONSOLIDATED SPECIFICATIONS OF ALL THE JGTS DEVELOPED
Construction
Width (cm) at
20 % MR
Weight (gsm)
Tensile strength
(kN/m)
MD X CD
Ends X Picks / dm
Thickness (mm)
Elongation at break
(%)
MD X CD
Puncture Resistance
(kN)
Burst Strengnth (KPa)
Permittivity at 50 mm
constant head (/sec)
A.O.S. (Micron) O95
Open Area (%)
Water Holding
Capacity (%) on dry
weight
Double Warp Plain
Weave (DW Plain) for
application in rural
road
Double Warp Plain
Weave (DW Plain) for
application in river
bank
Open weave jute geotextile for hill slope management
≥ 200 cm*
≥ 200 cm*
≥ 122 cm
724 (- 5%, + 10%)
627 (- 5%, + 10%)
(To be treated with
Bitumen / any other
additives)
500 (- 5%, +
10%)
600 (- 5%, +
10%)
700 (- 5%, +
10%)
≥ 25 X 25
≥ 20 X 20
≥ 6.5 X 6
≥ 12 X 6
≥ 14 X 7
≥ 94 X 39
1.85 (± 10%)
≥ 85 X 32
1.70 (± 10%)
≥ 6.5 X 4.5
4.50 (± 10%)
≥8X7
5.25 (± 10%)
≥8X8
5.50 (± 10%)
≤ 12 X 12
≤ 12 X 12
≤ 14 X 14
≤ 14 X 14
≤ 14 X 14
0.500 (± 10%)
0.400 (± 10%)
-
-
-
3500 (± 10%)
3100 (± 10%)
-
-
-
350 x 10-3 (± 10%)
350 x 10-3 (± 10%)
-
-
-
150 - 400
-
150 - 400
-
50 - 65
45 - 50
40 - 45
-
-
450 - 500
450 - 500
550 – 600
724 gsm also appears to be an better alternative to earlier 760 gsm JGT for application in railways
Jute Fibre
Softening
Carding
(Woven JGT)
Drawing
(Open Weave JGT)
Drawing
Spinning
Spinning
Winding
Cop winding ( weft)
Beaming
Weaving
Weaving
Rot Resistant
Treatment
Packing
Manufacturers of Newly designed JGT in India
DW Plain Weave JGT
Open Weave JGT
1
Gloster Limited
Gloster Limited
2
Reliance Jute Mills (International)
Ltd.
Reliance Jute Mills (International)
Ltd.
3
Ludlow Jute & Specialties Ltd.
Naffar Chanda Jute Mills Ltd.
4
Birla Jute Mills
Bristi Vinimay Pvt. Ltd
5
Hastings Jute Mills
6
Hukumchand Jute Mills
7
Cheviot Co. Ltd.
8
Shree Gouri Shankar Jute Mills Ltd.
9
Tripura Jute mills, Agartala Tripura
10
East India Commercial Co. Ltd,
Eluru, AP
 Special care was taken for maintaining the quality of JGT during its
manufacture by adopting strict process & quality control measures to
ensure that fabrics would also be free from the following faults that
can affect the specified porometry (O95) and tensile strength causing
impairment of the expected geotechnical functions –
 Missing warp/weft ,Multiple warp breakage ,Gaw, Smash
,Shuttle),Inserted Cop,Reed mark / dent mark
 As FA as well as a part & parcel of the project IJIRA also provided
technical guidance to the mills for manufacturing right type of JGT.
 IJIRA also provided installation guidance to all the end users in India.
PHOTOGRAPHIC VIEW OF FEW M/Cs, FABRIC SAMPLES AND
APPLICATIONS ARE SHOWN IN NEXT FEW SLIDES ….
Jute Plant
Jute Fibre
Jute Bales
Softener
Piling
Emulsion Application
Different types of woven JGT developed
DW Twill Weave 760 gsm-20 kN/m
DWP 627 gsm - Grey
20 kN/m
DWP 627 gsm – Treated
20 kN/m
DWP 724 gsm
25 kN/m
DIFFERENT TYPES OF OW JGT DEVELOPED
500gsm
600 gsm
700 gsm
JGT-Acceptance at site
 Check the name of the supplier-mill, brand-mark if any, type of JGT
supplied vis-à-vis specifications stated in the contract document, test
certificate (whether by the mill or by any independent testing outfit),
whether the material recommended for laying by the competent
authority and the quantity in the consignment
Note: One set of tests for each consignment of 16,000 sqm of JGT or as specified
shall be carried out.
 Any palpable shortcoming in JGT-construction should be brought to the
notice of the Engineer
JGT-Storage & handling
• JGT to be kept in a covered shed without removing the protective pack-
sheet & not to be kept directly on ground/floor
• JGT not to be stored normally beyond 1 month
• JGT to be carried by inserting a bamboo or similar pole into the central
hole of the roll when the fabrics come in the form of roll
• Check that the fabric does not get damaged during handling
JGT-Installation
• For slope protection work prepare the slope & dress properly
• Demarcate the entire area to be covered by JGT & measure the area
• Ascertain how JGT is to be placed considering the size (especially width)
with the specified overlaps
• Decide on cutting the fabric supplied in rolls considering the length &
width to be covered including the length needed inside anchoring
trenches and ensuring minimum wastage
• Stitching of JGT is discouraged as it is difficult to achieve seam-strength
of the order of 90%. Overlapping is advised usually.
• Ensure anchoring of JGT at the beginning and the end of a roll.
• In road construction, anchoring is done by pinning staples spaced @ 150
mm along the length and the width
• In slopes & river-banks, JGT shall be secured in anchor-trenches
invariably at the top of the slope. The usual dimension of such a trench
of rectangular section is 250 mm (base) x 500 mm (ht).
JGT-Installation
• Ensure that JGT touches the base and the two sides of the anchor trench
uniformly at all points
• There shall be at least 2 staples at the bottom of the trench & 3 at the two
sides
• Longitudinal spacing of staples within the trench shall be @150 mm
usually.
• All trenches shall be filled with brick bats /stones after stapling is
complete
• In river-bank erosion control, JGT is to be taken to the LWL.
• A sand-filled toe-beam is to be made by folding the end-fringe of the
JGT-roll with river sand inside and sewing it . Alternatively, a bevel at the
lower end of the bank could be made.
• In other slope protection works (embankment slope, hill slope etc), it is
advisable to construct a rubble-filled drain at the toe that will serve both
as anchor and drain.
• The shape of the drain-cum-anchor could be similar to the top anchor
trench in shape & size.
JGT-Installation
• Usual overlap is 150 mm.
• JGT should be stapled by inserting U-shaped or broad-headed nails or
fork-shaped wooden pegs.
• May have closer staples in case of roads with CBR <5%, slopes > 30°, eroding
river banks with eddies at the toe, large water-level fluctuation (>3 m) and
flow velocity > 1 m/sec
• Ensure that the overlaps of successive JGT rolls do not fall along the same
line.
• Ensure that the fabric touches ground at all points, staples are firmly
embedded in the ground
• Installed fabric shall not be left uncovered except in case of slopes.
• Heavy granular overlay over JGT should be placed softly to avoid
puncturing of the fabric
JGT-Installation
• Usually a thin cushion of sand (15 mm to 25 mm) is spread over and
under JGT to avoid direct contact with the sharp aggregates and soil.
Note that JGT is more durable when sandwiched between sand-layers
• JGT should not be placed directly over soil-slurry or mud. It is advisable
to level off the ground, remove the muddy portion & place a thin cushion
of sand before placing JGT
•
 Find from the drawing the position of JGT in the pavement-structure i.e.
whether it is placed over sub-grade or over sub-base or over the basecourse.
 Similarly, follow the working drawing in case of a river bank erosion
control and ensure placement of JGT at the right place.
INSTALLATION OF JGT IN ROAD CONSTRUCTION
PREMIX CARPET WITH SEAL COAT
WBM GR III
WBM GR II
GSB
SAND CUSHION
SUB-GRADE
JUTE GEOTEXTILE
TYPICAL CROSS-SECTION OF ROAD WITH JGT
INSTALLATION OF JGT IN RIVER BANK PROTECTION
INSTALLATION METHOD OF JUTE GEOTEXTILE
Direction
of laying
+
Grass plant
Graded slope
150
Fixing nail
Shoulder anchor
(150 mm x 150mm)
Jute Geotextile
50 mm
150 mm
Fixing nail
(II Gauge wire)
Toe anchor
(150 mm x 150mm)
ROAD CONSTRUCTIONPreparation of Road Sub-grade, Nihinagar to Hajratpur, Balurghat, WB
RIVER BANK PROTECTION
CONDITION OF JGT TREATED RIVER BANK AFTER ONE
YEAR
HILL SLOPE MANAGEMENT
Nature of Erosion in Hill Slope , Derhadun, Uttarakhand
Installation of OW JGT on the Prepared Hill Slope
Growth of Vegetation on the Hill Slope Covered with JGT
RIVER BANK PROTECTION
Eroded Left Bank of River Bhagirathi, Santipur, Nadia, WB
Laying of treated woven JGT on the prepared river bank
Finished Work – Armoring of JGT with Boulders
Experimental study with different types of OW JGT to Assess efficacy on Soil
Loss & Growth of Vegetation, CSWCRTI. Ooty
Effect of Type of OW JGT on Control of Soil Loss & Growth of
Vegetation, CSWCRTI, Ooty

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