development of durable jute geotextile for erosion control of river bank dr. s. k. chakrabarti

Development of Durable Jute Geotextile for Erosion control of River bank

Dr. S. K. Chakrabarti

INDIAN JUTE INDUSTRIES’ RESEARCH ASSOCIATION17,Taratala Road, Kolkata- 700088

Jute Geotextile (JGT) for its typical functional characteristics and eco-concordance has emerged out as a potential natural Geotextile for many civil engineering applications

For commercial exploitation of Jute Geotextile in addressing various geotechnical issues, there is a need to improve its end use specific functional properties

River bank erosion being a recurrent problem in our country demands appropriate measures for its prevention wherein Jute Geotextile can be used with minimum adverse impact

Existing practices of use copper and bitumen based compounds for enhancing life seems to be inadequate both technically and environmentally

For wider acceptance of JGT in erosion control of river bank comprehensive durability of woven JGT under combined soil and water ambience has to be ensured by an ALTERNATE ROUTE.

Brief Background

Woven Jute Geotextile

Weight - 627 gsm Width : 1.0 - 1.5 metreEnds x Picks : 85x32/dm Tensile strength (kN/m), MD x CD: 20 x 20 AOS (micron) O95 : 150 – 400µ

(Designed and developed by IJIRA- NJB)

Specification of woven Jute Geotextile

A. Organic Biocide: Isothiazolinone derivative B. Water Repellent Compound: Fluorocarbon

derivativeC. Wet pick up : 80-90%D. Drying : 100ºCE. Curing : 120-130ºC

Pad –Dry –Cure Method

Development of durable woven Jute Geotextile

Fabric

Padding Mangle

Trough (Bath)

Drying zone Curing zone

Water repellency of specially treated Jute Geotextile has been measured by Spray Test Method : As per IS 390-1975, R.A in 2003 ,Cone Test: IS 7941: 1976, R.A in 2004, Bundesmann Test: ISO 9865: 1991

Spray test method Untreated JGT Specially Treated JGT

Durable JGT : 90% water repellent

Water Repellency of Specially Treated woven Jute Geotextile

Sr. No. Woven Jute Geotextile % Retention in Strength

( Under enriched soil after 21 days)1. Untreated JGT 17.0

2. Specially Treated JGT 88.0

Soil Burial Test : As per IS: 1623, 1992

Durability of woven Jute Geotextile under soil

Sl. No.

Test Parameters Untreated JGT Fabric

(Control)

Specially treated JGT

Fabric (Experimental)

ASTM / IS Standard

1 Weight (g/m2) at 20% MR 631.7 638.4 D 5261 – 1996

2 Ends x Picks /dm 86.0 X 31.4 85 X 32 IS: 1963 – 1981

3 Tensile strength (kN/m) / Elongation at break (%)

MD CD

24.39 ( 7.08 )20.59 ( 8.04 )

22.25 ( 7.14 )19.74 ( 8.16 )

D 4595 – 94

4 Permittivity at 50 mm constant water head per sec

0.50 0.43 D 4491 – 99a

5 Apparent Opening Size(μm) (O95) 251 234 D 4751 – 99a

6 Rod Puncture Resistance(N) 386.3 373.8 D 4833 – 2000

7 Water Repellency (%) 0.0 90.0 IS: 390-1975

8 % Retention in Strength (Under enriched soil after 21 days)

17.0 88.0 IS: 1623, 1992

Characteristics of specially treated durable woven Jute Geotextile

Durability of both untreated and specially treated JGT in water ambience have been examined in the laboratory by putting the JGT fabrics on static water for different periods (up to 150 days) and finally their loss in tensile strength have been measured.

Experiment on durability of treated JGT in Water Ambience

Durability of specially treated JGT in Water Ambience

0 20 40 60 80 100 120 140 1600

10

20

30

40

50

60

70

80

0 1.2 2.3 3 6.2 8.6 10.2 12.4

0

17.3

30 34.142.9

51.3 54.559.6

Untreated Treated

Days

% L

oss

in s

tren

gth

(War

p)

0 20 40 60 80 100 120 140 1600

10

20

30

40

50

60

70

80

0 1.6 2.6 3.4 5.612.4 14.4 17.8

0

14.5

26.331.8 34.7

49.2 53.157.2

Untreated Treated

Days

% L

oss

in s

tren

gth

(Wef

t)

Warp

Weft

Loss in Strength of Durable Woven Jute Geotextile under Water Ambience

Both untreated and treated JGTs were put in simulated experimental river bank conditions and finally % loss in tensile strength of both untreated (control) and specially treated JGT under combined soil and water ambience were measured up to 150 days.

Durability of Specially Treated woven JGT in Combined Water and Soil Ambience

Durability test of JGT in combined Soil-Water Ambience at IJIRA

Warp

Weft

Loss in Strength of Durable Woven Jute Geotextile under combined Soil-Water Ambience

0 20 40 60 80 100 120 140 1600

10

20

30

40

50

60

70

80

90

100

0 2 5.2 7.8 10.218.5 20.1 21.8

0

28.8

57.966.5

73.2

88.2 92.2 95.4

Untreated TreatedDays

% L

oss

in s

tren

gth

(War

p)

0 20 40 60 80 100 120 140 1600

10

20

30

40

50

60

70

80

90

100

0 2.4 3.2 512.4

20.8 22.4 23.6

0

24.834.8

50.5

64.772.8

78.689.4

Untreated TreatedDays

% L

oss

in s

tren

gth

(Wef

t)

(Microbial Count)(CFU/gm)

Soil Water

Bacteria 2.0x 107 2.7 x 102

Fungi 3.2 x104 Negligible

Microbial Analysis: As per Agar plate technique (AATCC 100, AATCC 30)

Microbial profile of soil & water used in durability test of treated JGT

Textural class of Soil used : Silt loam as tested by NBSS

Sample BOD5

(mg/L)COD

(mg/L)

Water 12 20

Water + untreated woven JGT 18 30

Water + specially treated woven JGT 16 26

Biological Oxygen Demand ( BOD) : IS 3025 (Part 44): 1993

Chemical Oxygen Demand ( COD) : IS 3025 (Part 58): 2006

Environmental Impact of durable woven Jute Geotextile

LIFE PREDICTION of specially treated woven Jute Geotextile (627 gsm ) had been carried out at IJIRA both under soil ambience and soil-water ambience and compared with untreated grey Jute Geotextile fabric. At different interval, loss in tensile strength was monitored and finally a statistical life prediction model as represented in has been suggested.

Life Prediction of Specially treated woven Jute Geotextile

Statistical Life Prediction of specially treated woven Jute Geotextile

Statistical Life Prediction of specially treated woven Jute Geotextile

Field Trial of Durable Woven JGT has been carried out

at the left bank of the river ( Bhagirathi, Shantipur, Nadia, West Bengal )

In association with:

1. National Jute Board (CFC-IJSG-21 Project)

2. Department of Irrigation and Water ways, Nadia Division Govt. of West Bengal

Bulk production of durable JGT Site of trial Performance Assessment of JGT

Field Trial on Specially Treated durable Woven Jute Geotextile

Identified chemical additives used to improve durability of woven JGT are aqueous based and readily available The effective add-on of the chemicals is low (0.5 %, w/w, approx.) and the weight gain of JGT fabric is negligibleThe loss of strength of the JGT fabric after treatment is within normal range (around 5%) Fabric characteristics of woven JGT are not affected much due to special treatmentSpecially treated woven JGT is rot-resistant & water repellentImproved functional properties is likely to increase the effectiveness of using such durable JGT in river bank protection

Contd…

Salient features of Durable Woven JGT

The treated JGT does not increase much the BOD and COD of water indicating no negative environmental impact Formulation developed for special treatment of JGT is user friendlyPredicted life of durable JGT is about two years in combined water-soil ambienceMay be considered as a cost effective alternative of copper and bitumen treatment in woven JGTFor large scale production of specially treated woven JGT, current cost of chemical is Rs. 12-14/- per sq.mt excluding its processing cost

Salient features of Durable Woven JGT

CONCLUSION

• Durable woven Jute Geotextile with improved anti-microbial and water repellent properties and useful life under combined soil-water ambience may be used for erosion control of river bank.

• Short and long term performance evaluation of durable woven JGT in erosion control of river bank are in progress.

ACKNOWLEDGEMENT

• National Jute Board, Ministry of Textiles, Govt. of India for

sponsoring the Project activity• CFC-IJSG-21 PROJECT for providing support in field

level performance evaluation of durable JGT in erosion control of river bank

Thank you