Presentation on theme: "A NATIONAL JUTE BOARD PRESENTATION"— Presentation transcript:
1A NATIONAL JUTE BOARD PRESENTATION Road Constructionwith Jute Geotextiles (JGT)A NATIONAL JUTE BOARD PRESENTATIONPresenter-T SanyalChief Consultant, National Jute Board
2What are Geotextiles?Geotextiles- more aptly Geosynthetics –belong to the class of Technical Textiles under GEOTECH category.Geotextiles are generically of two varieties—one variety is made of synthetic polymers (petrochemical derivatives) and the other of natural fibres (such as jute, coir)Geotextiles are intended to improve engineering performance of soil on or in which it is laid
3Jute GeotextilesJute Geotextiles (JGT)-as the name suggests –is made of bast fibres of jute plants—a renewable agri-resource under cultivation in the Ganga-Brahmaputra delta for centuries. Presently under cultivation in other areas/countries as wellThe British were the first to discover the potential of jute fibre for flexible packaging (sacks) after elaborate testsThe features of jute fibre conform to technical requirements of geotextiles, besides its added advantage of being eco-concordant, abundant availability, the back-up R & D support and industry-expertise to make customized JGTUse of JGT helps reduce carbon foot-print in road construction
4USP OF JUTE High moisture absorbing capacity Excellent drapability (the best of all GTs)High modulusLow extension-at-breakHigh roughness co-efficientExcellent spinnabilityBio-degradability with mulching & soil-nourishing propertiesAnnually renewable resource with abundant availabilityEconomical &Eco-concordant
5JGT - THE FORERUNNER OF MAN-MADE GT Jute fabric was used in road construction long before the concept of geotextiles with man-made fibres emergedJute hessian was applied successfully on Strand Road at Kolkata as early as in 1934 and in Myanmar during the 2nd World WarFirst concerted effort to promote use of Jute Geotextiles took off in 1980s with the support of UNDPExtensive R & D on JGT over the years have helped understand the mechanism of its functioning and develop improved varieties for its application in roads & other areas.
6JGT – Basic FunctionsJGT matches its man-made counterpart in the three basic functions of a geotextile viz Separation, Filtration, Drainage. Besides,Along-plane drainage capability (i.e. transmissivity) of JGT is higher than its man-made counterpart.Fineness of jute fibre enables manufacture of JGT according to the specified porometric featuresHigh Roughness Co-efficient of jute ensures better load transference & confining action on soilJGT has far greater water absorbency than all other GTs –a quality which enables sustained release of the absorbed water, thus creating a congenial micro-climate for better growth of vegetation
7in Filter-cake formation in soil Role of JGT IS AN OPTIMAL STATE OF SOIL CONSOLIDATIONTRIGGERING GRADUAL DEVELOPMENT OF EFFECTIVE STRESS WITHIN A SOIL MASS, THUS ENABLING IT TO BEAR GREATER LOAD.
8Civil engineering Applications of JGT Strengthening of road by improving CBRSlope managementProtection of river bank against erosionStabilizing embankmentsPrevention of railway track settlementConsolidation of soft soilControl of surface soil detachment
91. JGT in Road Construction Causes of failure of roads :Inadequate pavement thicknessHigher-than-design traffic load & intensityLow bearing capacity of sub gradeIntermixing of sub-base and sub gradeInsufficient drainage of surface and sub-surface waterLeading to “mud pumping”Permeable wearing courseBesides the distress /failure of road pavement, stability of a road also depends on the stability of the embankment on which it is built and slope stability the causes of distress/failure of which are different.
10Design parametersRoad pavements are usually designed on the basis of traffic load & its intensity or equivalent single axle load (ESAL), sub-grade CBR and allowable rut-depthThere are other design parameters followed in some of the overseas countries. USA, for instance, follows the concept of Structural Number.
11-inducing membrane effect, exerting confining action on sub-grade, JGT in Road ConstructionHow can JGT help?Enhances the CBR of the sub-grade by-inducing membrane effect, exerting confining action on sub-grade,preventing soil migration & facilitating water-dissipation along &across its plane (essentially ‘filtration’ function) leading to generationof effective stress within sub-grade-preventing intermixing of sub-grade and sub-base (“separation”function)-facilitating drainage in the sub-surface zoneIn fact all GTs act as change agents to the soil by concurrentfunctioning of separation, filtration & drainage at the formative phase
13JGT in Road Construction Rough Guidelines for designing a new road with JGT based on field trial results & lab. findingsCBR to be taken as 1.5 times the control value of CBR.Woven JGT should be selected in conformity with theaverage particle size distributionSub-surface drainage may be facilitated with suitable use ofnon-woven JGT concurrently.N.B Precise design guidelines are being finalised under an international project on JGT sponsored by the Common Fund for Commodities, a financial institution of the UN.
14JGT in Road Construction Note :Choice of JGT also depends on the allowable rut depth which is a factor of the level of service expected of a road vis-à-vis the level of its maintenancePorometry range: 150 to 400 microns depending on the average grain size of the sub-gradeTensile strength: 25 kN/m is considered adequate for most of the roads [Recommended by the CFGG Manual (France) for SGT.]
15JGT in Road Construction Some Salient Findings of studiesPercentage elongation at break of JGT is significantlylower than that of synthetic geotextiles (maximum 15%against more than 50 % of SGT)(Ramaswamy & Aziz – 1989)Substantial reduction (more than 50%) in rut depthunder dynamic load tests with JGTLoss of strength of JGT after a year is not a deterrentas, by that time, JGT is seen to have helped inproviding a self sustaining sub-grade for most type ofsoils (Ramaswamy & Aziz – 1989)The gain in strength of the sub-grade with time iscompensated against the loss of strength of JGTwithin the same time frame (ibid & JU 2005)
18Effect of Jute Fabric on Compaction Characteristics of Subgrade Soil
19Studies by Ramaswamy & Aziz (1989) on Clayey Subgrade Table - I22421030826c) Strain at failure (%)i) without JGTii) with JGT366545115110330b) Undefined Compressive Strength (kN/m2)3525a) Water Content (%)Table - II5.0818.104.22.168.24.76.8b) CBR (%)i) without JGTii) with JGT353025a) Water Content (%)
202. Slope Management with JGT Roads built on high embankments require preventive measures to control erosion of slope surface.Slopes erode due to:Detachment of top soil by K E of rain dropsFlow of rain water (surface run-off)Severe windSurficial soil erosion can be controlled by reducing the velocity of surface run-off & entrapping detached soil particles.Wind-induced soil erosion can be controlled by suitable JGT- cover
212. Slope Management with JGT Remedial ConceptUniversal Hydrological Equation in its simplest form statesprecipitation surface flow + through flow ( sub-surface flow ) + storageIf through-flow and on-land storage can be increased, surface run-off gets reducedThrough-flow depends on hydraulic conductivity of the soil. Storage can be facilitated by creating micro-barriers on the slope. Such micro-barriers also curb the velocity of surface flowJGT is the ideal material that fulfills the requirements, besides facilitating fast growth of vegetation on its bio-degradation as a result of its mulching properties and by increasing the hydraulic conductivity of soil
22deposition of sediments material in suspension Soil Erosion Process on a SlopeRAIN- - -- -XCbelt of no erosionFLOWactiveerosiondeposition of sedimentsDadbb’ec’cmaterial in suspensionoverland flow
23- - - - - - - - - Dam Storage ) L D β Weft of open mesh JGTD2.87 litres / sq.m. of water on a 1:2 slope can be impounded when an open weave JGT having 45 wefts in a metre, and dia of 4mm in weft with an overall weight of 500 gsm. JGT is laid
24Installation of JGT on slope Directionof layingJute GeotextileFixing nailGraded slopeGrass plantToe anchor(150 mm x 150mm)150Shoulder anchor150 mm50 mm(II Gauge wire)+
253. Stability of Embankments Embankment is an essential component of a road.Almost all roads are built on embankments.Expansive or compressive soils used as fills inembankments may lead to:Vertical settlementLateral dispersionDownslope migrationRotational slides (slip circle failure)
26Stability of Embankments JGTabsorbs stress and strain induced due to moving loads on embankmentshigh soil - JGT interfacial friction acts as a good medium of transference of the induced stress and straincan directly reinforce the soil mass in an embankment during its useful lifespanSoil is otherwise stabilized due to separation, filtration and drainage effects acting concurrently
27Basal Reinforcement with JGT for any new embankment is effective JGT can also be used in successive layers of an embankment and may be folded at the fringes asside restraint for protection against rotational slideIn new embankments woven JGT may be used as basal reinforcement to avert settlementPRECAUTIONPrevent ingress of water into an embankmentDrain out entrapped water from an embankment for which installation of JGT- encapsulated concealed drains and, in more severe cases, prefabricated vertical jute drains (PVJD) deserves consideration.
28Durability of JGT As already indicated Loss of strength of JGT after a year is NOT a deterrent – for, by that time, JGT provides a self-sustaining sub-grade for most soilsThe gain in strength of the sub-grade compensates the loss of strength of JGT within the same time frameWith the passage of time dependence on JGT for soil stability continues to decreaseHowever there is need to ensure JGT-durability ranging from 2 to 4 years (depending on the application-type) by special treatment. Eco-friendly durability treatments have been developed by IIT, KgP & IJIRA
29Is Bio-degradability of JGT a Technical Disadvantage? The answer is NO. Optimal consolidation(development of effective stress) is seen to take placewithin the effective life of JGTN.B. Effective life of JGT may be enhanced by speciallydeveloped eco-friendly water-repellent treatment (developed by IIT Kgp & IJIRANecessity of JGT or, for that matter, of any GT ceases afterfilter-cake formation.Bio-degradability of JGT is thus not a technical disadvantage. Additionally JGT lends environmental advantage to road construction
30ENVIRONMENTAL ASPECTS Jute fibres are eco-friendly, soil-friendly, biodegradable, annually renewable resourceFollowing points are relevant in context of eco-concordance and socio-economic value of juteDuring 100 days of jute growing period, 1 hectare of jute plant can absorb about 15 MT of CO2 from atmosphere and liberate about 11 MT of O2. Studies reveal that CO2 assimilation rate of jute is higher than trees (Inagaki, 2000; IJSG 2003). In fact jute helps in carbon sequestration.
31(contd.)Main use of jute sticks (a retting output) is as fuel and household uses. Yield of jute sticks is 2.5times the fibre by weight. Jute sticks annually saves 5.06 million tons of forest wood(in India and Bangladesh) and help in preserving ecological balance.Leaves left in the field are good manures and increase fertility of land. Increases hydraulic conductivity of soil
32Field Experience with JGT Experience in India & elsewhere with JGT in geotechnical engineering applications numbering more than 150 in India alone corroborates its effectiveness in road construction and erosion control of diverse natureIn road construction enhancement of CBR value is minim 1.5 times and in some cases the increase has been even 3-5 times after 4 years!Soil continues to consolidate even after bio-degradation of JGT. In fact JGT triggers the process of consolidation thru’ development of effective stress. The process continues for a protracted period.
33SOME PROPERTIES OF WOVEN JGT Some salient properties of woven JGTSOME PROPERTIES OF WOVEN JGTVALUETensile Strength15 to 40 kN/mElongation-at-break8% to 12%Puncture resistance400 to 600 NBurst strength3000 to 4000 kPaPermittivity with 50 mm water head≈350 x 10-5 per secTransmissivity-on 724 gsm (25 kN/m) at kPa-on 627 gsm (20 kN/m) at kPa4.37 x 10-7 m 3 /m-s3.64 x 10-7 m3 /m-sAOS (O95)100 µ upwardsJGT has a high initial tangent modulus (comparableJGT offers a greater interfacial friction than SGTJGT has greater transmissivity than SGTPermittivity of JGT is comparable to that of SGT
34Advantages Of JGT – in summary EconomicalEasily availableCan be tailor made to meet the criteria of retention and permeability.Precise control on quality and workmanship possible.Quicker execution time.Better drapability than any other geo-textile.Provides a sustainable and eco-compatible solution.Conducive natural protection against erosion through quick growth of vegetation cover.
35Newly developed products Several new products have been developed recently based on Jute for highway applicationsJGT in asphaltic overlay for prevention of reflection cracks. (developed by IIT Delhi)—not triedPaving fabric for wearing course as alternative to mastic asphalt(developed by IJT & CRRI (under the JTM sponsored by MoT withNJB as the collaborating/facilitating organization) -under field trialDevelopment of durable & water-repellent JGT (recently developed by IIT, KgP under the JTM) -under field trial‘Jutecrete’-Jute-fibre reinforced concrete (developed by IIT, KgP)under the JTM sponsored project by MoT with NJB as thecollaborating/facilitating organization) -under field trialPre-fabricated vertical jute drain (PVJD) developed by IIT Delhi &Singapore Sate University (Prof R D Ramaswamy)-already tried
36Standards/Normative References IS 14986:2001—-Guidelines for application of Jute Geo-textiles for rain watererosion control in road & railway embankment and hill slope-2 BIS guidelines on rural road constn & river bank protectionwith JGT have recently been approved- under printRDSO, Ministry of Railways & Rly Board–-Specs for Open weave JGT in slope protection-Guideline no GE:G1 (July 2003)—-Guidelines for earthwork in railway projects-Included as an item in the unified SoR of Railways 2011Indian Roads Congress—-State-of-the-art report on use of jute Geotextiles in RoadConstn & Prevention of Soil Erosion/Landslides (2012)-Specifications for road & bridge works (2001) &-Recommended practice for treatment ofembankment slope & erosion control (1991)I & W Deptt & PW(Roads) of GoWB have included JGT items intheir SoRs
37Illustrative Case Studies Case Studies in road & slope erosion control
38Some Case Studies in Road with JGT Re-construction of damaged highway on soft marine soil using JGT at Kakinada Port – Andhra Pradesh2. Strengthening of UT Road - Jorabari with JGT(Assam)Strengthening of Chatumary - MDR14 road with JGT (Odisha)4. Widening and strengthening of Munshirhat – Rajpur Road with JGT (West Bengal).5. Strengthening of Andulia – Boyratola Road with JGT (West Bengal)
39Re-construction of damaged highway on soft marine soil using JGT at Kakinada Port – Andhra Pradesh
40Condition of Damaged Road Leveling of the damaged road with earth LOCATION :Kakinada Port Area, Andhra PradeshSITE CONDITION:The subsoil is soft clay up to 4m depth and water table is about 0.5m below G.L.SOLUTION:Woven JGT was used to re-build & strengthen the damaged carriageway on the existing soft soilCLIENT NAME:CRRI and Kakinada MunicipalityYEAR OF APPLICATION: 1996Condition of Damaged RoadLeveling of the damaged road with earth
41Finished road after 7 years of construction PAVEMENT COMPOSITIONJGT on prepared sub-grade overlain by compacted sand of 1.2 m as sub-base & 10 cm thick compacted gravel as base. 1m deep side drains on either sidePROPERTIES OF SUBGRADE SOIL:Plasticity Index:Soil type: CHPROPERTIES OF JUTE GEOTEXTILE USED:Weight : gsmTensile Strength : kN/mPore Size (O90) : micronType of JGT : Woven (Rot-proof)Laying of JGT over sandFinished road after 7 years of construction
42CBR VALUES OF SUB-GRADE SOIL BEFORE AND AFTER LAYING OF JGT Natural soil (before laying JGT)CBR %Improved soil (after laying JGT)*Un-soaked specimenSoaked specimen2.101.616.034.78* Test was performed after 30 months of laying JGT
43FINDING:Jute Geotextile helped increase of CBR% in weak marine soil even after reduction in the strength of JGT after a lapse of 7 years as reflected from the performance and increase in CBR.
44Strengthening of UT Road - Jorabari (Assam) with JGT
45Pavement composition LOCATION : The road (UT Road to Jorabari) is located at Udalguri in Darrang district, AssamSITE CONDITIONS:This was an earthen road under PMGSY Pilot project. Flash flooding of the area occurs occasionally. Deep ruts had formed at some locations. Average annual rainfall is 1600 – 1700 mm. The water table is 3 to 4 m below G.L during summer and 1.5 to 2 m during monsoon.SOLUTION:Jute Geotextile was used on sub-grade to strengthen the road.ROAD LENGTH: KmBefore constructionPavement compositionWoven JGT sandwiched bet. sand layers (100) & overlain by GSB (100), gravel (100) & WBM Gr III (75) with bituminous overlay
46Chief Engineer PWD, Rural Road Works, Assam YEAR OF APPLICATION: 2007 CLIENT NAME:Chief Engineer PWD, Rural Road Works, AssamYEAR OF APPLICATION:PROPERTIES OF SUBGRADE SOIL:Liquid Limit: %Plastic Limit: Non-plasticCBR of soaked specimen: %Soil type: MLPROPERTIES OF JGT USED:Weight : /760/810 gsmTensile Strength : 15/20/30 kN/mPore Size (O90) : – 200 micronType of JGT : Woven (Rot-proof)Laying of Jute Geo-textileFinished Road
47CBR VALUES OF SUB-GRADE SOIL BEFORE AND AFTER LAYING OF JGT Natural soil (before laying JGT)CBR %Improved soil (after laying JGT)*Soaked specimen4.0014.30*after 3 years
48FINDING:The CBR values increased by more than 3.5 times with decrease in moisture content.The blacktop pavement surface was distress-free in all the sub-sections during the entire period of performance monitoringShoulders as well as side slope was in shape without any rain-cut or settlement with green grass over it.
49Strengthening of Chatumary – MDR-14 road, Odisha with JGT
50Pavement composition LOCATION : The road (Chatumari to MDR 14) is located under Tehsil – Bari in Jajpur district, Odisha.SITE CONDITIONS:This was an earthen road under PMGSY Pilot project. Deep ruts had formed at some locations. Average annual rainfall is 1400 mm. The water table is at a depth of 1.5 to 3 m.SOLUTION:Jute Geotextile was used on sub-grade to add to stability of the road.ROAD LENGTH: KmBefore constructionPavement compositionWoven JGT sandwiched bet. sand layers (100) & overlain by GSB (100), gravel (100) & WBM Gr III (75) with bituminous overlay
51Chief Engineer PWD, Rural Works – II Orissa YEAR OF APPLICATION: 2007 CLIENT NAME:Chief Engineer PWD, Rural Works – IIOrissaYEAR OF APPLICATION: 2007PROPERTIES OF SUBGRADE SOIL:Liquid Limit: %Plastic Limit: Non-plasticCBR of Soaked specimen: 3%Soil type: MLPROPERTIES OF JGT USED:Weight : /760/810 gsmTensile Strength : 15/20/30 kN/mPore Size (O90) : – 200 micronType of JGT : Woven (Rot-proof)Laying of Jute Geo-textileFinished Road
52CBR VALUES OF SUB-GRADE SOIL BEFORE AND AFTER LAYING OF JGT Natural soil (before laying JGT)CBR %Improved soil (after laying JGT)*Soaked specimen3.0010.13*after 2 years
53FINDING:The CBR values increased more than 3 times with decrease in moisture content.The blacktop pavement surface was distress-free in all the sub-sections during the entire period of performance monitoringShoulders as well as side slope condition was satisfactory with a green cover of grass
54Widening and strengthening of Munshirhat – Rajpur Road (West Bengal) with JGT.
55JGT laid over sub-grade Brick metal laid over JGT LOCATION :Munshirhat to Penro Khila Rajpur Road, Howrah, West Bengal.SITE CONDITIONS:It is a rural road which was to be widened to carry the increased traffic.SOLUTION :Jute Geotextile was laid on the extended portionROAD LENGTH: 2 KmCLIENT:Howrah Highway Division, PW (Roads) Deptt., Government of West BengalYEAR OF APPLICATION: 2000JGT laid over sub-gradeBrick metal laid over JGT
56Pavement composition PROPERTIES OF SUBGRADE SOIL: O.M.C : 19% Plasticity Index : 19%CBR of Soaked specimen : 3.5%Soil type : OLPROPERTIES OF JGT USED:Weight : gsmTensile Strength : kN/mPore Size (O90) : micronType of JGT : Woven (Rot-proof)Finished RoadPavement compositionWoven JGT was placed on the sub-grade of the widened portion overlain by 2 layers of brick soling as sub-base and WBM (150) as base layer with bituminous top (20 cm PMC).
57CBR VALUES OF SUB-GRADE SOIL BEFORE AND AFTER LAYING OF JGT Natural soil (before laying JGT)CBR %Improved soil (after laying JGT)*Soaked specimen3.506.0*after 1 year
58FINDING:The sub-grade was strengthened by application of JGT attaining CBR value of 6% from initial 3.5% with decrease in liquid and plastic limits. No distress of the road was noticed after several years despite increase in projected traffic load.
59Strengthening of Andulia – Boyratola Road, West Bengal with JGT
60LOCATION :Andulia (Kalupukur More) to Boyratala in Haroa Block, District North 24-Paraganas, West Bengal.SITE CONDITIONS:Rural road under PMGSY on soft sub-grade resulting in reduction of effective pavement thickness due to interpenetration of sub-base and sub-grade.SOLUTION:Jute Geo-textile was used on the sub-grade and under the sub-base basically as a separator.ROAD LENGTH: KmPavement compositionWoven JGT overlain by GSB (200)) & WBM II& III (150) with bituminous overlay (PMC)
61North 24-Paraganas Zilla Parishad, West Bengal CLIENT NAME:North 24-Paraganas Zilla Parishad,West BengalYEAR OF APPLICATION:PROPERTIES OF SUBGRADE SOIL:Optimum Moisture Content: %Plasticity Index:Soaked CBR at 2.5mm penetration: %Soaked CBR at 5.0mm penetration: %Soil type : OLPROPERTIES OF JGT USED:Weight : gsmTensile Strength : kN/mPore Size (O90) : micronType of JGT : Woven JGTFinished Road
62CBR VALUES OF SUB-GRADE SOIL BEFORE AND AFTER LAYING OF JGT Natural soil (before laying JGT)CBR %Improved soil (after laying JGT)*Soaked specimenUn-soaked specimen3.1610.47* Test was performed after 18 months of laying JGT
63FINDING:The study substantiates the proven concept that limited durability of JGT is not a technical deterrent as soil gets consolidated due to separation, filtration and drainage functioning concurrently with the help of JGT within a year or so. CBR value got enhanced to more than 3 times despite loss in strength of JGT in the instant case.
64Some Photographs showing application of JGT for Stabilization of Slope of Road Embankment
70Typical cross-section of a low volume road with JGT
71Findings of the case studies Water content, void ratio and compression index decreased while dry density and CBR value of the sub-grade soil increased by use of Jute Geotextile.JGT appeared to be very effective even in weak sub-grade in reducing their compressibility and increasing their strength as reflected from the good performance even after a lapse of 10 years.JGT is the most effective among geotextiles for surficial soil erosion control
72MISSIVEJGT is an effective technical facilitator in building stronger and more durable roads with the added advantage of lending eco-concordance by reducing carbon footbprint & ensuring overall economy .Jute plays a significant role in national economy as a major FE earner & one of the largest employers of work-force in IndiaJGT JUSTIFIABLY DESERVES MORE PATRONAGE