TRAINING WORKSHOP ON NON-WOVENS IN GEOTEXTILES AT SURAT 5TH MARCH 2008 BY S.K. PURI CHIEF GENERAL MANAGER - NHAI

National Highways Total Length of NHs : 65,569 km (2% of total road length) Roads carry 85% of Passenger and 70% of Freight Traffic NHs carry about 40% of traffic NHAI is entrusted with implementation of National Highways Development Project (NHDP)

Components of NHDP Focus Phase Length (Km) Cost (Rs crore) Focus I Bal. 1738 Bal. 9071 Golden quadrilateral (GQ)- connecting Delhi-Mumbai-Chennai- Kolkata-Delhi Total Length 5846 II Bal. 6736 Bal. 43623 North South& East west Corridors (NS-EW) Total Length 7300 III 12,109 80,626 State capital connectivity,High traffic density, Imp.centers of tourism &economic activity IV 20,000 27,800 Widening & Strengthening to 2-lane with Paved shoulders V 6,500 41,210 Six laning of high density corridors VI 1000 Km 16,680 Expressway for connecting important places VII (Being identified) Ring roads to cities, flyovers, by-passes SARDP-NE 588 5208 Special Accelerated Road Development Programme for NE ICTT Cochin 17 557 International Container Transhipment Terminal Total 48,688 2,41,454

Definition, Type, Process and Properties

What is a Geotextile? Types of Geotextile Non-woven Woven Any permeable textile natural or synthetic, used with foundation soil, rock, earth, or any other geotechnical engineering related material. Types of Geotextile Non-woven Woven

Nonwoven Geotextiles

Needle Punched nonwoven Nonwoven Geotextiles Needle Punched nonwoven Thermally bonded nonwoven

Woven Geotextiles

Woven Geotextiles Slit film tape-on-slit film tape Extruded tape-on-extruded tape

Woven Geotextiles PET multifilament woven fabric Monofil woven fabric

Knitted Geotextiles

Knitted Geotextiles Knitted base Upper surface

Physical Properties Property Value range Specific gravity 0.9 – 1.7 Mass per unit area 135 – 1000 g/m3 Thickness 0.25 – 7.5 mm Stiffness Nil – 25,000 mg-cm

Mechanical Properties Property Value Range Compressibility Nil to high Tensile strength (grab) 0.45-4.5 kN Tensile strength ( wide width) 9-180 kN/m Confined tensile strength 18-180 kN/m Seam strength 50-100% of tensile Cycle fatigue strength Burst strength 350-5200 k Pa Tear strength 90-1300 N Impact strength 14-200 J Puncture strength 45-450 N Friction behavior 60-100% of soil friction Pullout behavior 50-100% of geotextile strength

Hydraulic Properties Property Value Range Porosity (non wovens) 50-95% Present open area (wovens) Nil to 36% Apparent opening size ( sieve size) 2.0 to 0.075 mm ( # 10 to # 200) Permittivity 0.02-2.2s-1 Permittivity under load 0,01-3.0s-1 Transmissivity 0.01 to 2.0 x10-3m2/min Soil retention: turbidity curtains Must be evaluated Soil retention: silt fences

Endurance Properties Property Value Range Installation damage 0.70% of fabric strength Creep response g.n.p.if <40% strength is being used Confined creep response g.n.p.if <50% strength is being used Stress relaxation Abrasion 50-100% of geotextile strength Long-term clogging m.b.e.for critical conditions Gradient ratio clogging m.b.e. for critical conditions Hydraulic conductivity ratio 0.4-0.8 appear to be acceptable g.n.p. – generally no problem, m.b.e. – must be evaluated

Degradation Properties Property Value Range Temperature degradation High temperature accelerates degradation Oxidative degradation m.b.e. for long service lifetimes Hydrolysis degradation m.b.c. for long service lifetimes Chemical degradation g.n.p.unless aggressive chemicals Radioactive degradation g.n.p. Biological degradation Sunlight ( UV) degradation Major problem unless protected Synergistic effects m.b.e. General aging Actual record to date is excellent

TYPICAL PHYSICAL PROPERTIES OF GEOTEXTILES

The polymers used for Geotextile Abbreviation: PE: Polyethylene PP: Polypropylene PET: Polyester

Durability Test Methods for Geotextile

Functions and properties of Geotextiles

The functions of Geotextiles Separator Reinforcement Drainage Filter Container Energy absorber

APPLICATIONS FOR GEOTEXTILES Roads Railroads Retaining walls Reservoirs, dams Liquid waste Solid waste Drainage systems Erosion protection

1 ROADS 1.1 APPLICATIONS IN FILTRATION AND DRAINAGE Pavement drains Sub-horizontal drains Curtains Trenches Settlement acceleration materials Geotextiles Geocomposite drain (PVD)

1 ROADS 1.2 APPLICATIONS IN EROSION CONTROL SUPERFICIAL EROSION silt fences MATERIALS GEOTEXTILES Detain carried particles: during construction, before vegetation or under wind effects

1 ROADS 1.3 APPLICATIONS AS BARRIER MEMBRANE-ENCAPSULATED SOILS - moisture barrier maintenance of base material properties for use in low cost pavements in: wet regions expansive clays good base soils (lateritic soils,..) Materials asphalt impregnated geotextiles reinforced geomembranes geogrids (when hard cracking)

1 ROADS 1.4 SEPARATION AND REINFORCEMENT MATERIALS GEOTEXTILES GEOCOMPOSITES REINFORCEMENT GEOGRIDS GEOSTRIPS

2 BENEFITS OF GEOSYNTHETIC SEPARATORS 2.1 TYPICAL APPLICATIONS Located at the interface between soil and aggregate prevent contamination avoid build-up of pore pressure avoid loss of granular material sub-base/sub-grade interfaces embankments

2 BENEFITS OF GEOSYNTHETIC SEPARATORS 2.2 MECHANISMS Avoid granular material penetration Puncture resistance Filtration Pore size and permeability Interlock advantages Tensile resistance

3 BENEFITS OF GEOSYNTHETIC REINFORCEMENT 3.1 PAVEMENT SYSTEMS 3.1.1 ASPHALT OVERLAY 3.1.2 BASE/SUBGRADE 3.2 EMBANKMENTS OVER SOFT SOILS 3.3 SLOPES AND WALLS

3.1 PAVEMENT SYSTEMS 3.1.1 ASPHALT REINFORCEMENT new roads Increase in fatigue life Reduction in rutting maintenance of existing roads

3.1 PAVEMENT SYSTEMS 3.1.1 ASPHALT REINFORCEMENT MECHANISMS GEOTEXTILE GEOGRID WITHOUT REINFORCEMENT

3.1 PAVEMENT SYSTEMS 3.1.1 ASPHALT REINFORCEMENT Note: thin nonwoven geotextiles can be used when cracking still keeps the aggregates interlocking (tensile characteristics are not required) The asphalt impregnated geotextile do not acts as a reinforcement, but as a protector layer and a moisture barrier. protector layer - retards crack propagation by deviation moisture barrier – increases life time after cracking

3.1 PAVEMENT SYSTEMS 3.1.2 SOIL STABILIZATION “The use of a geosynthetic placed at the sub-grade/fill interface to increase the support of construction equipment over a weak or soft sub-grade” Applications Temporary roadways Initial construction lift of permanent ways or embankments Area constructions platforms

3.1 PAVEMENT SYSTEMS 3.1.3 BASE AND SUB-BASE REINFORCEMENT The use of a geosynthetic placed as a tensile element at the bottom or within a flexible pavement base or sub-base to: increase the service life obtain equivalent performance with a reduced structural section avoid subsidence problems (sinkholes) Applications Permanents ways Parking lots Airport taxiways Container loading facilities Railway tracks

3.1 PAVEMENT SYSTEMS 3.1.4 ADVANTAGES -cost savings in construction and maintenance -increase of service life -decrease or eliminate over-excavation and required granular fill “in pavements systems, life cycle cost analysis are important to show additional maintenance cost savings”

3.2 EMBANKMENTS OVER SOFT SOIL 3.2.1 Applications -basal reinforcement -piled embankments with basal reinforcement -reinforcement over areas prone to subsidence

3.2 EMBANKMENTS OVER SOFT SOIL 3.2.2 Basal reinforcement mechanisms rotational stability bearing capacity foundation extrusion

3. 2 EMBANKMENTS OVER SOFT SOIL 3. 2 3.2 EMBANKMENTS OVER SOFT SOIL 3.2.3 Piled embankments basal reinforcement design Ultimate limit states Pile group capacity Pile group extent Vertical loading shedding Lateral sliding Overall stability Serviceability analysis Reinforcement strain Foundation settlement

3.2 EMBANKMENTS OVER SOFT SOIL 3.2.4 Construction

3.3 REINFORCED SLOPES AND WALLS 3.3.1 applications landslide reparation bridge abutment increase working area reduce filled area reduce filling material

3.3 REINFORCED SLOPES AND WALLS 3.3.2 types reinforcement spacing Walls (angle of inclination larger than 80o) Steep slopes Block walls .

3.3 REINFORCED SLOPES AND WALLS 3.3.2 types

3.3 REINFORCED SLOPES AND WALLS 3.3.3 benefits Economical solutions Rapid and simple construction method Allows construction in difficult terrain Allows use of cheaper fill material Satisfactory appearance structures Environmental: reduce damaged areas and reduce natural material extracting

4. REQUIREMENTS AND TECHNICAL PROPERTIES Mainly mechanical characteristics Tensile strength (ISO 10319) Seam tensile strength (ISO 10321) Puncture resistance (ISO 12236) Impact test (ISO 13433) Mainly hydraulic characteristics (for separation) Opening size (ISO 12959) Permeability normal to the plane (ISO 11058)

Breaking load not less than 10 kN/m Minimum Failure strain of 10% Technical Requirement as per MoSRTH Specifications for use in subsurface drains Breaking load not less than 10 kN/m Minimum Failure strain of 10% Apparent opening size 0.22mm – 0.43 as soil properties Allow water flow @ not less than 10lit/sqm/sec Minimum puncture resistance of 200 N Minimum tear resistance of 150N

Minimum Tensile strength 36.3 Kg Elongation 50% Technical Requirement as per MoSRTH Specifications for use in Highway Pavement Minimum Tensile strength 36.3 Kg Elongation 50% Asphalt Retention 10 kg/10sqm Melting Point 150C Surface Texture- heat Bonded on one side only

Aperture : Rectangular, square or oval Colour : Black Technical Requirement as per MoSRTH Specifications for use in Protection Works Aperture : Rectangular, square or oval Colour : Black Strength : Min 10kN/m Elongation: Max 15% Form : GR1-GG3 standards Life : Min 8 years

Typical Specification of NHAI Separation and drainage Properties Units Fabric PHYSICAL Grab Tensile Strength KN 0.900 Grab Tensile Elongation % 50 Mullen Burst KPA 2750 Puncture 0.575 Trapezoid Tear 0.355 UV Resistance %@hr 70/500 HYDRAULIC Apparent Opening Size (AOS) Mm 0.150 Permittivity Sec 1.5 Flow Rate 1/min/m2 3225 Life Period Years 120 MINIMUM AVERAGE ROLL VALUES

Typical Specification of NHAI Soil Reinforcement Sl. No. Minimum Partial FOS for calculation of 100 years long term design strength (TD) in accordance with BS-8006:1995 requirements Woven PP based geotextiles Woven PET based geotextiles 1 Partial FOS for deformation (at 40 C to meet less than 0.5% post construction strain requirement for retaining wall cases) 6.0 3.0 2 Partial FOS for variations in manufacture from control specimens (fm 11) 1.0 (use only MARV) 3 Partial FOS for extrapolation of creep test data (fm 12) 1.10 (10000 hours creep) 4 Partial FOS for construction/ installation damage (susceptibility to damage) [fm 21] 1.83 2.44 5 Partial FOS for potential chemical (at 40 C) and biological degradation. (Environment) [fm 22] 1.10 1.15

Distribution of Geotextiles in the United Kingdom

Distribution of Geotextile Use in South Asia

History of Geotextiles in India Used commercially since early ’80s However, during ’80 – ’90 the use was restricted to separation, filtration and drainage application for both non-woven and woven type Indian manufacturer like Hitkari, Tata Mills etc. participated in production of non-woven type for civil engineering application Major boost in usage came after 1995 with major ports and highway development projects. Application included marine protection below rip-raps and armour layers for separation and filtration for land reclamation projects.

History of Geotextiles in India Application in river Training works and erosion control also started National Highways saw the application in drainage, embankment protection, base course stabilization and separation below highway embankments, also protection against erosion. Growing usage for environmental projects such as landfills, waste storage etc. MSE block walls are also a major end user, specially for low – medium heights using geogrids and high strength woven Geotextile Now there are 10-15 non-woven as well as woven Geotextile manufacturer besides several unorganized participations

Few Examples of NHAI Projects Purpose Qty. Visakhapatnam In Marshy/ Slushy Soils 1,08,100 sqm Vallarpadam, Cochin Geotextile (non woven) as separation/ filtration layer 4,30,260 sqm Tuticorin Below sub-grade 2,55,000 sqm Paradip (i) for high embankment over land drains (ii) below sub-grade 1,04,250 sqm 40,640 sqm JNPT Package II (SH-54 & Aamra Marg) Woven geotextile below embankment 64,600 sqm

THANK YOU FOR YOUR ATTENTION