Specifications for Geotextiles in India by R. P. Indoria Secretary General, Indian Roads Congress 19...

Specifications for Geotextiles in India

byR. P. Indoria

Secretary General, Indian Roads Congress

19 November 2010

ABOUT IRC

Indian Roads Congress is a Society of Highways Engineers established in 1934

Frames Codes of Practice , Standards, Guidelines, Manuals etc. on various subjects for Roads and Bridges

Identification of research topics and Institutions Collection of data on research done and

utilization there of

(Cont…)

ABOUT IRC

Dissemination of Research findings for revision of IRC Codes and Special Publications

Holding Workshops and Seminars on Crucial Topics for dissemination of knowldge

Promoting Usages of New Materials and Technologies

IMPORTANCE AND USAGES OF GEOTEXTILE IN ROAD SECTOR

Use as Separator to Improve Pavement Performance

Use as reinforcement and drainage layer Use for Ground Improvement Use for drainage of ground (PVD/piped drains) Jute Geogrid for Erosion Control of Denuded

Slopes Jute Geotextile for Drainage and Filtration

Application Jute is low cost, renewable, biodegradable and

eco-friendly natural product (Cont…)

IMPORTANCE AND USAGES OF GEOTEXTILE IN ROAD SECTOR

Construction of road embankments in water logged area

Soil Nailing River Bank Protection Embankment slope protection

TYPES OF GEOTEXTILES

Geotextile: Non Biodegradable Synthetics Woven / Non Woven Fiber and perform discrete function i.e. separation, reinforcement, filtration, drainage and moisture barrier (when impregnated).

Geogrids :Open, grid like configuration, i.e., they have large apertures and used for the purpose of separation, but invariably they are being used in some form of reinforcement.

( Cont…)

TYPES OF GEOTEXTILES Geonets: another specialized segment of Geosynthetics

and Geonets are used for the purpose of drainage. It is to be noted that geonets are always used with a geotextile. Geonets used in protective works for highway structures

Geocomposite: A geocomposite consists of a combination of geotextile and/or geogrid and/or geomembrane or any of these three materials with another material in laminated or composite form and used for accelerating the consolidation of soft soils.

(Cont…)


Geomembranes : Geomembranes are also synthetic materials but they are impervious and made of thin sheets of rubber or plastic materials used primarily for lining and cover of liquid-or solid-storage facilities

Geocell : A three dimensional structure with interconnected cells which can be filled with soil/granular material forming a mattress for increased bearing capacity and manoeuvrability on loose or compressible subsoil of base or sub-base in pavements and slope protection

(Cont…)


Natural Geotextiles: Natural fibres are extracted from plants and are then converted into yarns by spinning. These fabrics are sometimes treated with rot resistance materials or reinforced with synthetic fibres to enhance their durability under different soil conditions without affecting its strength and other properties. Natural fibres such as jute, coconut and coir fabrics are used to improve soil erosion control and drainage applications.

USE OF GEOTEXTILE FOR IMPROVING PERFORMANCE OF

ROADS

Geosynthetics for Highway Pavements Geosynthetics Over Existing Bituminous Surface Provision of Geotextiles Against Subgrade and

Embankment Erosion Geotextiles In Sub-surface and Composite Drains Geogrid Applications For Reinforced Soil Slope

Protection

USE OF GEOTEXTILE FOR IMPROVING PERFORMANCE OF

ROADS

Road pavement as a drainage layer, Bioengineering measure for shoulders and earthen slopes, Improving the pavement performance and Reducing the pavement crust (?)

• Construction of road embankments in water logged area

• Soil Nailing , Soil Stabilization

IRC DOCUMENTS ON GEOTEXTILES

IRC has one document titled “State of the Art: Application of Geotextiles in Highway Engineering” published by IRC in 1994

It is a compilation of available literature (at the time of preparation of the report)

Since then a lot of developments have taken place in manufacturing and preparation of geotextiles, their usage and applications etc.


IRC has another document titled SP:59 – 2002 `Guidelines for use of Geotextiles in road pavements and associated works`

Being a Special Publication, this document does not have the status of a ‘Code of Practice” per se but nevertheless covers the following:

Scope

Raw Material and types of Geotextiles

Functions of Geotextiles


Handling and storage of geotextiles

Geotextiles properties and test methods

Geotextiles property requirements for various applications

Construction guidelines for use of geotextiles in various applications

References have been made to ASTM standards for test methods

GEOTEXTILES SPECIFICATIONS More comprehensive specifications are included

in the Ministry of Road Transport and Highways book of Specifications, popularly known as the “Orange Book”

The current edition of this book is also very old (2001) and a revision of the book has been almost finalised and is likely to be published soon

GEOTEXTILES SPECIFICATIONS The proposed specifications(section 700) cover

the following:

1 GEOSYNTHETICS IN ROAD AND BRIDGE WORKS

Scope

Testing, handling, certification, and acceptance

Minimum Geotextile strength property requirements

Installation condition

Type Strength property requirement (MARV)*

Grab Strength in

N as per ASTMD 4632

Tear Strength in

N as perASTMD 4533

Puncture Strength in N as per ASTM

D 4833

Burst Strength in N as per

ASTMD 3786

Elongation at Failure

<50%

>50%

<50%

>50%

<50%

>50%

<50%

>50%

Harsh installation

Type 1 1400 900 500 350 500 350 3500 1700

Moderate Installation condition

Type II 1100 700 400 250 400 250 2700 1300

Less Severe Installation condition

Type III 800 500 300 180 300 180 2100 950

Geotextile Requirements for Ultra Violet Light Degradation

S.No Properties of Fabric Test Methods

Units Requirements(Retained Strength)

1 Grab Strength ASTMD 4632 N Not lessthan 70%after 500 hrs of exposure

2 Tear Strength ASTMD 4533 N

3 Puncture Strength ASTMD 4833 N

4 Burst Strength ASTMD 3786 N

Properties for Prefabricated Vertical Drains

Unit

Minimum Value Test Method

Physical Requirements

Weight gm/sq. m 90 -

Width mm 90 -

Thickness mm 5 -

Strength Requirements

Tensile Strength kN ≥ 1 at 10% elongation ASTM D4632

Puncture Strength N 150 ASTM D 4833

Tear Strength N 200 ASTM D 4533

Discharge Capacity

Index text using deformable foam layers

m3/sec 60x10-6 (300kPa)40x10-6 (500kPa)

ASTM D- 4716

Straight – embedded in bentonite

m3/sec 90x10-6 (300kPa ASTM D- 4716

Buckled – embedded in bentonite

m3/sec 80x10-6 (300kPa ASTM D- 4716

Typical Specifications for Geocells

Property Min. Required Value Test method

Density 0.935gm/cm3 ASTM D1505

Environmental Stress crack resistance (ESCR)

5000 Hrs. ASTM D1693

Carbon Black Content 1.5 to 2% by Weight

Strip / Cell Wall thickness 1.27mm, -5% +10% ASTM D5199

Seam Peel-Strength Test Min. 355 N per 25mm of cell depth. ASTM E41

Creep Rupture Strength Creep Rupture Load at 10,000 hours shall be 95 kg minimum obtained from the 95% prediction interval at 10,000 hours considering a logarithmic time/creep rupture model.

ASTM D2990

Typical Specifications of Natural Geotextile

Type of Fibre

Weight Width Thickness Open Area

Tensile Strength(KN/m)

Water Holding Capacity

Porometry (O95)

(gsm) (cm) (mm) (%) MD CD (%) micron

Open Mesh

500 120 4.0 50 10 7.5 - -

Woven Geotextile

1)Ordinary 700 75 2.0 - 20 20 - 3002) Rot Resistance

700 75 2.0 - 20 20 - 300

3)Bitumen treated

1200 75 2.0 - 20 20 - 150

Non- woven Fibre

500 150 4.0 - 5 2.5 300 -

2 GEOTEXTILES IN SUB SURFACE DRAINS

Scope

Materials

Construction requirements

Measurement for payment

Rate

Geotextile Requirements for Subsurface Drainage

Per cent in-situ passing 0.075 mm

sieve

Geotextile drainage property requirement

Recommended geotextile *

Permittivity, per sec ASTM D 4491 (Minimum ARV)

Apparent opening size, mm ASTM D 4751 (Maximum ARV

< 15 0.5 0.43 Type II from Table 700-1

15 to 50 0.2 0.25

> 50 0.1 0.22

Recommended Permittivity for Different Soils

Soil type Typical Permeability, Ks (cm/sec)Range of

Soil

Minimum Recommended Geotextile Filter

Permittivity, Y(per second)

Sandy Gravel 1 X 10-1 to 1 X 10-2 0.5 to 0.1

Clean Sand 1X10-2 to 1 X 10-3 0.1 to 0.01

Silty Sand 1X10-3 to 1 X 10-4 0.01

Silt 1X10-4 to 1X10-5 0.01

Clay 1X10-5 0.01

3 USE OF GEOSYNTHETICS IN COMPOSITE DRAINS

Scope

Material

Installation


Rate

Apparent Opening Size for Geo-composite Drains

Test Method Units Requirements Percent in-situ

soil passing 0.075 mm

ASTM D 4751 mm <15 15 to 50 >50

0.43 0.25 0.22**

4 GEOTEXTILES FOR EROSION CONTROL

Scope

Materials

Construction requirements

Slope protection placement

Seams

Repair


Rates

Erosion Control Geotextile Requirements

Percent in-situ passing

0.075 mm sieve

Geotextile drainage property requirement

Recommended geotextile

Permittivity, per sec ASTM D

4491 (Min. ARV)

Apparent opening size, mm ASTM D

4751 (Max. ARV)

<15 0.7 0.43 Type I from table 701

15 to 50 0.2 0.25

>50 0.1 0.22

5 GEOGRID APPLICATIONS FOR REINFORCED SOIL SLOPE PROTECTION

Description

Material

Installation

Measurement and basis for payment

Rates

6 GEOSYNTHETICS FOR HIGHWAY PAVEMENTS

Scope

Materials

Certification

Installation


Rate

Separation/Filtration Property Requirement for subgrade Soil with LL < 35 (such as ML, CL, CL-ML etc) **

** The soil classification shall be as per BIS-1498 – 1970 (Re-affirmed 1987)

Sl. No. Geotextile Property RequirementRecommended

Geotextile

1.Permittivity* as per

ASTM D 4491

0.02 sec -1 (per sec) (Minimum average

roll value)Type II from Table:

701

2.Apparent Opening

Size as per ASTM D 4751

0.06 mm (Maximum average roll value)

Separation/Filtration Property Requirement for subgrade Soil with LL > 35 (such as CL, CH, MH etc)**

** The soil classification shall be as per BIS-1498 – 1970 (Re-affirmed 1987)

Sl. No.Geotextile Property

RequirementRecommended

Geotextile

1.Permittivity* as

per ASTM D 4491

0.05 sec -1 (per sec) (Minimum

average roll value) Type I from

Table: 701

2.

Apparent Opening Size as

per ASTM D 4751

0.43 mm (Maximum

average roll value)

Requirements for Geogrid for Sub-Base/base of Flexible Pavements

Note 1) All numerical values in the Table represent MARV in the specified direction.

2) All geogrids shall be placed along machine direction parallel to the centre line of roadway alignment.

3) Junction strength is required to maintain dimensional stability of the geogrid during deployment. It is not applicable to geogrid/geotextile composite products.

Property

Test Method

Required

value , kN/m

Machine Direction

Cross Direction

Tensile strength@1% strain ASTM D6637 4.3 6.6



Tensile modulus @5% strain ASTM D4355 437 656

Junction Efficiency, % of rib ultimate tensile strength

90 90

Ultraviolet stability (after 500 hrs) ASTM D4355 70 %

7 GEOSYNTHETICS OVER EXISTING BITUMENOUS SURFACE

Scope

Paving Fabrics

Material Requirement

Specifications for bitumen coated fiber glass fabric

Placement

Measurement

Rate

Physical Requirements for Paving Fabrics

Property Units Standard Requirements

Test Method

Tensile Strength KN/m 9KN/m ASTM D 4632

Elongation % ≥50 ASTM D 4632

Mass per unit area

Gm/m2 140 ASTM D 3776

Asphalt Retention

Kg/10 sq.m 10 Texas DOT 3099

Melting Point °C 150 ASTM D 276

Surface Texture - Heat bonded on One side only

Visual Inspection

Properties for Glass Grid Fiber

Property Test Method Grid

Tensile strength

MD (kN/m) ASTM 6637/ ISO

13439

≥50

CMD (kN/m) ≥50

Elongation at break (%)

>5

Minimum Mesh size (mm)

12.5 x 12.5

Melting point 0C - >218

Framework for promoting usages of Geotextile

Majority of the National Highway Development Programme to be implemented on PPP mode on BOT basis

The use of geotextile for road structure i.e. part of new or existing pavement does not bring the desired reduction in crust thickness since the pavement has to be designed as per IRC:37

There is a strong need to establish relationship between use of a type of geosynthetic and corresponding reduction in crust thickness


This can only be achieved by concerted research (may be industry sponsored) with the involvement of research institutes and academia

This could lead to formulation of definitive specifications and design methods using geotextiles/ geosynthetics

For the interim, the Government has created an enabling environment for the Concessionaire to use any material / technology / equipment as long as it meets any of the established international standards


The Manuals for four and six laning of highways, which form part of the Concession agreement, have been published by IRC containing this provision

Industry need to come out with ways and means to demonstrate to the prospective users (Concessionaires) the cost effectiveness (short term and long term) of the use of geotextiles

Industry also to come out with other innovative usage of geosynthetics besides the existing ones


On our part in IRC we have started a process of accreditation of new material / technologies / equipment etc. for use in the design and construction of highways

The proposals are examined by an Accreditation Committee constituted within IRC and comprising of experts from public as well as private sector

Upon satisfaction, the Committee issues an Accreditation Certificate which acts as a confidence measure with the prospective buyers


We also insist on field trial / usage reports from clients

In case of satisfactory performance reports, the new material, technology or equipment will then be suitably incorporated in Codes of Practices / Specifications

Conclusion

Need to establish relationship with cost (crust) reduction with usage of geosynthetics

Concerted research to have road crust design methods and formulate specifications

Concessionaires to be apprised of benefits of geosynthetics

Thank You for your kind attention

Specifications for Geotextiles in India by R. P. Indoria Secretary General, Indian Roads Congress 19...

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