Role of standards in Promotion of Technical Textiles

Role of standards in Promotion
of Technical Textiles
Presentation on Use of Geotextiles in highway sector
On behalf of
Indian Roads Congress
Former DG(RD) & Spl Secretary,
Ministry of Road Transport & Highways
Geosynthetics and their varieties
• Geotextiles
– Synthetic fibres (Polypropylene, Polyester, Polyvinyl Chloride,
Polyamide, or Polyethyleyne) converted into fabric by (a) weaving
(woven), or (b) bonding of random fibres (non-woven), or (c) knitting
– Good drainage property
• Geogrids
– Extruded sheets of Polypropylene and Polyethyelne punched to form
a grid pattern having large apertures
– Good strength properties
• Geonets
– Polymer strands crossing one another at an angle (usually acute angle
to give a diamond pattern aperture) and bonded at joints by thermal
– Used in combination with Geotextile or Geomembrane for drainage
– Not used for strength
Geosynthetics and their varieties
• Geocomposites
– A composite material of usually three out of geotextile, geogrid,
geonet, and geomembrane in laminated or other form.
– Good drainage property and used for Prefabricated Vertical
• Geomembranes
– An impervious geosyntheitc material
– Used for checking migration of water(e.g lining of drains/ canals)
• Geomats
– A three dimensional (as opposed to two dimensional geotextile
and geogrid) open mat
– Good drainage property, suitable for draining filling behind
bridge abutment
Geosynthetics and their varieties
• Geocells
– These are formed by connecting HDPE strips in series
to form a pattern of grid in three dimensions, the
width of strips forming the walls of the cells which are
filled with soil/gravel/stones etc
– The confinement provided by cell walls gives strength
– Improves the bearing capacity of weak foundations
• Natural geotextiles
– Naturally growing fibres (like jute) and their strands
form these geotextiles
– Usually biodegradable and used for slope protection
by vegetation
Areas of Application of Geo Synthetics
and predominant properties
Retaining Wall: Strength
Embankment in soft soil: Strength, drainage
Repairs of damaged Pavement: Strength
Slope protection and Erosion Control:
Separation, filtration, aperture size
• Drainage of embankment, subgrade, fill
behind abutment, and surface drains:
Separation, filtration, drainage
Standardization of Geotextile
• Indian efforts:
– 1994: Indian Roads Congress published a State-of-the-Art
Report: Application of Geotextile in Highway Engineering
– 2001: Ministry of Road Transport and Highways included a
chapter in its Specifications (MORTH Specficification for Roads
and Bridges)
– 2002:Indian Roads Congress published Guidelines for use of
Geotextiles in Road Pavements and associated works
– 2011: MORTH Specifications including chapter on Geptextile
under revision
– 2011: IRC Council approved for publication the State-0f-the-Art
Report on use of Jute Geo textile (under print)
– 2011: IRC Council approved for publication Guidelines for the
Deesign and Construction of Geosynthetic reinforced
embankment on soft soils
Standardization of Geotextile
applications (..contd)
• International efforts
– 1995/2010: British Standard BS 8006 Code of
Practice for Strengthened/ Reinforced soils and
other fills was published
– 1998/2001: Federal Highway Administration of US
published a document (Publication No. FHWANHI-00-43) on reinforced soils
General Specifications for Geosynthetic Systems
• Material properties: These are generally specified and accepted if the
material tests are as per standard procedures specified by
American Society for Testing of Materials (ASTM)
International Standardization Organization (ISO)
British Standards (BS)
Accredited laboratories
• Design: This required to be done as per BS or FHWA procedure
• Certification: A certification by the system supplier about conformity
– ISO for manufacturing process
– BBA (British Board of Agreement, AASHTO (American Association of
State Highway and Officials)
– Accredited laboratories
• Warranty:Client seeks a warranty from the supplier
– The warranty can be for as long as for 50 years
Typical geotextile properties
Test Method
Minimum Average Roll Value (MARV) at more than 50% elongation under different
installation conditions
Grab strength
Newton (N) ASTM D 4932
Tear Strength
ASTM D 4533
Puncture strength
ASTM D 6241
Burst strength
ASTM D 3786
Ultraviolet Stability: Not less than 70 % of the above values after 500 hrs exposure
Filtration and separation
Apparent Opening Size (AOS)
ASTM D 4533
> 0.5
per sec
EN ISO 11058
Tensile strength (MD/CMD)
Strain at max strength(MD/CMD)
Indian Test Procedures
• IS 13162 (part2): Test Method for deterioration of
Geotextile for exposure to Ultraviolet Light and
• IS 14324: Test methods for Water Permeability of
Geotextile by Permittivity
• IS 14294: Test Method for Detrming Apparent
Opening Size for Geotextiles
• IS 13162 (Part 4):Test Method for Index Puncture
Resistance of Geotextiles and related products
(Source : IRC SP 59:2002)
Gaps in Design Procedures
• Indian standards on Geotextiles are practically
– One Guideline recently approved by IRC Council
and will be released shortly
• Design, particularly where strength is the main
concern ( like retaining walls, embankment,
pavement rehabiltation) is an involved process
– Design Approach particularly for internal stability
of structures (i.e where geotextiles come into
play) has to be standardized
Gaps in Design Procedures
• Design (..contd)
– Factors of safety, reduction factors, partial factors
etc used in the British and US standards have to
be evolved for our national codes and Guiodelines
• Testing Standards
– There is huge gap in the requirement and
availability of national testing procedures
– An indicative list of subjects on which test
procedures need to be developed are as follows:
Gaps in Design Procedures
• Indicative list of tests
– Determination of friction between the soil and geotextile
reinforcement at different levels of strain
– Determination of vulnerability of geotextiles to chemicals and
microbiological substances present in soil and water
– Detrmination of the effects of creep and long term stability
– Determination of relationship between ultimate strength and design
– Suggesting reduction factors (or partial factors or factors of safety on
the basis of
Manufacturing Process
Serviceability conditions
Installation factors
Temperature variations
Durabilty factors
Construction imperfections
Thank You for your attention