Coir Bhoovastra (Geotextiles) for Civil Engineering ... Fibre...آ  27-07-2016 1 27 July 2016 Coir Geotextiles

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    27 July 2016 1 Coir Geotextiles G V RAO

    Coir Bhoovastra (Geotextiles)

    for

    Civil Engineering Applications – Experiences & Potential

    Dr. G.Venkatappa Rao

    Guest Professor, Indian Institute of Technology, Gandhi Nagar

    Chairman Saimaster Geoenvironmental Services P Ltd

    Hyderabad

    Historical

    • Use of coconut leaf mattresses in Kerala in road construction

    • Dragging a bogged down vehicle using leaves, brushes etc

    • Cordruoy roads using tree trunks packed next to one another and levelling with gravel for traffic in forest areas

    • Natural erosion control by vegetation – turfing, trees etc

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    Coconut groves

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    COIR FIBRE

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    Coir – Essential features

    Coir fibres length : 50 --150 mm  diameter : 0.2 – 0.6 mm High production in India : Social welfare Woven coir geotextiles and non-woven coir blankets :Erosion control

    Biodegradability : 5 years life in saturated condition

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    DURABILITY

    • BUNDENSTAT’S results:

    Whereas cotton degrades totally in six weeks and jute in 8 weeks, coir has retained 2% strength even after one year, and

    It takes 15 times longer than cotton and 7 times longer

    than jute to degrade.

    • The growth of micro -organisms depends on their chemical composition. The longer resistance of coir due to its high lignin content (about 35%) compared to say 12% for jute.

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    RAO 14

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    SEM MICROGRAPH OF COCONUT HUSK

    COIR FIBRE BROKEN IN LIQUID NITROGEN

    CLOSE UP VIEW OF SAME COIR FIBRE 27 July 2016 Coir Geotextiles G V RAO 15

    H2M6

    400gsm

    H2M5

    700gsm

    H2M9

    900 gsm

    Coir woven geotextiles

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    Property Coir geotextile

    Roll width (m) Roll length (m) Roll weight (kg) Runnage of yarn

    Aperture size (mm*mm) Thickness (mm)

    Mass per unit area (g/m*2) Tensile strength m/c (kN/m)

    %Elongation m/c Tensile strength X-m/c (kN/m)

    % Elongation X-m/c Initial tangent Modulus at 5 mm

    deformation (kN/m)

    E 1.2 25 10

    45*30

    7.3 335 3.86 20 2.5

    27.5 30

    F 1,2,4

    50 1/20,2/40,4/80

    240 25*25

    6.7 360 6.34

    19.17 4.38

    31.67 48

    G 1,2,4

    50 1/35,2/70,4/140

    240 6.25*6.25

    8 610

    10.63 31.67

    7.5 26.25

    46

    H 1.2 24 42 7*4 9.5 1335 31.50 42 12.73 18 100

    Physical and mechanical properties of woven Coir geotextiles

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    Non-woven coir geotextiles

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    Non-woven coir geotextiles - types

    Studies carried out

    at

    Indian Institute of Technology,

    New Delhi Venkatappa Rao, G., Dutta, R. K. and Balan, K.

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    Property Non-woven coir geotextiles

    Roll width (m) Roll length (m) Roll weight (kg) Thickness (mm)

    Mass per unit area (g/m*2) Tensile strength m/c (kN/m)

    %Elongation m/c Tensile strength x-m/c (kN/m)

    % Elongation x-m/c Initial tangent Modulus at 5 mm

    deformation (kN/m)

    A 2.2 25 33 12

    865 7.6 11.3

    3 9.7 68

    B 2.2 25 22 8.9 420 1.7 35 0.8

    15.8 10

    C 2.2 42 69 9 750 2.3 27.5 0.7 19.2 13.8

    D 2.0 25 50

    13.6 1175 15.4 27 8.3 24 49

    Physical and mechanical properties of non-woven coir geotextiles

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    Strength reduction for coir when submerged in soft saturated clay

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    APPLICATION POTENTIAL

    1. Erosion Control

    2. Rural Roads

    3. Road Edge Drains

    4. Silt fence

    5. Ground Improvement

    6. Reinforcement

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    RILL and GULLY SLOPE

    EROSION

    EROSION

    CONTROL

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    EROSION

    • Surface Soil Erosion - dislodgement of soil particles and their transportation down slope as a series of events...

    • Erosion control - restraining the initial movement of soil particles by wind and water.

    • An effective erosion-control material will reduce the impact of raindrops on the soil and impede overland water flow.

    • So, fewer soil particles become dislodged during rainfall. • Slowing the flow of water down slope accomplishes two things

    1. Reduction in the transport capacity of the thin sheet flow , thereby minimising the displacement of dislodged soil particles,

    2. Infiltration of more rainfall into the soil, providing desirable

    moisture to newly planted seedlings.

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    • ROLLED EROSION CONTROL PRODUCTS (RECPs).

    Expected to serve mitigation of erosion both in the short term as well as long term

     through the establishment and maintenance of vegetation cover

    Such solutions are also known as Biotechnical Engineering Solutions.

    • Before the advent of RECPs MULCHING has been in use for acceleration of vegetation establishment.

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    Rolled Erosion Control Product

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    Being

    installed in a ditch

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    Figure illustrates the overlap provisions schematically.

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    Additional anchorage is achieved by installing a row of staples along the crest and toe

    Bridge across Vasista Godavari – Chinchinada, W.G.Dt., A.P.

    • 20 m – 25 m thick black cotton soil deposit • 12m high embankment • Basal Geocell Mattress • 3 m high reinforced soil wall • Erosion control Blanket in place of pitching

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    ROLLED EROSION CONTROL PRODUCTS

    • These products can be classified as:

    I. Erosion Control Nettings (ECN)

    II. Erosion control meshes (ECM)

    III. Erosion Control Blankets (ECB) with single/double net

    IV. Geosynthetic (polymeric) Mattings or Turf Reinforcement Mats (TRM)

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    EROSION CONTROL TECHNOLOGY COUNCIL (ECTC) CLASSIFICATION

    Low velocity degradable RECPs

    High-velocity degradable RECPs

    Long term nondegradable RECPs

    ECPS HAVE MAJOR APPLICATIONS IN:

    • Shore-line stabilization • Beautification of lakes and ponds • Landscaping and Golf Courts • Plant and tree protection systems • Sand dune stabilization • Ski slope and high altitude vegetation • Protection and revegetation of waste dumps • Wasteland development • They could also be highly useful in controlling dust and

    vegetating ash-pond dikes and dams with ore tailings.

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    CSEB - KORBA SITE (Gar-mat with grass turfing)

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