1.

1 Introduction to Geotextiles

Fig: Geo-Textile

Geotextiles are synthetic materials used in civil engineering and construction projects to
enhance soil stability, drainage, and separation between different materials. These textiles are
designed to perform a variety of functions, including reinforcement, filtration, drainage, and
protection, which are essential for the longevity and functionality of infrastructure such as
roads, dams, embankments, and foundations.

Geotextiles are typically made from polymers like polypropylene, polyester, and
polyethylene, and are available in different forms such as woven, non-woven, and knitted
fabrics. Their selection depends on the specific engineering requirements of a project.

1.2 Types of Geotextiles

Geotextiles are categorized into three types based on their manufacturing process and the
way the fibers are arranged to form the geotextile material. Those are:
i) Woven
ii) Non-woven
iii) Knitted
Geotextiles can also be categorized based on the materials used in their construction. Two
major classifications within this are:
i) Fiber-based geotextiles
ii) Fabric-based geotextiles

1.2.1 Woven Geotextiles:

These are made by weaving yarns in a regular pattern, creating a fabric with high tensile
strength. Woven geotextiles are often used in applications requiring high mechanical
strength, such as road construction and retaining walls.
1.2.2 Non-Woven Geotextiles:
Produced by bonding fibers together through needle-punching, heat bonding, or chemical
bonding, non-woven geotextiles are more flexible and typically used for filtration, drainage,
and separation. They are less durable than woven geotextiles but excel in providing filtration
and preventing soil erosion.

1.2.3 Knitted Geotextiles:

These geotextiles are created by interlacing yarns in a loop pattern. They are used in
applications requiring both flexibility and elasticity, often in areas with fluctuating soil
conditions.

Fig : Woven, Non-woven and Knitted Geo-Textile

1.2.4 Fiber-Based Geotextiles

Fiber-based geotextiles are made from synthetic or natural fibers that are either spun,
woven, or bonded together. These fibers give the geotextile its primary structural properties
and are designed to perform specific functions such as reinforcement, filtration, drainage, or
separation.
Key Characteristics:
  Material: Primarily made from synthetic fibers (e.g., polypropylene, polyester) or
natural fibers (e.g., jute, coir, hemp).
 Structure: The fibers may be woven, non-woven, or needle-punched to form the
geotextile.
 Types of Fiber-Based Geotextiles:
o Woven Fiber-Based Geotextiles: Produced by weaving synthetic fibers into a
fabric. These geotextiles are stronger and more durable, often used in
applications requiring high tensile strength.
o Non-Woven Fiber-Based Geotextiles: Produced by bonding fibers together
through heat, chemical bonding, or needle-punching. These are more flexible
and are used for applications like drainage and filtration.
o Natural Fiber-Based Geotextiles: Made from biodegradable fibers like jute,
coir, or hemp. These are typically used for temporary applications, such as
erosion control or slope stabilization in environmentally sensitive areas.

Fig: Natural Fiber Based Geotextile

1.2.5 Fabric-Based Geotextiles

Fabric-based geotextiles are made by weaving or knitting synthetic or natural yarns into a
textile structure, creating a continuous fabric-like material. These fabrics may also be non-
woven but still classified as fabric-based due to their textile-like properties. Fabric-based
geotextiles tend to focus on providing mechanical support, separation, and filtration, with
their performance largely dictated by the type of fabric and method of production.
Key Characteristics:
 Material: Typically made from synthetic fibers (like polyester or polypropylene) but
can also use natural fibers in some cases.
  Structure: Fabric-based geotextiles are primarily woven or knitted fabrics, which
involve the interlacing of threads or yarns in a regular pattern.
o Woven Fabric-Based Geotextiles: These are created by interlacing yarns in a
two-dimensional grid pattern. They offer excellent tensile strength and are
ideal for reinforcement and load-bearing applications.
o Non-Woven Fabric-Based Geotextiles: Created by bonding fibers together
through methods such as needle punching, which forms a fabric-like textile.
These are commonly used for filtration and drainage.

Fig: Fabric Based Geotextile

1.3 Materials Used in Geotextiles

Geotextiles are primarily made from synthetic and natural materials, chosen for their
strength, durability, and suitability for specific applications. Here's a brief overview of the
main materials used:

Synthetic Materials
i) Polypropylene (PP):
o Properties: Lightweight, UV resistant, chemically stable.
o Uses: Reinforcement, filtration, drainage.
ii) Polyester (PET):
o Properties: High tensile strength, durable at high temperatures.
o Uses: Reinforcement, soil stabilization, road construction.
iii) Polyethylene (PE):
 o Properties: Flexible, UV resistant.
o Uses: Drainage, separation, erosion control.
iv) Nylon (Polyamide):
o Properties: High tensile strength, abrasion-resistant.
o Uses: Reinforcement in high-load areas.
Natural Materials
i) Jute:
o Properties: Biodegradable, eco-friendly.
o Uses: Temporary erosion control, slope stabilization.
ii) Coir (Coconut fiber):
o Properties: Biodegradable, rot-resistant.
o Uses: Erosion control, vegetation support.
iii) Hemp:
o Properties: Strong, biodegradable.
o Uses: Erosion control, slope stabilization.
iv) Cotton:
o Properties: Biodegradable, water-absorbing.
o Uses: Temporary soil stabilization.
Composite Materials
 Combination of synthetic and natural fibers for enhanced performance, such as
strength and biodegradability, in specific applications like erosion control or filtration.
Geotextile materials are selected based on the required strength, flexibility, permeability, and
environmental conditions for the project.

1.4 Basic Properties of Geo-textiles:

1. Tensile Strength: Resists stretching.
2. Elongation: Flexibility before breaking.
3. Permeability: Allows water flow.
4. Bursting Strength: Resists pressure.
5. Puncture Resistance: Resists sharp objects.
6. UV Resistance: Withstands sunlight.
 7. Thickness: Affects strength and filtration.
8. Density: Mass per area.
9. Biodegradation Resistance: Resists decay.
10. Thermal Resistance: Withstands temperature changes.
These properties ensure geotextiles perform well in reinforcement, filtration, and drainage
applications.

1.5 Functions of Geotextiles

Geotextiles perform multiple essential functions in civil engineering and construction, which
include:
 Separation: Geotextiles separate different layers of materials (e.g., separating
aggregate from subgrade soil), preventing the intermixing of materials that could lead
to reduced strength or instability.
 Reinforcement: When used as reinforcement, geotextiles enhance the tensile strength
of soil, enabling it to support heavier loads. This is especially useful in road
construction, embankments, and slope stabilization.
 Filtration: Geotextiles allow water to pass through while preventing the passage of
soil particles. This function is vital in applications such as drainage systems and
sediment control.
 Drainage: In drainage applications, geotextiles help channel water through soil or
structures, preventing water accumulation and reducing hydrostatic pressure, which
can lead to structural damage.
 Protection: Geotextiles can act as a protective layer, preventing mechanical damage
to underlying materials, especially in the case of geomembranes or liners in landfills
and reservoirs.
 Erosion Control: When used in conjunction with soil and vegetation, geotextiles
provide effective erosion control in areas subject to wind or water erosion, such as
riverbanks, coastal areas, and construction sites.

1.6 Applications of Geotextiles

Geotextiles are used in a wide range of applications across civil, environmental, and
geotechnical engineering. Some common uses include:
 Road and Pavement Construction: Geotextiles improve the stability and load
distribution of roads, highways, and airports by preventing soil movement and
providing additional reinforcement.
 Fig: Use of geotextile in road and pavement Construction

 Slope Stabilization: Geotextiles prevent soil erosion on slopes, embankments, and

hillsides, stabilizing the soil structure and reducing the risk of landslides or slippage.

Fig: Use of geotextile in slope stabilization

 Drainage Systems: Geotextiles are used in subsurface drainage systems to filter

water and prevent clogging of the drainage pipes. They are also used in stormwater
management systems to control the flow and distribution of water.
 Fig: Use of geotextile in drainage

 Erosion Control: Geotextiles are applied to prevent the loss of soil in coastal areas,
riverbanks, and slopes prone to erosion. They can be combined with vegetation to
enhance soil retention and prevent washouts.

Fig: Use of geotextile in erosion control

 Landfill Construction: Geotextiles serve as protective barriers in landfills,

preventing the infiltration of leachate into the surrounding environment and
supporting waste containment systems.

 Retaining Walls and Embankments: Geotextiles reinforce the structural integrity of

retaining walls and embankments, enabling them to withstand the pressure from
surrounding soil and water.
 Fig: Use of geotextile in embankment and retaining wall

 River, Canals and Coastal Works: Geotextiles protect river banks from erosion
due to currents or lapping. When used in conjunction with natural or artificial
enrockments, they act as a filter.

Fig: Use of geotextile in a canal

 Agriculture: It is used for mud control. For the improvement of muddy paths
and trails those used by cattle or light traffic, nonwoven fabrics are used and are
folded by overlapping to include the pipe or a mass of grit.

 Railway Works: The woven fabrics or the non-woven ones are used to separate
the soil from the sub-soil without impeding the groundwater circulation where
the ground is unstable. Enveloping individual layers with fabric prevents the
material from wandering off sideways due vibrations from running train.
 Fig: Use of geotextile in railway works

 Marine and River Bank Protection: Geotextiles protect river banks from erosion due
to currents or lapping. When used in conjunction with natural and artificial
enrockments they act as a filter. For erosion prevention, geotextiles can be either
woven or non-woven . The woven fabrics are recommended in soils of larger particle
size as they usually have larger pore size. Nonwovens are used where soils such as
clay silt are formed, where hydrostatic uplift is expected, these fabrics must be of
sufficiently high permeability.
 Fig: Use of geotextile in marine and river bank protection

1.7 Advantages of Geotextiles

The use of geotextiles in civil engineering projects offers several significant advantages:
 Cost-Effective: Geotextiles are relatively inexpensive compared to traditional
construction materials like gravel and concrete, making them a cost-effective solution
for many infrastructure projects.
 Environmental Benefits: Geotextiles help reduce soil erosion, minimize material
waste, and reduce the carbon footprint of construction activities. Additionally, many
geotextiles are made from recyclable materials.
 Durability: Geotextiles are resistant to biological degradation, and they are
engineered to withstand environmental stresses such as UV radiation, temperature
fluctuations, and mechanical wear.
 Versatility: With a wide range of available types and materials, geotextiles can be
tailored to meet the specific needs of various applications, making them a versatile
solution in many civil engineering projects.
 Improved Performance: Geotextiles enhance the performance of soil by providing
additional strength, stability, and drainage, leading to improved long-term
infrastructure durability and reduced maintenance costs.


1.8 Challenges and Limitations

Despite their many advantages, geotextiles have some limitations and challenges:
 Sensitivity to Installation: Improper installation, including damage during
placement, improper alignment, or inadequate coverage, can significantly reduce the
effectiveness of geotextiles.
  Environmental Concerns: While geotextiles are generally made from durable, long-
lasting materials, their disposal after the end of their service life can present
environmental challenges. This is especially the case for non-biodegradable materials.
 Chemical Compatibility: Geotextiles may degrade or lose their properties when
exposed to certain chemicals or extreme temperatures, so their use should be carefully
considered in environments where such conditions are present.
 Strength Variations: The strength of geotextiles varies depending on the material,
type, and construction process. It is crucial to select the appropriate geotextile for
each specific project to ensure optimal performance.

1.9 Application of Geo Textiles in Bangladesh:

In Bangladesh, geotextiles are used in several key projects:

1. Riverbank Protection: In the Padma River Protection Project, geotextiles prevent

erosion and stabilize embankments.
2. Road Construction: Used in projects like the Dhaka-Chattogram Highway for soil
stabilization and drainage.
3. Landfills: In the Madhupur Landfill, geotextiles act as liners to prevent
contamination.
4. Flood Control: In the Southwestern Flood Control Project, geotextiles stabilize
embankments and reduce erosion.
5. Agriculture: In greenhouse farming in Barisal, geotextiles help with weed control
and moisture regulation.
6. Slope Stabilization: In the Chittagong Hill Tracts, geotextiles prevent landslides
and stabilize slopes.
7. Irrigation: Used in irrigation projects in Jessore and Khulna to improve water
filtration and soil separation.
8. Embankment Protection: In Padma and Jamuna River Embankments – Geotextiles
were applied to prevent soil erosion and improve the stability of embankments along
these major rivers, which are prone to high water flow and frequent erosion.
9. Drainage and Filtration: In flood-prone areas like the Brahmaputra River,
geotextiles have been used to facilitate drainage and prevent water buildup behind
embankments, reducing the risk of failure due to excessive pressure.
10. Use in Dams: Geotextiles were used to enhance the stability of the Karnaphuli Dam
by reinforcing the embankment structure and preventing the mixing of the soil layers.
In Ganges Barrage Embankments – Geotextiles have been used to protect the
embankments and dam walls from erosion due to high water flows, preventing soil
loss and maintaining the structural integrity of the dam.
Geotextiles help with erosion control, soil stabilization, and sustainable development in
various sectors across Bangladesh.

1.10 Jute Geo Textile:

Jute geotextiles are fabric-like materials made from natural jute fibers, which are
biodegradable and eco-friendly. These geotextiles are used in a wide range of civil
engineering and environmental applications due to their ability to stabilize soils, prevent
erosion, and enhance soil drainage.
Jute geotextiles offer a sustainable alternative to synthetic materials like polypropylene and
polyester geotextiles.
Jute geotextiles are widely used in Bangladesh due to the country's abundant jute production
and the material's environmental benefits.

Fig: Jute Geotextile

1.11 Advantages of Jute Geotextiles

 Eco-friendly: Fully biodegradable, reducing environmental impact compared to
synthetic alternatives.
 Sustainability: Supports the local economy, particularly in countries like
Bangladesh, where jute is a major crop.
 Effective in Erosion Control: Ideal for soil stabilization and erosion prevention in
flood-prone and coastal areas.
 Cost-effective: More affordable than synthetic geotextiles, especially in regions
where jute is grown locally.
1.12 Collected Pricelist
Observed Sample from Siraj Tech:

PSF 250 GSM PSF 550 GSM

PSF 350 GSM PSF 400 GSM

 Geo-textile Price (BDT) per sqm
product rate
according to
PWD
Geo-textile Product Dhaka, Chattogram, Khulna, Rajshahi,
product type Mymensing Sylhet Barisal, Rangpur
Gopalganj
Natural Fibres Jute Hessian 30 30 30 30
(Biodegradeble) (500 GSM)
Synthetic Fibers Polyprophylene 113 113 113 113
(Non- (200 GSM-2mm)
Biodigradable)

Cost of Geo-Textiles Products (According to PWD schedule of Rates 2022)

Comparison Between Collected Prices and PWD Rates

Geo-textile Price (BDT) per sqm

product rate
Geo-textile Product Siraj Tech PW(Dhaka, PWD( PWD( PWD(
product type Mymensing Chattogram, Khulna, Rajshahi,
) Sylhet) Barisal, Rangpur)
Gopalganj
)
Natural Fibres Jute Hessian 60 30 30 30 30
(Biodegradeble) (500 GSM)
Synthetic Fibers Polyprophylene 75 113 113 113 113
(Non- (200 GSM-2mm)
Biodigradable)