Geotextiles are permeable synthetic cloths with the ability to separate, filter, seal, reinforce and protect the soil. These fabrics are often used in civil construction projects to improve soil stability and reduce erosion. Thus, they allow construction projects to take place in areas that would otherwise be unsuitable.
The 2 common types of fabrics include woven and non-woven materials.
Progress ABMS is the leading building material supplier in Singapore with a range of geosynthetic products.
Functions of Geotextile
- Separation
Placing these between two layers of different materials can help to prevent them from intermixing.
- Filtration
The permeable nature of this material allows it to be used for filtration. This limits the loss of soil while allowing water to flow through freely.
- Sealing
When geotextiles are placed between layers of old and new asphalt, they are able to absorb the asphalt and become an impermeable layer. This helps to reduce the amount of vertical water flowing to the pavement structure.
- Reinforcement
By placing geotextiles within a weak layer, the tensile strength of that layer increases by a great deal. They are good fill materials as they have high soil fabric friction coefficient and tensile strength.
- Stabilisation
When placed on compressible material, they allow water to pass through and into a more freely draining material. This strengthens the bottom layer and stabilises the base.
- Protection
This material is able to protect synthetic membranes from being damaged as it is puncture resistant and able to withstand high pressure.
Advantages of Geotextile
- Multi-functional
This material has 6 main functions when used in association with soils: filtration, drainage, reinforcement, cushion, waterproofing and separation.
- Excellent filter for civil engineering
These fabrics work as an excellent filter and are able to separate water from larger soil particles.
- Ability to withstand or overcome adverse conditions or rigorous testing
Non-woven variations have superior strength and are resistant to tear and puncture.
- High resistance for long term usage
Their high resistance to chemicals, bacteria and fungi allow them to be used for a long time.
- Reduces soil erosion
While gabions and gabion walls reduce soil erosion by lowering the water velocity, geotextiles offer the same advantage of erosion control by increasing the stability of loose soil.
Common Applications of Geotextile
This material is commonly used for civil engineering purposes and are ideal materials for many infrastructure works such as the following:
- Landscaping
- Harbours
- Landfills
- Drainages
- Roads and railways
- Pipeline construction
How To Choose The Right Geotextile
There are a few factors to consider when choosing the right material for your project. The two main factors are:
- Size of rock fill
- Type of soil
Soil can be generally classified as soft or firm. If the soil is soft, it would require a stronger material to hold the rocks in place. On the other hand, if the soil is firm, a thinner one can do the job.
Here’s a gauge of the class that may be suitable:
| Rock Size | Soft Soil | Firm Soil |
|---|---|---|
| 0-40mm | Class C | Class A |
| 41-75mm | Class C | Class B |
| 76-200mm | Class D | Class C |
| 201-400mm | Class E | Class D |
| 401-600mm | Class E | Class E |
FAQs About Geotextiles
FAQs About Geotextiles
| Woven geotextile fabric | Non-woven geotextile fabric | |
|---|---|---|
| Manufacturing process | Made by intertwining polypropylene tapes in a crisscross pattern | Made by thermally, chemically or mechanically fusing short-staple fibres or continuous filament yarn |
| Tensile strength | High | Low |
| Water permeability | Low | High |
| Applications | Roads, parking lots, pathways | Soil separation, stormwater drainage systems |
In general, woven and non-woven fabrics are constructed using different processes, where the former is weaved together while the latter may be needle punched (such as polyester fibres) or heat bonded.
Additionally, woven fabrics have a higher tensile strength but a lower water permeability rate as compared to non-woven ones. As such, non-woven ones are often preferred for situations where water drainage is paramount.
Landscape fabric is made from geotextile fabric. However, it has a more limited range of applications.
- Geotextile fabric: Various landscaping projects and drainage systems
- Landscape fabric: Gardens and planting beds as a physical barrier to prevent the growth of weeds
While woven geotextiles typically last up to 20 years, non-woven types can last over 50 years.