Usually constructed of polyester or polypropylene, geotextiles are. Depending on the intended usage, the fibers used to manufacture geotextiles are either natural or synthetic.
The most common forms of natural fibers include paper strips, wood shavings, jute nets, and wool mulch. Geotextiles must survive for over a century in some soil reinforcement applications. However, biodegradable natural fabrics are designed to decompose quickly. They are typically employed to stop soil erosion while waiting for the region to become vegetated.
Natural Fiber Geotextiles: Types
Jute is a multipurpose vegetable fiber that is very biodegradable, blends well with the soil, and offers nutrients to the flora. When utilized as a geotextile, rapid biodegradation, however, also presents a drawback. Nevertheless, different treatments and mixing can extend its longevity to up to 20 years. As a result, customized biodegradable jute geotextile can be produced with desired tenacity, porosity, permeability, and transmissibility depending on the demand and location. The application and the choice of jute geotextile to employ will be determined by factors such as the amount of water available, soil composition, water flow, and water quality, among others.
A form of natural fiber known as “coir,” commonly referred to as a “Coir mat,” is made from the natural fiber extracted from the coconuts’ outer husk. Frequently, these materials are used to create brushes, mattresses, doormats, and turf reinforcement mats (TRM). Since coconut fiber is natural, many people prefer using it to synthetic fiber since it is more resilient and less susceptible to harm from saline water.
Synthetic fibers including polyamide, polyester, polyethylene, and polypropylene are frequently utilized as raw materials for geotextile fabrics. The last one, which was discovered in 1931, is the oldest synthetic fiber. The “needle-punching” method, which is illustrated below, is used to create several nonwoven fabrics from synthetic fibers.
Types of Geotextiles Made of Synthetic Fiber
PA, or polyamide: Nylon 6 and Nylon 6.6, two further subcategories of polyamide, are hardly ever utilized in geotextile fabrics. The first polyamide (Nylon 6) was created through the polymerization of caprolactam, a petroleum product. Hexamethylene diamine and the salt of adipic acid are polymerized to create the second form of polyamide. They are created in the form of thin threads, which are subsequently divided into granules. Comparing the resulting goods to polyester and polypropylene, they typically have lower moduli but substantially greater strength. Additionally, they are vulnerable to hydrolysis.
By polymerizing ethylene glycol with either terephthalic acid or dimethyl terephthalate acid, polyesters (PSF) are created. The end material has a significantly higher strength modulus, skulk resistance, and general chemical inertness, making it ideal for use in geotextile fabrics. At pH levels between 7 and 10, it can survive up to 50 years, however polar solvents like phenol, benzyl alcohol, and meta-cresol can impact how long it lasts. High UV resistance is a feature of this geotextile material. To avoid unnecessary exposure to UV rays, however, it should be installed carefully.
Polyethylene (PE): PE can be produced in crystalline form, which is a need for any polymer that forms fibers. Low density (LDPE), linear low density (LLDPE), and the widely used high density are the three primary forms of polyethylene (HDPE). A handful of Root Barriers or Bamboo Barriers contain HDPE as well.
Polypropylene (PP) is a crystalline thermoplastic created when propylene monomers are polymerized using the Zeigler-Natta catalyst.
What distinguishes woven geotextiles from non-woven ones?
On a loom, textiles are combined and weaved into a single, even length to create woven geotextile fabrics. The finished product is extremely well-equipped to withstand any ground stability issues in addition to being strong and resilient, which makes them great for applications like parking lots and road constructions.
The produced goods don’t offer the best separations against particles and are only moderately impermeable. To be more suitable for long-lasting applications, woven geotextile will resist any UV deterioration.
Most often, tensile strength and strain, which represent the material’s resistance to breaking stress, are used to measure woven geotextiles.
Woven geotextile fabrics offer drainage by allowing water to permeate while removing any sediments that can obstruct the rest of the drainage system. They serve as a barrier between the materials above and below the textiles, protecting the construction project from erosion.
Although all geotextiles are capable of carrying out each of these activities, filtering, draining, separating, strengthening, waterproofing, and protecting are the six main functions of a geotextile. For various duties related to the road construction project, several textiles are needed. You must start with your end goal in mind in order to choose the best geotextile for your building project.
Although a variety of materials can be used to make woven textiles, weave or yarn-blend is normally the most popular. When finished, woven geotextiles typically look like plastic sheets; the weaving is only noticeable under careful inspection. The aim of your construction project will determine whether you require a medium- or lightweight weave.
Strength is the first objective when using woven geotextile, and impermeability is a huge value. Having said that, it might be a drawback when drainage is crucial since its tightly woven tapes prevent water from penetrating the materials’ deeper layers.
More effective materials have been produced over time as a result of the development of woven geotextiles. By providing confinement, separation, and reinforcement, these new advances have improved flow rates and raised interaction coefficients, making them more suited for practically all civil applications. They also make considerably better drainage and filtration possible.
*Take note that high-performance woven fabrics are now available; they permit both high strength and drainage.
Nonwoven geotextiles are made by tying together long and short fibers using needle punching or other suitable techniques. Thermal treatment is sometimes utilized to further increase the tensile strength of the geotextile. Non-woven geotextiles are often employed in drainage applications, separation, filtration, and protection because of this manufacturing technique and their permeability.
In order to create needle-punched non-woven fabrics, a lot of microscopic textiles are typically taken and meshed together with a barbed needle.
Also Read: Trails made of geotextile material. Benefits and applications.
Non-woven geotextiles are typically weighed and then measured in terms of their weight, such as gsm (grams per square meter) or oz/sq yd.
Generally speaking, non-woven geotextiles degrade more quickly than woven geotextiles. However, non-woven fabrics are typically the ideal option for construction projects when water pooling is the main problem as they offer improved drainage.
When comparing the material parameters, it can be challenging to distinguish between woven and non-woven geotextiles. However, non-woven geotextiles have substantially higher flow rates while woven geotextiles are typically produced with stronger strength.
Setting the fabric apart
Examining the elongation is the simplest approach to distinguishing between the two textiles. The elongation of non-woven geotextiles is often substantially higher than that of their woven counterparts. While woven geotextiles list elongation as low as 5% and 25%, non-woven geotextile specifications will list elongation as superior to 50%. This is occasionally not even listed.
People sometimes misunderstand the weights of woven and non-woven materials while attempting to identify their differences. Because woven geotextiles are typically employed to provide separation and reinforcement and are not weight dependent, their weight is rarely reported.
Contrarily, the weight of non-woven geotextile is a common way to distinguish one material from another. Nonwoven textiles are frequently referred to by their weight in ounces per square yard, such as 4oz, 6oz, 8oz, and so on. The fabric is more durable the higher the weight.
Since the weight of geotextiles has always been used as a standard, a finished fabric would weigh 8 oz per square yard. The weight of the product would directly affect the other two specifications, which are strength and puncture.
What is the geotextiles’ history?
Filter fabrics were the initial name for geotextiles. While a lot of people think that R.J. Berrett invented geotextiles in the 1950s, the truth is that these materials have a long history. Geotextiles were frequently employed in the construction of roads during the time of the pharaohs to provide better solidity on the roads and their edges.
According to some estimates, geotextiles were some of the first textile items ever utilized by humans. The use of grass mats and linen has been discovered at numerous Egyptian excavation sites. In the past, geotextiles were created using natural fibers or a blend of dirt and plant to increase the stability of roads.
Today, how are geotextiles used?
The use of geotextiles is widespread in modern construction. They are used to manage hillside erosion on applications for roads, railways, harbor works, sewers, and breakwaters. Separation, stabilization, reinforcement, filtration, moisture barrier (or waterproofing), and drainage are some of the most typical uses for geotextiles.
Also Read: Rehabilitation of Flood-Damaged Roads and Infrastructure: Geosynthetics
There are six uses for geotextiles:
1. Dissolution
Between two layers of various materials, such as two distinct types of soil, new construction, and dirt, or new and old pavement, the fabric is placed. Although there are subtle differences, separation and stabilization are sometimes used synonymously.
2. Stabilization
In stabilization, the fabric is placed on top of a highly compressible substance. This substance is typically soft, moist earth. Here, the geotextile allows water to percolate through the porous soil and into the drainage material. As a result, the basement layer is strengthened and made into a more reliable base by consolidating it.
3. Strengthening
In contrast to stabilization, where the geotextile strengthens the bottom layer, reinforcement uses the geotextile as a source of strength. The following applications for geotextile as reinforcement material are typical:
Slopes that are steep allow for the construction of slopes that are even steeper while conserving the necessary land surface and sealing materials.
Retaining walls: In this application, geotextile materials for retaining walls are far more successful in accommodating settlements than conventional building materials.
Control sea embankments and bay shoreline erosion.
hydraulic fill-in land reclamation
4. Filtering
Similar to stabilizing, geotextile infiltration is used. In both situations, allowing water to escape from the covered layer is the primary goal. This application’s objective is to drain water while obstructing the passage of any fine particles, including soil. Combining a filter behind the geotextile fabrics allow for this. Instead of being filtered into a different material, water is taken out during this process.
5. Waterproofing
This application is virtually exactly the opposite of the ones mentioned above. The geotextile fabrics are utilized in the moisture barrier to stop water instead of allowing it to pass through. Applying an asphaltic suspension achieves this. The cloth is thereby made impermeable and appropriate for use in construction tasks like paving restoration.
6. Drainage
In order to provide seamless transmission, geotextile material can help collect water or gas and then move it along its plane. This procedure, which is also known as the drainage function, can be quite useful in drip drains as well as chimney drains.
Resources:
Technical Paper by Dr. Bipin J. Agrawal. “GEOTEXTILE: IT’S APPLICATION TO CIVIL ENGINEERING – OVERVIEW,” accessed January 2020 Engineering College B.V.M.
2. Geosynthetics History, “https://en.wikipedia.org/wiki/Geosynthetics,” accessed January 2020
