Over the course of the last century, there has been a consistent rise in the application of geotextiles. In the beginning, geotextiles were derived from pre-existing textiles that were easily accessible on the market. Some examples of these textiles include carpet back and upholstery fabric. The manufacturers of geotextiles have improved their products so that they now offer increased benefits to the construction of roads. In spite of the fact that there are two primary types (wovens and nonwovens), there is frequently still some confusion regarding which product you should use on your Jobsite. Typical misunderstandings regarding the functions of a woven geotextile versus those of a nonwoven geotextile frequently contribute to an increase in the level of confusion. This technical note will provide an in-depth discussion of the two most common types of geotextiles as well as the purposes they serve.
Woven geotextiles: The first woven geotextiles were made of slit tapes and were of the first generation.
1. Slit tapes are flat yarns that have been extruded and then woven at an angle of ninety degrees to produce a strong fabric
2. They have low soil interaction properties and very poor water permittivity because of their wide, smooth surface
3. Due to these factors, they are not a good option for use in civil applications, particularly in moist environments
The evolution of high-performance woven geotextiles has, over the course of time, resulted in the production of a material that is more efficient. These advancements have higher interaction coefficients and higher flow rates, which makes them much more suitable for civil applications by providing separation, confinement, and reinforcement. In addition, the flow rates have increased significantly. They also make it possible to have improved drainage and filtration.
Nonwoven Geotextiles:
Geotextiles that are nonwoven are created with a synthetic textile, just like woven geotextiles. However, because of the way the fibers interlock, they have a structure that is more chaotic than other materials. Both woven and nonwoven materials are used for applications that are very similar, which can lead to confusion. The physical characteristics of a geotextile can be used to differentiate between woven and nonwoven geotextile fabric varieties in the quickest and most direct way. Geotextiles made of materials have the appearance and texture of felt, right down to the characteristic fluffy appearance of the material.
There are a great deal of distinct approaches that can be taken in the production of nonwoven geotextiles in the modern era. Needle-punching is the most common method used in the manufacturing process. The production of needle-punched nonwoven geotextiles involves taking a large number of small fiber fibers and using a barbed needle to interlock the fibers together in order to create the geotextile. When used in a civil application, nonwoven geotextiles are typically put to use to provide separation, in addition to filtration and drainage functions.
When looking at material specifications, it can be difficult to differentiate between woven and nonwoven geotextiles because of the similarities between the two types. In general, the strength values of woven materials are higher, while the flow rates and permittivity of nonwoven materials are higher. The elongation of one of the materials is the best place to begin when attempting to differentiate between the other two materials. The elongation of a nonwoven fabric will be significantly greater than that of a woven fabric. If the elongation is listed at all, a nonwoven material's specification will state that it is greater than 50%, while a woven material's specification will state that it is between 5% and 25%, if it is listed at all.
The chart that follows provides two examples of standard specifications for traditional woven materials and nonwoven geotextile fabric materials, respectively. There are substantial differences between them in terms of both their elongation and their permittivity. On the other hand, given that they are made from the same kinds of materials, the tensile strengths are comparable. When selecting the type of geotextile that is most suitable for your application, it is essential to take into account all of these factors. It is of the utmost importance to check that you are utilizing the appropriate product for the appropriate reasons.
Weight of Nonwovens When comparing woven geotextiles to polyester nonwoven geotextile fabric, one of the differences that can be confusing to people is how heavy each type of material is.
Both of the examples that follow lack a listing for the weights. There is almost never any mention made of the weight of a woven geotextile. The reason for this is that they are typically used to provide separation and reinforcement, and their function is unrelated to the amount of weight present.
On the other hand, the weight of a nonwoven geotextile is frequently specified. This is the reason why you will typically hear or say something along the lines of "I am looking for an 8 oz, 4 oz, 10 oz, etc."Nonwoven geotextiles have been measured in terms of their weight for a significant amount of time. This indicates that the finished product would be 8 ounces per square yard. The remaining aspects of the specifications, such as the strength, puncture resistance, and so on, would be an indirect consequence of the product weight.
The production methods for geotextiles have evolved to keep up with the expanding and developing field of use for these materials. The majority of nonwovens can now be manufactured with a lower weight while still achieving the same level of strength, which results in cost savings. There is always an exception to the rule, such as when nonwovens are used as cushion geotextiles underneath geomembranes. This is just one example. In situations like these, the properties of weight, thickness, and puncture resistance are more important than the properties of permittivity and strength.
