What is geotextile? What are the features and differences between woven geotextile and non-woven geotextile? The following article is a detailed introduction to woven geotextile and non-woven geotextile.
Geotextile is a kind of used geosynthetics. There are many kinds and specifications of geotextiles, which can be classified according to different properties. According to the material classification, the geotextile has PP and PET materials. Omit technology, Geotextiles can be divided into woven geotextiles and non-woven geotextiles.
Geotextile has excellent isolation, filtration, and water permeability, and can be used in many fields. Today, we introduce woven geotextiles and non-woven geotextiles and compare the differences between them to help you know them better.
What’s woven geotextile?
The woven geotextile is interlaced by at least two groups of parallel yarns (or flat filaments). We can weave warp and weft yarns into cloth like geotextiles with different weaving equipment and processes. The longitudinal yarn along the loom is called warp yarn, which is also the direction of the fabric. The other group arranged is called weft yarn. Warp and weft yarns can be woven together in different variations of three basic tissues: plain, twill, and satin. Common woven geotextiles include split film woven geotextiles (PP material) and filament woven geotextiles (PP, PET material).
Geotextiles in different applications have many different requirements. Thus, woven geotextiles have different thickness and density specifications. The executive standard of woven geotextile is GBT 17640-2008, and the width is generally 1m-5.2m. 5.2m is the largest width that Chinese factories can produce at present.
Compared with non-woven geotextile, the woven geotextile with the same weight is thinner, that is, the density of woven geotextile is higher. Because the yarn of the spun geotextile is a coarse fiber twisted by many bundles of fibers. Woven geotextiles have quite strong tensile strength in both longitudinal and transverse directions, and generally, the longitudinal tensile strength is greater than the transverse tensile strength, but the two can also be equal. Woven geotextiles have good stability and can meet various uses. Thus, it is used in geotechnical engineering such as rivers, coasts, harbors, highways, railways, wharves, tunnels, and bridges.
What’s non-woven geotextile?
Non-woven geotextile is a kind of geotextile that is formed by long fibers or short fibers that are fixed together in an irregular way without being woven. The process of geotextile comes from heat and pressure. The materials of non-woven geotextile can still be divided into PP and PET. The raw fiber can be divided into long filament and short filament geotextile. The width of a geotextile is generally 1m-6m. Wider geotextiles can also be produced. Yet, due to its lightweight, we recommend the size below 6m.
Here introduce two common non-woven geotextiles.
1. Short-filament needled geotextile
The raw material of short fiber needled geotextile is polyester crimped short fiber or polypropylene fiber, and their length is generally 54-64mm. It is made into cloth by the production process of non-woven production equipment, such as opening, carding, disorderly (short fibers are interwoven), mesh laying (standardized entanglement and fixation), needling, and so on.
The executive standard of short fiber needled geotextile is the executive standard GB/T 17638-2017. It has excellent properties such as acid and alkali resistance, corrosion resistance, aging resistance, high strength, stable size, and good filtration. It can be used for engineering reinforcement, isolation, filtration, and drainage, and is used in water conservancy, highways, railways, and other fields.
2. Long-Filament Geotextile
The executive standard of short fiber needled geotextile is the executive standard GB/T 17639-2008. The width can be 1m-6m.
The long-filament geotextile is made of PP or PET long fibers by spinning and needling consolidation, and the fibers are arranged into a three-dimensional structure. The fiber of the long-filament geotextile can reach several meters long, and the product specification is between 80-1000 g/m2. long-filament geotextiles have better mechanical properties than short-filament geotextiles because of their longer fibers. It also has good vertical and horizontal drainage performance, good extension performance, and high chemical stability performance such as biological resistance, acid and alkali resistance, and aging resistance. At the same time, the long filament geotextile also has a wide range of pore sizes, tortuous pore distribution, excellent permeability, and filtration performance. Thus, long filament geotextiles have been used in the field of infrastructure construction and will be used in a wider range of fields in the future.
Characteristics of long filament geotextile
1. Strength: under the same weight specification, the tensile strength in all directions is higher than that of other needled non-woven fabrics. Anti-ultraviolet light, with high anti-ultraviolet ability.
2. High-temperature resistance: the high-temperature resistance is up to 230 ℃, and the structural integrity and original physical properties are still maintained under high temperatures.
3. Permeability and plane drainage: the long filament geotextile is thick and needle punched, with good plane drainage and vertical permeability, and can still maintain this performance after many years.
4. Creep resistance: long filament geotextile has better creep resistance than other geotextiles, so it has good long-term performance. It can resist the erosion of common chemical substances in the soil and the corrosion of gasoline and diesel oil.
5. Ductility: the long filament geotextile has a good elongation under certain stress so that it can adapt to uneven and irregular foundation surfaces.
Differences between woven geotextiles and nonwoven geotextiles
1. Compared to the raw material fiber, the yarn of woven geotextile is thicker because it is formed by many bundles of fibers. The transverse and longitudinal fibers of woven geotextiles are very regular.
2. Compared to the density, the woven geotextile with the same weight is thinner, that is, its density is higher. For the same length of geotextile roll, the roll diameter of a woven geotextile is smaller and more compact than that of a non-woven geotextile.
3. Compared to the performance comparison, the difference between the woven geotextile and the non-woven geotextile is also obvious. Woven geotextiles have a strong tensile strength in both longitudinal and transverse directions, which is why it is not easy to be pulled, and can better maintain shape. While the looser non-woven geotextile has no such property. In some engineering applications requiring strong tensile strength and supporting force, woven geotextile is a better choice.
4. Compared by the cost. Because the requirements of woven geotextile are higher, the cost is higher than that of non-woven geotextile. Thus, in projects that do not need very high tensile strength, only the permeability and filtration/reverse filtration of geotextile are required, so the selection of non-woven geotextile can meet the needs.
Which is better, woven geotextile or non-woven geotextile
Compared with woven geotextiles and non-woven geotextiles, both have their own advantages and disadvantages, not necessarily which one is better:
- Advantages and disadvantages of non-woven geotextiles
(1) Advantages: good ventilation, strong filterability, good thermal insulation performance, water absorption, waterproof, good stretchability, no mess, good hand feeling, soft, light, elastic, recoverable, no directionality of the fabric, high productivity, Fast production speed, low price, mass production and so on.
(2) Disadvantages: relatively poor strength and durability, cannot be cleaned, easily cracked at right angles, etc.
- Advantages and disadvantages of woven geotextiles
(1) Advantages: high strength can maintain sufficient strength and elongation in dry and wet conditions; corrosion resistance, long-term corrosion resistance in soil and water with different pH levels; good water permeability, there are gaps between fibers, so It has good water seepage performance; good anti-microbial properties, no damage to microorganisms and insects; convenient construction; complete specifications.
(2) Disadvantages: Compared with non-woven geotextiles, the main disadvantage of woven geotextiles is that they do not have the function of filtering (that is, plane drainage), and the relative cost is higher.
In general, the choice between woven geotextiles and non-woven geotextiles mainly depends on the needs of the project. For example, woven geotextiles are more effective than non-woven geotextiles in the reinforcement and reinforcement of geotechnical engineering.
Construction and installation of geotextile
Because woven and non-woven geotextile is still flexible materials, it is necessary to try to avoid a puncture, damage, stretching amount, and other problems in practical application. The following are some precautions for the installation of woven and non-woven geotextiles.
1. Firstly, protective measures will be taken during the transportation and placement of woven and non-woven geotextiles. After the pit is excavated, pay attention to clearing the stones and sundries on the ground, and try to make the construction ground flat and free of sharp hard objects.
2. If stacked, it will be placed flat. Avoid placing in wet or ponded places, because excessive humidity may affect the welding and use of woven and non-woven geotextile.
3. During the laying of geotextile, avoid large impact by an external force. In particular, a puncture may cause damage to the geotextile and cause leakage. If the woven and non-woven geotextile is damaged, it must be repaired or replaced with a new slope. In short, it is necessary to ensure that new and complete geotextile liners are used for construction in the project.
4. All woven and non-woven geotextile products have a certain amount of deformation and expansion. When paving geotextile, a certain deformation space will be reserved to prevent the pad surface from being too tight. Generally, a tensile coefficient of at least 10% will be reserved
5. The woven and non-woven geotextiles are assembled by different slopes, so the joints will be welded or sewn. Note that the width of the overlapped part is generally 7-15cm. The woven and non-woven geotextile must be welded and sewn to ensure that there is no gap, so about ensure the anti-seepage connection effect of the woven and non-woven geotextile.
Shandong Dajin is a professional manufacturer of geotechnical materials. We can provide professional anti-seepage solutions, products, and services. If you have any questions about geotextiles and geomembranes, please do not hesitate to contact us. Looking forward to your visit!