What Is a Geotextile?
Geotextile, also known as geotextile, is a water-permeable geosynthetic material made of synthetic fibers by needling or weaving. Geotextile is one of the new materials, geosynthetics. The finished product is cloth-like, with a width of 4-6 meters and a length of 50-100 meters. Geotextiles are divided into woven geotextiles and non-woven filament geotextiles.
- Geotextile has excellent
- Specifications and parameters
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| 250 | 300 | 350 | 400 | 450 | 500 | 600 | 800 | Remark |
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| 8 | 8 | 8 | 8 | 7 | 7 | 7 | 7 | 6 | 6 | 6 | |
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| 0.9 | 1.3 | 1.7 | 2.1 | 2.4 | 2.7 | 3.0 | 3.3 | 3.6 | 4.1 | 5.0 | |
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| -0.5 | |||||||||||
| 4 |
| 2.5 | 4.5 | 6.5 | 8.0 | 9.5 | 11.0 | 12.5 | 14.0 | 16.0 | 19.0 | 25.0 | Aspect |
| 5 |
| 25 100 | |||||||||||
| 6 |
| 0.3 | 0.6 | 0.9 | 1.2 | 1.5 | 1.8 | 2.1 | 2.4 | 2.7 | 3.2 | 4.0 | |
| 7 | Equivalent Aperture 0 (0), mm | 0.07 0.2 | |||||||||||
| 8 |
| Kx (10 10) | K = 1.0 to 9.9 | ||||||||||
| 9 |
| 0.08 | 0.12 | 0.16 | 0.20 | 0.24 | 0.28 | 0.33 | 0.38 | 0.42 | 0.46 | 0.60 | Aspect |
- 1) Specifications are based on mass per unit area. When the actual specifications are between the adjacent specifications in the table, the corresponding evaluation indicators are calculated by interpolation; when the actual specifications are outside the range in the table, the evaluation indicators are determined through consultation between the supply and demand parties.
2) The standard value is according to design or agreement.
3) The above technical data is subject to change without notice.
4) Other specifications can be produced according to user requirements.
- I. Treatment of old pavement 1. The old pavement should be cleaned of dust, loose particles and sundries, cleaned and the surface kept dry. Sharpen and abrupt parts of the pavement shall be leveled. For severely damaged and broken pavement, the broken part shall be removed and repaired with asphalt concrete. For pavements with severe cracks or ruts, a leveling layer of 1 to 2 cm needs to be laid.
2. When spreading asphalt viscous layer oil, viscous layer oil is liquid petroleum asphalt, the atmospheric temperature is above 5 ° C; when viscous layer oil is used as emulsified asphalt, the atmospheric temperature is above 10 ° C. When the road surface is wet on rainy days or after rain, do not spray with sticky oil. Pay attention to the selection of the type and amount of viscous oil. Practice has proved that it is best to use EVA or SBS modified asphalt, these products have good crack resistance and thermal stability. If emulsified asphalt is used, its asphalt content must be greater than 60% to make good use of it.
Before laying the geotextile, spray the asphalt sticky layer again, the amount is about 0 · 4 0 · 6kg / m2, then spread the geotextile, and then sprinkle a layer of the same type of sticky oil on the geotextile, the amount is about 0 5 0 6kg / m2. Attention should be paid to the following points: (1) It is recommended to use a hot asphalt adhesive sleeve, and the oil temperature should be maintained between 150 and 170 ° C; (5) The lateral range of the sprayed adhesive layer oil is 5-10 cm wider than the geotextile; The layer of oil should be sprayed evenly and the measurement should be accurate.
If a single pouring is used, the total amount of viscous layer oil cannot be reduced. The recommended value is 1 · 0 1 · 3kg / m2, and the oil temperature cannot be lower than 180 . One-time oiling is prone to impregnation of the geotextile and delamination, which will cause the surface layer to peel off.
- 2. Laying and overlapping of geotextiles 1. Geotextiles should preferably be laid by machines or manually. When laying, care should be taken so that the rough side of the singe is facing up, and then one end is fixed with a fixture and tightened mechanically or manually. The tensile elongation rate is about 1.0% to 1.5%, and it is straight and tight. Lay forward against the road.
The holder includes a fixing nail and a fixing iron sheet. Cement nails or shot nails should be used for the fixing nails, and the nail length is 8 to 10 cm; iron rods with a thickness of 1 mm and a width of 3 mm can be used for the fixing iron.
2. The geotextile overlaps about 4 to 5 cm in the transverse direction. According to the paving direction, the rear end is pressed below the front end, cemented with hot asphalt or emulsified asphalt, and fixed with a fixture; the longitudinal overlap is also about 4 to 5 cm. It can be dried directly with bonding oil. The overlap is too wide, the interlayer at the overlap becomes thicker, and the binding force between the surface layer and the base layer is weakened, which may easily cause the surface layer to bulge, detach, and displace. Therefore, the overlapped area should be cut out.
3. The geotextile should be laid as straight as possible. When it is necessary to turn, cut the bend of the fabric, lay it on top of each other and spray with a layer of oil cement. Wrinkles should be avoided as much as possible. If wrinkles occur during laying (wrinkle height> 2cm), the wrinkles in this part should be cut, then overlapped in the laying direction, and connected with adhesive oil.
4. When the geotextile is laid, spray the asphalt sticky layer of oil a second time and cool it for about 2 hours. After that, the appropriate amount of fine yellow sand should be thrown in time to prevent the vehicle from passing over the geotextile due to the wheel sticky oil or Destroyed, the amount of fine sand is about 1 ~ 2kg / m2.
- Construction of asphalt surface course 1. The construction method of asphalt surface course is the same as that of ordinary asphalt pavement surface. The design of pavement structure and thickness should adopt the "Code for Design of Highway Asphalt Pavement" (JTJ014) or "Technical Specification for Highway Maintenance" (JTJ073) ) Prescribed method. The thickness of the asphalt overlay is generally 4 to 6 cm on the old asphalt concrete pavement.
When paving the asphalt mixture, the paving temperature must be strictly controlled!
If the temperature is too high, the concrete will burn easily; if the temperature is too low, the compaction will be affected.
2. Road compaction treatment
- The application of geotextiles abroad has begun as early as the 1960s. The United States is the country with the largest consumption of geotextiles in the world. In the early 1990s, its annual usage was more than 300 million m 2 and the usage reached 700 million m 2 . Geotextiles in Europe and Japan have also developed rapidly. The annual usage of European geotextiles is also about 400 million m 2 , of which spunbonded nonwovens account for about 60% of non-woven geotextiles. The use of geotextiles has grown significantly. The largest amount of non-woven geotextiles in Japan is spunbond, which accounts for about 60% of the total number of non-woven geotextiles, and is mainly PET spunbond.
- China's geotextiles started in the early 80's, but the amount used at that time was very small, only experimental applications. It was not until 1998 that the catastrophic flood caused the government's attention. The construction sector included the application of geotextiles in design specifications and formulated relevant national standards. Only then did geotextiles receive real attention and development. The amount of geotextiles in China has exceeded 300 million m 2 , and non-woven geotextiles account for about 40% of the total. China's civil engineering construction has a huge potential market, and its potential will never be lower than the US's 700-800 million m 2 of consumption. Experts estimate that China's geotextiles will continue to grow in double digits in the next 15 years. The fastest growth rate is PET spunbond filament geotextiles.
- During the Tenth Five-Year Plan period and the Eleventh Five-Year Plan period, China plans to invest heavily in various projects such as water conservancy, electric power, transportation, environmental protection, river management and other projects, including water conservancy construction, south-to-north water diversion project, power investment, highway and railway Construction and environmental engineering, as well as projects such as ports, airports, garbage treatment, rivers and lakes treatment, sand control, etc., have invested over trillion yuan. In the next 10 years or more, China will have more infrastructure projects to build and the demand for geotextiles will increase. China will become the world's largest market for geosynthetics.
- Main areas of hydraulic engineering:
- Reaching standards for sea, river and lake embankments; reservoir reinforcement projects; reclamation projects; flood control and rescue.
- Application of geotextile in hydraulic engineering
- Highway and railway air port project: soft foundation reinforcement treatment; slope protection; pavement anti-reflection crack structure layer; drainage system; green isolation zone.
- Electrical Engineering:
- Nuclear power plant basic engineering; thermal power ash dam project; hydropower station engineering.
- other information:
- The good air permeability and water permeability of the geotextile are used to allow water flow to pass through, thereby effectively retaining sand loss.
Geotextile has good water conductivity, it can form drainage channels inside the soil, and drain excess liquid and gas from the soil structure.
Effectively spread, transfer or decompose concentrated stress to prevent soil from being damaged by external forces.
Prevent the mixing of sand, gravel, soil and concrete in the upper and lower layers.
High water permeabilityunder the pressure of soil water, it can still maintain good water permeability.
Corrosion resistanceusing polypropylene or polyester as the raw material, acid and alkali resistance, non-corrosion, no moth-eaten, and oxidation resistance.
Simple constructionlight weight, easy to use, and simple construction. [3]