1. Treatment of old pavement

1. The old pavement should be cleaned of dust, loose particles and sundries, and the surface should be kept dry. The sharp and abrupt parts of the road surface shall be leveled; for the seriously damaged and broken parts of the road surface, the broken parts shall be removed and repaired with asphalt concrete. For the pavement with serious cracks or ruts, a layer of 1-2cm leveling layer should be filled.
2. Sprinkle asphalt sticky oil
When using liquid petroleum asphalt for sticky layer oil, the atmospheric temperature is above 5℃; when using emulsified asphalt for sticky layer oil, the atmospheric temperature is above 10℃. When the road is wet in rainy days and after rain, do not pour sticky oil. Pay attention to the selection of the type and amount of sticky oil. Practice has proved that it is best to use asphalt modified by EVA or SBS, 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.
Before laying the geotextile, spray the bituminous sticky layer oil, the dosage is about 0·4～0·6kg/m2, then lay the geotextile, and then sprinkle a layer of the same type of sticky oil on the geotextile, the dosage is about 0・5～0・6kg/m2. The following points should be noted: (1) It is recommended to use hot asphalt sticky sleeves, and the oil temperature should be kept between 150 and 170 °C; (2) The lateral range of spraying sticky oil is 5 to 10 cm wider than that of geotextiles; The layer of oil should be sprayed evenly and the measurement should be accurate.
If one pouring oil 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 impermeability and delamination of the geotextile, which leads to the peeling of the surface layer.
2. Laying and overlapping of geotextiles
1. The geotextile is preferably erected mechanically, or manually laid. When laying, care should be taken to make the rough side of the singeing face up, and then fix one end with a fixer, and tighten it mechanically or manually. Pave the road ahead.
The fixer includes a fixation nail and a fixation iron sheet. Cement nails or shooting nails should be used for fixing nails, with a length of 8 to 10 cm; iron strips with a thickness of 1 mm and a width of 3 mm can be used for the fixed iron sheet.
2. The geotextile is lapped horizontally by about 4-5cm. According to the paving direction, press the rear end under the front end, cement it with hot asphalt or emulsified asphalt, and fix it with a fixer; the longitudinal lap is also about 4-5cm , can be directly dried with binding oil. If the lap joint is too wide, the interlayer at the lap joint will become thicker, and the bonding force between the surface layer and the base layer will be weakened, which will easily lead to adverse effects such as bulging, detachment, and displacement of the surface layer. Therefore, the parts that are too wide should be cut off.
3. The geotextile should be laid in a straight line as much as possible. When turning is required, the fabric bends are cut, overlapped and glued with tack coat. The wrinkling of the fabric should be avoided as much as possible. If there are wrinkles during the laying (when the wrinkle height is > 2cm), this part of the wrinkle should be cut, and then overlapped in the laying direction and handed over with adhesive layer oil.
4. When the geotextile is laid, after spraying the asphalt sticky oil for the second time and cooling for about 2 hours, a suitable amount of fine yellow sand should be thrown in time to prevent the vehicle from passing on the geotextile. Destruction, the amount of fine sand is about 1 ~ 2kg/m2.
3. Construction of Asphalt Surface
1. The construction method of the asphalt surface layer is consistent with the construction method of the ordinary asphalt pavement surface layer. The design of the pavement structure and thickness should adopt the methods specified in the "Code for Design of Highway Asphalt Pavement" (JTJ014) or "Technical Specification for Highway Maintenance" (JTJ073). The thickness of the asphalt overlay is generally 4 to 6 cm for the old asphalt concrete pavement.
When paving asphalt mixture, the paving temperature must be strictly controlled!
If the temperature is too high, the concrete will be easily burnt out; if the temperature is too low, the degree of compaction will be affected.
2. Pavement compaction treatment Pavement compaction is very important to pavement quality. Insufficient pavement compaction will cause cracking, loosening, rutting and other phenomena, which will seriously affect the service life of the pavement.
4. Precautions for construction
1. Try to avoid turning or braking suddenly on the geotextile, especially when paving the asphalt surface, any sharp turning or car sliding may lift or destroy the geotextile.
2. Construction in rainy, humid or cold climates will affect the bond strength and finish of the coating.
3. Traffic must be closed during the laying process. Except for construction vehicles, other vehicles are only allowed to pass over the geotextile in emergency situations.
4. If the paver slips when paving the hot mix asphalt mixture, sprinkle a small amount of stone chips on the surface of the sticky oil.
In general, when we master the construction points of geotextiles proficiently, we can make it exert greater economic benefits and make greater contributions to our urban construction.