Construction technology of asphalt pavement
Before asphalt pavement construction, the pavement should be closed. When paving formally, the surface of qualified pavement base shall be thoroughly cleaned first, and then 2 ~ 3 forest fire-extinguishing blowers shall be arranged along the longitudinal diagonal to blow away the floating ash, so that the surface aggregate can be exposed as much as possible, which is beneficial to the bonding between asphalt and base.
Spray:
1) After the surface of the pavement base is dried, spray a small amount of water with a sprinkler one hour before spraying the modified emulsified asphalt to make the surface of the pavement base moist.
2) Spray with high-precision intelligent distributor, and often dredge and clean all kinds of oil pipes and nozzles of machinery to prevent blockage and always maintain good working performance of machinery and equipment.
3) Manual spraying or supplementary spraying shall be carried out for the sections or parts that cannot be operated by the distributor, as well as the missing parts.
4) dosage of modified emulsified asphalt: According to the design requirements, the modified emulsified asphalt is generally 0.9- 1. 1kg/m2 or the aggregate dosage is about 6-8m3/ 1000m2. Aggregate distribution is completed before demulsification of modified emulsified asphalt.
Rolling: After the aggregate is paved, it will be rolled with a tire roller for three times, each time with an overlap of 1/3 wheel width, and rolled from two sides to one side to ensure the effective compaction width. The rolling sequence is from shoulder side to middle side.
Maintenance: After rolling, the traffic can be closed for 7 days, and then the traffic can be opened. The following is a detailed explanation of the process provided by Beijing Ludeli, hoping to help everyone.
Construction methods and steps of asphalt pavement
Mixing and paving test section:
1. test material: constantly check and adjust the asphalt mixture produced by the mixer to make the mixture composition meet the design requirements;
2. Paving test section: 200-meter-long sections that are the same as or similar to the main route are selected for paving.
3, check the construction organization, construction technology, mechanical equipment matching, combination is appropriate; Determine the loose paving coefficient, optimum paving temperature, rolling temperature, rolling times, rolling speed, roller combination and personnel organization;
4. Summarize, formulate improvement measures for the existing problems, submit the summary report of the test section to the headquarters and the director's office, and start work only after approval.
Mixing of asphalt mixture (operation and operation);
A, feeding cold materials; B, aggregate drying and heating, control between 160- 1800c. C, collecting dust and controlling smoke emission; D, sieving the hot aggregate; E, weighing the hot aggregate; F, asphalt heating, temperature control155-1650c; G, asphalt weighing; H, asphalt mixture mixing and temperature control, temperature control in 145- 1650c.
Check frequently asked questions
A visual inspection: whether there is "grey material" and whether the mixing is uniform; B, detecting the temperature of the mixture; C through Marshall test, test the indicators; Extraction test to check the requirements of oil-stone ratio; Mineral aggregate grading in mineral aggregate screening test.
Transportation: a car is in good condition, the carriage is clean and covered with tarpaulin;
B. Determine the number of transport vehicles according to the output, transport distance and guaranteed road conditions.
Laying of asphalt concrete:
1, paving preparation:
A, acceptance cleaning the lower bearing layer; B, ensure that the machine is in good condition, and preheat the screed 0.5- 1h before the paver starts, so that its temperature is not lower than 100℃.
2, paving process:
The asphalt mixture is paved by an LTU 120 and an ABG423, staggered 10-20m from front to back, and stepped.
The group road shall be paved synchronously, with an overlap of about 30mm between two pictures, and the upper and lower overlap positions shall be staggered by more than 200mm;
B Paver must spread slowly, evenly and continuously, and it is not allowed to change the speed or stop halfway at will.
So as to improve the flatness and reduce the segregation of the mixture;
C coarse-grained asphalt concrete adopts non-contact balance beam to control elevation and thickness;
D medium and fine grained asphalt concrete shall be leveled automatically by non-contact balance beam to control the thickness and smoothness;
E. The loose paving coefficient of asphalt concrete is determined by trial paving and pressure test according to the type of mixture;
F. The spiral distributor of the paver should be adjusted according to the paving speed to maintain a stable speed and uniform rotation.
When moving, both sides should be kept not less than 2/3 of the height of the mixture of the feeder to reduce the segregation of the mixture during paving.
Rolling of asphalt concrete:
1, and detect the temperature of each rolling process (initial pressure temperature, re-pressure temperature and final pressure temperature).
2. The rolling times shall be subject to the compaction times of the test road (the determination method is the same as that of graded crushed stone subbase).
3. Rolling procedure: When rolling, the wheel width should overlap 1/3- 1/2, and the rear wheel must exceed two joints. The initial speed pressure of the roller is 1.5- 1.7km/h, the pressure is stabilized at 2.0-3.0km/h, and the final pressure is 3-5 km/h. It is forbidden to stop, turn around and make sharp turns where the roller is rolled or the temperature is higher than 70℃.
Joint treatment: the joint should be smooth, and the end of each working joint should be leveled with a three-meter ruler every day. The uneven part should be cut off with a cutting machine, and the joint should be pressed horizontally with a roller first. If it is uneven, it should be measured with a three-meter ruler in time, and then manually removed or repaired.
Open traffic:
When the surface temperature of concrete is lower than 50℃, the traffic can be opened. If the traffic area cannot be closed, the water wheel can be used to cool down.
Asphalt pavement is the most commonly used pavement in our country at present, and it has many characteristics. Asphalt pavement is a variety of pavements paved with asphalt materials mixed with mineral materials. And has excellent leveling property, sand prevention property, water tightness, abrasion resistance, practicality and long service life. So now most roads in our country are paved with asphalt. Asphalt pavement is also divided into many layers, such as surface layer, base layer, subbase layer and cushion layer, so the overall performance is very good.