Road and Bridge Engineering Internship Report

First, the purpose of the internship:

Through the on-the-spot internship of the Annan Expressway, I have a comprehensive understanding of the construction of the asphalt pavement of the expressway, the design of the road and the design and layout of other highway-related facilities, and deepened our knowledge of the course. The understanding makes learning and practice a combination.

Second, internship time:

May 5th to October 10th, XX

Third, the internship location:

Annan Expressway oil surface two standard one work area.

High-speed overview: Annan Expressway is a key highway construction project planned by Henan Province. The starting point is located in Daguanzhuang, southeast of Anyang City, connecting with the highway from Anyang to Linzhou, intersecting with Beijing-Zhuhai Expressway, and ending at Qingshitun, Nanle County. In the north of the village, it is connected to the Fuyang section of the A-Shenzhen Expressway. The Annan Expressway has a total length of 64.8 kilometers, two-way four-lane, and a designed driving speed of 120 km/h. The total estimated investment of the project is 1.79 billion yuan. Annan Expressway is an important part of the connecting of the east and west expressways of Shanxi, Henan and Shandong. Its construction will effectively alleviate the shortage of traffic in the east-west direction of northern Henan, further improve the network skeleton of Yubei Road and construct the northern Henan area. Sexual central cities will enhance the competitiveness of the northern Henan region and neighboring provincial cities.

Fourth, the internship content:

1. Practice the mixing process of asphalt mixture

Mixing and transportation

There are two types of stationary mixing equipment for mixing the mixture in the factory, both batch and continuous. The former measures the weight of various materials of the mixture during each mixing, while the latter is continuously fed into the mixer after metering various materials. The mixing station uses the German Amman 4000 batch mixer.

Before mixing the asphalt mixture, the test mixture should be tested according to the determined mixing ratio. The various minerals and asphalt used should be strictly measured during the trial mixing. Through the trial mixing and sampling test to determine the mix ratio of each hot mix and its total weight, or the opening of various mineral feed inlets and the speed of asphalt and mineral feed. The test section shall be paved before the construction of the expressway and the primary road. The length of the test section shall be determined according to the purpose of the test and shall be 100 to 200 m. The test section should be laid on a straight section. If paved on other roads, the conditions of the pavement structure should be the same, and the test of each structural layer of the pavement can be arranged on different test sections.

Asphalt mixes can be paved manually or mechanically, and high-grade road asphalt pavements should be mechanically paved. Asphalt mix pavers are available in both crawler and tire versions. The construction and technical performance of the two are roughly the same. This project uses the dt1600 large width and anti-separation paver produced by Shanxi Zhongda Machinery Group. The main components of the asphalt paver are the hopper, chain conveyor, spiral spreader, vibrating plate, spread plate, exercise part and engine.

c rolling

The compaction of petroleum asphalt mixture is carried out in three stages: initial pressure, double pressure and final pressure. It is proposed to adopt the following mechanical combination: combination i: initial pressure: double pressure roller compactor initial pressure; recompression: rubber roller compactor static pressure 2 Once, the double drum compactor re-vibrates 2 times; the final pressure: the double-roller roller static pressure 1 to 2 times. Combination ii: Initial pressure: double pressure roller double press initial pressure; recompression: double drum roller re-vibration 2 times, rubber roller compactor 2 times; final pressure: double drum roller static pressure 1~2 times

The modified asphalt compaction is carried out immediately after paving, and the waiting time of following the crushing and compacting to the rolling is performed, the initial pressure is not lower than 150 ° C, and the surface temperature after rolling is not lower than 90 ° C. The re-pressing is preferably carried out by roller compaction to increase the water tightness. The length of the roller compaction section of the road roller is determined by the principle of balance with the speed of the paver, and is kept substantially stable. The roller is advanced by the stepped shape of the paver each time the roller is folded back, so that the foldback is not in the same section. On the upper part, the section is marked by the flag method. During the continuous paving of the paver, the roller should not be stopped at random. The roller must not be turned, turned or parked on unrolled or uncooled sections, and the vibratory roller should be vibrated when it is worn on the formed road.

Seam construction

Various construction joints of asphalt pavements are often due to insufficient compaction, which are prone to problems such as steps, cracks, looseness, etc., affecting the flatness and durability of the pavement, and must be paid attention to during construction. In particular, the processing of the upper layer construction joints should be smooth and smooth, and try to avoid the phenomenon of jumping and affecting the flatness and driving comfort.

Drainage facility

The whole road surface is an arch type, so the general road surface adopts the slope to face the two sides and flows into the side ditch on both sides of the road; in the section of the road curve, the outer side of the road is super high, using single-sided drainage, and the central separation belt is set. There is a rainwater passage to collect rainwater from the road outside the curve, and then a horizontal drain pipe laid under the roadbed flows into the side ditch.

2. Learn to summarize asphalt quality assurance measures

During the mixing process of asphalt concrete, various aggregate heating temperatures and modified asphalt temperatures are strictly controlled in accordance with construction specifications and design requirements. The storage time of the mixed mixture shall not exceed 24h, and the temperature drop shall not exceed 10 °C during the period, and the phenomenon of aging of the binder, dripping and segregation of coarse aggregate particles shall not occur, otherwise it shall be treated as a material.

It is covered with thick canvas with rainproof function during the transportation of asphalt concrete. The paving of the modified asphalt concrete shall be continuous, uniform and uninterrupted paving, and the paving temperature shall be between 150 and 165 °C. The rolling is carried out immediately after paving: the initial pressure is not lower than 150 ° C, and the final pressure is not lower than 120 ° C. Due to its large viscosity, tire roller should not be used. All double-drive double-vibration roller compactors should be used. The overall pressure rolling policy is: high temperature, compact rolling, uniform and slow pressure; high frequency, low amplitude, first After the middle, the echelon advances, the vibratory roller must close the vibrating device when it is reversing.

V. Internship summary

Through this road internship in the field, we have a comprehensive understanding of the design and construction of the asphalt pavement of the expressway and honed the will, further understanding the knowledge in the classroom, and the theory has been obtained in the actual production. use. In recent years, China's highway industry, especially highways, has developed rapidly and its demand is increasing. This is both an opportunity and a challenge for workers engaged in roads. As students who are going out of school, they should master more professional knowledge and strengthen their practical and design skills in a limited time. This will be more conducive to future development and enable them to make a difference in this field.

"1" "2"