Traffic Engineering Internship Report

I. Internship purpose

In order to enhance the ability of social practice, and flexibly apply the theoretical knowledge of the construction and roadbed pavement engineering, according to the requirements of the syllabus, the knowledge theory is linked to the reality, and the social communication ability is suddenly cultivated, not just the campus life. To lay a solid foundation for stepping into the society after graduation.

Second, the internship time

Third, the internship content

1) Construction process

Construction preparation - → lofting - → mixing - → transportation - → paving - → rolling - → inspection - → health.

Construction preparation

a. Material preparation: Feed according to technical specifications.

b. Mechanical preparation:

Asphalt concrete pavement construction

Preliminary preparation

1 Before the construction of the asphalt surface layer, a serious inspection of the base layer should be carried out, especially the key inspection: whether the elevation meets the requirements; whether the surface is loose; whether the flatness meets the requirements, and the non-standard section should be treated. The above inspections shall have inspection reports and treatment measures and final quality reports.

2 test section

1 The test section should be completed before construction to determine the following:

1 determine the reasonable number of machinery, machinery and combination;

2 to determine the processing speed of the mixer, mixing quantity, mixing temperature and other operating processes;

3 determine the paving temperature speed, rolling sequence, temperature, speed, number of passes, etc.;

4 determine the looseness factor, joint method, etc.;

5 verify the asphalt mixture ratio;

6 comprehensive inspection of materials and construction quality;

7 determine the construction organization and management system, personnel, communication and command methods;

8 First, there are plans, and then complete the summary report approval.

5 The purpose of the test is to confirm the stability of the mixture and the efficiency of the mixing, paving, compaction equipment, construction methods and construction organization. Determine the compacted standard density of asphalt concrete. It is necessary to summarize the experience of the looseness of the mixture, the rolling sequence of the roller, the rolling speed and the number of passes.

2 paving and compacting equipment

a. Use one paver to spread the whole piece at a time. The paver should have an automatic leveling function, a vibratory impact function, and high precision, which can lay out a high quality asphalt layer. The screed can be heated automatically when needed and can be spread over the width of the lane in accordance with the specified typical cross section and the thickness shown on the drawing.

b. When paving the mixture, the advancing speed of the paver should be coordinated with the feeding speed, and the paving speed of the bottom layer and the surface layer should be controlled by 1.7m/min and 2.5m/min respectively.

c. The paver should be equipped with a screed automatic control device. The sensor is installed on one or both sides. The elevation and flatness can be controlled by the reference line and the reference point, so that the paver can lay the ideal vertical and horizontal slope. The sensor should be operated by a reference line or a skid reference plate.

d. The cross slope controller should be able to maintain the ideal slope of the slab with an accuracy of ±0.1%.

e. The compaction equipment should be equipped with 2 sets of vibratory roller and 2 sets of rubber roller, which can be combined and compacted according to reasonable compaction process.

f. The bottom layer paver adopts the “walking wire” reference line to control the elevation, and the bottom and surface layer paver sets the floating reference beam to control the thickness.

2 construction plan

Our company's asphalt concrete is a commercial asphalt concrete.

1 mixture transportation

a. During the continuous paving process, the transport truck stops at 10-30cm in front of the paver and must not hit the paver. During the unloading process, the transport truck should be vacant and propelled by paving.

b. The mixture that has been isolated or formed into a non-crushed hard shell, agglomerate or transport vehicle that is left on the vehicle when it is unloaded, and the mixture that is below the specified paving temperature or wetted by the rain should be discarded. Used in this project.

c. Unless the materials shipped can be laid out during the day and can be compacted, or there are sufficient reliable lighting facilities at the paving site, the mixed materials that cannot be compacted during the day or on duty cannot be transported to the site, otherwise, the excess mixing It is not allowed to be used in this project.

2 paving of the mixture

1 Before laying the mixture, the lower layer must be inspected. Pay special attention to the pollution of the lower layer. If it does not meet the requirements, it must be treated. Otherwise, the asphalt concrete will not be paved.

The 2 lanes are divided into two pavings, paved by pavers, and 8m automatic leveling balance beams are placed on both sides of the paver.

3 Normal construction, paving temperature is not lower than 130-140 °C does not exceed 165 °C; at 10 °C temperature, the construction is not lower than 140 °C, not exceeding 175 °C. Before the paving, the asphalt mixture of each car should be inspected. It is found that the super warm materials, white materials and unqualified materials should be refused to be paved and returned to waste.

4 The paver must maintain the continuity of the paving. There is a special person to command. When the first car is unloaded, it should be immediately followed up. It should be driven at a uniform speed to ensure uniform and uninterrupted paving of the mixture. It is necessary to keep more than 3 vehicles in the past. During the paving process, the speed should not be changed at will, avoiding pauses in the middle and affecting the construction quality. The paving room should be filled and the feeding should be uniform.

5 The operation of the paver shall not cause the mixture to accumulate along the sides of the receiving hopper. For any reason, the mixture cooled below the specified temperature shall be removed.

6 Where the pavers with irregular shape, different thickness and limited space can not work, the artificial paving mix can be used with the approval of the engineer.

7 When there is water in the rain or on the surface, and the construction temperature is lower than 10 °C, the mixture should not be paved.

8 Mixtures encountered water, must not be used, must be scrapped, pay attention to the construction of the rainy season, the middle layer, the surface layer is paved with floating reference beams.

3 compaction of the mixture

1 Check the pavement immediately after the mixture has been paved and leveled, and manually adjust the irregularities in time, and then fully and evenly compact.

2 Compaction work shall be carried out according to the combination and program of compaction equipment determined by the test road.

3 compaction is divided into three stages: initial pressure, double pressure and final pressure.

a. Initial pressure: Immediately after paving, it is completed with a static two-wheel roller, and the initial pressure temperature is controlled at 130°-140°. The initial pressure should be crushed by a light-duty steel drum compactor or a vibrating roller with vibration. When rolling, the driving wheel should face the paver. The rolling line and the direction of rolling will not change suddenly, resulting in the mixture being displaced. After the initial pressure. Check the flatness and road arch and trim if necessary.

b. Recompression: The recompression is carried out immediately after the initial pressure. The recompression is completed by the vibratory roller and the rubber roller. Generally, it is crushed 3-4 times with a vibratory roller, and then crushed 4-6 times with a rubber roller. To achieve the degree of compaction.

c: Final pressure: the final pressure is carried out immediately after the recompression, and the final pressure is crushed by a vibratory roller which is closed by a two-wheeled steel drum compactor to eliminate the wheel track.

4 The initial pressure and vibration rolling should be carried out at a low speed to avoid the transfer and cracking of the hot material. Rolling should be as advanced as possible at higher temperatures after paving. Generally, the initial pressure should not be lower than 130 °C. The higher the temperature, the easier it is to improve the pavement flatness and compaction. It is necessary to change the habit of starting to crush before the temperature of the mixture is lowered to 110 °C.

5 Rolling work should be carried out according to the test results determined by the test road.

6 During the rolling, the roller must not stop, turn or brake.

7 The roller should not stay on the pressed mixture above 70 °C. At the same time, effective measures should be taken to prevent oil, lubrication fingers, cars or other organic impurities from spilling on the road during operation or parking of the roller.

8 In the immediate pressure, if the temperature of the mixture at the seam can not meet the compaction temperature requirement, the heater should be used to increase the temperature of the mixture to the required compaction temperature and then compacted to the seamless track.

9 During the paving and rolling process, special personnel should be organized to carry out quality inspection control and defect repair. The compaction inspection should be carried out in time, and if it is not enough, it will be replenished in time within the specified temperature. The paved road has been completed and the skin cannot be repaired. The construction compaction test can be carried out by sand filling method.

4 seam processing

1 Vertical and horizontal joint seams should be vertically seamed.

2 The mixture on the longitudinal joint should be statically rolled under the static steel drum roller immediately behind the paver. The rolling work should be carried out continuously until the seam is smooth and compact.

3 The misalignment between the upper and lower layers of the longitudinal joint shall be at least 15 cm.

4 Due to the interruption of the workbench, the end of the paving material has been cooled, or when the work is resumed the next day, a transverse seam should be made. The transverse joint should be at a right angle to the paving aspect. It is strictly forbidden to use the oblique joint. The transverse joint should be staggered by at least 1 m between adjacent levels and adjacent strokes. The transverse seam should have a vertical crushed into a good edge.