In order to explore the adaptability and construction technology of pavement construction machines and tools, and provide experience and relevant data for large-scale construction in the future, the experimental section of 5% cement stabilized macadam base was constructed. The paving length was 300 meters and the compaction thickness was 36cm, which was divided into two layers, namely the compaction thickness of each layer 18cm. Second, the paving purpose of the test section 1, mix ratio verification. 2. Determine the loose paving coefficient of the mixture. 3, determine the standard construction scheme. Mainly includes the following points: a, suitable mixing machinery and mixing method; B, paving method of mixture and applicable machinery; C, control method of water content of mixture; D, using suitable machines and methods for leveling and shaping; F, the selection and combination of compaction machinery, the order and speed of compaction; G, mixing, transportation, paving and rolling machinery coordination and cooperation; 4. Determine the appropriate length of each operation part. Iii. Construction plan (1), material preparation 1, cement: Huaxin (Chibi) P.C32.5 cement, the initial setting time of cement is more than 3 hours, and the final setting time is more than 6 hours, and the stability is qualified. The strength indexes of 3d and 28d should meet the specification requirements and meet the national standard GB 175- 1999. 2. Gravel: The stone is processed by large-scale impact combined crushing equipment, and the stone is clean and does not contain harmful substances such as clods. Gravel at the grass-roots level is processed by three Tongshan gravel yards, which are stacked according to four specifications: 0 ~ 4.75 mm, 4.75 ~ 9.5 mm, 9.5 ~ 19 mm and 19 ~ 37.5mm respectively. The maximum particle size is less than 37.5mm, and all indicators meet JTJ 034-2000 and supplementary technical specifications. 3. Water: Use clean drinking water without harmful substances. (II) Composition design of the mixture The design of the mixture shall be carried out in the laboratory qualified by the supervision engineer, and the test shall be carried out according to the standard method specified in the Test Code for Stabilized Materials with Inorganic Binders for Highway Engineering. The inspection items of raw materials shall be inspected according to the technical specifications. The composition design of the mixture conforms to the relevant provisions of Technical Specification for Construction of Highway Pavement Base. Design mix proportion of concrete: cement: macadam = 5: 100, in which the macadam ratio is: 0 ~ 4.75mm for 30%, 4.75~9.5mm for 20%, 9.5 ~ 19~37.5mm for 25%,19 ~. (3), the mixture mixing 1, before mixing, submit the factory mixing equipment and location to the supervision engineer, and carry out installation, maintenance and debugging according to the instructions of the supervision engineer, so that the particle composition and water content of the mixed mixture can meet the specified requirements. 2. The mixing station adopts WBC-600 forced mixer, which is equipped with four stone silos and one cement silo. Automatic water supply device is used to add water, and the designed mixing capacity is 600 tons/hour. The mixing quality is controlled by laboratory and mixer operators. 3. Before mixing the mixture formally, all the equipment must be debugged, and the feeding speed of the cold hopper and the cement pump and the size of the water valve of the pump should be controlled according to the mixture ratio, so that the mixture conforms to the mixture ratio and its water content is 0.5% higher than the optimal water content. At the same time, the water content should be adjusted according to the transportation distance and the construction climate, so that the water content of the mixture during paving and rolling is slightly higher than the optimal water content. (4), mixture transportation, paving, shaping, rolling 1, transportation a, according to the position of the water-stable mixing station we set, considering the transportation distance and paving capacity of the mixture, and according to the specific situation of future construction, make detailed adjustment arrangements to ensure the continuity of mixing, paving and compaction operations. B, when loading, ensure the uniform loading height in the hopper to prevent segregation; When necessary, the transportation of the mixture should be covered with tarpaulin to prevent rain and water loss, and ensure that the water content of the mixture is the best when it is rolled after being transported to the site for paving. C. When the dump truck transporting the mixture passes on the surface of the completed paving layer, the speed should be slow, and sudden braking is strictly prohibited to reduce uneven rolling or damage the surface strength; The mixture shall be transported to the site for paving as soon as possible, and the stacking time of the mixture shall not exceed 24 hours and 72 hours at the latest. 2. Paving and shaping A. The design thickness of water-stabilized base is 360mm, and it is paved and compacted in two layers. After acceptance and maintenance, the base course shall be laid for seven days, and the base course shall be laid in time; Before paving, the floating ash and loose parts of the subbase should be cleaned up and properly watered. Before subbase and upper subbase construction, clean cement slurry should be sprayed on the top surface of subbase and lower subbase respectively after removing floating ash (according to cement quality: 1.0 ~ 1.5 kg/m2). The consistency of cement slurry shall be uniform, and the paving length shall not exceed 30m~40m before the paver. B, the paving of the mixture should be carried out by machinery approved by the supervision engineer, and the mixture should be evenly spread on the required width according to the specified paving thickness. C. Construction machinery configuration: two RP95 1 pavers, three 20t single-wheel vibratory rollers, 1 XP30 1 tire roller are adopted. Single-sheet paving adopts double echelon operation to ensure the coordination of transportation capacity and paver production capacity during construction and reduce the phenomenon of downtime; Two pavers spread the mixture forward about 5 ~ 10 m in tandem, and the tracks of the two pavers overlap 50 ~ 100 mm ... d, and elevation control: as two pavers are used for joint paving, the elevation control of the top surface of the base course adopts a thickness sensor extending from one side of the previous paver to be placed on the aluminum alloy guide beam, and the sensor moves along the top surface of the aluminum alloy guide beam, and the other side adopts a cross inclinometer sensor to meet the elevation. On one side of the latter paver, the thickness sensor extended from the paver is placed on the wire rope reference rope, and on the other side, the elevation is controlled by the thickness of the newly paved water-stable layer. E, paving operation should match the production capacity of mixer, according to the production capacity and transportation capacity of mixer, determine the paving speed of paver, and control the paving speed at about 3m/min. When paving, the mixture is filled to 2/3 of the height of the spiral distributor of the paver, so as to ensure that the paving mixture is smooth and does not segregate; When paving, the deviation between the water content of the mixture and the optimal water content should be controlled at-1% ~+ 1.5%, and at the same time, the weather conditions during construction should be considered, such as the water content in high temperature weather can be appropriately higher than the optimal water content 1.5%, and the water content in rainy days can be appropriately lower than the optimal water content 1%. Behind the paver, assign a special person to eliminate the segregation of coarse and fine aggregates, especially coarse aggregate nests or coarse aggregate belts, and fill or supplement the fine mixture with new mixture and stir it evenly; Paving at the grass-roots level should be carried out in accordance with the principles of "rather high than low" and "rather scraping than mending", and leveling with thin patches is strictly prohibited to avoid "shelling"; Before the paver, it should be ensured that there are more than 5 trucks waiting for unloading, so as to reduce the situation of the paver waiting for materials, so as to ensure the continuity of paving operation and improve the smoothness; In the construction of water-stable layer, special attention should be paid to the construction period. Because the activation of cement will directly affect the final strength of the water-stable layer, the water-stable mixture should not be left for too long after mixing, otherwise the cement will lose its activity, thus reducing the strength of the water-stable layer. The total time from mixing with water to final rolling should be controlled within 4 hours. If the total time exceeds 4 hours due to other uncertain factors, the paved and rolled parts can be jointed first after the field test, and the paved and unpaved mixture should be discarded or used for other purposes. F, paving operations, determine the specialized technical personnel to track and control the elevation and thickness of the paving base, and fine-tune the paver sensor according to the test results to ensure the construction quality. G, behind the paver should be designated persons to eliminate the segregation phenomenon of coarse aggregate, especially to eliminate local coarse aggregate "nest", and fill it with fresh mixture, and do a good job of trimming, shaping and compaction to ensure the edge is straight and dense. 3. Compaction In this test section, it is planned to adopt two rolling methods: the first one (before 100 meter test): firstly, use a single steel roller to statically press 1 ~ 2 times in the whole width of subgrade, then vibrate for 4 ~ 5 times, and then use a rubber roller for 2 times to collect light until the required degree of compaction is achieved. The second type (final test within 100m): firstly, use a single steel roller to carry out static pressure for 1 ~ 2 times within the full width of subgrade, then vibrate and roll it for 2 ~ 3 times, and then roll it with a rubber roller for 3 ~ 4 times to collect light until the required degree of compaction is achieved. A the above two rolling methods and specific rolling times are finally determined according to the test section results. B, when rolling, the straight cross slope section should be rolled from low to high, and the ultra-high section should be rolled from the inner shoulder to the outer shoulder, and from low to high. When rolling, the roller is horizontally staggered by half, and the traveling speed of the roller is 1.5 ~ 1.7 km/h during initial rolling, and then 1.8 ~ 2.2 km/h is adopted. Ensure that the road roller does not turn around or brake suddenly on the completed or rolling section, so as to ensure that the surface of the water-stable layer is not damaged. After compaction, the surface is smooth, without wheel tracks or bulging, washboard cracking and loose peeling, and the section is correct. The camber of the transverse slope is consistent with the surface layer, and the compactness meets the specification requirements. C, in the process of rolling, water should be sprayed properly to keep the water stable surface moist all the time. When the moisture on the surface of the mixture evaporates too much in hot weather, it should be opened manually in time and replaced with a new mixture to meet the quality requirements. After rolling forming, test the degree of compaction. D, the length of the rolling section should be adjusted according to the mixing, transportation and paving capacity, from mixing to paving and rolling should be adjusted within 4 hours. (5), horizontal and vertical joint treatment 1, horizontal joint treatment A. When paving the mixture with a paver, it should not be interrupted. If the interruption time exceeds 2 hours or the work shift ends, a horizontal joint shall be set, and the paver shall leave the end of the mixture. B, finally, tidy up the mixture with appropriate water content, and place two square logs close to the mixture, the height of which should be the same as the compaction thickness of the mixture, and level the mixture close to the square logs, which should be perpendicular to the road center line. C, the other side of the square wood with gravel or about 3M long gravel backfill, its height should be a few centimeters higher than wood. D, rolling the mixture. E, before paving the mixture again, remove gravel or crushed stone and square timber, and clean up the subbase and top surface of the next layer. 2. Treatment of longitudinal joints In the construction of water-stable layer, longitudinal joints should be avoided as much as possible. If the longitudinal joint cannot be avoided, the longitudinal joint must be connected vertically, and shall not be mitered, and shall be treated as follows: a. When laying the previous picture, the square wood or steel formwork shall be used as support on one side of the latter picture, and the height of the square wood or steel formwork shall be the same as the compacted thickness of the water-stable layer. B, after the mixture is mixed, the part close to the supporting wood or steel formwork shall be artificially supplemented and mixed, and then shaped and rolled. C, after the maintenance, before laying another picture, dismantle the wood or steel template. D, if there is no square wood or steel formwork support in the above picture, it is difficult to compact the edge of about 30CM, forming a slope. When paving the rear image, the part with incomplete compaction and the part that does not meet the requirements of the road arch should be dug loose and filled with cement slurry. After paving the rear image of the mixture, it should be leveled and rolled together. (VI) Determination of loose paving coefficient of mixture The loose paving coefficient is tentatively set as 1.27 (the loose paving thickness of upper and lower subbases is 23cm), which is determined through trial paving. (7), the rainy season construction measures 1, the establishment of flood control rescue team, the construction site to prepare enough plastic sheets, used to cover the cement stabilized mixture in case of sudden precipitation. In order to prevent precipitation and rain, cement stabilized mixture should be crushed to survive in time during construction. 2. In rainy season, the designed drainage system can be connected with the existing drainage system. Keep the drainage system on the construction site unblocked to avoid rain soaking the foundation. 3. Transport vehicles should use a closed trunk. 4. Monitor the weather forecast before the base construction to avoid rainy days. 5. If the cement stabilized mixture is wet by rain before rolling, it must be completely removed and refueled. 6. The water content of cement stabilized mixture should be strictly controlled in rainy season. The water content in hot weather can be higher than the optimal water content 1.5% and lower than the optimal water content 1% in rainy weather. (8), traffic control and health a, after each section of water-stable layer has been rolled and passed the compaction inspection, health care should be started immediately. B, considering the site conditions, it is proposed to use geotextile to cover and spray water for maintenance, and the number of times of spraying water every day depends on the climate, so as to keep the surface of the stable layer moist during the whole maintenance period. C, maintenance period of not less than 7 days, strictly closed traffic during the maintenance period, try to avoid construction vehicles driving in the maintenance field. (9), test detection and quality control 1, screening result of cement stabilized macadam mixture (qualified rate %)2, cement dosage detection 3, thickness control evaluation 4, on-site compactness evaluation 5, flatness, elevation, width, cross slope evaluation 6, strength evaluation 7, loose paving coefficient determination 4, quality safety control measures (1), quality control measures. 3. Actively accept the quality supervision of the construction unit and the supervision of the supervision engineer, and actively provide convenient conditions for the work and life of the site designers and supervision engineers. 4, the main management personnel choose high level, rich experience, excellent performance, arrange the professionals with professional qualifications to undertake the construction. Implement the system of holding certificates for construction management personnel and special type of work personnel to ensure that the quality of personnel meets the needs. 5. The feeding of the mixer should be accurate, and the feeding amount of each silo should be sampled on the feeding conveyor belt regularly. 6, stir well, can not appear segregation phenomenon of coarse and fine material separation. 7, strictly control the rolling water content, with the best water content 65438 0% rolling. 8. The mixed mixture should be paved and rolled in time, which is usually completed within 2 hours. (2), safety control measures 1, establish and improve the safety production leading group, mainly intends to emphasize the production principle of "production must be safe", and implement the responsibility system for safety production for all employees. 2, set up a safety leading group with the first person in charge as the core, with managers and full-time security officers as the backbone, and implement the responsibility system for safe production for all employees. The project manager, project team leader, class (group) leader and workers should establish the responsibility system for production safety step by step. The team shall have a full-time safety inspector, and the class (group) shall have a part-time safety officer, so that the division of labor shall be clear and the responsibility shall be assigned to people. 3, ZuoYeDui must formulate safety production management rules and regulations, set up full-time security officer. Before entering the site, give safety education to the participants to improve their safety awareness. 4. All participants must wear safety helmets when entering the construction site. Full-time security officers shall be set up at the site to be responsible for daily construction safety patrol inspection. 5. Resolutely stop the illegal operation in operation. Operators must be familiar with the safety operation procedures of this type of work and the safety production system of the construction site, and do not operate illegally. They have the right to refuse illegal operation instructions and have the responsibility to stop others from doing illegal operations. Construction personnel must receive safety education. 6. Personnel entering the site must use labor protection articles that meet national and industry standards. 7. When the subgrade passes under the existing high-voltage line, height limit signs and warning signs should be set under the high-voltage line, and construction and machinery should be connected. 8. Strengthen the management of transportation and construction vehicles, check the vehicles frequently, and it is forbidden to work with diseases. Sprinklers are not allowed to drive at high speed when driving on up and down slopes and curves to avoid emergency braking. 9, power line erection should comply with the specified requirements, distribution box, knife box should be locked, outdoor distribution box, knife box should have good protection measures. 10, establish and improve the temporary electricity safety management system, and regularly conduct comprehensive maintenance on the electrical equipment and temporary electricity lines on the construction site to ensure the safety of electricity consumption. 1 1. Electricians should hold relevant certificates. It is forbidden for non-professional operators to connect wires and use electrical appliances without permission. 12, the distribution system adopts three-phase five-wire system for hierarchical distribution, with reliable zero protection. The electrical appliances in the distribution box are reliable and intact, with complete appearance, meeting the requirements of rain and dust prevention, and obviously coated with color codes. 13. Temporary distribution lines shall be erected according to the specifications and insulated wires shall be used. It is forbidden to use plastic flexible cords, or to lay them in bundles or overhead along the ground. 14, 220V lighting power supply is arranged according to regulations; The lighting power supply voltage of the traveling lamp is less than 36V, the lamp body and the handle are firmly connected, the insulation is good, and there are moisture-proof and rain-proof facilities. 15, commanding pavers, road rollers, graders and other construction machinery shall comply with the following provisions: a. First, check roads, remove obstacles on the ground and in the air, and do a good job in safety protection of dangerous parts such as wells and pits. B, the traffic must be diverted during the journey. When it is necessary to pass the social intersection, it must be approved by the person in charge of on-site construction and confirmed to be safe before passing. C, remove the mixture stuck on the roller, must work behind the roller, never work backwards in front of the roller. D, command roller operators should coordinate with the driver, and command people around to avoid. E. When commanding the vehicle to retreat, the commander should stand at one side of the gangway and keep a certain distance from the vehicle. F, homework personnel at rest, shall not rest under the vehicle.