An asphalt concrete mixing plant plus auxiliary machinery can complete the production process of asphalt concrete mixture from raw materials to finished materials. Its nature is equivalent to a small factory. Regarding the entire production process of the asphalt plant, we summarize the factors that affect production quality into 4M1E according to the traditional method, namely Man, Machine, Material, Method and Environment. Strict independent control over these factors, changing post-inspection to in-process control, and changing from managing results to managing factors. The influencing factors are now stated as follows:

1. Personnel (Man)
(1) Supervisory leaders must have a strong awareness of total quality management and do a good job in quality education for engineering and technical personnel and production workers. During the production process, the competent department issues mandatory production plans, supervises the implementation of various rules and regulations, and organizes and coordinates a series of production support tasks, such as material supply, finished material transportation, paving site coordination, and logistics support.
(2) Engineering and technical personnel play a decisive role in the mixing production process. They must direct and coordinate the work of various production positions, accurately grasp the technical performance and working principles of the equipment, keep production records, pay close attention to the operation of the equipment, discover potential accident hazards early and accurately determine the cause and nature of the accident. Develop equipment repair and maintenance plans and systems. Asphalt mixtures must be produced in accordance with the technical indicators required by the "Technical Specifications", and data such as the gradation, temperature and oil-stone ratio of the mixture should be grasped in a timely manner through the laboratory, and the data should be fed back to the operators and relevant departments so that corresponding adjustments can be made.
(3) Host operators must have a strong sense of work responsibility and quality awareness, be proficient in operation, and have strong judgment and adaptability when a failure occurs. Under the guidance of technical personnel, operate according to the chapter and follow the troubleshooting procedures for various types of faults.
(4) Requirements for auxiliary work types in the asphalt mixing plant: ① Electrician. It is necessary to master the performance and use of all electrical equipment, and regularly measure various performance indicators; have an understanding of the superior power supply, transformation and distribution system, and get in touch frequently. Regarding planned power outages and other situations, relevant personnel and departments of the asphalt plant must be notified in advance.
② Boilermaker. When producing asphalt mixture, it is necessary to observe the operation of the boiler at any time and understand the reserves of heavy oil, light oil and liquid asphalt. When using barreled asphalt, it is necessary to arrange barrel removal (when using barreled imported asphalt) and control the asphalt temperature.
③Maintenance worker. Closely monitor the cold material transportation, check whether the grating screen on the cold material bin is blocked, promptly notify the equipment failure and report it to supervisors and operators for timely elimination. After shutting down every day, perform routine maintenance on the equipment and add various types of lubricating grease. Major parts should be filled with lubricating grease every day (such as mixing pots, induced draft fans), and the oil levels of vibrating screens and air compressors should be checked every day. If the lubricating oil is filled by non-professionals such as migrant workers, it must be ensured that each oil filling hole is fully filled to prevent omissions.
④Data manager. Responsible for data management and conversion work. Properly keeping the relevant technical information, operation records and relevant data of the equipment is a necessary means for quality management and ensuring the normal operation of the machinery. It is the original voucher for establishing technical files and provides a basis for the competent department's decision-making and production.
⑤Loader driver. We must do our job seriously and establish the ideology that quality is the life of the enterprise. When loading materials, it is strictly forbidden to put materials into the wrong warehouse or fill the warehouse. When storing materials, a layer of materials must be left at the bottom of the materials to prevent soil.

2. Machines
(1) In the production process of asphalt mixture, there are at least four links from the input of cold materials to the output of finished materials, and they are closely linked. No link can fail, otherwise it will not be possible to produce qualified products. of finished product materials. Therefore, the management and maintenance of mechanical equipment are crucial.
(2) It can be seen from the production process of the asphalt plant that all kinds of aggregates stored in the material yard are transported to the cold material bin by a loader, and are quantitatively transported by small belts to the aggregate belt according to the required gradation. Toward the drying drum. The stone is heated by the flame generated by the heavy oil combustion heating system in the drying drum. While heating, the dust removal system introduces air to remove dust from the aggregate. The dust-free hot material is lifted to the screening system via a chain bucket elevator. After screening, the aggregates at all levels are stored in corresponding hot silos respectively. Each aggregate is measured to the corresponding value according to the mix ratio. At the same time, the mineral powder and asphalt are also measured to the value required for the mix ratio. Then the aggregate, ore Powder and asphalt (wood fiber needs to be added to the surface layer) are put into a mixing pot and stirred for a certain period of time to become a finished material that meets the requirements.
(3) The location of the mixing plant is very important. Whether the power consumption can be guaranteed, whether the voltage is stable, whether the supply route is smooth, etc., should be carefully considered.
(4) The season for asphalt mixture production is from May to October every year, and this is exactly the time when industrial and agricultural production uses a lot of electricity in society. The power is tight, and regular and unscheduled power outages occur from time to time. Equipping a generator set with appropriate capacity in the mixing plant is necessary to ensure the normal production of the mixing plant.
(5) In order to ensure that the mixing plant is always in good working condition, the equipment must be properly repaired and maintained. During the shutdown period, routine maintenance and inspection must be carried out according to the requirements of the equipment manual. Maintenance work must be performed by dedicated electrical engineers and mechanical engineers. Personnel involved with the equipment must be familiar with the operating principles of the machinery. In order to prevent oversized stones from entering the equipment, the cold material bin must be welded with a (10cmx10cm) grid screen. All types of lubricants must be filled by dedicated personnel, checked frequently, and maintained at normal cleaning and maintenance levels. For example, the finished product warehouse door can be opened and closed flexibly by spraying a small amount of diesel after it is shut down every day. For another example, if the mixing pot door does not open and close smoothly, it will also affect the output. You should spray a little diesel here and scrape off the asphalt. Proper maintenance will not only extend the service life of equipment and components, but also save costs and improve economic benefits.
(6) When the production of finished materials is normal, attention should be paid to transportation management and coordination with road construction. Because the storage capacity of asphalt mixture is limited, it is necessary to maintain good communication with the road surface and grasp the required amount of mixture to avoid unnecessary losses.
(7) It can be seen from the production process that transportation problems have a greater impact on production speed. Transportation vehicles vary in size and speed. Too many vehicles will cause congestion, disorder, and serious queue jumping. Too few vehicles will cause the mixing plant to shut down and require re-ignition, affecting output, efficiency, and equipment life. Because the mixing station is fixed and the output is stable, the paver construction location changes, the construction level changes, and the demand changes, so it is necessary to do a good job in vehicle scheduling and coordinate the number of vehicles invested by the unit and external units.

3. Materials
Coarse and fine aggregates, stone powder, asphalt, heavy oil, light oil, equipment spare parts, etc. are the material conditions for the production of the drainage plant. On the basis of ensuring the supply of raw materials, energy, and accessories, it is necessary to strictly inspect their specifications, varieties, and quality, and establish a system for sampling and testing raw materials before ordering. Controlling the quality of raw materials is the key to controlling the quality of finished materials.
(1) Aggregate. Aggregate can be divided into coarse and fine. Its proportion in the asphalt mixture and its quality have an important impact on the quality, constructability and pavement performance of the asphalt mixture. The strength, wear value, crushing value, solidity, particle size gradation and other indicators of the aggregate must meet the requirements of the relevant chapters of the "Technical Specifications". The storage yard should be hardened with appropriate materials, built with partition walls, and well drained within the station. When the equipment is in good operating condition, aggregate specifications, moisture content, impurity content, supply volume, etc. are important factors that affect the production of the leaching and asphalt mixing station. Sometimes the aggregate contains large stones, which may cause the unloading port to be blocked and the belt to be scratched. Welding the screen and sending someone to look after it can basically solve the problem. The particle size of some aggregates does not meet the specification requirements. When drying the aggregate for a certain period, the waste increases, the waiting time for weighing is extended, there is more overflow, and the discharge time of the finished product is greatly extended. This not only causes a waste of energy, but also seriously restricts output and Affect production efficiency.The moisture content of the aggregate after raining is too high, causing quality problems such as clogging of the hopper, uneven drying, sticking to the inner wall of the heating drum, difficulty in controlling the temperature, and whitening of the aggregate. Since stone production in society is not planned, and the specifications of highway and construction materials are different, the specifications processed by stone quarries often do not match the required specifications, and supply often exceeds demand. Certain specifications of aggregates have been out of stock on the Xinhe Expressway, so material specifications and material requirements should be grasped and materials prepared in advance.
(2) Electricity, light oil, heavy oil and diesel. The main energy produced by the mixing plant is electricity, light oil, heavy oil and diesel. Adequate power supply and stable voltage are necessary guarantees for production. It is necessary to get in touch with the power department as soon as possible to clarify the power consumption, power consumption time and the responsibilities and rights of both supply and demand parties. Heavy oil and light oil are the energy sources for aggregate heating, boiler heating, asphalt decanning, and heating. This requires ensuring supply channels for heavy and diesel oil.
(3) Reserve of equipment spare parts. When purchasing equipment, we randomly purchase some key components and accessories for which there are no domestic substitutes. Some wearing parts (such as gear pumps, solenoid valves, relays, etc.) must be kept in stock. Some imported parts are affected by various factors and cannot be purchased at the moment. If they are prepared, they may not be used, and if they are not prepared, they must be replaced. This requires engineering Technicians use their brains more and have a good grasp of the actual situation. Engineering and technical personnel in charge of mechanical and electrical engineering should not be changed frequently. Some oil seals, gaskets and joints are processed by yourself and the results are very good.

4. Method
(1) In order for the asphalt mixing plant to fully play its role and achieve comprehensive quality management of the production mixture, the mixing station and the superior management department should formulate various systems and quality inspections. Before starting production, preparations for materials, machines, and organizational structures must be made. When starting production, we must pay attention to the management of the production site, establish good contact with the paving section on the road, confirm the specifications and quantity of the required mixture, and establish good communication.
(2) Production personnel must master the operating procedures, work in strict accordance with the specifications, establish safety, resolutely control quality, and obey the business management of technical personnel. Pay close attention to the work quality of each position to ensure the quality of the entire process of asphalt mixture production. Establish and improve safety management systems and safety protection measures. Hang safety warning signs on all transmission parts and motor and electrical parts of the asphalt plant. Equip fire-fighting equipment, assign posts and personnel, and prohibit non-production personnel from entering the construction site. No one is allowed to stay or move under the trolley track. When heating and loading asphalt, special attention should be paid to preventing personnel from being scalded. Preventative supplies such as washing powder should be prepared. Effective lightning protection devices should be installed to prevent electrical appliances, machinery, etc. from being affected by lightning strikes and affecting production.
(3) Production site management mainly involves the scheduling of loading and transport machinery, ensuring that finished materials are delivered to the paving site in a timely manner, and keeping abreast of the conditions of road paving and various equipment so that technicians can adjust the production speed in a timely manner. The production of the mixing plant is often continuous, and the logistics department must do a good job so that the production front-line workers can take turns eating and have plenty of energy to devote to construction and production.
(4) In order to ensure the quality of the mixture, it is necessary to equip sufficient test personnel with considerable technical level; establish a laboratory that meets the routine inspection of the construction site and equip it with more modern testing equipment. Before starting the machine, randomly check the moisture content and other indicators of the materials in the storage yard, and provide them in writing to the operator as a basis for the operator to adjust the grading and temperature. The finished materials produced every day must be extracted and inspected at the frequency specified in the "Technical Specifications" to check their gradation, oil-stone ratio, temperature, stability and other indicators to guide road construction and inspection. Marshall specimens must be prepared every day to determine the theoretical density for use in calculating the pavement compaction, as well as to calculate void ratio, saturation and other indicators. Test work is very important and is one of the guiding departments for the entire production. Relevant technical data must be accumulated to prepare for brass tube inspection and handover acceptance.

5. Environment
A good production environment is an indispensable condition for the normal operation of the mixing plant.
(1) During the production period, the site must be cleaned every day. Make sure each car is sprayed with an appropriate amount of diesel to prevent the asphalt mixture from sticking to the car. The roads in the aggregate yard should be kept clear, and the feeding vehicles and loaders should be on both sides of the pile.
(2) Workers’ work, living environment, and equipment working environment are the main factors affecting production. For areas with hot climates, it is a test for equipment production and personnel. Special efforts must be made to prevent workers from heatstroke, and all new insulation board rooms must be installed. The rooms are equipped with air conditioners, which will help ensure workers' rest.
(3) Comprehensive consideration. Before building a website, comprehensive consideration must be given to nearby transportation, electricity, energy, materials and other factors.

6. Conclusion
In short, the key factors affecting the production quality of the asphalt mixing plants are complicated, but we must have a work style of facing difficulties, constantly explore ways to solve problems, and make due contributions to my country's highway projects.