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Basic principles and process flow of asphalt mixing equipment

Asphalt mixture mixing equipment is a factory-style complete set of equipment that mixes dry and heated aggregates of different particle sizes, fillers and asphalt according to the designed mix ratio at a specified temperature into a uniform mixture. It is widely used in high-grade highways and urban roads. , airports, docks, parking lots and other engineering construction. It is a key equipment for asphalt pavement construction, and its performance directly affects the quality of asphalt pavement.
Generally, there are two types of asphalt concrete mixing equipment: intermittent type and continuous type. The continuous process flow is simple and the equipment is simplified. As for the intermittent forced mixing equipment, due to the secondary screening of aggregates, various components are measured in batches, and forced stirring and mixing can reliably ensure gradation, and the measurement of powder and asphalt can also achieve very high accuracy; so the mixing equipment The asphalt mixture produced is of high quality and can meet various construction requirements.

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Asphalt mixture mixing equipment is a factory-style complete set of equipment that mixes dry and heated aggregates of different particle sizes, fillers and asphalt according to the designed mix ratio at a specified temperature into a uniform mixture. It is widely used in high-grade highways and urban roads , airports, docks, parking lots and other engineering construction. It is a key equipment for asphalt pavement construction, and its performance directly affects the quality of asphalt pavement.
Generally, there are two types of asphalt concrete mixing equipment: intermittent type and continuous type. The continuous process flow is simple and the equipment is simplified. As for the intermittent forced mixing equipment, due to the secondary screening of aggregates, various components are measured in batches, and forced stirring and mixing can reliably ensure gradation, and the measurement of powder and asphalt can also achieve very high accuracy; so the mixing equipment The asphalt mixture produced is of high quality and can meet various construction requirements.
Since my country currently mainly uses forced intermittent asphalt mixing equipment, the following content is mainly based on Sany Heavy Industry’s LB series asphalt mixing equipment as a representative. 1. Mechanical system process flow
The main process characteristics of the intermittent asphalt mixture mixing equipment are: various ingredients are measured in batches, and are put into the mixer in a pre-set order for forced mixing. After the mixed finished materials are discharged, the next cycle is carried out to form A cycle of work that starts over and over again. The so-called intermittent type refers to the mode in which the dresser measures and stirs production in batches.
Use a loader to shovel sand and gravel materials of different specifications into the corresponding cold silos; after volume measurement of the belt feeder controlled by the frequency converter (the frequency converter parameters are preset according to the grading type, output and mix ratio), Material belt conveyor and feeding belt conveyor transport it to the drying drum.
The drying drum uses countercurrent heating to dry and heat the sand and gravel to a certain temperature (the control system automatically adjusts the flame size of the burner). Due to the rotation of the drum, the sand and gravel are repeatedly lifted and dropped by the blades in the drum, forming a material curtain. , which enhances the heat exchange effect, and with the help of the inclination of the drum, the sand and gravel materials continue to move forward while being heated; after coming out of the drum outlet, together with the coarse powder collected by the gravity dust collector, they are lifted up and unloaded by the hot aggregate elevator. into the hot aggregate screening machine.
The high-temperature dusty flue gas discharged from the drying drum first enters the gravity dust collector for preliminary purification through the first-level flue. The collected powder with a particle size of 0.075mm or more is sent to the entrance of the hot aggregate elevator by a screw conveyor; The dust and flue gas enter the bag dust collector, and the filtered flue gas is directly discharged into the atmosphere by the induced draft fan. The dust recovered from the bag dust collector is sent to the recycled powder supply system by a screw conveyor for storage.
The hot aggregate is screened into several specifications through a screening machine, and then flows into corresponding hot material storage silos for storage. According to the set ratio, aggregates of different specifications are put into the stone measurement bin in batches in order of small and then large for cumulative measurement; at the same time, the hot asphalt sent from the asphalt supply system and the powder sent from the powder supply system are separately Put it into the respective measuring device for measurement according to the set ratio. After weighing is completed, put it into the mixing pot according to the preset order for forced stirring. The mixed finished product materials are unloaded into the finished product lifting trolley, and then lifted by the winch and unloaded into the finished product silo for storage. You can also choose to unload them directly into the material transport dump truck.
The control system relies on the signals detected by each sensor to monitor important parameters such as material ratio, asphalt content, and mix temperature in real time to ensure that the quality of the mix produced can meet the user’s requirements. Throughout the process, the electronic control system is also equipped with interlocking protection devices to protect the equipment from unexpected mechanical accidents.
It should be noted that the volume measurement of cold aggregate passing through the belt feeder is pre-measurement, and the measurement of screened hot aggregate, powder and hot asphalt is measurement. Because of the secondary measurement, it can ensure the gradation of the mixture and the proportion of aggregate, powder and asphalt with relatively high precision. The current static metering accuracy for aggregates and powders does not exceed ±0.5%, and the static metering accuracy for asphalt does not exceed ±0.25%. Since it is intermittent mixing, it is also very convenient to change the mixture ratio, and the formula can be changed or replaced without stopping the machine.

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    More Road Maintenance

    We need to prepare a lot of work when using modified asphalt equipment. What kind of work do we need to prepare? Next, let me briefly introduce the relevant knowledge points.
    1. Heat transfer oil heats and insulates the modified asphalt equipment and nozzle. After spraying, the asphalt pump and nozzle do not need to be cleaned with diesel. Use high-pressure air to press the asphalt in the pipeline and spray pipe back to the tank, and then blow the nozzle; use heat transfer oil to keep warm, so that the pipeline and nozzle are smooth and unobstructed. 2. Various asphalts can be spread: high-viscosity asphalt, hot asphalt, emulsified asphalt, etc.; the spreading width can be freely adjusted, each nozzle can be controlled separately, and the maximum spraying width is up to 6m. Flexible handheld spray guns can be used to spray asphalt on corners. 3. Excellent thermal insulation performance, average cooling ≤1-2℃/h. 4. Convenient loading and unloading function. In addition to filling asphalt from the asphalt tank port, hot asphalt can be sucked out by itself, and external asphalt can also be pumped and transferred. 5. The modified asphalt equipment is evenly spread, and the nozzle design can be used for triple overlapping spraying.
    The above are the relevant knowledge points of modified asphalt equipment. I hope the above content can be helpful to everyone. Thank you for your viewing and support. More information will be sorted out for you later. Please pay attention to our website updates.

    Emulsified modified asphalt equipment is classified according to the production process and can be divided into three types: intermittent emulsified modified asphalt equipment, semi-continuous emulsified modified asphalt equipment, and continuous emulsified modified asphalt equipment. During the production of emulsified modified asphalt equipment, demulsifier, acid, water, and latex modified materials are blended in a soap mixing tank, and then pumped into the asphalt into the colloid mill. After a can of soap is used up, the soap is redispensed, and then the production of the next can is completed.
    The emulsified modified asphalt equipment mentioned here includes hot water pumps and circulation pumps. This type of centrifugal water pump generally uses a pipeline centrifugal pump. There is a sewage outlet at the bottom of the pipeline centrifugal pump. Pay attention to the sewage outlet at the bottom of the emulsified modified asphalt equipment pump. The water in the water tank is released through the filter valve. Some emulsified modified asphalt equipment does not have a filter valve to save equipment costs, so it can only be emptied by loosening the flange bolts at the bottom. There are basically two methods of moisturizing emulsion pumps for emulsified modified asphalt equipment on the market, gear oil pumps or centrifugal water pumps. The gear oil pump can only drain the liquid in the pump through the connecting flange of the pipeline. The centrifugal water pump carries out sewage treatment through its own sewage outlet.
    When used in the production of emulsified modified asphalt equipment, depending on the modified material technology, the latex pipeline can be connected in front of the colloid mill or behind the colloid mill, or there may be no latex pipeline and it must be made manually. Add the required amount of latex into the soap jar.

    We should select products that meet the specifications, and we should not select raw materials that do not meet the specifications. The other thing is the operation technology of asphalt heating equipment. Skilled operation technology is the most important, and training is required before taking up the post.
    In recent years, with the continuous development of various industries, the production of various equipment including modified asphalt equipment has been further developed and applied. Professionals introduced that in the process of using modified asphalt equipment for production, the terminal control system implements full automatic control of medium weight, working temperature, working flow, valve opening and closing, etc., thereby ensuring the quality of modified asphalt and greatly improving production efficiency. Now Shandong Duxiu Factory will explain the operating advantages of modified asphalt equipment to customers:
    The base asphalt is heated to 150-170℃ in the rapid heating tank and then enters the blending tank to mix with the modifier fed in through the feeding device. The asphalt pump at the bottom of the blending tank then sends it to the colloid mill for high-speed grinding and shearing, so that the modifier and base asphalt are fully dissolved in extremely small particles, thereby improving the various properties of the asphalt. The finished modified asphalt after high-speed shearing and grinding enters the finished product development tank at the rear for direct use.

    We have conducted in-depth research on asphalt distributors and have accumulated a lot of production technology experience. We have conducted professional and in-depth research on some problems existing in the market to provide convenience for everyone in future production applications.
    Every time when spraying asphalt, the asphalt distributor does not spray asphalt. Troubleshooting. The asphalt distributor does not spray asphalt. It is a common fault. The following teaches you how to solve the problem of not spraying asphalt.
    1. No asphalt spraying
    Analysis of the reasons may be the following reasons:
    1. Is the asphalt pump working?
    2. Are the valves adjusted correctly?
    3. Is the pump or pipeline blocked?
    2. Troubleshooting method
    1. Check whether the hydraulic system is working properly?
    2. After adjusting the valve position, the asphalt distributor must be cleaned to avoid pipeline blockage when used next time. Because the asphalt distributor has different high and low configurations, it can spread various high-viscosity and high-temperature modified asphalts and rubber asphalt in high configuration. If you mistakenly use a low-configuration asphalt truck to spread this type of asphalt, you must spray the asphalt inside the entire vehicle clean after the first use. After spraying, in order to leave no residual asphalt, you can use waste diesel to clean it. Our company’s vehicles are equipped with air cleaning and gravity cleaning devices. Diesel cleaning is a reliable cleaning method.

    Improve the understanding of the importance of preventive maintenance
    We should further improve the understanding of the importance of preventive maintenance and raise preventive maintenance to the level of highway asset protection and road protection. At present, leaders at all levels and maintenance departments do not fully understand the significance of preventive maintenance of asphalt pavement. We should deepen our understanding of the important role of preventive maintenance and improve the strategic awareness, initiative and creativity of preventive maintenance. At the same time, the maintenance department should strengthen communication and exchanges with transportation authorities and financial management departments at all levels, so that departments at all levels understand the importance and necessity of preventive maintenance and create conditions for the implementation of preventive maintenance and funding sources. At the same time, it is very necessary to add preventive maintenance to the classification of maintenance projects, which will help the management of leaders at all levels and the implementation of preventive maintenance.
    Improve the decision-making and planning of preventive maintenance
    According to the decision-making and planning process, reasonably arrange the preventive maintenance of asphalt concrete pavement structure to ensure the safe and stable operation of highway projects throughout the life cycle, and reduce production costs while providing high-quality traffic services. Therefore, the key to preventive maintenance of asphalt concrete pavement structure lies in establishing a scientific decision-making and planning mechanism. The Ministry of Transport proposed in the “13th Five-Year Plan for Highway Maintenance Management Development” that the average annual mileage of preventive maintenance for expressways should not be less than 8%, and that for ordinary national and provincial roads should not be less than 5%. In the actual application process, local governments should also actively summarize experience and propose different preventive maintenance ratios based on the specific conditions of different regions.

    In order to better play the role of slurry seal vehicles, this article explains the matters that should be noted from the aspects of the scope of application, type and material selection, construction technology, common diseases, etc. of slurry seal vehicles.
    The slurry seal vehicle is thin in thickness and mainly plays the role of waterproofing, anti-skid, wear-resistant and improving the appearance of the road surface. In the pavement structure system, it can only serve as a surface protection layer and wear layer, but not a load-bearing structure. It is widely used in the construction and maintenance of highways. Practice has proved that the slurry seal can also play an important role by reasonably selecting the thickness and type of the slurry seal and strictly controlling the construction technology and quality.
    (1). The scope of application of slurry seal vehicles includes the following aspects:
    1. When the pavement damage index of expressways and first-class highways is evaluated as medium and below, or the pavement damage index of second-class and below highways is evaluated as secondary and below, when medium repair and overlay measures should be taken, slurry seal can be selected.
    2. When the pavement driving quality index of expressways and first-class highways is evaluated as medium or below, or the pavement driving quality index of second-class and below highways is evaluated as second or below, medium repair and overlay measures should be taken to improve its flatness, and slurry seal can be selected.
    3. For sections of expressways and first-class highways with insufficient anti-skid capacity (SFC<40), or sections of second-class and below highways with insufficient anti-skid capacity (SFC<33.5), measures such as adding overlays should be taken to provide anti-skid capacity of the road surface. 4. Anti-skid layer and waterproof protective layer used for third- and fourth-class highways to improve the appearance of the road surface.