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Description and cause analysis of common problems in asphalt mixing plants

The quality of the asphalt mixing plant will be a key factor affecting the quality of the project. After reviewing relevant materials related to the production and construction of asphalt concrete, we summarized some cases of failures in asphalt concrete mixing stations during construction and analyzed the reasons.
1. Unstable output and low production efficiency of asphalt mixing plants
(1) Improper proportioning. The mix ratio of asphalt concrete is divided into target mix ratio and production mix ratio. Among them, the target mix ratio controls the cold material transportation ratio of sand and gravel materials, and the production mix ratio is the mixing ratio of various types of sand and stone materials in the finished asphalt concrete materials specified in the design. The production mix ratio is determined by the laboratory, which directly determines the off-site grading standard of the finished asphalt concrete. The target mix ratio is set to further ensure the production mix ratio, and can be adjusted appropriately during production according to the actual situation. When the target mix ratio or the production mix ratio is not appropriate, the stones stored in each measurement of the asphalt mixing station will be disproportionate, with some overflowing and some other materials, unable to be weighed in time, and the mixing cylinder will be idling, resulting in reduced output.

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The quality of the asphalt mixing plant will be a key factor affecting the quality of the project. After reviewing relevant materials related to the production and construction of asphalt concrete, we summarized some cases of failures in asphalt concrete mixing stations during construction and analyzed the reasons.
1. Unstable output and low production efficiency of asphalt mixing plants
(1) Improper proportioning. The mix ratio of asphalt concrete is divided into target mix ratio and production mix ratio. Among them, the target mix ratio controls the cold material transportation ratio of sand and gravel materials, and the production mix ratio is the mixing ratio of various types of sand and stone materials in the finished asphalt concrete materials specified in the design. The production mix ratio is determined by the laboratory, which directly determines the off-site grading standard of the finished asphalt concrete. The target mix ratio is set to further ensure the production mix ratio, and can be adjusted appropriately during production according to the actual situation. When the target mix ratio or the production mix ratio is not appropriate, the stones stored in each measurement of the asphalt mixing station will be disproportionate, with some overflowing and some other materials, unable to be weighed in time, and the mixing cylinder will be idling, resulting in reduced output.
(2) Material gradation is unqualified. If the feed material is not within the appropriate range, it will not only produce a large amount of “waste” during production, but also affect the output. The production capacity of the drying barrel of the asphalt mixing station matches the equipment model accordingly. When the water content in the sand and stone is too high, the drying capacity decreases, and the amount of sand and stone provided to the metering bin to reach the set temperature per unit time is reduced, thus Reduced production.
2. The discharging temperature of asphalt concrete is unstable
If the temperature is too high or too low, it will affect production, resulting in poor quality or a large amount of “waste” produced on site. This requires that during the production process of asphalt mixing stations, relevant personnel must observe carefully, measure frequently, and have a high sense of quality responsibility.
3. It is dusty and pollutes the construction environment.
During construction, the site of some asphalt mixing stations is smoky, which not only harms the health of workers, but also pollutes the environment. The main reasons are: the amount of mud and dust in sand and stone is too large and seriously exceeds the standard; 2. Dust removal system failure.

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    The actual operation steps of drying drum of asphalt mixing equipment: 1. Pay attention to routine inspection; 2. Proper operation steps; 3. Effective maintenance.
    Drying drum is a cylindrical device specially used for heating and drying stones in asphalt mixing equipment. Proper application and maintenance of drying drum can maximize the performance of drying drum, increase its service life and reduce application cost. Let’s take a look at the actual operation steps below.
    1. Pay attention to routine inspections
    The asphalt mixing equipment drying drum has been tested and inspected before leaving the factory, but it will be subjected to vibration and vibration during transportation to the construction site. A comprehensive inspection should be carried out before use: check whether all anchor bolts are tightened; whether all key pins are properly driven; whether all drive devices are adjusted according to the manufacturer’s instructions; whether all pipe connections are appropriate and whether the three-way joints are reliable; whether the entire equipment is fully lubricated; start the motor and check whether all parts can rotate steadily in the correct rotation direction; whether the pressure gauge can work normally and whether the valve is adjusted to the correct working pressure; whether the burner ignition mechanism is available and whether the gate valve is open.
    2. Correct operation steps
    After the equipment is started, it is recommended to control the machine manually at the beginning, and then switch to the automatic control mode after achieving the required production volume and pouring temperature. The stone should be dried and have a stable moisture content as much as possible so that the stone can maintain a stable final temperature when passing through the drying drum. If the stones delivered to the drying drum change frequently and the moisture content changes each time, the burner should be adjusted frequently to compensate for these changes.
    The stones directly from the crushed stone have a relatively constant moisture content, while the stones from the outdoor storage yard have a higher moisture content, and the moisture content of different piles varies greatly. Therefore, it is best for the stones to come from the same source.

    The drive unit is one of the important components of the asphalt mixing plant, so whether it can be reliably operated must be highly valued to avoid adverse effects on the entire asphalt mixing plant. In order to ensure that the drive unit in the asphalt mixing plant is indeed complete and reliable, the following maintenance measures are essential.
    The first thing to pay attention to is the universal rotating part of the drive unit of the asphalt mixing plant. This part has always been a fault-prone part. In order to reduce the occurrence of faults, grease should be added on time, and the wear should be checked frequently, and repaired and replaced in time. Users should also prepare the universal shaft assembly to avoid affecting the working process of the entire asphalt mixer.
    Secondly, the cleanliness of the hydraulic oil used in the asphalt mixing plant must be ensured. After all, the working environment of the equipment is relatively harsh, so it is necessary to prevent sewage and mud from entering the hydraulic system. The hydraulic oil should also be replaced regularly according to the requirements of the manual. Once water or mud is found mixed in the hydraulic oil during inspection, the hydraulic system should be stopped immediately to clean the hydraulic system and replace the hydraulic oil.
    Since there is a hydraulic system, of course, a matching cooling device is also required, which is also an important focus in the drive system of the asphalt mixing plant. To ensure that its function can be fully exerted, on the one hand, the hydraulic oil radiator should be cleaned regularly to prevent the radiator from being blocked by cement; on the other hand, the radiator electric fan should be checked to see if it is running normally to prevent the hydraulic oil temperature from exceeding the standard.
    In general, as long as the hydraulic oil of the asphalt mixing plant drive device is kept clean, there are generally few faults; but the service life varies from manufacturer to manufacturer, so pay attention to its alkalinity observation and replace it in real time.

    The mobile forced asphalt mixing equipment adopts intermittent drying cylinder, double forced mixer, the main machine can be towed, small footprint, short installation cycle, convenient operation and maintenance, good stability, high degree of automation, high degree of standardization, and high quality of finished products, and the technology of continuous improvement. The mobile forced asphalt mixing plant is suitable for high-grade road asphalt paving and maintenance.
    1. The combined structure of the drum dryer and the batching machine is installed on a movable bracket for easy movement.
    2. The asphalt mixing plant is equipped with a double horizontal shaft to boil the aggregate and ensure uniform mixing.
    3. In the densely arranged hanging barrels, the hot aggregate rises vertically. This lifting tool is easy to use and reliable.
    4. For accurate weighing of aggregates, asphalt and powder ore, a measuring scale is used, which contains a weighing sensor for electronic measurement.
    5. The movement of the power material follows a closed spiral path, which ensures little material loss and provides safe transfer.
    6. On the cyclone burner, high-pressure oil is sprayed out and quickly atomized. In the combustion chamber, the material is fed in a spiral manner and automatically ignited by the oil mist, which ensures combustion efficiency. The cylindrical barrel of the burner is separated from the burner head. The furnace cavity can be pushed in and pulled out, which is convenient for replacing the damaged side column bricks inside the burner. The entire burner has a large heat capacity and high thermal strength. This is cost-effectiveness.