In the asphalt pavement construction, the asphalt mixing station plays a key role. The performance of the asphalt mixing station and the working condition of the asphalt mixing station directly affect the quality of the asphalt mixture, thus affecting the quality and progress of the entire project. Therefore, the main points of the construction control of the asphalt mixing station are now explained.
Control of various indicators of the mixture
(1) Temperature control of the mixture
The temperature of the mixture is one of the conformity assessment criteria for the mixture. If the temperature is too high or too low, it is waste and cannot be used. So how to control the temperature is one of the basic skills that the operator should have.
One of the factors that affect the temperature of the mix is the quality of the fuel. If the quality of the fuel is poor, the calorific value is low, and the combustion is insufficient, the heating of the stone is unstable, the temperature is low, and the residue after burning remains in the mixture, which seriously affects the quality of the mixture. If the viscosity of the fuel is too large, the content of impurities is large, and the water content is large, it will cause difficulty in ignition, blockage of the pipeline, and difficulty in controlling the temperature. The water content of the raw material is another factor affecting the temperature. The raw material has a large water content and is uneven. In the production process, the heating temperature of the stone is difficult to control. In addition, the technical state of the combustion system, the pressure of the fuel supply pump, and the amount of fuel injection are related to the temperature of the mixture. Failures such as wear, air leakage, and blockage of the combustion system prevent the components from maintaining the original performance, resulting in lower system pressure; unstable oil supply, poor atomization and combustion effects, and severely affecting the mixing temperature.
Although the current mixing equipment has an automatic temperature control function, since a process is required from the detection of the temperature to the addition and subtraction of the flame to adjust the temperature, the temperature control has hysteresis. In order to ensure the mixing temperature, the mixing station can not produce waste. By carefully observing the rate of change of temperature, predict the temperature change result in advance, and manually increase or decrease the flame or increase or decrease the feed amount to control the temperature change, so that the change result is not Exceed the specified range to reduce or eliminate waste.
(2) Gradation control of the mixture
The gradation of the mixture directly affects the performance of the pavement. If the gradation of the mixture is unreasonable, the pavement will have some problems such as large void ratio, small size, water permeability, rutting, etc., which will reduce the service life of the pavement and seriously affect the quality of the project. Therefore, grading control of the mixture is also one of the skills that the operator must have.
Factors affecting the grading of the mixture include: changes in the particle size of the raw materials, changes in the screen of the mixing station, and measurement errors. The size of the raw material particle size directly affects the gradation of the mixture. When the raw material is found to change, the operator should cooperate with the laboratory to fine-tune the production mix ratio; the change of the hot mesh screen of the mixing station affects the gradation of the mixture. Important factors, if the screen is clogged, the hot material screening is not sufficient, the grading will be fine. If the screen breaks, breaks, leaks, and wears out of limits, the mix will become coarser; the mixing station measurement error, It also directly affects the gradation. If the measurement error range is adjusted too much, the deviation of the production mix ratio and the target mix ratio will be large, which will seriously affect the quality of the mix. If the measurement error range is adjusted too small, the measurement time will be increased. The output will also make the measurement frequently exceed the limit and affect the normal operation of the mixing station.