Types of asphalt concrete
Asphalt concrete pavement should use appropriate hot mix asphalt mixture according to usage conditions, environment, construction conditions, pavement properties, highway grade, etc. The following types are commonly used:
1. Ordinary asphalt mixture
That is AC type asphalt mixture, which is suitable for urban secondary roads, auxiliary roads or sidewalks.
2. Modified asphalt mixture
Modified asphalt mixture refers to an asphalt mixture made by adding rubber, resin, high molecular polymer, finely ground rubber powder or other fillers and other additives (modifiers) to improve the performance of asphalt or asphalt mixture.
Compared with AC-type asphalt mixture, modified asphalt mixture has higher high-temperature rutting resistance, good low-temperature resistance to cracking, higher wear resistance and longer service life. The modified asphalt mixture surface layer is suitable for urban expressways and trunk roads.
3. Asphalt masculine mixture (SMA for short)
SMA mixture is a mixture composed of asphalt, mineral powder and fiber stabilizer, which is filled in the discontinuous skeleton. SMA is a discontinuously graded asphalt mixture. The proportion of coarse aggregate over 5mm is as high as 70%~80%, the amount of mineral powder is 7%~13% and the amount of asphalt is relatively high, up to 6.5%~7%.
SMA is an asphalt surface mixture with strong deformation resistance and good durability that is currently used at home and abroad; it is suitable for urban expressways and main roads.
4. Modified (asphalt) asphalt masala gravel mixture
This type uses modified asphalt and adopts SMA structure type. It has very good high-temperature anti-rutting performance, low-temperature anti-deformation performance and water stability, and has a large structural depth, good anti-skid performance, and greatly improved aging resistance and durability.
Types of asphalt mixing plants
The hot mix asphalt machine is a complete set of equipment used for batch production of asphalt concrete. The asphalt mixing station uses aggregate, powder and asphalt as raw materials and mixes them according to a certain mix ratio. According to the mixing method, it can be divided into batch type and continuous type. According to the transportation method, it can be divided into stationary, mobile and semi-fixed.
The quality control of asphalt mixing plant
1. Asphalt temperature control
Asphalt temperature is one of the important factors affecting the quality of asphalt mixture. During the production process, the temperature of asphalt must be strictly controlled to ensure that it is within the specified range. Generally speaking, the temperature of asphalt should be maintained between 130℃-170℃.
2. Aggregate gradation control
Aggregate gradation is an important indicator of asphalt mixture, which directly affects the strength and stability of the mixture. During the production process, the gradation of aggregates must be controlled through testing and inspection to ensure that it meets specified requirements.
3. Asphalt mixture oil-stone ratio control
The asphalt mixture oil-stone ratio refers to the ratio of the mass of asphalt in the asphalt mixture to the total mass of aggregates and fillers. During the production process, batching must be carried out in strict accordance with the design requirements of the oil-stone ratio, and the oil-stone ratio must be controlled through testing and inspection.
4. Mixing time control
The length of mixing time also affects the quality of asphalt mixture. During the production process, mixing must be carried out strictly in accordance with the mixing time requirements to achieve a uniform and consistent effect.
5. Equipment maintenance
The asphalt drum plant maintenance is also one of the important factors to ensure the quality of asphalt mixing plants. Equipment must be inspected and maintained regularly to ensure the integrity of the equipment and the stability of its operation.
Original source: https://www.haomei-machinery.com/a/hot-mix-asphalt-machine-asphalt-drum-plant.html
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