Asphalt basically refers to a semi-solid compound produced by mixing sand, various aggregate, filler and bitumen binding. Asphalt mixing plant has been used for large scale production of construction asphalt for a long time. There are two main types of such plants namely batch heater and continuous heater. The batch heater mainly produces hot asphalt in batches, which is why it is suited to small volume production. Continuous heaters use predetermined feeding rates to produce continuous volumes of asphalt in controlled environments. You can find a mobile hot mix asphalt plant (mostly in batch heaters). There also exist stationary installed asphalt plants (characterized in most continuous systems). Workable asphalt is required to remain hot (about 100-200ºC) when delivered to construction sites.
Asphalt plant system features
An asphalt plant consists of various systems that work together to hold processing materials, regulate feeding and control mixing environment. Different manufacturers produce asphalt plants with varying work procedures although work mechanism remains the same. Some of the features in a hot mix asphalt plant include;
• Feeding system for cold aggregate and a separate one for filler
• Drum dryer and heating/burning system
• Hot aggregate elevator
• Weighing system
• Mixing tower and stone dust collection system
• Electronic control system
• Finished asphalt storage
The feeding systems hold materials (cold aggregate and sand) which are then fed to the processing unit. Finished asphalt is then transferred to hot storage units.
How hot mix asphalt plants work
The work mechanism of any asphalt plant is quite simple and easy to understand. The system has various hopers that hold materials (such as aggregate, sand, filler…) to be used in asphalt production. These materials are fed into a burning unit that heats them to required temperatures. Once the mixture is hot, filler and binding is added. Fillers (like stone dust) bridge voids in the mixture grains while bitumen binding holds the compound together and toughens bonding. Filling improves wear capabilities of concrete asphalt and binding ensures the asphalt becomes a strong solid substance when cooled. To get more information, you can visit asphalt-mixing-plant.net.
After filler and binding has been added to the hot mixture, it becomes hot asphalt. It can then be delivered into small collector hopers or directly to construction-site delivery vehicles. Asphalt is a real-time product which means it is required hot for its workability. Storage silos are therefore maintained at hot temperatures using electronically regulated systems to prevent cooling and solidification. For batch heaters, the asphalt is produced in given proportions (batches). The process is therefore slower and used in cases that require low volumes or frequent changing of recipes. Continuous systems on the other hand utilize preset material feeding rates and controlled processing environments for seamless production of asphalt. Binding and filler is added in the burning drums as soon as sand and aggregate have been heated. Continuous systems are more efficient and can be used to produce large volumes of asphalt since most processes are automated.
Your hot mix asphalt plant should exhibit superior systems with modern computerized technologies. Feeding rate, work efficiency and end-product consistency are some of the important value evaluation points. Asphalt is a real time product and any incorrect combination may result in quality damage of an entire volume which corresponds to resource wastages. It is important to purchase high quality plants that have high precisions and are easy to manage.