Asphalt mixing plant, also known as hot mixing plant or asphalt batch mixing plant, is a facility for the production of asphalt concrete. Asphalt concrete is a mixture of asphalt binder and aggregate used in the construction of roads, parking lots, airports and other infrastructure projects. The process of producing asphalt concrete involves several common operations, which are described below.
Aggregate Handling and Storage
The first operation of an asphalt mixing plant is the handling and storage of aggregates. Aggregate, usually crushed stone, gravel or sand, is transported to the plant and stored in hoppers or silos. The aggregate is then conveyed to the batching system where it is batched according to the mix design.
Drying and Heating of Aggregate
Before aggregates can be used in a mix, they must be dried and heated to remove moisture. This is usually done in a tumble dryer, which is a rotating drum heated by burners. As the aggregates pass through the drums, they are heated and dried, removing all moisture.
Mixing of aggregate and asphalt binder
Once the aggregates are dry and heated, they are mixed with an asphalt binder. Bituminous binders are stored in tanks at the factory and heated to a specified temperature before being mixed with the aggregate. The mixing process is done in a mixer or twin-shaft mixer to ensure that the aggregate is thoroughly covered with the bituminous binder.
Finished product warehousing and loading
After the mixing process is complete, the finished asphalt concrete is stored in silos until it is ready to be loaded onto trucks for transport to the construction site. Storage silos are designed to keep asphalt concrete at a constant temperature, ensuring the product remains usable and easy to transport.
Control System
In order to ensure the efficient operation of the asphalt mixing plant and produce high-quality asphalt concrete, the equipment is equipped with a series of control systems. These systems include sensors that monitor the temperature of the aggregate and asphalt binder, as well as the flow rate of the material through the plant. The control system also includes software that allows plant operators to adjust mix designs, monitor production rates and track inventory levels.
environmental control
Asphalt mixing plants generate significant amounts of air pollution, including particulate matter, carbon monoxide, and volatile organic compounds. To minimize these emissions, asphalt mixing plants are equipped with a range of environmental controls. These controls include baghouses, which filter air before it is released into the atmosphere, and scrubbers, which use water to remove pollutants from the air.
Common operations in an asphalt mixing plant include aggregate handling and storage, drying and heating of aggregate, mixing of aggregate and asphalt binder, storage and loading of finished products, control systems, and environmental control. Each of these operations is critical to producing high-quality asphalt concrete that meets the needs of construction projects. By understanding the common operations of asphalt mixing plants, construction professionals can make informed decisions about which plant to use in their projects and how to optimize plant performance to achieve desired results.
