Most Americans could not tell you where asphalt comes from. The simple answer is that asphalt comes from asphalt plants. What does that mean though? Last week, we explored the basics of asphalt plants. This includes the different types of plants, as well as the advantages of each one. This week, we are focusing on comparing and contrasting the types of asphalt plants. Read on to learn just how the two processes stack up against one another.

Similarities

The two types of asphalt plant operate quite differently. However, where they are similar is the components that are used in the production of the asphalt.

Cold Feed Bins

These bins send the various aggregates into the drying drum. The aggregates are stored in either stockpiles, silos, or even bunkers.

Asphalt Cement Storage

The asphalt cement storage is where liquid part of the final asphalt product is stored. These storage areas operate under insanely tight restrictions to avoid spills.

Drying Chamber

Drying drums heat the aggregate via hot, dry air. Essentially, this is one of the most vital components of the entire process.

Baghouse

The baghouse, more formally called the dust collection system, is one of the environmental protections of the asphalt producing process. It captures all of the fine particles, such as dust and sand, that escape from the aggregate and return them back to the mix.

Storage Silos

Storage silos are where the produced asphalt is stored and warmed. They are absolutely essential in drum plants, and keep the produced asphalt warmed and ready to go. Bath plants also use the silos in order to increase production rates. The silos are always insulated, and some, designed to be heated, are for longer term storage. Some asphalt sits in silos as much as a few days.

Differences

While the components are similar, there are a wide variety of differences between the types of plants as well.

Mixing

The mixing process for asphalt is highly important. It is essential that the plant makes sure that the aggregate materials and liquid components of asphalt actually combine. Batch plants use a very traditional method of mixture, where mechanized arms with large puddles do the work. The time spent mixing is adjusted for every mixture’s needs. Meanwhile, drum plants mix the materials through the rotation of the drum. The only way to adjust the mixing time is by slowing or speeding up the entire production line.

Measurement

In batch plants, the employees weigh aggregate and liquid components with load cells for improved accuracy. The aggregate is dried and then added to the mixer based on the specific formulations desired. However, drum plants are much more automated to keep the production moving along. Workers in drum plants use flow meters and calibrated feed belts to measure the components into the mixer.