Making Asphalt


A short look into how making asphalt is done in asphalt plants.

For asphalt production, there is a need for a large asphalt plant that mixes asphalt material into the deliverable, very hot, format.

The ingredients, mixture of sand, aggregate (small and large rocks), and heated asphalt cement need to be mixed in the right order and in the right proportions to make the type of asphalt needed.

This mixture can be changed with the instrumentation of the plant, if there is a need to increase, for example, the durability features of the asphalt, or to produce asphalt for pavements with lighter trafffic.

Once the asphalt is mixed to its final format, it is loaded into a delivery truck which carries the hot material to its final destination. Because the material needs to stay hot for the final "assembly" at the asphalting site, asphalt drivers often use special thermal mats on top of the material to keep it warmer longer, and the asphalt plants need to be quite close to the destination paving sites.

There are two main types of asphalt plants that do the asphalt: batch plants (for making asphalt in batches as needed), and drum plants (that make asphalt continuously and can store the asphalt for several days in heated storage silos).

Some of the common components in each of the types for asphalt plants include cold feed bins, asphalt cement storage, dryer drums, emission control system, and storage silos.

Of these, the cold feed bins are there to supply in accurate quantities and mixes the different aggregates used in the asphalt mix to the drying drum.

The dryer drum, in turn dries the aggregates with hot air.

The asphalt cement storage provides a storage tank for the asphalt cement.

Emission control systems are often called baghouses, and they catch and remove fine sand and dust from the mix and returns them to the product.

Both types may also have different types of storage silos, but for batch plants, they are not necessary, but may be present to increase the productivity of the plant.

You can also take a tour of an asphalt plant that is available from the website beyondroads.com, at

www.beyondroads.com/index.cfm?fuseaction=page&filename=tourPlant.html


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