Before constructing anything, it is essential to know how these ingredients are made. Like any good recipe, the ingredients should be high quality, they should be carefully measured, and they should be cooked at exactly the right temperatures. At the asphalt plant, the aggregates are precisely blended into a gradation and then dried and heated to the right temperature. The mixture is then completely coated with liquid asphalt cement. There are two types of asphalt plants, batch and drum. Drum mix plants dry the aggregate and blend it with asphalt in a continuous process in the same piece of equipment. With batch plants, the rocks are first dried and heated, then added to the pugmill and blended with the asphalt one batch at a time.