Fig. 1 shows a schematic representation of a star-shaped system. The individual aggregate grades are stored in open bays with a star-shaped grouping. A centrally located rotary scraper uses a bucket to convey the aggregates to the batching star where they are weighed before being transported to the mixer by a feed hopper or conveyor. The cement is stored in separate bins.
Star-shaped systems are mainly used as mobile mixing units on construction sites. They require a relatively large footprint, and the aggregates are exposed to the weather. These systems are used only to a limited extent in concrete plants owing to the restricted number of possible aggregate grades and because fluctuations in the aggregate moisture content may adversely affect the quality of the concrete.