Method of Batching

The number of aggregates to be included depends on the number of available aggregate bins at the mixing plant and the method of mixing. Various mixer types have been used, but the types shown in figures 6 and 7 are the standard recommendation for consistent production and mixing efficiency.

The batch-type horizontal shaft mixer can yield production rates up to approximately 100 to 140 cy/hour while providing excellent mixing efficiency for dry materials. This mixer is reasonably mobile and can be easily set up in one day. This mixer needs to be augmented with a batching operation as it is inserted underneath a dry batch ready mix plant.

The continuous-type horizontal shaft mixer provides a higher range in production rates up to 500 cy/hr, with most around 200 cy/hr. The mixture consistency is good, maintaining minimal moisture fluctuation and easy moisture adjustment. This type of mixer can also be easily moved and erected on site, as it is a self-contained operation that requires only two or three people to operate it. It can typically handle up to two aggregate sources, but it can be augmented with additional aggregate bins allowing up to four aggregate sources.