Concrete mixers are municipal machines that are used to prepare and transport concrete. They are necessary on every construction site where cement mortar is needed. They consist of a rotating drum or cup in which the concrete ingredients are mixed, an electric or combustion engine that drives the mixer, and a chassis with wheels that enable the machine to be moved. The capacity of a concrete mixer drum can range from several dozen to several hundred liters, depending on demand. Concrete mixers are used not only in construction, but also in gardening, road construction and renovation.