The current market requires more and more consistent homogeneity and short mixing times for industrial production of ready-mixed concrete, and even more so for precast / prestressed concrete. This allowed refining mixing technologies for concrete production. Different models of stationary mixers have been developed, each with its own inherent strengths targeting different parts of the concrete production market. The most commonly used mixers fall into three categories:
Concrete mixer with two shafts for concrete plant
Two-shaft mixers, known for their high-intensity mixing and short mixing times. These mixers are typically used for high strength concrete, RCC and SCC, usually in batches of 2 to 6 m3 (2.6 to 7.8 m3).
Vertical axis mixers, most often used for precast and prestressed concrete. This type of mixer cleans well between batches and is preferred for colored concretes, smaller batches (usually 0.75-3 m3 or 0.98-3.92 yd) and multiple points of rejection. In this category, plate mixers are becoming less popular with more efficient planetary (or countercurrent) mixers  because the additional mixing action helps produce more critical concrete mixes (color consistency, SCC , etc.).
Drum mixers (Reversible Drum Mixers and Inclined Drum Mixers), used when large volumes (batch sizes of 3 to 9 m3 or 3.9 to 11.8 cubic yards) are produced. This type of mixer dominates the ready-to-use market because it is capable of producing high production speeds and is ideal for slumped concrete. It is used when the overall cost of production is important. Drum mixers have the lowest maintenance and operating costs of the three mixer styles.
All mixing styles have their own strengths and weaknesses and all are used around the world in varying degrees of popularity.