Concrete Batching Plant 35 cbm/hour means that a concrete batching plant has a size or capacity of 35 cubic metres. This means that the mixing plant can produce 35 cubic metres of concrete at a time. This size of mixing plant is usually suitable for small and medium-sized projects, such as house building and road construction. The larger the scale of the mixing plant, the higher the production capacity, which can meet the needs of larger-scale projects.