Ready-mixed concrete plants
The majority of concrete is supplied from ready-mixed plants. The plants combine the materials (aggregate, cement, water and admixtures if required) in the specified proportions. (The batching is usually fully or partially automated.) The batched materials may be mixed prior to discharging into the ready-mixed concrete truck but generally they are loaded in dry and mixing is carried out in the truck itself prior to leaving the plant.
For large contracts, dedicated plants may be installed on site, serving only that contract. This provides greater control over supply than obtaining concrete from a regular source.