Precast concrete refers to concrete that is cast in a factory. Once sufficient strength has been gained the concrete units are transported to site where they are joined to form the complete structure or part of the structure. Units range in size from bricks and blocks up to bridge beams. The sizes of the large units are limited by the requirements for transport and lifting/handling on site.
Precast yards are sometimes set up next to construction sites to minimise transport.
For further information see main heading ‘Precast’ and subsequent sub-headings.