Precast- Architectural precast
Architectural Precast is specified in section 03450 and generally used as large wall panels, columns, spandrels and other “structural” members with architectural finish. It is made with ingredients including white or grey cement and graded sieve aggregates typically 1” or smaller. The compression strength is approximately 5000 psi at 28 days. Architectural Precast is typically installed by the producer company or a contracted steel or precast erection company. The quality requirements for architectural precast are typically governed by the Precast/Prestressed Concrete Institute (PCI).
Architectural Precast Concrete is not normally used as a masonry product and is usually used in the form of large curtain wall panel units or large spandrel members. An adaptation of precast concrete, it is commonly made from larger aggregates of various colors mixed with a wet slurry of sand and cement which is poured into a mould. The surface of it is usually treated by sandblasting or chemical means, to expose the aggregates, resulting in a pebbly-with-voids type of finish.
Architectural precast concrete is best suited for large crane set (vs. mason set) units and for projects where the appearance of a natural stone installation is not an important consideration.