The two most common forms of structural concrete decks used are cast-in-place and slab over steel pan decking.  Cast-in-place (CIP) concrete deck serves a vital role in the structure and is designed to carry heavy loads, these decks are formed and forms are stripped after the concrete has cured.  Slab over steel pan decking also supports large loads, these decks are poured & finished over steel pan decking that is permanently left on-site.