the consist of precast slabs fixed on concrete posts

yes

unlike standard concrete which is in a liquid form and poured were it is needed and formed, precast concrete is molded offsite into the form that is required and then shipped to the site where it will be set into place.

Martin J. Gutzwiller has written:

'Use of precast, prestressed concrete for bridge decks' -- subject(s): Bridges, Floors, Precast concrete, Prestressed concrete, Testing

A. H. Gustaferro has written:

'Design for fire resistance of precast prestressed concrete' -- subject(s): Fire testing, Precast concrete, Prestressed concrete

'Fire resistance of prestressed concrete beams' -- subject(s): Concrete beams, Fire testing, Testing