insulating elevated floor slab

huangyhg

insulating elevated floor slab
i am working on the design of a structural floor slab supported on concrete columns and beams about 15' above finish grade. due to the use of the floor, the finished floor surface must be concrete (cip or precast w/ topping), so any insulation would have to be installed under or in the slab. because concrete has extremely poor insulating qualities (.01 r value per inch thickness) we must somehow insulate the floor (r12 minimum)since the building is heated. any ideas?
we did something similar many years ago. elevated structural concreteslab, rigid expanded(?) glass panels (they were about 4" thick), then a poured-in-place concrete topping. the "glass" insulating panels were rated for a specified uniform load. other than that, i don't recall the specifics. perhaps you can google for the info.
i saw a slab forming process that uses styrofoam and rebar for a deck. iwill look around and see if i can find the reference.