Masonry Magazine August 1973 Page. 21
Floor Filler Block
Filler block may be used to make the platform over which concrete joist floors may be cast in place. They are designed to be laid out on solid decking to provide the forms in which concrete joists are cast. The block are produced in sizes that vary from 4 to 12" deep. They are made with lightweight aggregate and contain hollow cores that constitute 40 to 60 percent of their volume so that they impose a considerably lower dead load than a solid concrete slab of equivalent load carrying capacity.
Another kind of filler block is designed to be supported on precast joist girders or beams. A floor slab is cast over the top to tie the whole system together.
Block Plank
A number of systems are in use for assembling floor plank from high strength block units that contain openings for prestressing steel or reinforcing rods and grout. They are designed to provide initial camber in the plank which disappears under design load. Some systems are assembled with mild steel, some with post-tensioning steel grouted in the openings, and some with both reinforcing steel and post-tensioning steel.
Sound Block
Although all block can provide good resistance to sound reflection, one patented system provides an unusually high degree of sound absorption. Slotted openings in one face shell of the block permit entry of sound waves into the cores where their energy is dissipated through internal reverberation and absorption. They are useful in the noisy areas of schools, factories, mechanical equipment rooms, highway underpasses, wind tunnels and any other location where noise levels would otherwise be high. They may be used either in walls or as floor filler block. These block are patented, however, and may not be available everywhere.