Biaxial tiles, also known as hollow biaxial tiles, are concrete structural elements reinforced with metal frames and iced with pockets with air seals in plastic containers. These voids reduce the density and weight of the ultimate material by up to 50% compared to solid concrete, making them more affordable, less harmful to the environment, more resistant to seismic activity and better suited to certain design aspects, such as horizontal surfaces
Empty plates have been used since the 1950s, with different designs from simple hollow cores to waffle shapes. Biaxial tiles are so named because their internal structure has beams of concrete along two axes. Property variations have included different materials and shapes for the air pockets, in some cases the air has been replaced with blocks of polystyrene.
All biaxial plates have some internal reinforcement, although the shapes and components may vary widely. Although it may take more time to construct biaxial tiles in place, this method may ultimately be less expensive than using prefabricated elements.