Access floor-panel and core

A structural panel for use in an access floor, the structural panel comprising:

• A concrete core for use in a structural floor panel, the concrete core comprising:
• substantially parallel, substantially flat, opposite top and bottom surfaces separated by a predefined thickness;
• at least one edge, said at least one edge contiguous with the respective peripheries of said top and bottom surfaces;
• a monolithic casting of a concrete material comprising cement, coarse lightweight aggregate, water, fly ash, and sand;
• said concrete material having a mass density in the range of 1650-1850 kilograms per cubic meter;
• a pan comprising a bottom panel, said bottom panel having a profile substantially identical to the bottom surface of the concrete core;
• said pan located proximate to and oriented substantially parallel to the bottom surface of the concrete core, separated therefrom by a gap;
• a bond layer comprising an adhesive filler material, said bond layer adhering to the concrete core, said bond layer adhering to the metal pan;
• said bond layer spanning and substantially filling the gap between the metal pan and the concrete core.

A process for making a concrete core for use in a structural panel, the process including the steps of,

• providing an ingredient set comprising:
• 18%±1% cement by mass,
• 45%±1% coarse lightweight aggregate by mass,
• 7%±1% water by mass,
• 6%±1% fly ash by mass,
• 24%±1% sand by mass;
• providing an apparatus for measuring the moisture content of coarse lightweight aggregate and sand;
• providing an apparatus for drying coarse lightweight aggregate and sand;
• providing a concrete dry-casting apparatus comprising mixing apparatus and a mold;
• drying said lightweight aggregate and said sand to a predetermined moisture value;
• Mixing and forming the ingredients for using the concrete dry-casting apparatus, forming thereby a monolithic casting of a reinforced cementitic concrete material;
• in which the reinforced cementitic concrete material formed thereby having a mass density selected from the range 1650-1850 kilograms per cubic meter, a compressive strength selected from the range 40-50 megapascals, and a flexural strength selected from the range 5-7 megapascals.