| abstract |
The present invention describes an improved building material composition, useful for example as a fire door core and the improved methods of making this composition. More particularly, the building material of the present invention is prepared from hollow microspheres and an aqueous mixture of a cementitious composition containing at least one of the following: a hydraulic cement, an accelerant, or a refractory binder, which composition can be molded and shaped into a fire door core. |