| 摘要 |
<p>The present invention describes an improved building material composition, useful for example as a fire door core and to improved methods of making thi s composition. The building material of the present invention is prepared from an aqueous mixture of expanded perlite and a fast setting, cementitious composition consisting essentially of a hydraulic cement having (1) a Portla nd cement and (2) a calcium aluminate cement, which composition can be molded a nd shaped into a fire door core.</p> |
