| 摘要 |
Prepn. of inert constituents for concrete, uses as a prim. matl., sand resulting from serpentine rocks, the sand is subjected to energetic washing with water and then to rigorous treatment in hydrocyclones to eliminate all the very fine constituents in the sand; the constituents removed are replaced with good quality rock which is ground very fine and is of the same type. The good quality rock is pref. of high grade, such as peridotite, silica, or another similar product. Process removes very short and submicroscopic asbestos fibres which both retard the setting of the concrete and impair its strength. |
