| 摘要 |
<p>A cement composition comprises cement, a pozzolan material, fine aggregate, air, water, at least one alkali metal constituent selected from the group consisting of sodium, potassium, and lithium ions, and at least one anionic constituent which is capable of forming complexes with ferric ions, is soluble in water, and forms a calcium salt which is also water soluble, wherein the alkali metal constituent is present in an amount up to approximately 4.0 percent by weight, in terms of the equivalent weight of sodium ions, of the pozzolan material; the anionic constituent is present in an amount up to approximately 6.0 percent by weight, in terms of the equivalent weight of chloride ions, of the pozzolan material; and the cement composition is further characterized by: (a) having a solid volume ratio of cement to the pozzolan material within the range of approximately 0.05 to 2.0; (b) having a ration of the volume of pasta (pozzolan material, cement, air, and water) to the solid volume of fine aggregate within the range of approximately 0.75 to 2.5; and (c) having a ratio of the solid volume of cement to the volume of mortar (cement, pozzolan material, water end fine aggregate) less than about 0.19. As an alternative to the alkali metal and anionic constituents may be used calcium chloride. The pozzolan material may be trass, volcanic ash, pumice, slag, diatomaceous earth, silicious clay, calcined shale and fly ash. The alkali metal constituent and anionic constituent may be constituted by various alkali metal salts. Additives such as plasticisers may be present. <IMAGE></p> |
