| 摘要 |
<p>The present invention is directed to blended hydraulic cement compositions which are formed with subbituminous fly ash. In one embodiment, the cement composition comprises from about 0.1 wt. % to about 7 wt. % of a retarding agent; from about 0.1 wt. % to about 4 wt. % potassium carbonate; from about 0.1 wt. % to about 4 wt. % citric acid; from about 0.1 wt. % to about 5 wt. % lithium carbonate; and from about 85 wt. % to about 99.7 wt. % of a subbituminous fly ash. In another embodiment, the cement composition comprises from about 0.1 wt. % to about 7 wt % of a retarding agent; from about 0.1 wt. % to about 6 wt. % of an alkali source selected from the group consisting of potassium carbonate, potassium hydroxide and blends thereof; from about 0.1 wt. % to about 4 wt. % citric acid; from about 0.1 wt. % to about 5 wt. % lithium carbonate; from about 25 wt. % to about 91.7 wt. % of a first subbituminous fly ash having a lime content; and from about 8 wt. % to about 60 wt. % of a second fly ash selected from the group consisting of lignite fly ash, bituminous fly ash and scrubber material.</p> |
