Cementitious composition
AssigneeAsh Grove Cement Company
InventorHarry A. Harris
Life of this patent
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Abstract
An improved cementitious composition is the subject of the present invention. The composition comprises 25-60 weight percent cement component. The cement component is 3 to 50 weight per pozzolan. The pozzolan should have a sulfate reactivity factor of no greater than 12 utilizing a function obtained from the Dunstan formula. The composition is 40 to 75 percent by weight alpha gypsum (calcium sulfate hemihydrate). Various additives may be included to enhance the performance of the composition. These include polymer modifiers, a water reducing agent, a set retarding agent and a set accelerating agent.
Claims9
A cementitious composition comprising:
- about 25-60 weight percent of a cement component selected from the group comprising Type I and Type II portland cement, said cement component comprising about 3-50 weight percent pozzolan having a sulfur reactivity factor of 12 or less;
- about 40 to 75 weight percent calcium sulfate hemihydrate;
- and
- about 1 to 20% by weight of a compatible polymer modifier, based on the weight of said cement component.
An additive for either of Type I and Type II portland cement to increase the life and durability of said cement, said additive comprising:
- about 3-50 weight percent pozzolan, relative to the weight of said cement,
- said pozzolan having a sulfur reactivity factor of twelve or less;
- about 50-97 weight percent calcium sulfate hemihydrate, relative to the combined weight of said portland cement and said pozzolan;
- and
- about 2 to 40 weight percent of a compatible polymer modifier, based on the combined weight of said pozzolan and said cement.
Dependencies are inferred from the claim text.