High early strength cement
AssigneeUnited States Gypsum Company
InventorsRichard E. Galer, John R. Blasius, Paul C. Webb
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Abstract
A rapid reaction of high alumina cement, gypsum, lime and water produces cementitious compositions in which the only significant factor contributing to strength during the very early stages of hydration (i.e., a few minutes to a few hours) is the formation of an amount of ettringite equal to from about 40% to about 60% of the weight the paste of water, the high alumina cement, the gypsum source, and the lime source. A substantially impermeable concrete having a 4-hour compressive strength of about 8000 p.s.i. may be produced from the cement powder of this invention.
Claims21
A hydratable cement powder which during the early stages of hydration produces an amount of ettringite equal to from about 40% to about 60% of the weight of the cement/water paste, said powder comprising, by weight, from about 18% to about 65% high alumina cement, from about 16% to about 35% calcium sulfate, from 0% to about 65% portland cement, and from 0% to about 8.5% extraneous lime, said portland cement and said extraneous lime being alternative or complementary sources of from about 3.5% to about 8.5% of calcium oxide during hydration of the cement powder.
Dependencies are inferred from the claim text.