Very high early strength cement

A method for preparing a cement composition comprising mixing from about 3.75% to about 40% , based on the total dry weight of the composition, of 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4 with from about 0.1% to about 5% of lime, from about 3% to about 35% of calcium sulfate, from about 0.1% to about 2% of a hydroxy polycarboxylic acid, from about 0.25% to about 4% of sucrose, and dicalcium silicate as the substantial remainder.

A method for retarding the setting of a cement composition comprising from about 4% to about 40% of the ternary compound 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4, from about 0.1% to about 5% of lime, from about 3% to about 35% of calcium sulfate and dicalcium silicate as the substantial remainder, said method comprising the addition to said cement of a combination of admixtures consisting of from about 0.25% to about 1% of citric acid and from about 0.25% to about 4% sucrose, based on the total dry weight of said cement and said admixtures, in which combination the ratio of sucrose to acid is from about 1:1 to about 6:1.

A method for reducing the demand for water in the formation of easily placeable cement/water mixes from a cement comprising from about 4% to about 40% of the ternary compound 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4, from about 0.1% to about 5% of lime, from about 3% to about 35% of calcium sulfate, and dicalcium silicate as the substantial remainder, said method comprising the addition to said cement of a combination of admixtures consisting of about 0.5% citric acid and from about 0.5% to about 4% sucrose, based on the total dry weight of said cement and said admixtures.

A method of reducing the demand for water in the formation of easily placeable cement/water mixes from a cement comprising from about 4% to about 40% of the ternary compound 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4, from about 0.1% to about 5% of lime, and about 3% to about 35% of calcium sulfate and dicalcium cilicate as the substantial remainder, said method comprising the addition to said cement of a combination of admixtures consisting of about 1% citric acid and from about 2% to about 4% sucrose, based on the total dry weight of said cement and said admixtures.

A method for reducing the demand for water in the formation of easily placeable cement/water mixes from a cement comprising from about 4% to about 40% of the ternary compound 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4, from about 0.1% to about 5% of lime, from about 3% to about 35% of calcium sulfate, and dicalcium silcate as the substantial remainder, said method comprising the addition to said cement of a combination of admixtures consisting of about 2% of citric acid and 2% of sucrose, based on the total dry weight of said cement and said admixtures.

A method for increasing the compressive strength, upon full or partial hydration, of a hydraulic cement comprising from about 4% to about 40% of 3CaO.3Al.sub.2 O.sub.3.CaSO.sub.4, from about 0.1% to about 5% of lime, from about 3% to about 35% of calcium sulfate, and dicalcium silicate as the substantial remainder, said method comprising the addition to said cement of a combination of admixtures consisting of about 1% citric acid and from about 1% to about 3% sucrose, based on the total dry weight of said cement and said admixtures.