Cement retarder and rapid hardening cement containing the same

• US 4,190,454 A
• Filed: 06/26/1978
• Issued: 02/26/1980
• Est. Priority Date: 10/20/1977
• Status: Expired due to Term

• Current Assignee: Denki Kagaku Kogyo Kabushiki Kaisha (TDK Corporation)
• Original Assignee: Denki Kagaku Kogyo Kabushiki Kaisha (TDK Corporation)
• Inventors: Nakagawa, Koji, Sirasawa, Minoru, Sakamaki, Shozo, Yamagisi, Hirosi
• Primary Examiner(s): Poer, James
• Application Number:
  US05/919,163
• Time in Patent Office: 610 Days
• Field of Search: 106/315, 106/90, 106/97
• US Class Current: 106/695
• CPC Class Codes: C04B 14/06 Quartz; Sand
• CPC Class Codes: C04B 18/08 Flue dust , i.e. fly ash
• CPC Class Codes: C04B 18/141 Slags
• CPC Class Codes: C04B 22/00 Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators , shrinkage compensating agents
• CPC Class Codes: C04B 22/0093 Aluminates
• CPC Class Codes: C04B 22/10 containing carbon in the anion
• CPC Class Codes: C04B 22/14 containing sulfur in the anion, e.g. sulfides
• CPC Class Codes: C04B 22/142 Sulfates
• CPC Class Codes: C04B 24/06 containing hydroxy groups
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/04 Portland cements
• CPC Class Codes: C04B 28/065 Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
• CPC Class Codes: Y02W 30/91 Use of waste materials as fillers for mortars or concrete

Abstract

A cement retarder is provided which comprises 5 to 20% by weight, based on the weight of said retarder, of gluconic acid and/or tartaric acid and/or a water soluble salt thereof, 30 to 10% by weight, based on the weight of said retarder, of citric acid and/or an alkali salt thereof, and 50 to 85% by weight, based on the weight of said retarder, of an alkali carbonate. A rapid hardening cement is also provided which contains the above cement retarder.

Claims

1. A rapid hardening cement comprising a cement rapid hardening agent, a cement and a cement retarder and/or water, said cement rapid hardening agent comprising an amorphous calcium aluminate and an inorganic sulfate in an amount of 1 to 3 times by weight as that of said amorphous calcium aluminate, the chemical composition of said amorphous calcium aluminate consisting essentially of 35 to 47% by weight of calcium oxide based on the weight of said amorphous calcium aluminate and the balance of aluminum oxide, said cement retarder comprising 5 to 20% by weight, based on the weight of said retarder, of gluconic acid and/or tartaric acid and/or a water soluble salt thereof, 30 to 10% by weight, based on the weight of said retarder, of citric acid and/or an alkali salt thereof, and 50 to 85% by weight, based on the weight of said retarder, of an alkali carbonate, and said water being added in an amount of 2% or less by weight based on the weight of said cement rapid hardening agent.

2. The rapid hardening cement as claimed in claim 1, wherein the chemical composition of said amorphous calcium aluminate consists essentially of 38 to 44% by weight of calcium oxide based on the weight of said amorphous calcium aluminate and the balance of aluminum oxide.

3. The rapid hardening cement as claimed in claim 1, wherein said inorganic sulfate is added in an amount of 1.5 to 2.5 times by weight as that of said amorphous calcium aluminate.

4. The rapid hardening cement as claimed in claim 1, 2, or 3, wherein said inorganic sulfate is selected from one or more of the group consisting of dihydrate, hemihydrate and anhydride of calcium sulfate, sodium sulfate, potassium sulfate and magnesium sulfate.

5. The rapid hardening cement as claimed in claim 4, wherein said anhydrous calcium sulfate is Type II anhydrous calcium sulfate.

6. The rapid hardening cement as claimed in claim 1, 2 or 3, wherein the amount of said cement rapid hardening agent is 5 to 25% by weight based on the total amount by weight of the rapid hardening cement.

7. The rapid hardening cement as claimed in claim 1, 2 or 3, wherein said cement is selected from one or more of the group consisting of ordinary Portland cement, high early strength Portland cement, super rapid hardening Portland cement, moderate heat Portland cement and a mixture thereof with silica, fly ash, blast furnace slag and a mixture thereof.

8. The rapid hardening cement as claimed in claim 1, wherein said water soluble salt of gluconic acid and/or tartaric acid is selected from one or more of the group consisting of sodium gluconate, potassium gluconate, calcium gluconate, sodium tartrate, potassium tartrate and calcium tartrate.

9. The rapid hardening cement as claimed in claim 1, wherein said alkali salt of citric acid is selected from one or more of the group consisting of sodium citrate, potassium citrate and calcium citrate.

10. The rapid hardening cement as claimed in claim 1 wherein said alkali carbonate is selected from one or more of the group consisting of sodium carbonate, potassium carbonate, sodium hydrogencarbonate and potassium hydrogencarbonate.

11. The rapid hardening cement as claimed in claim 1, wherein said cement retarder is added in an amount of 0.3 to 1.5% by weight based on the total amount by weight of the rapid hardening cement.