Admixture for hydraulic cement

Abstract

The present invention is a specific combination of components having unique properties both in composition and benefits. Such a combination has been found in alkali or alkaline earth metal nitrates, alkanolamines and alkali or alkaline earth metal thiocyanates. In such combinations it has also been found that alkaline and alkali earth thiosulfates and chlorides below the concentration level where corrosion is promoted may advantageously be substituted for all or part of the thiocyanates and that diethanolamine, N,N-di(hydroxyethyl)glycine (bicine) and N,N-di(hydroxyethyl)- beta -aminopropionic acid (DAPA) and certain alkanolamines and alkanolamino acids and derivatives may advantageously be substituted for all or part of the triethanolamine.

What is claimed is: 
     
       1. A hydraulic cement mix comprising hydraulic cement, aggregate, sufficient water to effect hydraulic setting of the cement, and an admixture comprising a composition or a mixture of compositions selected from the group consisting of alkali, ammonium and alkaline earth salts of thiocyanic acid, and water soluble thiosulfates; a composition or a mixture of compositions selected from the group . .comprising.!. .Iadd.consisting of .Iaddend.alkanolamine; and . .related water soluble alkanolamines and.!. alkanolamino acids; and a composition or a mixture of compositions selected from the group . .comprising.!. .Iadd.consisting of .Iaddend.alkali and alkaline earth salts of nitric acid; said additive being present in an amount sufficient to accelerate the rate of hardening of said hydraulic cement mix and to increase its compressive strength after hardening. 
     
     
       2. A hydraulic cement mix in accordance with claim 1 wherein said hydraulic cement comprises portland cement. . .3. A hydraulic cement mix in accordance with claim 1 wherein said salts of thiocyanic acid are sodium, potassium, ammonium and calcium thiocyanate; said soluble thiosulfates are sodium, potassium, ammonium, calcium and magnesium thiosulfates; said alkanolamines are diethanolamine and triethanolamine; said alkanolamino acids are bicine and di(hydroxyethyl)-β-propionic acid; a said related soluble alkanolamine is tetra(hydroxyethyl)ethylenediamine; and said salts of nitric acid are sodium, potassium, calcium, magnesium and ammonium nitrates..!. . .4. A hydraulic cement mix in accordance with claim 1 wherein said salt of thiocyanic acid is present in an amount from about 0.01% to about 2.50% based on the weight of the cement; said alkanolamine is present in an amount from 0.005% to about 0.08% based on the weight of the cement; said salt of nitric acid is present in an amount from about 0.05% to about 2.00% based on the weight of the cement; said alkanolamino acid is present from about 0.005% to 0.10% based on weight of cement; and said thiosulfate salt is present in an amount from about 0.05% 
     
     
        to about 2.00% based on weight of cement..!. 5. A hydraulic cement mix in accordance with claim 1 wherein said salt of thiocyanic acid is present in an amount from about 0.025% to about 0.50%; said alkanolamine from about 0.005% to about 0.02%; and said salt of nitric acid from about 0.10% to 
     
     
        about 1.00%, based on the weight of the cement. 6. A hydraulic cement mix in accordance with claim 1 wherein said salt of thiocyanic acid is sodium 
     
     
        thiocyanate. 7. A hydraulic cement mix in accordance with claim 1 wherein 
     
     
        said salt of nitric acid is sodium nitrate. 8. A hydraulic cement mix in accordance with claim 1 wherein said salt of nitric acid is calcium 
     
     
        nitrate. 9. A hydraulic cement mix in accordance with claim 1 wherein said salt of nitric acid is a mixture of sodium nitrate and calcium nitrate. 
     
     
            A hydraulic cement mix in accordance with claim 1 wherein said salt of 
     
     
        nitric acid is a mixture of magnesium nitrate and calcium nitrate. 11. A hydraulic cement mix in accordance with claim 1 wherein said alkanolamine 
     
     
        is triethanolamine. 12. A hydraulic cement mix in accordance with claim 1 
     
     
        wherein said alkanolamine is diethanolamine. 13. A hydraulic cement mix in accordance with claim 1 wherein said thiosulfate salt is sodium 
     
     
        thiosulfate. 14. A hydraulic cement mix in accordance with claim 1 wherein 
     
     
        said thiosulfate salt is calcium thiosulfate. 15. A hydraulic cement mix in accordance with claim 1 wherein said . .water soluble.!. alkanolamino 
     
     
        acid is bicine. 16. A hydraulic mix in accordance with claim 1 wherein said . .water soluble.!. alkanolamino acid is 
     
     
        di(hydroxyethyl)-β-aminopropionic acid. 17. A hydraulic mix in accordance with claim 1 wherein said . .water soluble.!. alkanolamino acid 
     
     
        is di(hydroxyethyl)-β-amino-α-methylpropionic acid. 18. A hydraulic mix in accordance with claim 1 wherein said alkanolamino acid is 
     
     
        N,N-di(hydroxyethyl)aminomethyl succinic acid. 19. A hydraulic cement mix in accordance with claim 1 wherein said . .water soluble.!. alkanolamine 
     
     
        is tetra(hydroxyethyl)ethylenediamine. 20. A process for accelerating the hardening of hydraulic cement mixes which includes sequentially adding hydraulic cement, aggregate in an amount up to 80% by weight based on total weight of said cement mix, and sufficient water to effect hydraulic setting of the cement, comprising incorporating an admixture comprising mixtures of (a) a composition selected from the group . .comprising.!. .Iadd.consisting of .Iaddend.ammonium, alkali, and alkaline earth salts of thiocyanic acid, and mixtures thereof; and water soluble thiosulfates that may be substituted in whole or in part for the thiocyanates; and   (b) an alkanolamine; and water soluble alkanolamino acids, substituted in whole or part for the alkanolamine;   (c) a composition selected from the group . .comprising.!. .Iadd.consisting of .Iaddend.ammonium, alkali, and alkaline earth salts of nitric acid, and mixtures thereof; said additive being incorporated in an amount sufficient to accelerate the rate of hardening of said hydraulic cement mix and to increase its     
     
     
        compressive strength after hardening. 21. A process in accordance with claim 20, wherein said hydraulic cement comprises portland cement. . .22. A process in accordance with claim 20, wherein the thiocyanate is present in an amount from about 0.01% to about 0.50%; the alkanolamine is present in an amount from about 0.005% to about 0.08%; and the nitrate is present in an amount from about 0.05% to about 2.00% based on the weight of the cement in the mix; said soluble alkanolamino acid is present from about 0.005 to 0.10% based on weight of cement; and said thiosulfate salt is present in an amount from about 0.05% to about 2.00% based on weight of 
     
     
        cement..!. 23. A process in accordance with claim 20 wherein the 
     
     
        thiocyanate is sodium thiocyanate. 24. A process in accordance with claim 
     
     
        20 wherein the alkanolamine is triethanolamine. 25. A process in 
     
     
        accordance with claim 20 wherein the nitrate is sodium nitrate. 26. A process in accordance with claim 20 wherein the nitrate is calcium 
     
     
        nitrate. 27. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein the nitrate is a mixture of sodium nitrate and calcium 
     
     
        nitrate. 28. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein the nitrate is a mixture of magnesium nitrate and calcium 
     
     
        nitrate. 29. A process in accordance with claim . .17.!. .Iadd.20 
     
     
        .Iaddend.wherein said thiosulfate salt is sodium thiosulfate. 30. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein said 
     
     
        thiosulfate salt is calcium thiosulfate. 31. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein said water soluble . .of.!. 
     
     
        alkanolamino acid is bicine. 32. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein said water soluble alkanolamino acid is 
     
     
        di(hydroxyethyl)-β-aminopropionic acid. 33. A process in accordance with claim . .17.!. .Iadd.20 .Iaddend.wherein said . .water soluble.!. 
     
     
        alkanolamine is tetra(hydroxyethyl)ethylenediamine. .Iadd.34.  A hydraulic cement mix in accordance with claim 1 wherein said composition or mixture of compositions selected from the group consisting of alkali, ammonium and alkaline earth salts of thiocyanic acid and water soluble thiosulfates is present in an amount from about 0.01% to about 0.50% based on the weight of the cement;   said composition or mixture of compositions selected from the group consisting of alkanolamine and alkanolamino acids is present in an amount from about 0.005% to about 0.10% based on the weight of the cement, with the proviso that alkanolamines, when present, are present in an amount from about 0.005% to about 0.08% based on the weight of the cement; and   said composition or mixture of compositions selected from the group consisting of alkali and alkaline earth salts of nitric acid is present in an amount from about 0.05% to about 2.00% based on the weight of the cement. .Iaddend. .Iadd.35. A hydraulic cement mix in accordance with claim 34 wherein thiocyanate is present in an amount from about 0.01% to about 0.50% based on the weight of the cement, and wherein alkanolamine is present in an amount from about 0.005% to about 0.08% based on the weight of the cement. .Iaddend. .Iadd.36. A process in accordance with claim 20 wherein   said composition selected from the group consisting of ammonium, alkali, and alkaline earth salts of thiocyanic acid, and mixtures thereof, and water soluble thiosulfates that may be substituted for the thiocyanates is present in an amount from about 0.0% to about 0.50% based on the weight of the cement;   said alkanolamine and water soluble alkanolamino acids substituted for the alkanolamine are present in an amount from about 0.005% to about 0.10% based on the weight of the cement, with the proviso that alkanolamine, when present, is present in an amount from about 0.005% to about 0.08% based on the weight of the cement; and   said composition selected from the group consisting of ammonium, alkali, and alkaline earth salts of nitric acid, and mixtures thereof is present in an amount from about 0.05% to about 2.00% based on the weight of the cement. .Iaddend. .Iadd.37. A process in accordance with claim 36 wherein thiocyanate is present in an amount from about 0.01% to about 0.50% based on the weight of the cement, and wherein alkanolamine is present in an amount from about 0.005% to about 0.08% based on the weight of the cement. .Iaddend. .Iadd.38. A hydraulic cement mix comprising hydraulic cement, aggregate, sufficient water to effect hydraulic setting of the cement, and an admixture comprising:   a) composition or a mixture of compositions selected from the group consisting of alkali, ammonium and alkaline earth salts of thiocyanic acid, and water soluble thiosulfates, wherein said salts of thiocyanic acid are sodium, potassium, ammonium and calcium thiocyanate; and said soluble thiosulfates are sodium, potassium, ammonium, calcium and magnesium thiosulfates;   b) a composition or a mixture of compositions selected from the group consisting of alkanolamine and alkanolamino acids, wherein said alkanolamines are diethanolamine, triethanolamine or tetra(hydroxyethyl)ethylenediamine; and said alkanolamino acids are bicine and N,N-di(hydroxyethyl)-β- aminopropionic acid; and   c) a composition or a mixture of compositions selected from the group consisting of alkali, ammonium and alkaline earth salts of nitric acid, wherein said salts of nitric acid are sodium, potassium, calcium, magnesium and ammonium nitrates; said admixture being present in an amount sufficient to accelerate the rate of hardening of said hydraulic cement mix and to increase its compressive strength after hardening. .Iaddend.