CENTRIFUGAL CASTING METHOD
First Claim
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2. The method of claim 1 wherein said salt is selected from the group consisting of sodium and calcium salts.
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Abstract
This invention relates to a method of making mortar or concrete pipes by centrifugal casting. The method is characterized by using mortar or concrete prepared from a cementiteous material incorporated with a salt of Beta -naphthalenesulfonic acidformaldehyde condensate, and curing the mortar or concrete pipes made by the above condition with high pressure steam in an autoclave.
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Citations
16 Claims
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2. The method of claim 1 wherein said salt is selected from the group consisting of sodium and calcium salts.
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3. The method of claim 1 wherein said condensate comprises at least 70 percent Condensation polymers having at least five Beta -naphthalenesulfonic acid units in a molecule.
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4. The method of claim 1 wherein said salt is present in an amount of from 0.8 to 1.2 by weight based on the cementitious material.
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5. The method of claim 1 wherein said cementitious material is selected from the group consisting of Portland cement and mixtures of Portland cement and a material selected from the group consisting of fine silica, fly ash, and blast furnace slag.
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6. The method of claim 1 wherein said cast pipes are subjected to high pressure steam curing in an autoclave.
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7. In a method of making cementitious pipe by centrifugal casting, the improvement which comprises adding from 0.2 to 1.5 percent by weight of a salt of a Beta -naphthalenesulfonic acid-formaldehyde condensate and from 0.03 to 2 percent by weight of any member selected from the group consisting of carboxylic acids, hydroxy carboxylic acids, derivatives thereof, and alkali and alkaline earth metal salts thereof, to the cementitious material prior to casting, the weight percent being based on the cementitious material.
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8. The method of claim 7 wherein said condensate comprises at least 70 percent condensation polymers having at least five Beta -naphthalenesulfonic acid units in a molecule.
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9. The method of claim 7 wherein said condensate is present in an amount of from 0.4 to 1.2 percent by weight.
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10. The method of claim 7 wherein said member is present in an amount from 0.06 to 0.15 percent by weight.
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11. The method of claim 10 wherein said condensate is present in an amount of from 0.4 to 1.2 percent by weight.
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12. The process of claim 7 wherein said member is selected from the group consisting of lactic acid, gluconic acid, adipic acid, succinic acid, malleic acid, heptanedioic acid, and alkali metal salts, alkaline earth metal salts and derivatives thereof.
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13. The method of claim 12 wherein said condensate comprises at least 70 percent condensation polymers having at least five Beta -napthalenesulfonic acid units.
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14. The method of claim 13 wherein the member is a sodium salt of an adipic acid derivative.
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15. The method of claim 13 wherein the member is calcium lactate.
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16. The method of claim 7 wherein the cast pipes are subjected to high pressure steam curing in an autoclave.
Specification