Hydration control of cementitious systems
AssigneeSandoz Ltd.
InventorsJohn T. Pacanovsky, Lan Huang, Frank T. Gay, Samy M. Shendy
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Abstract
A method of controlling the hydration of a cementitious composition comprising the steps of: i) providing a cementitious composition containing an amount of a neutralized salt of an alpha-monohydroxy carboxylic acid effective to retard the cementitious composition, said carboxylic acid containing two or more carboxylic acid groups, and subsequently, ii) adding an additional amount of said neutralized salt of an alpha monohydroxy carboxylic acid or a second neutralized salt of an alpha monohydroxy carboxylic acid in an amount sufficient to activate hydration of the retarded cementitious composition, said cementitious composition comprising hydraulic binder and water.
Claims33
A method of controlling the hydration of a cementitious composition comprising the steps of:
- i) providing a cementitious composition containing an amount of a neutralized salt of a .alpha.-monohydroxy carboxylic acid effective to retard the cementitious composition, said carboxylic acid containing two or more carboxylic acid groups, and, subsequently,
- ii) adding an additional amount of said neutralized salt of a .alpha.-monohydroxy carboxylic acid or a second neutralized salt of a .alpha.-monohydroxy carboxylic acid in an amount sufficient to activate hydration of the retarded cementitious composition, said cementitious composition comprising hydraulic binder and water.
A method for reclaiming concrete which comprises the steps of
- i) retarding the hydration of concrete to be reclaimed by adding to the concrete an amount of a neutralized salt of a .alpha.-monohydroxy carboxylic acid effective to retard the concrete, said carboxylic acid containing two or more carboxylic groups, and subsequently,
- ii) adding to said retarded concrete or to a retarded mixture thereof with fresh concrete an additional amount of said neutralized salt of a .alpha.-monohydroxy carboxylic acid or a second neutralized salt of a .alpha.-monohydroxy carboxylic acid in an amount effective to activate the hydration of the retarded concrete or a retarded mixture thereof with fresh concrete.
Dependencies are inferred from the claim text.