Rice hull ash concrete admixture
AssigneeW. R. Grace & Co.-Conn.
InventorsLawrence J. Kindt, Ellis M. Gartner
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Abstract
A cement admixture and cement composition containing said admixture comprising finely ground rice hull ash formed by slurry grinding of said ash to a volume medium particle diameter or up to 4 micrometers.
Claims20
A product comprising rice hull ash having ultra-high fineness particle size of a volume-median particle diameter measured by laser-light scattering of up to about 4 micrometers, a BET specific surface area of at least 20 m.sup.1 /g, a silica content of at least 80% by weight, a carbon content of less than 10% by weight and being substantially amorphous as shown by x-ray diffractometry, said product being in combination with from about 0.05 to about 10 weight percent of a cement water reducing agent.
An aqueous suspension comprising from about 0.01 to about 10 percent by weight of a water-reducing agent selected from at least one of naphthalene-sulfonate formaldehyde condensates, melamine sulfonate formaldehyde condensates, lignin sulfonates, alkali or alkaline earth metal polyacrylates or copolymers thereof;
- from about 40 to 60 weight percent of rice hull ash product composed of RHA-PF having a volume-median particle size of up to about 4 micrometers measured by laser-light scattering, a BET specific surface area of at least 20 m.sup.2 /g, a silica content of at least 80% by weight, a carbon content of less than 10% by weight and being substantially amorphous as shown by x-ray diffractometry;
- and up to about 15 wt. percent of calcium nitrite.
Dependencies are inferred from the claim text.