| 摘要 |
Provided are: a cement admixture having excellent strength developability and an excellent durability-improving effect; and a method for producing the cement admixture. A cement admixture which contains an SiO2-Al2O3-based substance produced by the heat treatment of a catalyst residue produced during the purification of petroleum at 350 to 950°C inclusive in an oxidative atmosphere, wherein an SiO2 component is contained in an amount of 40 to 55%, an Al2O3 component is contained in an amount of 40 to 55%, R2O is contained in an amount of 1% or less, and the ignition loss is 1% or less, the Blaine's specific surface area is 3000 to 9000 cm2/g, an anhydrous gypsum is additionally contained, and the anhydrous gypsum is contained in an amount of 20 to 80 parts and the SiO2-Al2O3-based substance is contained in an amount of 20 to 80 parts. A method for producing the cement admixture, which comprises milling an SiO2-Al2O3-based substance produced by the heat treatment of a catalyst residue produced during the purification of petroleum at 350 to 950°C inclusive in an oxidative atmosphere and an anhydrous gypsum separately and then mixing these components together or milling and mixing the components simultaneously. |
