CEMENT COMPOSITION FOR HIGH-TEMPERATURE ENVIRONMENTS, AND CONCRETE FOR HIGH-TEMPERATURE ENVIRONMENTS

摘要

The present invention is a cement composition for high-temperature environments containing at least Portland cement and fly ash satisfying all the fly ash conditions in (F1) to (F6), the fly ash content ratio being 10 to 50% by mass when the sum total of the Portland cement and the fly ash is 100% by mass, and the cement composition being used for concrete defined by the definition for the following concrete for high-temperature environments. [Fly ash conditions](F1) Blaine specific surface area for the fly ash is 2,500 to 6,000 cm²/g(F2) After the fly ash has been heated at 975±25°C for 15 minutes, the fly ash mass loss rate is 5% by mass or less(F3) In the fly ash, the SiO₂ content ratio is 50% by mass or more(F4) In the fly ash, the mass ratio (Na₂O+0.658×K₂O)/(MgO+SO₃+TiO₂+P₂O₅+MnO) is 0.2 to 1.0 (in the formula, the chemical formula units are percentages by mass)　(F5) In the fly ash, the sphere-converted specific surface area of particles wherein iron oxide and a non-crystalline substance are mixed, is 2,800 to 11,000 cm²/cm³(F6) In the fly ash, the sphere-converted specific surface area of non-crystalline particles containing Ca is 2,100 to 22,500 cm²/cm³[Definition for the concrete for high-temperature environments]Concrete containing at least (Cn1) to (Cn5) to be used where the mean temperature (environmental temperature) in the vicinity of the concrete is 25°C or higher.　(Cn1) Cement composition for high-temperature environments(Cn2) Super retarding water-reducing agent (R1)(Cn3) Water-reducing agent (R2) excluding super retarding water-reducing agent (R1), retarding-type water-reducing agent, retarding-type AE water-reducing agent, and retarding-type high-performance AE water-reducing agent(Cn4) Fine aggregate(Cn5) Coarse aggregate(Cn6) Water