Composite mineral additive for high-strength and high-performance concrete and method for preparing concrete

Abstract

The invention discloses a composite mineral additive for high-strength and high-performance concrete and a method for preparing concrete. The composite mineral additive for the high-strength and high-performance concrete comprises superfine steel slag micro powder as a core material as well as hemihydrate desulfurization gypsum, II-level pulverized fuel ash and mineral slag. The preparation method of the composite mineral additive comprises the following steps of: placing raw materials in a mixer, and then mechanically stirring and uniformly mixing to form the composite mineral additive for the high-strength and high-performance concrete. The composite mineral additive for the high-strength and high-performance concrete, obtained in the method, has high early-stage strength in 3 days, the activity index is not less than 80%, and the activity index in 28 days is not less than S95%, which is higher than the standard of the issued state and local like products; and when used for preparing the concrete, the composite mineral additive can equivalently replace more than 60% of 52.5-level ordinary Portland cement, and meanwhile fragments generated by producing above 75% of broken stones can also be utilized for replacing natural sand, thereby low-carbon concrete having good durability and meeting the circulated economic requirement is produced.

Description

technical field [0001] The invention relates to a composite mineral admixture for high-strength and high-performance concrete and a method for preparing concrete, belonging to the technical field of building materials. Background technique [0002] Mineral admixtures for high-strength and high-performance concrete (GB / T18736-2002) standards promulgated by the state only have monomer technical standards for ground slag powder, ground fly ash, ground zeolite powder and silica fume, and there is no steel slag Technical standards for composite mineral admixtures of powder and desulfurized gypsum. In addition, the main technical indicators of the first-grade steel slag powder (GB / T20491-2006) used in cement and concrete promulgated by the state: specific surface area ≥ 400m 2 / kg; activity index ≥ 65% for 7 days; ≥ 80% for 28 days; the composite steel slag powder in the technical regulation CDG / TJ08-2013-2007 promulgated by Shanghai is composed of slag powder, fly ash, silica fu...

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Problems solved by technology

[0003] With a specific surface area ≥ 600m 2 / kg ultra-fine steel slag powder as mineral admixture to prepare concrete or use ultra-fine steel slag powder as core material and hemihydrate desulfurization gypsum, Ⅱ grade fly ash and slag powder to form composite mineral admixture to prepare concrete and design concrete mix The sum of the mass of hemihydrate desulfurized gypsum, ultra-fine steel slag powder, fly ash and the mass of debris replacing natural sand accounted for more than 30% of the total mass of concrete has not been reported.

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