Preparation method of composite cement with low clinker dosage and high flexural compression ratio

Abstract

The invention discloses a preparation method of composite cement with low clinker dosage and high flexural compression ratio. The preparation method is to mix three size ranges of powder particles and obtain the composite cement. The three size ranges of powder particles are as follows: 1) the grain size of particles is less than 8mu m, the particles are composed of high-activity supplementary cementing material with the grain size; 2) the grain size of particles is 8-24mu m, the particles are composed of cement clinker particles with the grain size; and 3) the grain size of particles is 24-80mu m, and the particles are composed of low-activity supplementary cementing material or inert filler. The volume percentages of the three size ranges of powder particles are 25-40%, 25-30% and 30-45% respectively. The clinker volume percentage of the composite cement is 25-30%, the 28-day compressive strength is up to 35-50MPa, the flexural strength is up to 10-12Mpa, the flexural compression ratio is 1/3-1/4; and the composite cement has low hydration heat and good anti-cracking capability and can be used in the civil construction/engineering with the demand on the anti-cracking capability.

Description

technical field [0001] The invention relates to a preparation method of composite cement, in particular to a preparation method of low clinker consumption and high folding ratio composite cement. Background technique [0002] Cement concrete is currently the most widely used man-made building material. The production of Portland cement needs to consume a large amount of natural resources and energy, and the inconsistency between resources and the environment is getting worse day by day. In 2009, my country's cement production reached 1.65 billion tons, accounting for 55% of the world's total cement production, consuming 1.46 billion tons of limestone, 240 million tons of clay, about 182 billion kW h of electricity, more than 190 million tons of standard coal, and emitting CO 2 More than 1 billion tons, SO x More than 480,000 tons, NO x More than 1.9 million tons. CO2 emissions from the cement industry to the atmosphere from 1996 to 2009 2 Cumulatively reaching 17 bill...

AI Technical Summary

Problems solved by technology

Although most of the auxiliary cementitious materials used in the production of composite cement have a certain activity (gelling activity, potential gelling activity or pozzolanic activity), their activity is far lower than that of cement clinker, and even the potential activity cannot be exerted. lead to poor performance of composite cement

At present, composite cement can only produce low-strength cement such as 32.5 cement and masonry cement, which limits its application range and dosage

At the same time, the amount of auxiliary cementitious materials in the composite cement is relatively low (the amount of slag is about 35%, the amount of fly ash is about 15%, and the amount of steel slag is generally lower than 10%), which cannot be used in large quantities. The purpose of producing composite cement from waste residue

[0005] Since the production of composite cement mainly adopts the method of mixing and grinding, the particle gradation of composite cement is poor due to the different grinding properties of various auxiliary cementitious materials.

On the one hand, the original accumulation of composite cement is not dense, resulting in a large water demand and the slurry structure is not dense; waste of gelling components

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