Composite activated low-calcium fly ash cement and preparation method thereof

Abstract

The invention provides composite activated low-calcium fly ash cement and a preparation method thereof, and belongs to the technical field of resource utilization of building materials and solid wastes. The concrete is prepared from the following raw materials in parts by weight: 30-40 parts of fly ash, 10-20 parts of slag, 5-7 parts of anhydrite, 35-45 parts of ordinary Portland cement, 3 parts of a strong alkali solution (with the mass fraction of 30%), 0.5 part of NaSO4 (with the mass fraction of 17%), 1 part of a water reducing agent and 0.5 part of a grinding aid. The concrete has the beneficial effects that the compactness, corrosion resistance and impermeability of the concrete can be improved, and the water demand is reduced, the early strength of the fly ash concrete is improved,the early hydration is accelerated, and the activation effect on the fly ash is improved, materials are easy to obtain, the cost is low, operation is easy, the mechanical property can be well improved, popularization is facilitated, the application range is wider, solid waste accumulation can be effectively solved, and the problem of non-renewable resources is relieved.

Description

technical field [0001] The invention relates to a composite activated low-calcium fly ash cement and a preparation method thereof, belonging to the technical field of resource utilization of building materials and solid waste. Background technique [0002] Fly ash is fine-grained dust collected after pulverized coal is burned in boilers in coal-fired power plants. In view of my country's energy characteristics of "rich in coal, poor in oil, and low in gas", coal has become the most important primary energy source. As coal production and the number of coal-fired power plants increased rapidly, so did fly ash production. In 2013, the national output of fly ash reached 460 million tons, accounting for 14.8% of the total industrial solid waste. A large amount of stockpiling of fly ash not only occupies a large amount of land, but also has a serious impact on the environment, such as air pollution caused by flying dust, and damage to soil caused by toxic heavy metals in fly ash...

AI Technical Summary

Problems solved by technology

Low-calcium fly ash mainly has the following disadvantages: (1) less spherical particles, more irregular particles, relatively large water demand, and poor adaptability to admixtures; (2) coarse particle size, large diameter, and low activity The index is low, (3) often contains a lot of unburned carbon particles, the carbon content is high, and the burning vector is large; (4) the calcium oxide content is low, which cannot meet the needs of forming hydraulic gelling materials; (5) Soluble SiO 2 and Al 2 o 3 Too little, slow hydration reaction, low activity index

Because the activity of fly ash is latent, it takes a long time to play out in concrete, which greatly limits the application of fly ash. If the proportion of fly ash added exceeds 30%, it will reduce the strength of concrete, especially It is the lack of early strength, which will affect the performance of concrete and cause concrete shrinkage and cracking

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