High-chlorine fly ash cementing material and preparation method thereof

Abstract

The invention discloses a high-chlorine fly ash cementing material as well as a preparation method and application thereof. The preparation method of the high-chlorine fly ash cementing material comprises the following steps: (1) respectively carrying out ball milling on high-chlorine fly ash, slag and mineral micro-powder for 4-8 hours; (2) uniformly mixing the ball-milled high-chlorine fly ash, slag and mineral micro-powder; and (3) adding an early strength agent and an alkali activator into the mixture obtained in the step (2), and uniformly mixing to obtain the high-chlorine fly ash cementing material. The potential volcanic ash activity of the high-chlorine fly ash is excited through a composite activation process, namely physical and chemical activation methods, so that the optimal effect of curing chloride ions is achieved. According to the high-chlorine fly ash cementing material disclosed by the invention, the raw material components in the cementing material are mutually cooperated and excited to form rich hydration products, namely Friedel salt, AFt crystals and C-S-H gel, so that the chemical binding capacity of minerals and chloride ions in the hydration process and the physical adsorption capacity of the hydration products to the chloride ions are promoted, and meanwhile, the mechanical property of the high-chlorine fly ash cementing material is also improved.

Description

technical field [0001] The invention belongs to the technical field of building materials, in particular to a high-chlorine fly ash gelling material and a preparation method thereof. Background technique [0002] Fly ash is the main solid waste discharged during the power generation process of coal-fired power plants, and it is an artificial pozzolanic material. At present, the largest and most important way of comprehensive utilization of fly ash is still in construction and building materials, such as for the production of cement or as an admixture for concrete. The content of chloride ions in high-chloride fly ash is relatively high. If high-chloride fly ash is prepared as a cementitious material and used in concrete, it will have a certain impact on the durability of concrete. In ordinary environments, corrosive ions such as chloride ions migrate inwards through concrete cracks and capillary pores, causing destructive expansion such as steel corrosion and salt crystalli...

AI Technical Summary

Problems solved by technology

However, in actual construction, the control range of the water-cement ratio is small, and the work performance and mechanical properties of the cementitious material are high, which leads to the limited improvement effect of the traditional method on the chloride ion erosion resistance of the cement paste.

Moreover, due to the high concentration of free chloride ions in high-chloride fly ash, whether it is used as an admixture of cement or concrete, the concentration of chloride ions will exceed the standard, corrode the steel bars in the concrete, and affect the safety of concrete components.

At present, the cementitious materials prepared by using fly ash have the disadvantages of low activity and slow reaction speed, and no major breakthrough has been made in the preparation of cementitious materials.

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