Alkali-free liquid accelerating agent and preparation method thereof

Abstract

The invention belongs to the technical field of tunnel construction, and relates to an alkali-free liquid quick-setting agent applied to tunnel wet shotcrete and a preparation method thereof. The alkali-free liquid quick-setting agent uses aluminum sulfate as the main quick-setting component, and adds aluminum in the form of aluminum fluoride to the aluminum sulfate solution for polymerization, so as to achieve the purpose of introducing aluminum ions to the greatest extent and reducing the introduction of other ions, ensuring Accelerated effect; the composition and mass percentage of alkali-free liquid accelerator are: aluminum sulfate: 30-55%, aluminum hydroxide: 5-15%, hydrofluoric acid: 10-30%, water glass: 0.5-5% %, stabilizer: 0-0.2%, and the rest is water. The present invention has the following positive effects on shotcrete: under a lower dosage, ordinary cement can be initially set within 2 minutes and final set within 4 minutes; the 1d strength of cement mortar can reach more than 15MPa, and the 28d compressive strength The ratio is greater than 100%; it has good adaptability to different varieties of cement.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and relates to a liquid alkali-free quick-setting agent for wet shotcrete, in particular to an alkali-free liquid quick-setting agent used in tunnel wet shotcrete and a preparation method thereof. Background technique [0002] Accelerator is a chemical admixture that can make cement set quickly. Its use can make cement set and harden in a short time. It is mainly used in shotcrete and shotcrete construction. In recent years, due to the advantages of good construction environment, low springback and high construction efficiency, the wet spraying concrete process has gradually replaced the traditional dry spraying process and has been widely used. The quick-setting agent used in conjunction with the construction process is a liquid quick-setting agent. [0003] At present, the commonly used liquid accelerators for wet shotcrete include alkaline liquid accelerators and non-alkali liquid...

AI Technical Summary

Problems solved by technology

When the amount of aluminum sulfate is very large, a high content of sulfate will be introduced into the concrete, and when the sulfate content of the concrete is high, the possibility of secondary ettringite in shotcrete is greatly increased, and the secondary ettringite The formation of expansion stress will cause the concrete to crack or even completely lose its mechanical properties.

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