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 accelerating agent for tunnel wet jet concrete and a preparation method thereof. The alkali-free liquid accelerating agent is characterized in that aluminium sulphate is adopted to serve as a main accelerating component; aluminium is added to an aluminium sulphate solution to be polymerized in a form of aluminium fluoride; aluminium ions are introduced to the greatest extent so as to reduce other ion introduction; and the accelerating effect is ensured. The alkali-free liquid acceleratingagent comprises the following components in percentage by mass: 30-55% of aluminium sulphate, 5-15% of aluminium hydroxide, 10-30% of hydrofluoric acid, 0.5-5% of water glass, 0-0.2% of stabilizing agent, and the balance of water. For jetting concrete, the alkali-free liquid accelerating agent disclosed by the invention has the positive effects that: ordinary cement can be initially solidified within 2 min in lower doping quantity and finally solidified within 4 min; the 1d strength of cement plaster can achieve above 15 MPa; the 28d compressive strength ratio is more than 100%; and the alkali-free liquid accelerating agent has good adaptability to different types of cements.

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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