Low-alkaline liquid accelerating agent and preparation method thereof

Abstract

The invention belongs to the technical field of tunnel construction, and relates to a low-alkaline liquid accelerating agent and a preparation method thereof. For the low-alkaline liquid accelerating agent, aluminium sulfate solution is neutralized with sodium aluminate solution to produce aluminium hydroxide collosol, and then aluminium sulfate and aluminium hydroxide collosol conduct polymerization reaction in an original solution system to produce polymerized aluminium sulfate, so that the accelerating agent solution has higher aluminium ion content and liquid stability; the low-alkaline liquid accelerating agent is prepared by aluminium sulfate, sodium aluminate and stabilizing agent; and the mass percentage of the components are as follows: 40 to 60 percent of aluminium sulfate, 6 to12 percent of sodium aluminate, 0 to 0.2 percent of stabilizing agent, and the balance of water. The invention has the following positive effects to sprayed concrete: initial set of common cement can be realized in five minutes and final set of the common cement can be realized in eight minutes under lower doping amount; the 1d strength of cement mortar can reach more than 12MPa, and the 28d compression strength ratio of the cement mortar is more than 100 percent; and the invention has good adaptability to cement of different varieties.

Description

Technical field [0001] The invention belongs to the technical field of tunnel construction and relates to a liquid low-alkali accelerator for wet shotcrete, and in particular to a low-alkali liquid accelerator used in wet shotcrete for tunnels and a preparation method thereof. Background technique [0002] Accelerating admixture is a chemical admixture that can quickly set cement. Its use can make cement set and harden in a short time. It is mainly used in the construction of shotcrete and shot mortar projects. In recent years, the wet shotcrete process has gradually replaced the traditional dry spraying process and has been widely used due to its advantages of good construction environment, low springback, and high construction efficiency. The accelerating setting agent used in conjunction with this construction technology is a liquid accelerating setting agent. [0003] Currently, commonly used liquid accelerators for wet shotcrete include alkaline liquid accelerators and...

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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