Environment-friendly early-strength alkali-free liquid accelerator, preparation method and sprayed concrete

Abstract

The invention relates to an environment-friendly early-strength alkali-free liquid accelerator, a preparation method and sprayed concrete, the alkali-free liquid accelerator comprises aluminum sulfate, organic acid and organic amine, and the organic amine is selected from triisopropanolamine. According to the present invention, the organic acid and the organic amine are specifically selected to cooperate with the aluminum sulfate, such that the storage stability of the obtained accelerator is good, and the early strength and the later strength of the concrete can be improved by adding the accelerator provided by the present invention into the sprayed concrete.

Description

technical field [0001] The present disclosure relates to the technical field of building materials, in particular to an environment-friendly early-strength alkali-free liquid accelerator, a preparation method and shotcrete. Background technique [0002] Alkali-free liquid accelerators are generally used in shotcrete. They are additives for shotcrete and are in liquid state; their components are generally composed of aluminum salts and acids. The alkali-free liquid accelerator mainly introduces a large amount of trivalent aluminum ions and sulfate ions. The sulfate ions and aluminum ions react with the original tricalcium aluminate, tricalcium silicate and gypsum of the cement to produce dihydrate gypsum and ettringite. It can produce a large number of ettringites with a grid structure and release the heat of hydration, so that the concrete slurry can be rapidly coagulated in a short time to achieve the effect of initial support. [0003] At present, the research on alkali-f...

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Problems solved by technology

[0003] At present, the research on the non-alkali liquid quick-setting agent mainly has the following problems: although the existing non-alkali liquid quick-setting agent can make the concrete slurry set quickly, but the concrete The early strength is low or even no strength, and the production equipment requirements are high, the environmental process is complicated, and a large amount of harmful substances are used at the same time, causing varying degrees of damage to the ecological environment, construction environment, workers' respiratory system, eyes, skin, etc.

The raw materials of commonly used alkali-free liquid accelerators are generally aluminum compounds. Aluminum ions are prone to hydrolysis-polymerization-precipitation reactions in water, and the solubility of aluminum salts is small. Unstable phenomena such as flocculation, precipitation, and crystallization are prone to occur; the stability period of the current alkali-free liquid accelerators is generally poor, and the storage period is usually one week, and some even only 3 days before precipitation occurs. How to suppress high saturation The crystallization and hydrolysis of aluminum solution is the key to solve the stability of alkali-free liquid accelerator

[0004] At the same time, the use of non-alkali liquid accelerator makes the cohesion of shotcrete poor, resulting in greater rebound of shotcrete

And because the hydrated fluoride ions can produce hydrates, the concrete has a high shear resistance, the time required for the final setting of the cement is greatly reduced, and the fluoride ions can also play a role in complexing, combining with aluminum sulfate in the water. At the same time, complexes are produced, which are very stable. Therefore, fluoride-containing compounds are often used as raw materials in the current non-alkali liquid accelerators. Hydrofluoric acid, fluosilicic acid, etc. are often used, and their additions are even as high as 25-30%. Add magnesium fluorosilicate, aluminum fluoride and other substances; however, frequent contact with these fluorine-containing substances can easily lead to fluorosis and have a great impact on the environment

At present, although the alkali content and fluoride ion content of alkali-free accelerators are clearly defined, some existing alkali-free accelerators still use a large amount of alkali, chlorine, and fluorine in the production process. raw material

[0005] Moreover, compared with alkaline accelerators, the use of alkali-free accelerators will lead to low 1d strength of concrete, and the lack of strength in the early stage will affect the initial protection effect, although The strength in the later period has improved, but there is still a big difference compared with the alkaline accelerator. The loss of strength in the later period will have a negative impact on the durability of the concrete, reducing the practicability, and it is necessary to increase the strength level of shotcrete to make up for it. Late strength loss, resulting in increased cost

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