Alkali-free setting accelerator, preparation method and application thereof

Abstract

The invention relates to the technical field of engineering materials, in particular to an alkali-free setting accelerator, a preparation method and application thereof. The alkali-free setting accelerator is prepared from, by mass, 40-55% of aluminum sulfate, 10-15% of aluminum nitrate, 5.2-10.8% of alkylol amine, 1-1.5% of magnesium fluosilicate, 1-5% of silicate, 0.5-1% of a stabilizer and thebalance water; wherein the stabilizer is a composition prepared by mixing any one or more of sepiolite, zeolite or diatomite according to any proportion. The alkali-free setting accelerator is mainlycomposed of aluminum sulfate, aluminum nitrate, alkylol amine, magnesium fluosilicate and silicate, is extremely low in fluorine content, does not contain other harmful substances, is green and environment-friendly, and does not cause harm to a human body; when the alkali-free setting accelerator is used for spraying concrete, the addition amount of the setting accelerator is small, the initial setting time, the final setting time, the mortar 1d compressive strength, the 28d compressive strength ratio, the 90day compressive strength retention rate and the like of neat paste of the alkali-freesetting accelerator can meet the construction requirements of different types of cement sprayed concrete, and the alkali-free setting accelerator has good cement adaptability.

Description

Technical field[0001]The invention relates to the technical field of engineering materials, in particular to an alkali-free quick-setting agent and a preparation method and application thereof.Background technique[0002]Shotcrete relies on the power of compressed air to quickly spray concrete mixed with accelerators onto the building surface or rock surface, and bond it together, and at the same time play the role of filling pits and cracks on the surface. Reinforce the objects or rock surfaces to form a complete and stable structure with a certain strength, and then play a role in strengthening or protecting buildings or rock surfaces. Good shotcrete has the advantages of high early strength, small late strength loss, controllable mixing and transportation delay, necessary good pumpability, low rebound rate and good compactness, so it is widely used in coal mines , Tunnels, underground caverns of hydropower stations, and highway slopes have become a good technical solution for slope...

AI Technical Summary

Problems solved by technology

[0005] The traditional powdery alkali accelerators are mainly alkali metal aluminates, carbonates, and silicates, which have disadvantages such as high alkalinity, strong corrosion, polluting the environment, and easily causing serious injuries to construction personnel. , and the strength loss of concrete in the later stage can even be as high as about 30%.

In addition, the dry spraying shotcrete technology generally has the disadvantages of large dust, large rebound, and uneven strength distribution of shotcrete. Therefore, powdery alkali accelerators are gradually being replaced by liquid accelerators.

Most of the accelerators used in combination with the wet spraying process are liquid accelerators. Conventional liquid accelerators are likely to cause harm to the human body because they contain harmful substances. Due to the presence of a large amount of water in the coagulant, the solid content of its active ingredients is low. In order to speed up the setting time, the amount of liquid accelerator must be increased, which will also affect the strength and impermeability of concrete in the later stage

[0006] Liquid accelerators are mainly aluminum compounds and organic substances. Among them, amorphous aluminum hydroxide has also been used to prepare alkali-free liquid accelerators in recent years, but the solubility of aluminum salts is relatively small and it is not easy to store. In addition, the liquid on the market Accelerators are often mixed with fluorine-containing compounds as quick-setting components. Long-term use will seriously affect the health of construction workers, and the strength of concrete will lose 5-20% in the later stage.

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