Modified aluminate low-alkali liquid quick-setting agent

Abstract

The invention relates to a modified aluminate low-alkali liquid quick-setting agent which is prepared by adopting the following steps: 1) preparing a modifier: preparing the modifier by the followingraw materials according to the proportion by weight: 10-40% of silicate, 5-20% of carbonate and the balance of water; 2) preparing alkali metal aluminate solution as follows: preparing the alkali metal aluminate solution by the following raw materials according to the proportion: 20-35% of alkali metal hydroxide, 30-45% of aluminum hydroxide and the balance of water; and 3) preparing the quick-setting agent: adding the modifier prepared in the step 1) into the alkali metal aluminate solution prepared in the step 2) by the dripping way, and carrying out shear mixing, wherein, the proportion byweight of the modifier to the aluminate solution is 1:5.5-1:7, water needs to be added while dripping for dissolving a formed gel, and the adding amount of the water is 3.4-6 times of the weight of the modifier. The liquid quick-setting agent disclosed by the invention can particularly shorten the interval between initial setting time and final setting time, thereby having good adaptability to a variety of cement and being widely used in sprayed concrete construction.

Description

technical field [0001] The invention relates to a liquid quick-setting agent for sprayed concrete and mortar. The quick-setting agent can be widely used in sprayed concrete construction of tunnels, mines, underground workshops and other underground engineering constructions. Background technique [0002] Shotcrete has many advantages in underground construction and rock support, and has become a very important and necessary measure in modern underground engineering. With the development of wet-mix shotcrete technology, the scope of use of shotcrete in underground engineering has been greatly expanded. The most important function of the liquid quick-setting agent for shotcrete is to accelerate the setting of the concrete mixture and improve the early strength, which can increase the thickness of one sprayed layer and shorten the interval between spraying the next layer. [0003] The liquid quick-setting agent is added to the shotcrete to have a rapid hydration reaction with ...

AI Technical Summary

Problems solved by technology

In China, ordinary Portland cement can contain no more than 20% inactive admixtures, and the variety of admixtures causes the cement adaptability of liquid accelerators to be very prominent, which affects its use in shotcrete

[0004] The traditional aluminate liquid quick-setting agent has a single component, which mainly makes the cement set by promoting the hydration of the aluminate minerals in the cement

However, for cement with more mineral admixtures, due to the relatively low content of tricalcium aluminate, its coagulation-accelerating effect is difficult to meet the relevant requirements, so the cement has poor adaptability and its application range is limited.

In addition, the alkali content of aluminate accelerator (Na 2 O+0.658K 2 O) is very high, generally greater than 15%, which is likely to cause alkali-aggregate reaction and affect the durability of the project

For example, U.S. Patent No. 4,504,345 reports a liquid quick-setting agent prepared from potassium aluminate and potassium carbonate. The alkali content of this product exceeds 20%, and raw materials such as potassium hydroxide and potassium carbonate are expensive, which is not conducive to large-scale promotion and use.

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