Low-temperature-resistant liquid alkali-free accelerator and preparation method thereof

Abstract

The invention provides a low-temperature-resistant liquid alkali-free accelerator and a preparation method thereof. The accelerator is composed of the following components in percentage by mass: 40-50% of aluminum sulfate, 5-10% of alcohol amine, 0.01-0.05% of a stabilizing agent, 4-6% of a reinforcing agent, 1-2% of a modified nano material, 1-2% of a pH conditioning agent, and 29.95-48.99% of water. By applying the accelerator, the defect that the conventional alkali-free setting accelerator is easy to freeze at low temperature can be effectively overcome, and the product stability, the concrete mechanical property and the durability are remarkably improved.

Description

technical field [0001] The application relates to the technical field of concrete admixtures, in particular to a low-temperature resistant liquid alkali-free accelerator and a preparation method thereof. Background technique [0002] Accelerator is a kind of admixture mixed into concrete that can make concrete set and harden rapidly. Accelerators can be divided into powder and liquid according to their form, and can be divided into alkali and non-alkali according to their characteristics. After being mixed with cement, the quick-setting agent can promote the rapid hydration and coagulation of cement, and form sufficient strength in a short time to achieve the purpose of rapid repair or rapid coagulation of concrete in shafts. It is indispensable in the shotcrete construction method. additives. [0003] With the continuous improvement of people's attention to environmental friendliness and concrete durability, the alkali-free accelerator has no alkali, no chlorine, no irrit...

AI Technical Summary

Problems solved by technology

[0007] But, the shortcoming of the preparation method of this antifreeze type non-alkali quick-setting agent is: the antifreeze component-soluble starch that it adopts is adsorbed on the cement particle surface, can produce certain slow-setting effect, is unfavorable for the fast hydration of cement, Poor adaptability may occur when some cement is encountered at the same time

[0009] But, the shortcoming of this antifreeze type non-alkali liquid quick-setting agent and preparation method thereof is: it has adopted alkaline earth nitrate as antifreeze component, although improved the antifreeze of product to a certain extent, also introduced alkali Metal ions increase the alkali content of the product, which does not meet the core technical idea of ​​low alkali content and high durability of the alkali-free accelerator

[0011] But the shortcoming of this antifreeze non-alkali liquid quick-setting agent is: it has adopted methanol as antifreeze component, although can effectively reduce system freezing point, but does not have any helpful effect to strength growth and setting time, in addition methanol has stronger volatilization Sexuality, easy to irritate the eyes and skin of contact persons

[0013] But the shortcoming of this core masterbatch that is used for liquid alkali-free quick-setting agent and preparation method thereof is: it has adopted one or more in sodium sulfate, magnesium sulfate, urea as antifreeze component, and sodium sulfate, magnesium sulfate As an alkali metal sulfate, it does not have frost resistance, and it is easy to crystallize and precipitate at low temperature. At the same time, it also increases the alkali content of the product and reduces the durability of concrete.

Although urea can lower the freezing point, the country has strict requirements on the release limit of ammonia, and the volatile gas produced by urea will also cause harm to construction workers

[0014] In addition, the above-mentioned several existing technologies also have a common shortcoming: that is, the materials introduced are all components with only a single antifreeze performance, which cannot improve the main component of the quick-setting agent Al. 3+ The solubility of ions will instead increase the proportion of solute in the solution system, which may increase the solution saturation of the accelerator system and reduce the stability

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