CN117024025A - Alkali-free liquid accelerator and preparation method thereof - Google Patents

Abstract

The invention discloses an alkali-free liquid accelerating setting agent, which includes the following components in terms of mass percentage: accelerating setting component 25%-35%, accelerating setting component 4%-7%, and a fluorine-containing accelerating coagulation component The components are 3%-5%, early strength component 1%-5%, regulator 16%-28%, and the rest is water. The first quick-setting component is aluminum sulfate octahydrate, and the second quick-setting component It is one or both of aluminum fluoride or aluminum hydroxide. The present invention shortens the induction period of C3S by increasing the output of fluoride ions and regulators, and greatly improves the accelerating effect, early strength and stability of the accelerating coagulant.

Description

An alkali-free liquid quick-setting agent and its preparation method

Technical field

The invention relates to the technical field of concrete admixtures, in particular to an alkali-free liquid accelerator and its preparation method.

Background technique

In the construction process of shotcrete, accelerating setting agent is an essential chemical admixture, which can make the concrete solidify and harden quickly after adding water and mixing. According to the nature and state of the accelerating setting agent, it can be divided into two types: powder and liquid. Compared with powder accelerating setting agents, liquid accelerating setting agents have stable construction quality and good durability, and have obvious performance advantages. Liquid accelerators can be divided into high-alkali, low-alkali and alkali-free liquid accelerators according to alkali content. The alkali-free liquid accelerators represented by aluminum sulfate type are characterized by their high long-term strength retention rate, alkali-free, chlorine-free, The advantages of safety, environmental protection and high durability are gradually replacing high-alkali liquid accelerators as the development direction of liquid accelerators. The aluminum sulfate content in the alkali-free accelerator is far above 40%, and it contains components such as sodium fluoride, organic amines and stabilizers, such as Chinese patents (201710101577.5, 201710811820.2), but a large amount of sulfate radicals are introduced It will cause the formation of secondary ettringite in concrete, form expansion stress inside the concrete, and even cause concrete cracking. The introduction of a large amount of sodium ions is contrary to the research direction of alkali-free liquid accelerators. In highly corrosive construction projects , it is necessary to strictly control the contents of various sodium ions and sulfate ions in concrete admixtures to extend the service life.

Contents of the invention

The purpose of the present invention is to overcome the concrete corrosion problem caused by the large amount of sodium ions and sulfate ions contained in the existing alkali-free liquid accelerator, and to provide a low-sulfur and early-strength alkali-free liquid accelerator.

One of the objects of the present invention is to provide an alkali-free liquid accelerating setting agent, which includes the following components in terms of mass percentage, accelerating setting component 25%-35%, accelerating setting component 2 4%-7%, The fluorine accelerating coagulation component is 3%-5%, the early strength component is 1%-5%, the regulator is 16%-28%, and the rest is water. The first quick-setting component is aluminum sulfate octahydrate, and the quick-setting component is aluminum sulfate octahydrate. The second condensation component is one or both of aluminum fluoride or aluminum hydroxide.

Preferably, the fluorine-containing coagulation-promoting component is one or more of sodium fluoride, sodium fluorosilicate, and magnesium fluorosilicate mixed in any proportion.

Preferably, the early strength component is one or more of diethanolamine, triethanolamine, triisopropanolamine, and diethanolmonoisopropanolamine mixed in any proportion.

Preferably, the regulator is one or more of oxalic acid, lactic acid, citric acid, phosphoric acid, and tartaric acid mixed in any proportion.

The second object of the present invention is to provide a preparation method of alkali-free liquid accelerator, which includes the following steps:

1) Dissolve the fluorine-containing coagulant component with water at 60°C to prepare solution A;

2) Add the quick-setting component to solution A in one portion;

3) Use a regulator to dissolve the quick-setting component 2 at 80°C to make solution B;

4) Add solution B to solution A and stir for 4 hours;

5) Add the early strength component to solution A, stir for 30 minutes, and stir until it cools to room temperature.

The present invention has the following advantages: the present invention still uses aluminum sulfate as the main accelerator base material. The reason is that aluminum sulfate can react with the hydration of concrete to produce products such as hydrated calcium aluminate and hydrated calcium sulfoaluminate, which accelerates the setting of concrete. Condensation, but the presence of a large amount of sulfate ions will have an impact on the strength of subsequent concrete, so reduce the proportion of sulfate ions, and use aluminum hydroxide and aluminum fluoride to introduce new aluminum ions to compensate for the aluminum ion content caused by the reduction of aluminum sulfate. problem of deficiencies.

In addition to providing aluminum ions, aluminum fluoride can also provide additional fluoride ions. At the same time, the fluorine-containing accelerator component can also provide fluoride ions. The synergistic effect of the two allows fluoride ions to exist in large amounts. Since fluoride ions and aluminum ions are super strong Its complexing ability, its reactivity is higher than that of aluminum ions, and its ability to combine with calcium ions during the reaction process to form calcium fluoride has the ability to shorten the induction period of C ₃ S. The two work together to improve the rapid setting time. ; The fluorine-containing accelerating component is fluorosilicate, which can be hydrolyzed to produce silicic acid colloid, which can improve the early strength of concrete.

In addition to enhancing the early strength of concrete, the early strength component can also improve the stability of the liquid accelerator.

The regulators are oxalic acid, lactic acid, citric acid, phosphoric acid, and tartaric acid. The components can be replaced. On the one hand, the regulator can react with aluminum ions to generate a variety of aluminum salts, and can combine with calcium ions during the concrete hydration reaction to generate calcium phosphate. , calcium citrate, calcium oxalate and other insoluble matter, accelerate the precipitation of calcium ions, and cooperate with the joint action of fluoride ions, which can greatly shorten the setting time of concrete. On the other hand, the presence of the regulator can adjust the PH value of the alkali-free accelerator. , inhibit the hydrolysis of aluminum ions, reduce the alkali content in the accelerator system, and increase the stability of the accelerator system.

The low-sulfur alkali-free accelerator of the present invention fully complies with the national standard of "GB/T35159-2017 Accelerator for Shotcrete", greatly improves the accelerator effect of the alkali-free liquid accelerator, and at the same time improves the early stage of shotcrete. The strength is low, the raw materials are simple, the production process is simple, and the economic benefits are good.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

Example 1, a preparation method of alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 2 parts of sodium fluoride and 1 part of magnesium fluorosilicate with 30 parts of water at 60°C Prepare solution A in a flask. Add 25 parts of aluminum sulfate octahydrate to solution A in 5 portions. Dissolve 28 parts of 85% phosphoric acid and 7 parts of aluminum fluoride using 16 parts of water at 80°C. To form solution B, add solution B to solution A and stir for 4 hours. Add 3 parts of triethanolamine to solution A, keep stirring for 30 minutes, turn off the heating, and stir until it cools to room temperature.

Example 2, a method for preparing alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 2 parts of sodium fluoride and 1 part of sodium fluorosilicate with 30 parts of water at 60°C Prepare solution A in a flask, add 25 parts of aluminum sulfate octahydrate to solution A in 5 times, and use 16 parts of water to dissolve 28 parts of 85% phosphoric acid and 7 parts of aluminum hydroxide at 80°C. To form solution B, add solution B to solution A and stir for 4 hours. Add 3 parts of triethanolamine to solution A, keep stirring for 30 minutes, turn off the heating, and stir until it cools to room temperature.

Example 3, a method for preparing alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 2 parts of sodium fluoride and 1 part of sodium fluorosilicate with 30 parts of water at 60°C Prepare solution A in a flask. Add 25 parts of aluminum sulfate octahydrate to solution A in 5 portions. Dissolve 16 parts of 85% phosphoric acid and 4 parts of aluminum hydroxide using 19 parts of water at 80°C. To form solution B, add solution B to solution A and stir for 4 hours. Add 3 parts of triethanolamine to solution A, keep stirring for 30 minutes, turn off the heating, and stir until it cools to room temperature.

Example 4, a preparation method of alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 1 part of sodium fluoride and 2 parts of magnesium fluorosilicate with 30 parts of water at 60°C Prepare solution A in a flask. Add 30 parts of aluminum sulfate octahydrate to solution A in 5 portions. Add 16 parts of citric acid, 1 part of aluminum hydroxide, and 3 parts of aluminum fluoride using 14 parts of water at 80°C. Dissolve 3 parts of solution B to make solution B. Add solution B to solution A and stir for 4 hours. Add 3 parts of diethanol monoisopropanolamine to solution A. Keep stirring for 30 minutes. Turn off the heating and stir until it cools to room temperature. You get .

Example 5, a method for preparing an alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 2 parts of magnesium fluorosilicate and 3 parts of sodium fluoride with 30 parts of water at 60°C Prepare solution A in a flask. Add 30 parts of aluminum sulfate octahydrate to solution A in 5 portions. Add 16 parts of citric acid, 1 part of aluminum hydroxide, and 3 parts of aluminum fluoride using 12 parts of water at 80°C. Dissolve 3 parts of solution B to make solution B. Add solution B to solution A and stir for 4 hours. Add 3 parts of diethanol monoisopropanolamine to solution A. Keep stirring for 30 minutes. Turn off the heating and stir until it cools to room temperature. You get .

Example 6, a method for preparing alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: 1 part of sodium fluoride, 1 part of magnesium fluorosilicate, 1 part of magnesium fluorosilicate, 30 parts of water at 60°C Dissolve 1 part of sodium fluorosilicate in a flask to make solution A. Add 30 parts of aluminum sulfate octahydrate to solution A in 5 times. Add 16 parts of citric acid and aluminum hydroxide using 26 parts of water at 80°C. Dissolve 2 parts of aluminum fluoride and 2 parts of aluminum fluoride to make solution B. Add solution B to solution A and stir for 4 hours. Add 1 part of triethanolamine to solution A and keep stirring for 30 minutes. Turn off the heating and stir until it cools to room temperature. That’s it.

Example 7, a method for preparing an alkali-free liquid accelerator, in terms of parts by mass, proceed as follows. Dissolve 5 parts of magnesium fluorosilicate in a flask with 30 parts of water at 60°C to prepare a solution. A, add 35 parts of aluminum sulfate octahydrate into solution A in 5 times, and use 9 parts of water to dissolve 16 parts of 85% concentration phosphoric acid, 2 parts of aluminum hydroxide, and 2 parts of aluminum fluoride at 80°C. To form solution B, add solution B to solution A and stir for 4 hours. Add 1 part of triethanolamine to solution A, keep stirring for 30 minutes, turn off the heating, and stir until it cools to room temperature.

Example 8, a method for preparing an alkali-free liquid accelerator, in terms of parts by mass, proceed as follows: dissolve 4 parts of sodium fluoride and 1 part of magnesium fluorosilicate with 30 parts of water at 60°C Prepare solution A in a flask, add 35 parts of aluminum sulfate octahydrate to solution A in 5 parts, and use 8 parts of water at 80°C to mix 16 parts of 85% concentration phosphoric acid, 2 parts of aluminum hydroxide, and fluorinated Dissolve 2 parts of aluminum to make solution B. Add solution B to solution A and stir for 4 hours. Add 2 parts of triethanolamine to solution A, keep stirring for 30 minutes, turn off the heating, and stir until it cools to room temperature.

According to the national standard "GB/T35159-2017 Accelerated Setting Agent for Shotcrete", the accelerating setting agent prepared above is mixed with cement, mineral powder water reducing agent, gravel, machine-made sand and water with the accelerating setting agent parameter being 6%. Uniformly, high-strength concrete was obtained, in which Mengdian cement was used as cement. The setting time and mortar strength were tested in each embodiment. The test results are summarized in the following table:

Components Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Aluminum sulfate octahydrate 25 25 25 30 30 30 35 35 aluminum fluoride 7 0 0 3 3 2 2 2 Aluminum hydroxide 0 7 4 1 1 2 2 2 sodium fluoride 2 2 2 1 3 1 0 4 Magnesium Fluosilicate 1 0 0 2 2 1 5 1 sodium fluorosilicate 0 1 1 0 0 1 0 0 Triethanolamine 3 3 3 0 0 1 1 2 Diethanol monoisopropanolamine 0 0 0 3 3 0 0 0 citric acid 0 0 0 16 16 16 0 0 Phosphoric acid 28 28 16 0 0 0 16 16 water 46 46 49 44 42 56 39 38 Initial setting time 2:10 2:20 2:22 2:16 2:13 2:17 2:14 2:08 Final setting time 6:25 6:14 6:10 6:15 6:20 6:10 6:02 6:12 1d strength (MPa) 10.2 9.8 9.5 9.8 9.9 9.4 9.5 9.9 28d intensity ratio (%) 102 101 102 101 102 100 101 101

It can be seen from Example 1 and Example 2 that using aluminum fluoride or aluminum hydroxide to replace part of the aluminum sulfate octahydrate can have a good coagulation-promoting effect; it can be seen from Example 2 and Example 3 that with the use of aluminum hydroxide , the decrease in phosphoric acid content, the strength of concrete in one day also decreases; from Example 4 and Example 5, it can be seen that as the fluoride ion content increases, the accelerating effect and strength also increase; from Example 6, Example 7, It can be seen from Example 8 that the increase in the content of the coagulation-promoting component improves the coagulation-accelerating effect of the accelerator. A single magnesium fluorosilicate does not have as good a coagulation-accelerating effect as a mixture of multiple components. Overall, it can be seen that the alkali-free liquid accelerator of the present invention It has good setting accelerating effect and fully complies with the national standard of "GB/T35159-2017 Accelerating Setting Agent for Shotcrete".

Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (5)

1. An alkali-free liquid accelerating setting agent, characterized in that, in terms of mass percentage, it includes the following components, accelerating setting component 25%-35%, accelerating setting component 24%-7%, fluorine-containing accelerating agent The setting component is 3%-5%, the early strength component is 1%-5%, the regulator is 16%-28%, and the rest is water. The first quick-setting component is aluminum sulfate octahydrate, and the quick-setting component Divided into one or two types of aluminum fluoride or aluminum hydroxide. 2. A kind of alkali-free liquid accelerating setting agent according to claim 1, characterized in that: the fluorine-containing accelerating coagulation component is one or more of sodium fluoride, sodium fluorosilicate, and magnesium fluorosilicate. mixed in any proportion. 3. A kind of alkali-free liquid accelerating setting agent according to claim 1, characterized in that: the early strength component is diethanolamine, triethanolamine, triisopropanolamine, and diethanol monoisopropanolamine. One or more mixed in any proportion. 4. An alkali-free liquid accelerating setting agent according to claim 1, characterized in that the regulator is one or more of oxalic acid, lactic acid, citric acid, phosphoric acid and tartaric acid mixed in any proportion. 5. The preparation method of a kind of alkali-free liquid accelerator according to any one of claims 1-4, characterized in that it includes the following steps: 1) Dissolve the fluorine-containing coagulant component with water at 60°C to prepare solution A; 2) Add the quick-setting component to solution A in one portion; 3) Use a regulator to dissolve the quick-setting component 2 at 80°C to make solution B; 4) Add solution B to solution A and stir for 4 hours; 5) Add the early strength component to solution A, stir for 30 minutes, and cool to room temperature.