阅读说明：本技术 快凝高强型无碱液体速凝剂 (Quick-setting high-strength alkali-free liquid accelerator ) 是由 李晓宁 闫超强 郝利国 李婷 陈梦龙 武斌 马加营 仲从春 马强 于 2020-07-01 设计创作，主要内容包括：本发明涉及一种快凝高强型无碱液体速凝剂,原料包括硫酸铝、氢氟酸、氢氧化铝、预分散增强组分、悬浮组分、络合组分、有机酸、水,对水泥基材料适应性好,兼具快凝和高强双重技术功效,应用本发明的喷射混凝土凝结速度快、早期强度高、回弹率低、粉尘量小、粘结效果好,并且环保无腐蚀。(The invention relates to a quick-setting high-strength alkali-free liquid accelerator which comprises the following raw materials of aluminum sulfate, hydrofluoric acid, aluminum hydroxide, a pre-dispersion reinforcing component, a suspension component, a complexing component, organic acid and water, has good adaptability to cement-based materials, and has the dual technical effects of quick setting and high strength.)

1. A quick-setting high-strength alkali-free liquid accelerator is characterized by comprising aluminum sulfate, hydrofluoric acid, aluminum hydroxide, a pre-dispersion enhancing component, a suspension component, a complexing component, an organic acid and water.

2. The quick-setting high-strength alkali-free liquid accelerator as claimed in claim 1, which comprises, by mass, 35-55% of aluminum sulfate, 20-30% of hydrofluoric acid, 5-10% of aluminum hydroxide, 3-8% of a pre-dispersion enhancing component, 5-10% of a suspending component, 4-10% of a complexing component, 3-8% of an organic acid, and the balance of water.

3. The quick-setting high-strength alkali-free liquid accelerator as claimed in claim 1, wherein the pre-dispersion enhancing component comprises 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), Acrylamide (AM), a polymerization inhibitor, a solubilizing component and a thixotropic component.

4. The quick-setting high-strength alkali-free liquid accelerator as claimed in claim 3, wherein the polymerization inhibitor is hydroquinone, the solubilizing component is a mixture of glycerol, lactic acid and hydroxyethylidene diphosphonic acid HEDP, and the thixotropic component is disteardimonium lithium montmorillonite.

5. The quick-setting high-strength alkali-free liquid accelerator as claimed in claim 4, wherein the pre-dispersion enhancing component is prepared by the following steps: adding water into a stirring device, adding AMPS, AM and hydroquinone, stirring uniformly, adding solubilizing components, starting high-speed stirring, adding thixotropic components while stirring, and stirring at high speed for more than 10min to obtain the final product.

6. The quick-setting high-strength alkali-free liquid accelerator as claimed in claim 1, wherein the suspending component is at least one selected from the group consisting of magnesium silicofluoride, calcium silicofluoride, polyacrylic acid, carboxyethyl methyl cellulose, and hydroxypropyl methyl cellulose.

7. The quick-setting high-strength alkali-free liquid accelerator according to claim 1, wherein the complexing component is at least one of triethanolamine, diethanolamine, and triisopropanolamine.

8. The quick-setting high-strength alkali-free liquid accelerator according to claim 1, wherein the organic acid is at least one of oxalic acid and methacrylic acid.

9. The preparation method of the quick-setting high-strength alkali-free liquid accelerator as claimed in any one of claims 1 to 8, which is characterized by comprising the following preparation steps: adding hydrofluoric acid into a stirring device with the rotation speed of 200-fluid 300r/min, then slowly adding aluminum hydroxide powder, uniformly stirring, raising the reaction temperature to 70 ℃, adding aluminum sulfate and a pre-dispersion enhancing component, stirring until the aluminum sulfate and the pre-dispersion enhancing component are dissolved, adding a suspension component, raising the rotation speed to 400-fluid 500r/min, stirring for 30-60min, adding a complexing component, stirring for 30-60min, and finally adding an organic acid to adjust the pH value of the product, thereby obtaining the quick-setting high-strength alkali-free liquid accelerator.

10. The preparation method of the quick-setting high-strength alkali-free liquid accelerator as claimed in claim 9, wherein the hydrofluoric acid is a hydrofluoric acid solution with a mass concentration of 10-20%.

Technical Field

The invention relates to the technical field of cement-based building material additives, in particular to a quick-setting high-strength alkali-free liquid accelerator and a preparation method thereof, which are suitable for cement-based materials such as quick-setting repairing materials, sprayed concrete and the like.

Background

With the continuous promotion of infrastructure construction and urban construction engineering in China, rapid-setting repair materials, sprayed concrete and other rapid-setting concrete materials play more and more important roles in the engineering, particularly for the sprayed concrete, tunnel engineering related to the construction process of high-speed railways and highways is more and more, and the application of the sprayed concrete for supporting a lining body is continuously enhanced due to incomparable superiority, so that higher requirements are provided for the mechanical property and durability of the sprayed concrete.

The sprayed concrete is divided into a dry spraying method and a wet spraying method, the application of the accelerator provides guarantee for the construction of the sprayed concrete, the alkaline powder accelerator is low in price and good in accelerating effect, but the alkali content is high, so that the safety protection of constructors is not facilitated, in recent years, the alkali-free liquid accelerator is widely applied, the good alkali-free liquid accelerator has the characteristics of short setting time, low resilience, high early strength and the like, the accelerator industry in China enters a new development stage, and along with the promotion and implementation of new national standards, the use experience and scientific research achievement of a large number of domestic construction projects provide a better research and application platform for the development of the accelerator.

The Lixamine uses inorganic salt, organic amine, organic acid, liquid stabilizer, pH regulator and distilled water as principles to prepare the alkali-free liquid accelerator, has good adaptability to common portland cement, naphthalene-based and polycarboxylic acid-based high-efficiency water reducing agents, and meets the grade requirements of qualified products in the standard; the poplar force far adopts aluminum sulfate, fluorine-aluminum complex solution, oxalic acid, diethanol amine and stabilizer as main raw materials to synthesize the alkali-free liquid accelerator, and the homogeneity index of the alkali-free liquid accelerator is tested; li Chong Zhi adopts polycarboxylate aluminum salt dispersant, polyaluminium sulfate, triethanolamine and the like to synthesize the alkali-free liquid accelerator, and tests the performance of the alkali-free liquid accelerator; patent document CN110104987 prepares an accelerator from polyaluminium sulfate, metakaolin, nano silica sol, alcohol amine, organic acid, a thickener, a dispersant and water; CN110451844 uses 45-55 parts of polyaluminium sulfate, 3-5 parts of organic acid, 0.5-1 part of inorganic acid, 2-4 parts of stabilizing agent, 1-2 parts of early strength agent, 1-2 parts of thickening agent and 40-50 parts of water to prepare alkali-free liquid accelerator; CN110734242 discloses a sprayed concrete alkali-free liquid accelerator for alpine regions, which comprises the following components: 40-60% of aluminum sulfate, 6-10% of aluminum fluoride, 2-6% of alkalizer, 4-8% of anti-freezing component of accelerator, 4-6% of anti-freezing component of concrete, 1-5% of acid regulator, 0.01-0.1% of air entraining component of concrete and the balance of water; CN110510906 discloses an alkali-free liquid accelerator composed of polyaluminium sulfate, an alcohol amine substance, a complexing agent, an accelerator and water.

The alkali-free liquid accelerator develops rapidly, the accelerating mechanism is almost the same, along with the continuous application of engineering construction, the alkali-free liquid accelerator which has lower early strength and has both quick setting and high strength is widely required in the prior art, and the development of the novel quick-setting high-strength alkali-free liquid accelerator has higher economic value and social benefit.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides a quick-setting high-strength alkali-free liquid accelerator which has good adaptability to cement-based materials and dual technical effects of quick setting and high strength.

Specifically, the quick-setting high-strength alkali-free liquid accelerator comprises aluminum sulfate, hydrofluoric acid, aluminum hydroxide, a pre-dispersion enhancing component, a suspension component, a complexing component, an organic acid and water.

Preferably, the quick-setting high-strength alkali-free liquid accelerator comprises, by mass, 35-55% of aluminum sulfate, 20-30% of hydrofluoric acid, 5-10% of aluminum hydroxide, 3-8% of a pre-dispersion enhancing component, 5-10% of a suspending component, 4-10% of a complexing component, 3-8% of an organic acid, and the balance of water. The invention selects aluminum sulfate, hydrofluoric acid and aluminum hydroxide as the main components of the alkali-free liquid accelerator, the main components of the alkali-free liquid accelerator playing a role in cement-based materials are aluminum salts, and the aluminum sulfate and the active aluminum hydroxide ionize a large amount of Al³⁺、SO₄ ^2-Ions, said ions and a cement mineral C₃S dissolutionCa produced²⁺The ions react rapidly to generate ettringite AFt crystal, calcium ions in the liquid phase of the cement-based material are combined rapidly, and mineral C₃The C/S ratio of the C-S-H gel generated by S hydration is relatively small, the permeability is good, and water can gradually flow to C through the C-S-H gel₃S internal diffusion, while C₃Ca inside S²⁺Can also diffuse outward into the liquid phase, thereby preventing C₃The occurrence of the S induction period finally realizes the rapid coagulation of the slurry, and the SO₄ ^2-With Ca (OH) in the cement paste₂、Al₂O₃The components react rapidly to generate a large amount of gypsum and AFt crystals, newly generated crystals generate a network structure in a crossed manner to cause rapid setting of slurry, and most alkali-free setting accelerators in the prior art adopt the principle to cause rapid setting of cement; for alkali-free setting accelerators, Al is added³⁺When the concentration is too high, the flocculation and precipitation are caused by long-term storage, and the properties of the accelerator are unstable, and the aluminum ions are easily hydrolyzed to form Al (OH)₃，Al(OH)₃The solubility is poor, so the precipitation is easy to occur; the main approaches for solving the flocculent precipitate are two: firstly, the aluminum ions are relatively stable under acidic conditions, the stronger the acidity, the better the stability of the aluminum ions, and secondly, the Al can be mixed by selecting excellent complexing agents and coordination agents³⁺The maximum concentration is stable in the solution, so that a pH regulator, a complexing agent and a complexing agent are usually added into the alkali-free liquid accelerator, and the invention provides F by adding hydrofluoric acid^-Can form a stable complex system with aluminum ions, thereby increasing the stability of the aluminum ions in water.

Preferably, the pre-dispersion enhancing component comprises 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), Acrylamide (AM), a polymerization inhibitor, a solubilizing component and a thixotropic component.

Preferably, the polymerization inhibitor is hydroquinone, the solubilizing component is a mixture of glycerol, lactic acid and hydroxyethylidene diphosphonic acid HEDP, and the thixotropic component is distearyl dimethyl ammonium lithium montmorillonite.

Preferably, the preparation method of the predispersion enhancing component comprises the following steps: adding water into a stirring device, adding AMPS, AM and hydroquinone, stirring uniformly, adding solubilizing components, starting high-speed stirring, adding thixotropic components while stirring, and stirring at high speed for more than 10min to obtain the final product.

2-acrylamide-2-methylpropanesulfonic acid (AMPS for short) is an acrylamide derivative, is often used as an unsaturated monomer of a polycarboxylic acid water reducing agent, has strong anionic property and hydrophilic functional group sulfonic group and an amide group with a shielding function, and can improve the dispersibility of the water reducing agent on cement and promote the cement C by grafting the unsaturated monomer to the polycarboxylic acid water reducing agent₃S hydration is carried out, the quantity of rodlike ettringite AFt in an early hydration product is increased, and therefore the early mechanical property of cement is improved, the invention discovers that the addition of AMPS into an alkali-free liquid accelerator can shorten the setting time of a cement-based material and improve the early strength of the cement-based material, the effect is not recorded by the prior art, however, in practical application, the phenomena of layering and precipitation, insoluble impurity generation and the like can be generated when the alkali-free liquid accelerator added with AMPS is stored for a long time, the use effect of the alkali-free liquid accelerator is finally influenced, probably because AMPS monomers are polymerized in a small amount and the AMPS and a water-based accelerator have poor solubility, the AMPS is obtained by modifying the AMPS through a large number of experiments, after the AMPS is mixed with acrylamide and a small amount of polymerization inhibitor, glycerol, lactic acid and hydroxyl ethylidene diphosphate are added as solubilizing components for solubilization treatment, the solubility and the polymerization inhibition degree of AMPS can be improved, and then the distearyl dimethyl ammonium lithium montmorillonite is added for high-speed stirring, so that AMPS pre-dispersion slurry can be obtained to be used as a pre-dispersion enhancing component, and the problem of poor compatibility of AMPS in the alkali-free liquid accelerator is solved.

Preferably, the suspension component is selected from at least one of magnesium fluosilicate, calcium fluosilicate, polyacrylic acid, carboxyethyl methyl cellulose and hydroxypropyl methyl cellulose; more preferably, the suspension component is selected from magnesium fluosilicate, the addition of hydrofluoric acid in the invention provides F-to increase the stability of aluminum ions in water, however, F-if surplus is easily to cause the depolymerization of cement hydration product C-S-H gel, so that the polymerization degree of hydrated calcium silicate is reduced, the network structure of cement slurry is damaged, and the development of cement strength is seriously influenced, so that a substance capable of improving the cement strength is required to be introduced to supplement the damage of the accelerator to the cement strength. According to the invention, magnesium fluosilicate is preferably added as a suspension component, wherein magnesium ions can be preferentially combined with hydroxide ions to generate magnesium hydroxide to provide crystal nuclei, so that tricalcium silicate is promoted to hydrate and separate out C-S-H gel to fill pores in time, and the effect of ensuring that the strength of a cement slurry structure is not lost in a later period can be achieved.

Preferably, the complexing component is at least one of triethanolamine, diethanolamine, triisopropanolamine.

Preferably, the organic acid is at least one of oxalic acid and methacrylic acid.

The invention can obviously improve the cohesiveness and the cohesive force of a cement-based material, particularly sprayed concrete, and effectively reduce the rebound quantity and the dust quantity of the sprayed concrete by adding the complexing component and the organic acid into the alkali-free liquid accelerator.

The invention also relates to a preparation method of the quick-setting high-strength alkali-free liquid accelerator, which specifically comprises the following preparation steps: adding hydrofluoric acid into a stirring device with the rotation speed of 200-fluid 300r/min, then slowly adding aluminum hydroxide powder, uniformly stirring, raising the reaction temperature to 70 ℃, adding aluminum sulfate and a pre-dispersion enhancing component, stirring until the aluminum sulfate and the pre-dispersion enhancing component are dissolved, adding a suspension component, raising the rotation speed to 400-fluid 500r/min, stirring for 30-60min, adding a complexing component, stirring for 30-60min, and finally adding an organic acid to adjust the pH value of the product, thereby obtaining the quick-setting high-strength alkali-free liquid accelerator.

Preferably, the hydrofluoric acid is a hydrofluoric acid solution with a mass concentration of 10-20%.

The invention selects aluminum sulfate, hydrofluoric acid and aluminum hydroxide as the main components of the alkali-free liquid accelerator to provide a large amount of stably existing aluminum ions and sulfate ions, and the ions and the cement mineral C₃Ca dissolved out of S²⁺The ions react rapidly to generate ettringite AFt crystal and lead the mineral C₃The C/S ratio of C-S-H gel generated by S hydration is smaller, the gel has good permeability, and the hydrofluoric acid provides F < - > and can form a stable complex system with aluminum ions, so that the stability of the aluminum ions in water is improved, and the addition of the hydrofluoric acidThe modified AMPS is added as a pre-dispersion enhancing component, so that the quick-setting capability and early strength of the alkali-free liquid accelerator are improved, the complex component and the organic acid are added into the alkali-free liquid accelerator, the cohesiveness and the cohesive force of a cement-based material, particularly sprayed concrete, can be obviously improved, and the rebound quantity and the dust quantity of the sprayed concrete are effectively reduced.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.