阅读说明：本技术 一种无碱无氟液体速凝剂及制备和应用 (Alkali-free fluorine-free liquid accelerator and preparation and application thereof ) 是由 王林 李超 舒春雪 贺鑫鑫 宋少民 魏子程 雍涵 于 2021-11-02 设计创作，主要内容包括：本发明属于建筑材料技术领域,具体涉及一种无碱无氟液体速凝剂的制备和使用方法。无碱无氟液体速凝剂由促凝组分、有机醇、醇胺、悬浮稳定剂、纳米材料、pH调节剂和水组成。本发明的有益效果是,本发明的无碱无氟液体速凝剂能有效提高喷射混凝土早期强度,缩短喷射混凝土凝结时间,减少喷射混凝土的回弹率,对环境友好,无腐蚀和污染。本发明适用于隧道、涵洞、边坡、基坑等工程的面层支护以及堵漏或抢修工程。(The invention belongs to the technical field of building materials, and particularly relates to a preparation and use method of an alkali-free fluorine-free liquid accelerator. The alkali-free and fluorine-free liquid accelerator consists of a coagulation accelerating component, organic alcohol, alcohol amine, a suspension stabilizer, a nano material, a pH regulator and water. The alkali-free fluorine-free liquid accelerator has the beneficial effects that the alkali-free fluorine-free liquid accelerator can effectively improve the early strength of sprayed concrete, shorten the setting time of the sprayed concrete, reduce the rebound rate of the sprayed concrete, and is environment-friendly and free from corrosion and pollution. The invention is suitable for surface layer support and plugging or rush-repair engineering of tunnels, culverts, side slopes, foundation pits and other engineering.)

1. The alkali-free fluorine-free liquid accelerator is characterized by comprising the following components in parts by weight: 55-60% of a coagulation accelerating component, 1-3% of organic alcohol, 5-8% of alcohol amine, 1-4% of a suspending dispersant, 1-5% of a nano material, 0.2-1% of a pH regulator, 0-1% of a defoaming agent and the balance of water.

2. The alkali-free and fluorine-free liquid accelerator according to claim 1, wherein the accelerating component is polyaluminium sulfate and magnesium sulfate, and the mass ratio of the accelerating component to the magnesium sulfate is 28: 1.

3. The alkali-free and fluorine-free liquid accelerator according to claim 1, wherein the weight ratio of each component of the suspending dispersant is: 50-60% of magnesium aluminum silicate, 15-25% of xanthan gum and 15-25% of polycarboxylate.

4. The alkali-free and fluorine-free liquid accelerator according to claim 1, wherein the nano material is at least one of nano silica and nano aluminum hydroxide;

the pH regulator is dilute sulfuric acid.

5. The alkali-free and fluorine-free liquid accelerator according to claim 1, wherein the organic alcohol is at least one of methanol, ethanol, isopropanol or glycerol; the alcohol amine is at least one of diethanolamine or triethanolamine.

6. A method for preparing the alkali-free and fluorine-free liquid accelerator as claimed in any one of claims 1 to 5, which comprises the following steps:

s1) weighing each component according to the design components for later use;

s2) stirring and mixing alcohol amine, organic alcohol and water to obtain a mixed solution;

s3) heating the mixed solution in the S2) to 50-60 ℃, adding polyaluminium sulfate, and stirring at constant temperature to obtain a transparent solution;

s4) adding the residual materials into the transparent solution obtained in S3), stirring, fully dissolving, adding a pH regulator to control the pH to be 2-3, stopping stirring and standing, and naturally cooling the solution to obtain the high early strength alkali-free fluorine-free liquid accelerator.

7. The method as claimed in claim 6, wherein the stirring speed in step S3) is 250-350 r/min;

the stirring speed in the step S4) is 250-350r/min, and the mixing time is not less than 50 minutes.

8. The method as claimed in claim 7, wherein the stirring speed in step S3) is 275-295 r/min;

the stirring speed in the step S4) is 275-295r/min, and the mixing time is 50-120 minutes.

9. A shotcrete, which comprises the alkali-free fluorine-free liquid accelerator prepared according to claim 6, wherein the alkali-free fluorine-free liquid accelerator is added in the concrete in an amount of 5-8%.

10. The shotcrete of claim 9, wherein the cement paste prepared by adding the alkali-free and fluorine-free liquid setting accelerator to the shotcrete has an initial setting time of not more than 3min and a final setting time of not more than 5min, and has a 6h strength of not less than 1.3Mpa, a 1d compressive strength of not less than 13Mpa, and a 28d compressive strength ratio of more than 110%.

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to an alkali-free fluorine-free liquid accelerator applied to surface layer support and leakage stoppage or emergency repair engineering of tunnels, culverts, slopes, foundation pits and other engineering, and preparation and application thereof.

Background

With the fact that the proportion of wet-sprayed concrete in tunnel construction is larger and larger, the demand of high-quality liquid accelerator is larger and larger. At the present stage, the alkali-free liquid accelerator industry in China is in a rapid development stage, the technology is not mature, and a plurality of problems need to be solved urgently. As for the accelerator, there are mainly the following problems:

(1) the stability is poor, and the currently researched accelerator generally has the problem of short storage life, and the use of the accelerator is seriously influenced due to the phenomenon of layering in a short time.

(2) The mixing amount is high, in order to guarantee the concrete coagulation effect, the mixing amount of the accelerator is increased frequently, so that the production cost is increased substantially, and adverse effects are brought to the production benefits of enterprises.

(3) The toxicity of production raw materials is high, aluminum sulfate is the most commonly used raw material for preparing the accelerating agent at present, but the stability is low, and generally, fluorine-containing substances are added into production enterprises to improve the stability through complexation, but the early strength of concrete is often reduced. In addition, fluorine is harmful to human bodies, and serious diseases can be caused by long-term contact, so that the health and the safety of constructors are seriously threatened.

(4) The alkali content is higher. The alkali content is high, the corrosivity is high, and the influence on the later strength of the sprayed concrete is increased.

(5) Shotcrete has a long setting time and insufficient early strength, resulting in shotcrete

The rebound rate of concrete is high and the dust is much.

Therefore, under the background of the rapid increase of the demand of the current accelerator, the research of the liquid accelerator which has the advantages of good accelerating effect, high early strength, low mixing amount, no alkali, no chlorine, low price, good stability and accordance with the green development requirement is urgent.

Disclosure of Invention

The invention discloses an alkali-free fluorine-free liquid accelerator, and a preparation method and application thereof, which aim to solve any one of the above and other potential problems in the prior art.

In order to achieve the purpose, the technical scheme of the invention is as follows: the preparation method of the alkali-free fluorine-free liquid accelerator comprises the following steps: accelerating components, organic alcohol, alcohol amine, a suspension dispersant, a nano material, a pH regulator and water.

Further, the alkali-free and fluorine-free liquid accelerator comprises the following components in parts by weight: 55-60% of a coagulation promoting component, 1-3% of organic alcohol, 2-5% of alcohol amine, 1-4% of a suspending dispersant, 1-5% of a nano material, 0.2-1% of a pH regulator and the balance of water.

The coagulation accelerating component is aluminum sulfate and magnesium sulfate, and the proportion relation is 28: 1. The suspension dispersant is prepared by compounding magnesium aluminum silicate, xanthan gum and polycarboxylate.

Further, the organic alcohol is selected from at least one of methanol, ethanol and isopropanol; the alcohol amine is at least one of diethanolamine and triethanolamine; the nano material is selected from at least one of nano silicon dioxide and nano aluminum hydroxide; the pH regulator is selected from concentrated sulfuric acid.

The invention also aims to provide a preparation process of the alkali-free fluorine-free liquid accelerator, which specifically comprises the following steps:

s1) weighing each component according to the design components for later use;

s2) stirring and mixing the alcohol amine and the organic alcohol in the S1) with water to obtain a mixed solution;

s3) heating the mixed solution in S2) to 50-60 ℃, adding polyaluminium sulfate and magnesium sulfate, mixing and grinding the obtained mixed material, and stirring at constant temperature until the solution is transparent;

s4) adding other components into the solution obtained in S3), waiting for the last component to be fully dissolved, stopping stirring and standing for the prepared alkali-free fluorine-free liquid accelerator solution to be naturally cooled, bottling, and placing in a dry environment for use. And finally obtaining the alkali-free fluorine-free liquid accelerator.

Further, the stirring rotation speed in the steps S3) and S4) is 250-; in step S4), the mixing time is not less than 50 minutes, preferably 50 to 120 minutes.

Further, the initial setting time of the cement paste of the alkali-free fluorine-free liquid setting accelerator is not more than 3min (minutes), the final setting time is not more than 5min, the 6h strength of the prepared cement mortar is not less than 1.5MPa, the 1d compressive strength is not less than 13MPa, and the 28d (day) compressive strength ratio is more than 110%.

The invention also provides an application of the alkali-free fluorine-free liquid accelerator in shotcrete, and the method specifically comprises the following steps:

the mixing amount of the alkali-free fluorine-free liquid accelerator in concrete is 5-8%, and more preferably 5-7%.

The main component of the set accelerating component in the invention is aluminum sulfate, and the addition of the aluminum sulfate can simultaneously improve Al in a liquid phase in a cement-accelerator-water system³⁺、SO₄ ^2-And H⁺Ion content, due to high pH of the cement liquid phase, Al³⁺Will be converted into [ Al (OH)₄]^-With Ca²⁺And SO₄ ^2-The reaction quickly generates rod-shaped or needle-shaped ettringite crystals, and a large amount of needle-shaped ettringite crystals are spliced together to form a network structure with compact space, thereby playing the roles of accelerating coagulation and improving early strength. In order to solve the problem of poor stability of the traditional liquid alkali-free setting accelerator, the existence state of particles in the liquid setting accelerator is improved by adding alcohol amine and organic alcohol by using the principle of complex reaction, so that the stability is improved. The nano material is used as an inorganic material with filling function and reaction activity, is uniformly dispersed in a solution under the action of a dispersing agent, and can obviously improve the early strength of concrete when applied to a concrete material. On one hand, the nanometer materials can fill the pores of the concrete, and on the other hand, some nanometer materials play a role of crystal nucleus induction, so that the hydration of the cement monoore is accelerated. In addition, the pH regulator is added to improve the stability of the accelerator, and the lower the pH value is, the more difficult the hydrolysis of aluminum ions occurs, and the better the stability of the accelerator is.When preparing the alkali-free liquid accelerator, the stability of the accelerator needs to be further improved by adding a stabilizer, but the amount of the stabilizer is not required to be excessive.

The invention is milk white liquid, and when in use, the mixing amount of the alkali-free fluorine-free liquid accelerator in concrete is 5-8%, and more preferably 5-7%.

The invention can effectively avoid the concrete problem caused by the defects of large corrosivity, high mixing amount, poor stability, high rebound rate and the like of the sprayed concrete accelerator, can meet the requirements of the sprayed concrete on setting time and early strength, ensures later strength and meets the requirement of green development.

The invention has no corrosion effect on the steel bars in the concrete structure, and can be widely applied to surface layer support and plugging or rush-repair engineering of projects such as tunnels, culverts, side slopes, foundation pits and the like.

Drawings

FIG. 1 is a flow chart of a preparation method of an alkali-free fluorine-free liquid accelerator.

Detailed Description

The technical solution of the present invention is further explained below according to specific embodiments.

The invention relates to an alkali-free fluorine-free liquid accelerator which comprises the following components: accelerating components, organic alcohol, alcohol amine, a suspension dispersant, a nano material, a pH regulator and water.

The alkali-free fluorine-free liquid accelerator comprises the following components in parts by weight: 55-60% of a coagulation promoting component, 1-3% of organic alcohol, 5-8% of alcohol amine, 1-4% of a stabilizer, 1-5% of a nano material, 0.2-1% of a pH regulator and the balance of water.

The coagulation accelerating component is obtained by mixing aluminum sulfate and magnesium sulfate according to a ratio of 28: 1.

The suspension dispersant is prepared by compounding magnesium aluminum silicate, xanthan gum and polycarboxylate.

The organic alcohol is selected from at least one of methanol, ethanol and isopropanol; the alcohol amine is at least one of diethanolamine and triethanolamine; the nano material is selected from at least one of nano silicon dioxide and nano aluminum hydroxide; the pH regulator is selected from concentrated sulfuric acid.

As shown in fig. 1, another object of the present invention is to provide a preparation process of the alkali-free fluorine-free liquid accelerator, which specifically comprises the following steps:

s1) weighing each component according to the design components for later use;

s2) stirring and mixing the alcohol amine and the organic alcohol in the S1) with water to obtain a mixed solution;

s3) heating the mixed solution in the S2) to 50-60 ℃, adding polyaluminium sulfate and magnesium sulfate, and stirring at constant temperature until the solution is transparent;

s4) adding other components into the solution obtained in S3), waiting for the last component to be fully dissolved, adjusting the pH value of the solution by sulfuric acid, controlling the pH value of the solution to be 2-3, stopping stirring and standing for natural cooling of the prepared alkali-free fluorine-free liquid accelerator solution, bottling, and standing in a dry environment for use. And finally obtaining the alkali-free fluorine-free liquid accelerator.

The stirring rotation speed in the steps S3) and S4) is 250-350r/min, preferably 275-295 r/min; in step S4), the mixing time is not less than 50 minutes, preferably 50 to 120 minutes.

The alkali-free fluorine-free liquid accelerator has the advantages that the initial setting time of cement paste is not more than 3min, the final setting time is not more than 5min, the 6h strength of the prepared cement mortar is not less than 1.5Mpa, the 1d compressive strength is not less than 13Mpa, and the 28d compressive strength ratio is more than 110%.

The invention also provides an application of the alkali-free fluorine-free liquid accelerator in shotcrete, and the method specifically comprises the following steps:

the mixing amount of the alkali-free fluorine-free liquid accelerator in concrete is 5-8%, and more preferably 5-7%.

Example one

The alkali-free fluorine-free liquid accelerator is prepared from 57% of polyaluminium sulfate, 2% of magnesium sulfate, 3% of diethanolamine, 2% of ethylene glycol, 4% of a suspension dispersant, 4% of nano silicon dioxide, 1% of concentrated sulfuric acid and 27% of water. The initial setting time of the cement paste is 2min15s, the final setting time is 4min23s, the 6h strength of the prepared cement mortar is 1.6Mpa, the 1d compressive strength is 14.2Mpa, the 28d compressive strength ratio is 125%, and the 90d compressive strength retention rate is 122%.

Example two

The alkali-free fluorine-free liquid accelerator is prepared from 30% of polyaluminium sulfate (by weight percentage, the same below), 25% of aluminium sulfate, 6% of triethanolamine, 2% of glycerol, 2% of a suspension dispersant, 2% of nano-silicon dioxide, 1% of concentrated sulfuric acid and 32% of water. The initial setting time of the cement paste is 2min34s, the final setting time is 5min, the 6h strength of the prepared cement mortar is 1.3Mpa, the 1d compressive strength is 13.6Mpa, the 28d compressive strength ratio is 110%, and the 90d compressive strength retention rate is 110%.

The alkali-free fluorine-free liquid accelerator and the preparation and use methods thereof provided by the embodiments of the application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.