WO2024239390A1 - Composite modified pillared material and preparation method therefor, and fluoride-free and alkali-free accelerator based thereon and preparation method therefor - Google Patents

Abstract

The present invention belongs to the technical field of concrete admixtures. Disclosed are a composite modified pillared material modified with a hyperbranched quaternary ammonium salt, and a preparation method therefor. According to the composite modified pillared material, a hyperbranched quaternary ammonium salt having a specific structure is used as a modified material, and differs from a common modified material having a long-chain structure since the material itself contains a branched structure, thereby ensuring that after an orthorhombic pillared material is intercalated, the interlayer spacing is larger, and the CEC capacity is higher. Further disclosed in the present invention are a fluoride-free and alkali-free accelerator comprising the composite modified pillared material as a stabilizer, and a preparation method therefor. Compared with a traditional alkali-free accelerator, the fluorine-free and alkali-free accelerator increases the use amount of aluminum sulfate therein to 10% or above, such that the supersaturation degree of an accelerator solution system is significantly increased, and the excellent effect of the fluorine-free and alkali-free accelerator in a concrete material is ensured.

Description

Composite modified pillaring material and preparation method thereof, fluorine-free and alkali-free quick-setting agent based thereon and preparation method thereof Technical Field

The present invention belongs to the technical field of concrete admixtures, and in particular, relates to a composite modified pillaring material modified by a hyperbranched quaternary ammonium salt and a preparation method thereof, as well as a fluorine-free and alkali-free quick-setting agent using the composite modified pillaring material as a stabilizer and a preparation method thereof.

Background Art

Accelerator is a concrete admixture technology that allows cement and concrete to quickly solidify and harden. The research and development idea of accelerator is to use aluminum salt as the core component and promote the increase of aluminum salt concentration in various forms. Fluorine-free and alkali-free accelerator can avoid the harm of alkali-aggregate reaction to concrete, and at the same time avoid the harm of fluorine-containing materials in the preparation to production/life safety. Therefore, the development of fluorine-free and alkali-free accelerator is the focus of current research. In order to improve the performance of fluorine-free and alkali-free accelerator, increasing the aluminum phase content is the mainstream solution. At the same time, too high aluminum salt content will lead to high supersaturation of the solution system, poor stability, and product stratification. Therefore, suitable stabilizers have strong practical significance.

Unlike traditional stabilizer materials, pillared materials are widely studied because their porous/intercalated inorganic structures can be widely modified to bring different structural characteristics. At present, the more common modification objects are generally orthorhombic materials such as kaolin, montmorillonite, sepiolite, talc, etc. of layered silicates; modification technologies include ion exchange modification of metal ions, organic anion and cation intercalation modification, etc. Among them, anion surfactant modification such as sodium dodecyl sulfate or cation hexadecyltrimethylammonium bromide is widely reported.

For example, a suspension-type alkali-free liquid quick-setting agent supersaturated with aluminum sulfate and its preparation method. The amount of aluminum sulfate used is between 60% and 70%, and the stability of the supersaturated system is increased by ultrafine sepiolite powder and polyacrylamide. However, 1% to 4% fluoride salts are used in the system. The presence of fluoride ions is not conducive to the early strength of the product, and it is usually difficult to reach 10MPa; improper use of polyacrylamide is prone to cross-linking and flocculation, which is not conducive to the stability of the system; the preferred ultrafine sepiolite powder has an average particle size of less than 10μm. Although it has a significant improvement effect on the stability of the system, the overall viscosity of the system is as high as 2000mPa·s to 4000mPa·s due to the lack of modification, which is not conducive to practical application.

Another example is a modified sepiolite stabilizer for liquid quick-setting agent and its preparation method. It involves a method for modifying sepiolite, specifically by modifying it with hexadecyltrimethylammonium bromide and sodium silicate. However, the problem with the sepiolite stabilizer prepared by this method is that during the preparation of the accelerator, the surfactant-modified sepiolite with hexadecyltrimethylammonium bromide gradually releases the surfactant, a large number of bubbles are generated in the system, and the saturated salt system of the accelerator is easily disturbed, resulting in a phenomenon of poor system stability.

Another example is a special anti-settling agent for alkali-free quick setting agent, its preparation method and application technology, which introduces a method of modifying sepiolite by γ-methacryloxypropyltrimethoxysilane. This method modifies sepiolite by silane, and mixes it with a polymer obtained by free radical polymerization as a special anti-settling agent. The mechanism is the synergistic effect of the entanglement of polymer chains and the three-dimensional network structure of sepiolite itself. However, the problem with this technology is that since silane forms a hydrophobic layer after affinity on the surface of sepiolite, sepiolite will easily agglomerate and be difficult to disperse in water, resulting in a deterioration of the dispersion effect; in addition, since the polymer in this scheme is obtained by copolymerization under the condition of the presence of sepiolite, the presence of sepiolite may affect the molecular weight of the finished product, resulting in a low molecular weight of the polymer, a weakened entanglement effect, and a deteriorated anti-settling effect. In addition to the above-mentioned defects in preparation and use, since the polymer obtained by in-situ polymerization improves stability through a three-dimensional cross-linking system, the overall viscosity of the system will be larger, resulting in a weakened thixotropy of the system, which is not conducive to pumping in application construction.

Summary of the invention

In view of the technical problems existing in the modifiers of pillaring materials in the prior art, the present invention adopts two hyperbranched quaternary ammonium salts to modify the pillaring materials to obtain a composite modified pillaring material. The composite modified pillaring material has a larger pillaring material capacity (CEC) and has a better effect on improving the long-term stability when used as a stabilizer in an accelerator system.

The present invention specifically adopts the following technical solutions:

A composite modified pillaring material comprises an orthorhombic pillaring material modified by a quaternary ammonium salt corresponding to a hyperbranched polyamine as shown in the following formula I or a hyperbranched quaternary ammonium salt as shown in formula II.

In the above formula I, R is selected from the structure (a) or (b) shown in formula III, and the value range of n is 3-10; in the above formula II, the value range of m is 3-9.

It should be noted that the selection of the substituent R in the above formula I does not solely select structure (a) or structure (b), but during the preparation and synthesis, structure (a) or structure (b) can be freely connected at the same time.

The hyperbranched polyamine shown in the above formula I and its corresponding quaternary ammonium salt and the hyperbranched quaternary ammonium salt shown in formula II Both can be prepared according to the methods reported in the literature, and the preparation methods of the two will not be repeated here. For example, the hyperbranched structure shown in formula I can be prepared by the method described in the document "Preparation and Properties of Amino-Terminated Hyperbranched Polymers and Quaternary Ammonium Salts thereof", and the hyperbranched polyamine in formula I is further prepared according to the method therein to obtain the corresponding hyperbranched quaternary ammonium salt; and the hyperbranched quaternary ammonium salt shown in formula II can be prepared by the method described in the document "Synthesis, Properties and Applications of Hyperbranched Gemini Quaternary Ammonium Salts".

The orthorhombic pillaring material may be sepiolite or hydrotalcite.

The preparation method of the composite modified pillaring material comprises the following steps:

The hyperbranched quaternary ammonium salt and the orthorhombic pillaring material are mixed and modified in a mass ratio of 5 to 10:100 to obtain a composite modified pillaring material.

Specifically, the modification method can be any one of the conventional pillaring material modification methods such as direct intercalation method, solution blending macromolecular insertion method, melt macromolecular insertion method, etc.

The above-mentioned composite modified pillaring material provided by the present invention uses the above-mentioned hyperbranched quaternary ammonium salt with a specific structure as a modified material. Since it contains a branched structure, it is different from the ordinary modified material with a long-chain structure, which ensures that the interlayer spacing after intercalation of the orthorhombic pillaring material is larger and the CEC capacity is higher.

The comparison of the modification effect (measured by Na ⁺ exchange method) with other conventional modified materials in the prior art is shown in Table 1 below.

Table 1 CEC values of different modified materials before and after modification of different orthorhombic pillared materials

In the above-mentioned composite modified pillaring material, the hyperbranched quaternary ammonium salt structure has strong acid resistance, alkali resistance and salt resistance, and the CEC of the modified pillaring material is significantly improved, which is suitable for high-concentration fluorine-free and alkali-free quick-setting agent as a stabilizer therein. The CEC improvement of sepiolite and hydrotalcite after modification by the above-mentioned hyperbranched quaternary ammonium salt intercalation is significantly greater than that of montmorillonite. It can be seen that the hyperbranched quaternary ammonium salt is not suitable for every conventional orthorhombic pillaring material. For this reason, the present invention also provides a fluorine-free and alkali-free quick-setting agent and a preparation method thereof. The fluorine-free and alkali-free quick-setting agent increases the amount of aluminum sulfate by more than 10% compared with the traditional alkali-free quick-setting agent, so that the supersaturation of the quick-setting agent solution system is significantly improved.

A fluorine-free and alkali-free quick-setting agent, comprising the following components (in mass percentage) mixed evenly:

The balance is water;

Wherein, the stabilizer is the above-mentioned composite modified pillaring material.

Generally, the maximum solubility of aluminum sulfate, the core component of alkali-free accelerator, is 36g/L (20°C) at room temperature, which is far from the performance requirements of practical applications. The amount of aluminum sulfate in the common alkali-free accelerators on the market can reach 40% to 50%, but it is difficult to continue to increase, and the solid content of the final product is around 50%. Further increasing the solid content will lead to a significant decrease in the stability of the system, including multiple problems such as easy stratification of the system, excessive viscosity, and easy crystallization. The specific hyperbranched quaternary ammonium salt-modified pillaring material of the present invention is particularly suitable for fluorine-free and alkali-free accelerators with an aluminum sulfate concentration of more than 60%. The advantages include that more complexing sites can be provided by modifying the polyvalent quaternary ammonium salt, so that the high CEC of the composite modified pillaring material can provide space for intercalation exchange for a large amount of supersaturated (exceeding the conventional solubility) aluminum sulfate, reduce the probability of crystallization, and utilize the characteristics of the pillaring material itself, that is, to build a three-dimensional network structure to improve the stability of the entire system. Therefore, the effect of preparing a high-concentration fluorine-free and alkali-free accelerator product is achieved, and the finished product has good long-term stability and viscosity that meets construction needs.

Furthermore, the complexing agent A is selected from diethanolamine and/or triethanolamine, and the complexing agent B is selected from at least one of EDTA, phosphoric acid, oxalic acid and urea.

Furthermore, the ion inhibitor is selected from at least one of glycerol, sodium hexametaphosphate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, sodium dodecyl sulfate, and hexadecyltrimethylammonium bromide.

The preparation method of the above-mentioned fluorine-free and alkali-free accelerating setting agent specifically comprises the following steps:

The above components are mixed according to the predetermined mass ratio and dissolved uniformly.

The fluorine-free and alkali-free accelerator provided by the present invention uses aluminum sulfate as the main aluminum phase component, utilizes the synergistic effect of components such as complexing, stabilization and viscosity reduction, and uses the composite modified pillar support material of the present invention as a stabilizer to ensure that the solid content of the fluorine-free and alkali-free accelerator is increased by more than 10% compared with the traditional alkali-free accelerator, and the supersaturation of the accelerator solution system is significantly improved, thereby bringing about performance improvement. Alkali metal ions and fluoride salts are not used, which avoids the influence of fluoride ions on early strength and alkali-aggregate reaction on later strength in the applied concrete, which is of significant value especially for early-strength shotcrete. The independently synthesized orthorhombic pillar stabilizer of the present invention improves the supersaturation of the fluorine-free and alkali-free quick-setting agent system on the basis of ensuring product stability by utilizing charge and thixotropy, thus ensuring its excellent effect in concrete materials.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention may be implemented in many different forms, and the present invention should not be construed as being limited to the specific embodiments set forth herein. On the contrary, these embodiments are provided to explain the principles of the present invention and their practical applications, so that other persons skilled in the art can understand the various embodiments of the present invention and the various modifications suitable for specific intended applications.

Example 1

This embodiment provides a composite modified pillaring material and a preparation method thereof.

Specifically, 5 parts of the hyperbranched quaternary ammonium salt corresponding to the hyperbranched polyamine (n=3) shown in the above formula I and 100 parts of sepiolite powder are mixed by solution blending and macromolecular insertion method to prepare a composite modified pillaring material.

Example 2

This embodiment provides a composite modified pillaring material and a preparation method thereof.

Specifically, 10 parts of the hyperbranched quaternary ammonium salt (m=3) represented by the above formula II and 100 parts of sepiolite powder are mixed by solution blending and macromolecular insertion method to prepare a composite modified pillaring material.

Example 3

This embodiment provides a composite modified pillaring material and a preparation method thereof.

Specifically, 8 parts of the hyperbranched quaternary ammonium salt (m=9) represented by the above formula II and 100 parts of hydrotalcite powder are mixed by the melt macromolecular insertion method to prepare a composite modified pillared material.

Example 4

This embodiment provides a composite modified pillaring material and a preparation method thereof.

Specifically, 9 parts of the hyperbranched quaternary ammonium salt corresponding to the hyperbranched polyamine (n=10) shown in the above formula I and 100 parts of sepiolite powder are subjected to the melt macromolecular insertion method to prepare the composite modified pillaring material.

Example 5

Based on the composite modified pillaring material provided in Example 1, this embodiment uses it as a stabilizer to provide A fluorine-free and alkali-free quick-setting agent and a preparation method thereof are disclosed.

Specifically, the fluorine-free and alkali-free quick-setting agent is prepared by heating, dissolving and cooling according to the mass ratio of 62% aluminum sulfate 18hydrate, 7% diethanolamine, 0.5% phosphoric acid, 0.8% stabilizer and the rest water.

That is, the fluorine-free and alkali-free quick-setting agent provided in this embodiment includes the following components mixed evenly:

The balance is water.

Example 6

Based on the composite modified pillaring material provided in Example 2, this example uses it as a stabilizer to provide a fluorine-free and alkali-free quick-setting agent and a preparation method thereof.

Specifically, the fluorine-free and alkali-free quick-setting agent is prepared by heating, dissolving and cooling according to the mass proportion of 66% aluminum sulfate 18hydrate, 9% diethanolamine, 0.5% phosphoric acid, 1% EDTA, 0.5% oxalic acid, 0.5% urea, 0.3% glycerol, 0.6% stabilizer and the rest water.

That is, the fluorine-free and alkali-free quick-setting agent provided in this embodiment includes the following components mixed evenly:

The balance is water.

Example 7

Based on the composite modified pillaring material provided in Example 3, this example uses it as a stabilizer to provide a fluorine-free and alkali-free quick-setting agent and a preparation method thereof.

Specifically, the fluorine-free and alkali-free quick-setting agent is prepared by heating, dissolving and cooling according to the mass ratio of 60% aluminum sulfate 18hydrate, 4% diethanolamine, 1.5% triethanolamine, 0.5% phosphoric acid, 0.2% glycerol, 0.1% sodium hexametaphosphate, 0.7% stabilizer and the rest water.

That is, the fluorine-free and alkali-free quick-setting agent provided in this embodiment includes the following components mixed evenly:

The balance is water.

Example 8

Based on the composite modified pillaring material provided in Example 3, this example uses it as a stabilizer to provide a fluorine-free and alkali-free quick-setting agent and a preparation method thereof.

Specifically, according to the mass proportion of 62% aluminum sulfate 18hydrate, 4.5% diethanolamine, 0.5% phosphoric acid, 0.5% EDTA, 0.2% glycerol, 0.2% hexadecyltrimethylammonium bromide, 0.2% sodium dodecyl sulfate, 0.7% stabilizer and the rest water, the fluorine-free and alkali-free quick-setting agent is prepared after heating, dissolving and cooling.

That is, the fluorine-free and alkali-free quick-setting agent provided in this embodiment includes the following components mixed evenly:

The balance is water.

Example 9

Based on the composite modified pillaring material provided in Example 1, this example uses it as a stabilizer to provide a fluorine-free and alkali-free quick-setting agent and a preparation method thereof.

Specifically, the fluorine-free and alkali-free quick-setting agent is prepared by heating, dissolving and cooling according to the mass ratio of 61% aluminum sulfate 18hydrate, 6% diethanolamine, 0.3% phosphoric acid, 0.3% glycerol, 0.3% sodium dodecylbenzene sulfonate, 1% stabilizer and the rest water.

That is, the fluorine-free and alkali-free quick-setting agent provided in this embodiment includes the following components mixed evenly:

The balance is water.

In order to verify the effects of the fluorine-free and alkali-free quick-setting agents provided in the above embodiments, especially the stabilizing effect of the stabilizer therein, the following comparative experiments were conducted.

Comparative Example 1

The purpose of setting this comparative example is to illustrate the influence of the stabilizer on the performance of the fluorine-free and alkali-free quick-setting agent by forming a comparison with Example 5 which lacks a stabilizer.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

Due to the lack of modified pillar support materials to provide stability for the supersaturated accelerating setting agent, the comparative fluorine-free and alkali-free accelerating setting agent quickly solidified and precipitated after being cooled and left to stand, and lost its fluidity as a whole and could not be used.

Comparative Example 2

This comparative example is designed to illustrate the effect of the amount of aluminum sulfate on the performance of the fluorine-free and alkali-free quick-setting agent by forming a comparison with Example 5 in which an excess of aluminum sulfate is used.

This comparative example provides a comparative fluorine-free and alkali-free quick-setting agent, which differs from Example 5 only in that the amount of aluminum sulfate 18hydrate is adjusted to 67%, and the amount of water is reduced accordingly; the rest is referred to as described in Example 5.

Although the supersaturation is increased to form a high-concentration system under the synergistic effect of the complexing agent, the ion inhibitor and the stabilizer, when the amount of aluminum sulfate exceeds the critical point, the excess aluminum sulfate will act as a crystal nucleus to reduce the stability of the system. Therefore, the fluorine-free and alkali-free quick-setting agent in this comparative example quickly condenses and precipitates after being cooled and placed, loses fluidity as a whole, and cannot be used.

Comparative Example 3

The purpose of setting up this comparative example is to form a comparison without the complexing agent A, so as to illustrate the influence of the complexing agent A on the performance of the fluorine-free and alkali-free quick-setting agent.

This comparative example provides a comparative fluorine-free and alkali-free quick-setting agent, in which the composite modified pillaring material provided in the above Example 2 is used as a stabilizer.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

Due to the lack of complexing agent A, the aluminum sulfate that exceeds the solubility in water during the synthesis of the accelerator cannot be completely dissolved, the supersaturated stable system product cannot be effectively constructed, and the preparation of the finished product fails.

Comparative Example 4

The purpose of setting up this comparative example is to form a comparison without the complexing agent B, so as to illustrate the influence of the complexing agent B on the performance of the fluorine-free and alkali-free quick-setting agent.

This comparative example provides a comparative fluorine-free and alkali-free quick-setting agent, in which the composite modified pillaring material provided in the above Example 2 is used as a stabilizer.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The fluorine-free and alkali-free quick-setting agent lacks the complexing agent B, so the viscosity of the supersaturated finished solution system is too high and is greatly affected by temperature. After cooling, it is easy to precipitate and solidify and lose fluidity, and the finished product cannot be used.

Comparative Example 5

This comparative example provides a comparative fluorine-free and alkali-free quick-setting agent, in which the composite modified pillaring material provided in the above Example 1 is used as a stabilizer.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The fluorine-free and alkali-free quick-setting agent does not contain an ion inhibitor, which reduces the stability of the system and easily causes some components to precipitate, resulting in excessively high viscosity of the system.

Comparative Example 6

The purpose of setting up this comparative example is to form a comparison of excessive complexing agent B, so as to illustrate the influence of the dosage of complexing agent B on the performance of the fluorine-free and alkali-free quick-setting agent.

This comparative example provides a comparative fluorine-free and alkali-free quick-setting agent, in which the composite modified pillaring material provided in the above Example 1 is used as a stabilizer.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The dosage of the fluorine-free and alkali-free accelerator complexing agent B exceeds the recommended range. Although the stability is improved, the viscosity is too high, making it unusable, and the negative effects are obvious, affecting the strength of the concrete.

Comparative Example 7

The purpose of this comparative example is to form a comparison of the hyperbranched quaternary ammonium salt with a higher degree of branching as shown in Formula II, so as to illustrate the influence of the degree of branching of the hyperbranched quaternary ammonium salt on the performance of the fluorine-free and alkali-free accelerating setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 10 parts of the hyperbranched quaternary ammonium salt (m=10) represented by the above formula II and 100 parts of sepiolite powder were mixed by solution blending macromolecular insertion method to prepare a comparative composite modified pillared material.

The comparative composite modified pillaring material prepared above is used to prepare a comparative fluorine-free and alkali-free quick-setting agent as a comparative stabilizer therein.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The comparative fluorine-free and alkali-free quick-setting agent has poor stability due to the high degree of branching of the hyperbranched quaternary ammonium salt, insufficient water solubility, and poor intercalation effect. As a result, the comparative fluorine-free and alkali-free quick-setting agent has obvious stratification after being placed for 1 day, and the viscosity is too high, making it unusable.

Comparative Example 8

The purpose of this comparative example is to form a comparison of the hyperbranched quaternary ammonium salt with a lower branching degree as shown in Formula II, so as to illustrate the influence of the branching degree of the hyperbranched quaternary ammonium salt on the performance of the fluorine-free and alkali-free accelerating setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 10 parts of the hyperbranched quaternary ammonium salt (m=2) represented by the above formula II and 100 parts of sepiolite powder were mixed by solution blending macromolecular insertion method to prepare a comparative composite modified pillared material.

The comparative composite modified pillaring material prepared above is used to prepare a comparative fluorine-free and alkali-free quick-setting agent as a comparative stabilizer therein.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The comparative fluorine-free and alkali-free quick-setting agent has a lower degree of branching of the hyperbranched quaternary ammonium salt, which results in slightly poor overall stability. As a result, the comparative fluorine-free and alkali-free quick-setting agent has obvious stratification after being placed for 1 day, and the viscosity is too high. not available.

Comparative Example 9

The purpose of this comparative example is to form a comparison of the hyperbranched quaternary ammonium salt with a higher degree of branching as shown in Formula I, so as to illustrate the influence of the degree of branching of the hyperbranched quaternary ammonium salt on the performance of the fluorine-free and alkali-free accelerating setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 8 parts of the hyperbranched quaternary ammonium salt (n=11) represented by the above formula I and 100 parts of sepiolite powder were mixed by solution blending and macromolecular insertion method to prepare a comparative composite modified pillared material.

The comparative composite modified pillaring material prepared above is used to prepare a comparative fluorine-free and alkali-free quick-setting agent as a comparative stabilizer therein.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The comparative fluorine-free and alkali-free accelerator has a high degree of branching of the hyperbranched quaternary ammonium salt, which makes the molecules too large to achieve good intercalation and has slightly poor overall stability. As a result, the comparative fluorine-free and alkali-free accelerator has obvious stratification after being placed for 1 day, and the viscosity is too high, making it unusable.

Comparative Example 10

The purpose of this comparative example is to form a comparison with the hyperbranched quaternary ammonium salt of formula I having a lower degree of branching, so as to illustrate the influence of the degree of branching of the hyperbranched quaternary ammonium salt on the performance of the fluorine-free and alkali-free accelerating setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 8 parts of quaternary ammonium salt (n=2) prepared from the hyperbranched polyamine shown in the above formula I and 100 parts of sepiolite powder were mixed by solution blending macromolecular insertion method to prepare a comparative composite modified pillared material.

The above-prepared comparative composite modified pillaring material is used to prepare comparative fluorine-free and alkali-free quick-setting agent as Contrast stabilizer among them.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The comparative fluorine-free and alkali-free accelerator has a low degree of branching of the hyperbranched quaternary ammonium salt, and the intercalation effect is close to that of conventional ordinary surfactant intercalation, and has no significant advantages. Therefore, the overall stability performance is slightly worse. As a result, the comparative fluorine-free and alkali-free accelerator has obvious stratification after being placed for 1 day, and the viscosity is too high, making it unusable.

Comparative Example 11

The setting of this comparative example is intended to change the orthorhombic pillaring material in the composite modified pillaring material to reflect the influence of the type of the orthorhombic pillaring material on the performance of the fluorine-free and alkali-free quick-setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 8 parts of the quaternary ammonium salt corresponding to the hyperbranched polyamine (n=3) shown in the above formula I and 100 parts of kaolin powder were mixed by solution blending macromolecular insertion method to prepare a comparative composite modified pillared material.

The comparative modified pillaring material prepared above is used to prepare a comparative fluorine-free and alkali-free quick-setting agent as a comparative stabilizer therein.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

Since kaolin itself is a triclinic material, interlayer modification cannot be performed under the action of strong hydrogen bonds, so it is less effective as a pillaring material. When the comparative composite modified pillaring material prepared as described above is used in the comparative fluorine-free and alkali-free quick-setting agent, significant stratification occurs after 1 day and the viscosity is relatively high, making it impossible to achieve engineering application.

Comparative Example 12

The setting of this comparative example is intended to change the intercalation material of the orthorhombic pillaring material in the composite modified pillaring material to reflect the influence of the type of the intercalation material on the performance of the fluorine-free and alkali-free quick-setting agent.

This comparative example provides a comparative composite modified pillaring material and a preparation method thereof.

Specifically, 5 parts of sodium dodecylbenzene sulfonate (SDBS) and 100 parts of sepiolite powder were prepared by solution blending macromolecular insertion method to prepare comparative composite modified pillared materials.

The comparative composite modified pillaring material prepared above is used to prepare a comparative fluorine-free and alkali-free quick-setting agent as a comparative stabilizer therein.

The comparative fluorine-free and alkali-free quick-setting agent provided in this comparative example comprises the following components which are mixed evenly:

The balance is water.

The overall stability of the fluorine-free and alkali-free quick-setting agent is slightly worse. After one day of storage, stratification is obvious and the viscosity is too high, so it cannot be used.

Comparative Example 13

This comparative example provides a commercially available mature fluorine-containing alkali-free quick-setting agent as a comparison, and its specific model is Subo Specialty Product SBT-N (II).

In order to verify the application effect of the above-mentioned accelerators, the fluorine-free and alkali-free accelerators provided in Examples 5 to 9, the comparative fluorine-free and alkali-free accelerators provided in Comparative Examples 2 to 11, and the fluorine-free and alkali-free accelerators prepared from conventional modified materials provided in Comparative Example 12 were tested for application with the fluorine-containing alkali-free accelerator on the market in Comparative Example 13. try.

The various shotcrete mixes used in the application test are shown in Table 2 below; the corresponding dosage (the dosage after converting the dosage of cementitious materials), as well as the rebound rate and 8h core strength in the project site shotcrete test are shown in Table 3 below.

Table 2 Application test of various accelerators for shotcrete mix ratio

Table 3 Corresponding dosage, rebound rate and 8h drill core strength of each accelerator in the application test

As can be seen from Table 3, in Comparative Example 2, due to the higher amount of aluminum sulfate, the stability cannot be guaranteed, and the actual dosage under the actual working pump pressure is 4% to 6%, and the rebound rate is as high as 15% to 25%; in Comparative Example 3, due to the high amount of stabilizer, the viscosity is too large, which leads to the spraying machine obtaining a rebound rate of up to 20% to 25% under the condition of only 4% to 5% actual dosage under full load, and the actual dosage cannot be guaranteed; in Comparative Example 4, on the one hand, the viscosity of the stabilizer is too large, resulting in the spraying machine obtaining a rebound rate of up to 20% to 25% under the condition of only 4% to 5% actual dosage under full load, and on the other hand, the long-term stability is reduced due to the low dosage of the stabilizer; and the 8h drill core strength in each embodiment is significantly higher than that of the comparative example, indicating that the fluorine-free alkali-free quick-setting agent based on the above-mentioned composite modified pillar support material has a positive effect on the strength growth of early shotcrete.

Generally speaking, the rebound rate of shotcrete should be controlled within 15%, less than 10% is an excellent level, and close to 5% is a very excellent level. It can be seen that the above-mentioned fluorine-free and alkali-free quick-setting agents of the present invention have very excellent application effects.

At the same time, the performance and stability of the accelerating setting agents provided in the above embodiments and comparative examples were tested. The specific testing method is: using the benchmark cement to test the setting time and mortar strength, the accelerating setting agent dosage is 8%.

The test results are shown in Table 4 below.

Table 4 Performance and stability of each accelerating agent

Note: Mortar test is carried out according to QCR-807-2020

From the data in Table 4, it can be seen that the embodiments can achieve the purpose of early high strength through the synergistic effect of high aluminum phase and other complexing additives, and have a relatively reasonable viscosity under high solid content conditions, generally close to or The viscosity is lower than 500cp and has very good stability (28d water separation rate <5%), while the viscosity higher than 600cp may cause insufficient dosage, uneven dispersion, and even pipe blockage in actual spraying. In addition, the results of the mortar test of the embodiment product and the benchmark cement in the mortar experiment are all 6h mortar strength>1MPa, and 1d strength is greater than 8MPa, which meets the effect of early high strength.

Comparative Examples 1 to 6 are comparative fluorine-free and alkali-free quick-setting agents prepared using the composite modified pillaring materials of Examples 1 to 4. The necessity of the components in the above-mentioned mix ratio, the influence of the complexing agent A on the system stabilizer and the amount of aluminum sulfate used are as important; other components such as complexing agent B, ion suppression materials, etc. will also have a significant impact on the viscosity and stability of the system.

Comparative Examples 7 to 12 show the effects of different modifying materials and different pillaring materials on system performance under the same mix ratio. It can be seen that although the mix ratio is the same, the viscosity and water separation rate are not the same. Kaolin will bring the greatest viscosity improvement, because of its high viscosity, the water separation rate is relatively low; SDBS modification has a certain effect in preparing pillaring materials, but the viscosity and stability are weaker than those in the examples; and the unsuitable I and II structures used for modification are also weaker than the benchmark products.

Comparative Example 13 is a comparison of commercially available fluorine-containing products, which have lower solid content, lower viscosity, better stability, and faster coagulation, but their early strength is significantly weaker than that of fluorine-free and alkali-free products.

Claims (8)

A composite modified pillaring material, characterized in that it comprises an orthorhombic pillaring material modified by a quaternary ammonium salt corresponding to a hyperbranched polyamine as shown in the following formula I or a hyperbranched quaternary ammonium salt as shown in formula II,
In the above formula I, R is selected from the structure (a) or (b) shown in formula III, and n is The value range is 3 to 10; in the above formula II, the value range of m is 3 to 9; Wherein, the orthorhombic pillaring material is sepiolite or hydrotalcite. The method for preparing the composite modified pillaring material according to claim 1, characterized in that it comprises the steps of: The quaternary ammonium salt corresponding to the hyperbranched polyamine shown in the following formula I or the hyperbranched quaternary ammonium salt shown in the following formula II is mixed and modified with the orthorhombic pillaring material in a mass ratio of 5 to 10:100 to obtain the composite modified pillaring material;

In the above formula I, R is selected from the structure (a) or (b) shown in formula III, and n is in the range of 3 to 10; in the above formula II, m is in the range of 3 to 9; The orthorhombic pillaring material is sepiolite or hydrotalcite. The preparation method according to claim 2 is characterized in that the modification method is selected from any one of a direct intercalation method, a solution blending macromolecular insertion method, and a melt macromolecular insertion method. A fluorine-free and alkali-free quick-setting agent, characterized in that it comprises the following components which are mixed evenly:
Wherein, the stabilizer is the composite modified pillaring material described in claim 1. The fluorine-free and alkali-free accelerating setting agent according to claim 4, characterized in that the complexing agent A is selected from diethanolamine and/or triethanolamine. The fluorine-free and alkali-free quick-setting agent according to claim 4, characterized in that the complexing agent B is selected from at least one of EDTA, phosphoric acid, oxalic acid and urea. The fluorine-free and alkali-free accelerator according to claim 4 is characterized in that the ion inhibitor is selected from glycerol, sodium hexametaphosphate, sodium dodecylbenzene sulfonate, dodecyl sulfonate At least one of sodium sulfate, sodium lauryl sulfate, and hexadecyltrimethylammonium bromide. The method for preparing the fluorine-free and alkali-free accelerating setting agent according to any one of claims 4 to 7, characterized in that it comprises the steps of: 60% to 66% aluminum sulfate, 4.5% to 9% complexing agent A, 0.3% to 3% complexing agent B, 0.2% to 0.6% ion inhibitor, and 0.6% to 1% stabilizer are uniformly dissolved in the remaining amount of water to obtain the fluorine-free and alkali-free accelerator; the total amount of the fluorine-free and alkali-free accelerator is 100%; Wherein, the stabilizer is the composite modified pillaring material described in claim 1.