A concrete anti-segregation agent, its preparation method and application

Abstract

This application relates to the technical field of concrete admixtures, specifically disclosing a concrete anti-segregation agent, its preparation method, and its application. The concrete anti-segregation agent comprises component A and component B. Component A is obtained by mixing the following raw materials in parts by weight: 2-4 parts polyaluminum chloride; 10-15 parts hydrogenated lecithin; 20-30 parts cocamidopropyl betaine; and 100-150 parts deionized water. Component B is 5-10 parts filler particles. The concrete anti-segregation agent of this application can be used in concrete slurry mixing, and it has the advantages of ensuring good anti-segregation performance of the concrete slurry while also having good workability and workability.

Description

Technical Field

[0001] This application relates to the technical field of concrete admixtures, and more specifically, to a concrete anti-segregation agent, its preparation method, and its application. Background Technology

[0002] Anti-segregation agents are commonly used admixtures in concrete, which can improve the bleeding performance of concrete and enhance its anti-segregation stability.

[0003] Currently, products commonly used to prevent segregation in concrete include polyaluminum chloride, polyacrylamide, sulfonated polyacrylamide, sulfomethylphenol resin, and polystyrene sulfonic acid. However, due to their strong flocculation effect, they can cause the concrete to settle rapidly, resulting in the concrete losing its flowability instantly, which is detrimental to the workability of the concrete.

[0004] In actual concrete production, anti-segregation agents are usually added to the concrete mixing plant before the concrete is transported to the construction site by concrete mixer trucks. Therefore, it is necessary to ensure that the concrete has good anti-segregation properties as well as good workability. Summary of the Invention

[0005] To improve the segregation resistance and workability of concrete, this application provides a concrete anti-segregation agent, its preparation method, and its application.

[0006] In a first aspect, this application provides a concrete anti-segregation agent, which adopts the following technical solution: A concrete anti-segregation agent, comprising component A and component B, wherein component A is obtained by mixing the following raw materials in parts by weight: 2-4 parts of polyaluminum chloride; 10-15 parts of hydrogenated lecithin; 20-30 parts of cocamidopropyl betaine; 100-150 parts deionized water; The B component consists of 5-10 parts of filler particles.

[0007] By adopting the above technical solution, polyaluminum chloride in component A can improve the cohesiveness and anti-segregation properties of concrete slurry. Meanwhile, cocamidopropyl betaine, as a surfactant, has excellent foaming properties. The hydrophilic groups of hydrogenated lecithin help promote better dispersion of cocamidopropyl betaine in the concrete slurry. During the mixing and transportation of the concrete slurry, hydrogenated lecithin and cocamidopropyl betaine synergistically foam to form a dense foam protective layer, reducing water loss from the concrete slurry and thus ensuring its fluidity. As the foam continuously mixes into the concrete slurry, it overcomes the problem of rapid decrease in concrete slurry fluidity caused by the high cohesiveness of polyaluminum chloride, helping to reduce segregation and ensuring its workability. The synergistic effect of polyaluminum chloride, hydrogenated lecithin, and cocamidopropyl betaine in component A ensures both good anti-segregation properties and good workability.

[0008] Because the foaming components in component A can easily introduce air bubbles into the concrete slurry, which is not conducive to improving the compressive strength of the concrete during the later curing process, the filler particles in component B help to improve the fluidity of the concrete slurry. On the other hand, during the subsequent curing process, the filler particles can squeeze and fill the air bubbles introduced by component A during the mixing process, ensuring the workability of the concrete while improving its compressive strength.

[0009] Preferably, the filler particles comprise 3-6 parts of calcium hydroxide and 2-4 parts of calcium sulfoaluminate.

[0010] By adopting the above technical solution, calcium sulfoaluminate can expand in volume during the curing process of concrete slurry, thereby squeezing and filling the air bubbles mixed in the concrete slurry. The synergistic effect of calcium hydroxide and calcium sulfoaluminate can better fill the pores in the concrete, increase the density, and thus improve the compressive strength of the concrete.

[0011] Preferably, the filler particles are hydrophobically modified filler particles, and the processing steps are as follows: The modifier is dispersed in anhydrous ethanol, then filler particles with a particle size of 80-100 micrometers are added, ultrasonicated for 1-2 hours, and then dried to obtain hydrophobically modified expanded particles.

[0012] By adopting the above technical solution, in order to reduce the hydration reaction caused by the filling particles competing for water during the mixing and transportation of concrete, the filling particles are hydrophobically treated, which can ensure that the concrete slurry has good fluidity and anti-segregation properties. Furthermore, during the concrete curing process, the filling particles come into contact with the water in the concrete slurry and react.

[0013] When the concrete slurry is delivered to its destination for curing, on the one hand, calcium sulfoaluminate expands and squeezes water upon contact, filling the pores in the concrete slurry. On the other hand, the hydrophobically modified filler particles reduce the excessive contact and reaction of sodium hydroxide with water in the early stage of mixing, thus ensuring that sodium hydroxide can react with carbon dioxide in the bubbles to generate calcium carbonate precipitate and water. The generated water provides moisture for the hydration reaction, and the calcium carbonate precipitate further fills the pores in the concrete, enhancing the density of the concrete and improving its compressive strength.

[0014] Preferably, the modifier is a triglyceride.

[0015] By adopting the above technical solution, the hydrogenated lecithin in component A contains lipophilic groups that combine with the triglycerides in component B. During the concrete mixing process, components A and B can be better dispersed in the concrete slurry. The melting point of triglycerides is 46.5℃. When the concrete is cured, a hydration reaction occurs, generating a large amount of heat of hydration. At this time, the triglycerides melt under the influence of the heat of hydration, allowing the internal filler particles to come into contact with water, thereby improving the compressive strength of the concrete.

[0016] Preferably, sodium alginate is also added during the hydrophobic modification process, and the ratio of sodium alginate to expanded particles is (0.5-1):1. The preparation steps are as follows: Sodium alginate was dispersed in anhydrous ethanol, then filler particles with a particle size of 80-100 micrometers were added, mixed well, then a modifier was added, and the mixture was sonicated for 1-2 hours. After drying, hydrophobically modified expanded particles were obtained.

[0017] By adopting the above technical solution, sodium alginate is adsorbed on the surface of sodium hydroxide, further improving the adsorption of the sodium hydroxide surface, so that triglycerides are better adsorbed on the surface of the filler particles, fully encapsulating the filler particles hydrophobically. In addition, sodium alginate makes calcium sulfoaluminate more tightly bound to calcium hydroxide, ensuring that they work together to fill the particles and reduce the adverse effects of a large number of air bubbles introduced into the concrete slurry in the early stage on the concrete strength.

[0018] Preferably, the particle size of the hydrophobic modified filler particles is 0.2-0.3 mm.

[0019] By adopting the above technical solution, the hydrophobic modified expansion particles are selected in the range of 0.2-0.3mm, which can better ensure the workability and anti-segregation of the concrete slurry, and at the same time help the concrete slurry to have better compressive strength after curing.

[0020] Secondly, this application provides a method for preparing a concrete anti-segregation agent, employing the following technical solution: A method for preparing a concrete anti-segregation agent includes the following steps: S1. Preparation of component A: First, inject deionized water into the stirring device and heat it to 45-55℃. Add cocamidopropyl betaine while stirring and stir for 1-2 hours. Then add hydrogenated lecithin and continue stirring for 1-2 hours. Finally, add polyaluminum chloride and mix well for later use. S2. Mix component A with component B to obtain a concrete anti-segregation agent.

[0021] By adopting the above technical solutions, the polyaluminum chloride in component A acts as a binder, reducing segregation in the concrete slurry. Cocamidopropyl betaine and hydrogenated lecithin work synergistically to reduce the rapid increase in viscosity of the concrete slurry. Furthermore, during the mixing process of the concrete slurry, cocamidopropyl betaine and hydrogenated lecithin generate an air bubble layer, which is continuously incorporated into the concrete slurry during mixing. This ensures that the concrete slurry maintains stable anti-segregation properties and workability, preventing loss of fluidity due to rapid agglomeration. The filler particles in component B do not easily come into contact with water during concrete mixing and compete for moisture. When the concrete slurry is poured and cured, the filler particles fill the pores, enhancing the density of the concrete and thus improving its compressive strength.

[0022] Secondly, this application provides an application of a concrete anti-segregation agent, employing the following technical solution: An application of a concrete anti-segregation agent, wherein the concrete anti-segregation agent is applied to concrete slurry, and the concrete anti-segregation agent accounts for 1-1.5% of the weight of the concrete slurry.

[0023] By adopting the above technical solution, the concrete anti-segregation agent can be applied to the concrete slurry, ensuring that the concrete slurry has good workability during long-term transportation and mixing, is not prone to segregation, and has good compressive strength after the concrete has cured.

[0024] In summary, this application has the following beneficial effects: 1. Because this application uses polyaluminum chloride, hydrogenated lecithin and cocamidopropyl betaine in a synergistic effect, it can ensure that it has good anti-segregation properties as well as good workability.

[0025] 2. In this application, hydrophobically modified filler particles are preferred because they are less likely to come into contact with water and compete for moisture during concrete mixing. When the concrete slurry is poured and cured, the filler particles fill the pores, enhance the density of the concrete, and thus improve the compressive strength of the concrete.

[0026] 3. The method of this application, through the synergistic effect of component A and component B, ensures that the concrete slurry maintains stable anti-segregation performance and workability, and is less likely to lose fluidity due to rapid agglomeration. When the concrete slurry is poured and cured, the filling particles fill the pores, enhance the density of the concrete, and thus improve the compressive strength of the concrete. Detailed Implementation

[0027] Raw material source: All raw materials used in the embodiments of this application are commercially available. The disclosure of the sources of the above raw materials is only for clarity and should not limit the scope of protection.

[0028] Polyaluminum chloride CAS No.: 1327-41-9, Molecular weight: 80.4498; Hydrogenated lecithin CAS No.: 92128-87-5; Cocamidopropyl betaine CAS No.: 86438-79-1; Molecular weight: 342.517; Calcium hydroxide CAS number: 1305-62-0; Calcium sulfoaluminate molecular formula Ca4Al6SO 16 ; Triglyceride CAS No.: 538-24-9, Molecular weight: 639.001; Sodium alginate CAS No.: 31581-02-9; Silicate cement: PⅡ42.5R, with a 28-day strength exceeding 55 MPa; The polycarboxylate superplasticizer was purchased from Tangshan Jidong Cement Admixture Co., Ltd. Example

[0029] Examples 1.1-1.3 A concrete anti-segregation agent, comprising component A and component B, wherein component A is obtained by mixing the following raw materials by weight: 2-4 kg of polyaluminum chloride; 10-15 kg of hydrogenated lecithin; 20-30 kg of cocamidopropyl betaine; 100-150 kg of deionized water; Component B consists of 5-10 kg of filler particles.

[0030] The filling particles consist of 3-6 kg of calcium hydroxide and 2-4 kg of calcium sulfoaluminate.

[0031] The raw material usage for Examples 1.1-1.3 is shown in Table 1. Table 1. Raw material consumption (unit: kg) for Examples 1.1-1.3 A method for preparing a concrete anti-segregation agent includes the following steps: S1. Preparation of component A: First, deionized water is injected into a mixing tank and heated to 50°C. Cocamidopropyl betaine is added while stirring and stirred for 1.5 hours. Then, hydrogenated lecithin is added and stirred for another 1.5 hours. Finally, polyaluminum chloride is added and mixed well for later use. S2. Mix component A with component B to obtain a concrete anti-segregation agent.

[0032] Examples 2.1-2.3 A concrete anti-segregation agent, differing from Example 1.2 in that an equal amount of filler particles are replaced with hydrophobically modified filler particles. The preparation steps of the hydrophobically modified filler particles are as follows: Disperse 5-10 kg of modifier in anhydrous ethanol, then add filler particles with an average particle size of 80-100 micrometers, sonicate for 2 hours, remove and dry to obtain hydrophobically modified expanded particles.

[0033] The modifier is triglyceride. Furthermore, the amount of modifier used in Example 2.1 was 5 kg; The modifier used in Example 2.2 was 8 kg; The modifier used in Example 2.3 was 10 kg.

[0034] Example 3 A concrete anti-segregation agent, which differs from Example 2.2 in that an equal amount of glycerol is used instead of triglycerides.

[0035] Examples 4.1-4.3 A concrete anti-segregation agent, differing from that of Example 2.2, includes sodium alginate in the hydrophobic modification process, with a mass ratio of sodium alginate to expanding particles of (0.5, 0.8, 1):1. That is, the amount of sodium alginate used in Example 4.1 is 4 kg; In Example 4.2, the amount of sodium alginate used was 6.4 kg; In Example 4.3, the amount of sodium alginate used was 8 kg; The preparation steps are as follows: Sodium alginate was dispersed in anhydrous ethanol, then filler particles with an average particle size of 80-100 micrometers were added, mixed well, and then triglycerides were added. The mixture was sonicated for 2 hours, removed and dried to obtain hydrophobically modified swelling agent particles with a particle size of 0.25 mm.

[0036] Examples 5.1-5.4 A concrete anti-segregation agent, which differs from Example 4.2 in that the added hydrophobic modified expansion agent particles have a different particle size; The hydrophobic modified swelling agent particles in Example 5.1 have a particle size of 0.2 mm; The hydrophobic modified swelling agent particles in Example 5.2 have a particle size of 0.3 mm; The hydrophobic modified swelling agent particles in Example 5.3 have a particle size of 0.15 mm; The hydrophobic modified swelling agent particles in Example 5.4 have a particle size of 0.4 mm.

[0037] Comparative Example 1 A concrete anti-segregation agent, which differs from Example 1.2 in that the amount of component B is 0 kg.

[0038] Comparative Example 2 A concrete anti-segregation agent, which differs from Example 1.2 in that the amount of cocamidopropyl betaine used is 0 kg.

[0039] Comparative Example 3 A concrete anti-segregation agent, which differs from Example 1.2 in that the amount of hydrogenated lecithin used is 0 kg.

[0040] Comparative Example 4 A concrete anti-segregation agent, which differs from Example 1.2 in that an equal amount of lecithin is used instead of hydrogenated lecithin.

[0041] Comparative Example 5 A concrete anti-segregation agent, which differs from Example 1.2 in that an equal amount of lauramidopropyl betaine is used instead of cocamidopropyl betaine.

[0042] Comparative Example 6 A concrete anti-segregation agent, which differs from Example 1.2 in that the amount of calcium hydroxide used is 0 kg.

[0043] Comparative Example 7 A concrete anti-segregation agent, which differs from Example 1.2 in that the amount of calcium sulfoaluminate used is 0 kg.

[0044] Application examples Application Examples 1.1-1.3 An application of a concrete anti-segregation agent involves incorporating the agent into concrete slurry. The anti-segregation agent constitutes 1% of the weight of the concrete slurry, meaning the concrete slurry comprises a mixture of the following raw materials by weight: 300 kg of silicate cement, 600 kg of aggregate, 470 kg of sand with a particle size range of 0.25-0.5 mm, 70 kg of fly ash, 10 kg of polycarboxylate superplasticizer, 110 kg of water, and 15.6 kg of anti-segregation agent.

[0045] The anti-segregation agents were prepared sequentially from Examples 1.1-1.3.

[0046] Application Example 2-5 The application of a concrete anti-segregation agent differs from that in Application Example 1 in that the anti-segregation agent used is prepared sequentially from Examples 1.1-1.3, 2.1-2.3, 3, 4.1-4.4 and 5.1-5.4.

[0047] Compare and contrast examples 1-7 The application of a concrete antisegregation agent differs from that in Application Example 1.2 in that the antisegregation agent is prepared sequentially from Comparative Examples 1-7.

[0048] Performance testing The tests include: 1. Concrete grout bleeding rate test The concrete slurry prepared in the application example was subjected to a water bleeding test according to GB / T50080-2016 "Standard for Test Methods of Performance of Ordinary Concrete Mixtures". The higher the water bleeding rate, the worse the anti-segregation performance.

[0049] 2. Concrete grout spread test Samples of the concrete slurry prepared in the application example were placed into slump test buckets, and their spread was tested.

[0050] 3. Concrete compressive strength test The concrete slurry prepared in the application example was poured and cured for 28 days to make concrete sample blocks. Its compressive strength was tested in accordance with GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete".

[0051] Concrete slurry without anti-segregation agent was used as a control group.

[0052] Tests were conducted using test cases 1.1-1.3, the control group, and comparative application example 1. The test results are shown in Table 2. Table 2 shows the test results of Application Examples 1.1-1.3, the control group, and Comparative Application Example 1. Combining application examples 1.1-1.3 with the control group and comparative application example 1, it can be seen that the anti-segregation agent made by the synergistic effect of components A and B, when applied to concrete slurry, can ensure that the concrete slurry has good anti-segregation properties, while also ensuring good workability after long-term transportation, and that the concrete made after pouring has good compressive strength.

[0053] The seepage rate and spread were tested in comparative application examples 2-5, and the test results are shown in Table 3. Table 3 compares the test results of application examples 2-5. Combining Application Example 1.2 with Comparative Application Examples 2-5 and Table 2-3, it can be seen that the anti-segregation performance of Application Example 1.2 is better than that of Comparative Application Example 2.5. This indicates that the synergistic effect of polyaluminum chloride, hydrogenated lecithin, and cocamidopropyl betaine in Component A of this application ensures both good anti-segregation performance and good workability. The reason for this may be that hydrogenated lecithin has both hydrophilic and lipophilic properties, which helps to promote the dispersion of cocamidopropyl betaine in concrete slurry. Furthermore, cocamidopropyl betaine has good acid and alkali resistance, and can still foam stably in the alkaline environment of concrete slurry. During the continuous stirring of concrete slurry, the bubble layer formed by the generation of bubbles helps to reduce the decrease in workability of concrete caused by water evaporation. As the bubbles are continuously mixed into the concrete slurry, the rapid agglomeration caused by polyaluminum chloride is reduced. Therefore, the concrete slurry maintains good workability and anti-segregation performance even after a long period of stirring and transportation.

[0054] Compressive strength tests were conducted on comparative applications 6-7, and the test results are shown in Table 4. Table 4 compares the compressive strength test results of application examples 6-7. Combining the test results of Application Example 1.2 and Comparative Application Examples 6-7, as well as Tables 2 and 4, it can be seen that Application Example 1.2 is superior to Comparative Application Examples 6-7. This indicates that the synergistic effect of calcium hydroxide and calcium sulfoaluminate in this application can better fill the pores in concrete, increase the density, and thus improve the compressive strength of concrete.

[0055] Test the bleeding rate, expansion and compressive strength in the corresponding use cases 2.1-2.3.

[0056] The test results are shown in Table 5. Table 5 shows the test results of water bleeding rate, spread, and compressive strength for application examples 2.1-2.3. Combining the test results from Application Examples 1.2, 2.1-2.3, and 3, as well as Tables 2 and 5, it can be seen that Application Example 2.1-2.3 is superior to Application Examples 1.2 and 3. This indicates that hydrophobic treatment of the filler particles can ensure that the concrete slurry has good fluidity and anti-segregation properties. Furthermore, during the concrete curing process, the filler particles react with the water in the concrete slurry. The hydrophobically modified filler particles reduce excessive contact and reaction between sodium hydroxide and water in the early stages of mixing, thus ensuring that sodium hydroxide can react with carbon dioxide in the bubbles to form calcium carbonate precipitate and water. The generated water provides moisture for the hydration reaction, and the calcium carbonate precipitate further fills the pores in the concrete, enhancing the density of the concrete and improving its compressive strength.

[0057] The bleeding rate, spread, and compressive strength were tested according to application examples 4.1-4.3, and the test results are shown in Table 6. Table 6: Test results of bleeding rate, spread, and compressive strength in application examples 4.1-4.3 Combining the test results of Application Examples 2.2 and 4.1-4.3 and Tables 5-6, it can be seen that Application Examples 4.1-4.3 are superior to Application Example 2.2. This indicates that the sodium alginate of this application adsorbs onto the surface of sodium hydroxide, further improving the adsorption of the sodium hydroxide surface, allowing triglycerides to be better adsorbed onto the surface of the filler particles, fully encapsulating the filler particles in a hydrophobic manner. Furthermore, sodium alginate makes calcium sulfoaluminate more tightly bound to calcium hydroxide, ensuring their synergistic filling effect and reducing the adverse impact of a large number of air bubbles introduced into the concrete slurry in the early stage on the concrete strength.

[0058] Tests were conducted on the bleeding rate, expansion and compressive strength in accordance with test cases 5.1-4.4. The test results are shown in Table 7.

[0059] Table 7 shows the test results of water bleeding rate, spread, and compressive strength for application examples 5.1-4.4. Combining the test results of Application Examples 4.2 and 5.1-5.4 and Table 6-7, it can be seen that Application Examples 5.1-5.2 and 4.2 are superior to Application Examples 5.3-5.4. This indicates that when the hydrophobic modified expansive particles are selected within the range of 20-30mm, the workability and anti-segregation properties of the concrete slurry can be better guaranteed. At the same time, it helps the concrete slurry to have better compressive strength after curing. If the modified expansive particles are too small, they are not likely to effectively enhance the density. If the modified expansive particles are too large, they are likely to reduce the workability of the concrete slurry.

[0060] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A concrete anti-segregation agent, characterized in that, It includes component A and component B, wherein component A is obtained by mixing the following raw materials in parts by weight: 2-4 parts of polyaluminum chloride; 10-15 parts of hydrogenated lecithin; 20-30 parts of cocamidopropyl betaine; 100-150 parts deionized water; The B component consists of 5-10 parts of filler particles; The filler particles comprise 3-6 parts of calcium hydroxide and 2-4 parts of calcium sulfoaluminate; The filler particles are hydrophobically modified filler particles, and their processing steps are as follows: The modifier is dispersed in anhydrous ethanol, then filler particles with a particle size of 80-100 micrometers are added, ultrasonicated for 1-2 hours, and then dried to obtain hydrophobically modified filler particles. The modifier is triglyceride.

2. The concrete anti-segregation agent according to claim 1, characterized in that: Sodium alginate is also added during the hydrophobic modification process, and the ratio of sodium alginate to filler particles is (0.5-1):

1. The preparation steps are as follows: Sodium alginate was dispersed in anhydrous ethanol, then filler particles with a particle size of 80-100 micrometers were added, mixed well, then a modifier was added, and the mixture was sonicated for 1-2 hours. After drying, the hydrophobically modified filler particles were obtained.

3. The concrete anti-segregation agent according to claim 1, characterized in that: The hydrophobic modified filler particles have a particle size of 0.2-0.3 mm.

4. A method for preparing the concrete anti-segregation agent according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of component A: First, inject deionized water into the stirring device and heat it to 45-55℃. Add cocamidopropyl betaine while stirring and stir for 1-2 hours. Then add hydrogenated lecithin and continue stirring for 1-2 hours. Finally, add polyaluminum chloride and mix well for later use. S2. Mix component A with component B to obtain a concrete anti-segregation agent.

5. The application of the concrete anti-segregation agent according to any one of claims 1-3, characterized in that, The concrete anti-segregation agent is applied to the concrete slurry, wherein the concrete anti-segregation agent accounts for 1-1.5% of the weight of the concrete slurry.

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