A concrete foaming agent, its preparation method and application

Abstract

The application belongs to the technical field of building materials, and particularly relates to a concrete foaming agent and a preparation method and application thereof. Raw materials of the concrete foaming agent include a composite foaming component, a hyperbranched modified alkyl alcohol amide, a polycarboxylic acid water reducing agent and water; the composite foaming component includes a surfactant and modified plant protein; the modified plant protein is obtained by modifying reaction of plant protein and alkaline substances in the presence of a solvent; the hyperbranched modified alkyl alcohol amide is obtained by melt polymerization reaction of a cyclic fatty acid, an alkyl alcohol amine and a branched monomer; and the functionality of the branched monomer is greater than or equal to 2. The key of the application is to use the surfactant and the modified plant protein as the composite foaming component, and then compound the composite foaming component with the hyperbranched modified alkyl alcohol amide and the polycarboxylic acid water reducing agent to play a mutual compounding effect, so that the concrete foaming agent with good foaming effect and strong foam stability is obtained, and the application range is wider.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a concrete foaming agent, its preparation method, and its application. Background Technology

[0002] Foamed concrete is a lightweight, porous concrete with a closed-cell structure, made by introducing air bubbles into a slurry composed of cement, aggregates, admixtures, and water, using cement as the main binder. This slurry is then mixed, poured, and cured. Compared to ordinary concrete, foamed concrete offers numerous advantages, including simpler production processes, better thermal insulation, fire resistance, and earthquake resistance. Foaming agents are a crucial raw material in the production of foamed concrete, serving as the primary condition and material basis for its formation. They reduce liquid surface tension, generate a large number of air bubbles, and maintain high stability within the concrete slurry. Foaming agents are commonly used as concrete admixtures in the production of lightweight, porous materials.

[0003] Concrete foaming agents include physical foaming agents and chemical foaming agents. Physical foaming agents form foam by introducing a large amount of air into the foaming agent through mechanical force, and can be divided into rosin-based foaming agents, surfactant-based foaming agents, protein-based foaming agents, and composite foaming agents. Rosin-based foaming agents have a low bubble volume and poor foam stability. Surfactant-based foaming agents have disadvantages such as thin foam walls, poor stability, and a significant impact on cement strength, limiting their application. Composite foaming agents are composed of multiple functional components, combining the advantages of various foaming agents, but their complex composition and demanding production processes hinder widespread application. They may also contain harmful components that could impact the environment, and their effect on improving foaming effect and stability is limited. Therefore, there is an urgent need to develop an environmentally friendly concrete foaming agent with good foaming effect. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing composite foaming agents, such as complex composition and unstable foaming effect, by providing a concrete foaming agent, its preparation method, and its application. This concrete foaming agent has simple components, low production process requirements, and good foaming effect.

[0005] In a first aspect, the present invention provides a concrete foaming agent, wherein the raw materials of the concrete foaming agent include a composite foaming component, a hyperbranched modified alkylolamide, a polycarboxylic acid water-reducing agent, and water; the composite foaming component includes a surfactant and a modified plant protein; the modified plant protein is obtained by modifying plant protein with an alkaline substance in the presence of a solvent; the hyperbranched modified alkylolamide is obtained by melt polymerization of cyclic fatty acids, alkylolamines, and branched monomers; the branched monomers have a functionality of 2 or higher.

[0006] In a preferred embodiment, the content of the composite foaming component is 20-40 parts by weight, the content of the hyperbranched modified alkylolamide is 3-7 parts by weight, the content of the polycarboxylate water-reducing agent is 10-15 parts by weight, and the content of water is 40-70 parts by weight.

[0007] In a preferred embodiment, the mass ratio of the surfactant to the modified plant protein is (1-1.5):1.

[0008] In a preferred embodiment, the alkaline substance exists in the form of an alkaline solution during the preparation of the modified plant protein.

[0009] In a preferred embodiment, the concentration of the alkaline substance in the alkaline solution is 0.05–0.1 mol / L.

[0010] In a preferred embodiment, the mass ratio of the plant protein to the alkaline solution is 1:(10-50).

[0011] In a preferred embodiment, the plant protein is selected from at least one of tea seed protein, soy protein, pea protein, and brown rice protein.

[0012] In a preferred embodiment, the alkaline substance is selected from at least one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0013] In a preferred embodiment, the temperature of the modification reaction is 30–50°C and the time is 8–10 h.

[0014] In a preferred embodiment, the melt polymerization reaction is carried out in the presence of a catalyst.

[0015] In a preferred embodiment, the mass ratio of the cyclic fatty acid, alcohol amide, branched monomer, and catalyst is 1:(1-3):(0.8-1.0):(0.5-0.8).

[0016] In a preferred embodiment, the cyclic fatty acid is selected from at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, cycloheptanecarboxylic acid, cyclobutanecarboxylic acid, and cyclooctanecarboxylic acid.

[0017] In a preferred embodiment, the alkanolamine is selected from at least one of triethanolamine, diethanolamine, triisopropanolamine, and diisopropanolamine.

[0018] In a preferred embodiment, the branched monomer is selected from at least one of chitosan, pentaerythritol, and sorbitol.

[0019] In a preferred embodiment, the catalyst is selected from at least one of dipotassium hydrogen phosphate, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and dibutyltin dilaurate.

[0020] In a preferred embodiment, the temperature of the melt polymerization reaction is 160–180°C, and the time is 6–8 hours.

[0021] In a preferred embodiment, the surfactant is selected from at least one of potassium cocoate soap, sodium dodecylbenzene sulfonate, lauramide propyl dimethyl tertiary amine, erucamide propyl dimethyl tertiary amine, oleamide propyl hydroxysulfonate betaine, sodium dodecyl sulfate, sodium fatty acid methyl ester sulfonate, and sodium α-alkenyl sulfonate.

[0022] In a preferred embodiment, the number-average molecular weight of the polycarboxylate superplasticizer is 30,000 to 50,000 mol / L.

[0023] Secondly, the present invention also provides a method for preparing the above-mentioned concrete foaming agent, the method comprising the following steps: mixing the composite foaming component, hyperbranched modified alkylolamide, polycarboxylic acid water-reducing agent and water uniformly under heating conditions to obtain the concrete foaming agent.

[0024] In a preferred embodiment, the heating temperature is 60–90°C and the heating time is 4–20 min.

[0025] Thirdly, the present invention also provides the application of the above-mentioned concrete foaming agent in building materials.

[0026] The key to this invention lies in using surfactants and modified plant proteins as composite foaming components, which are then combined with hyperbranched modified alkylolamides and polycarboxylate superplasticizers to achieve a synergistic effect. This results in a concrete foaming agent with excellent foaming performance and strong foam stability, making it applicable to a wider range of applications. The reason for this is likely due to the following: using surfactants and modified plant proteins as foaming components results in a high foaming ratio, producing abundant foam; hyperbranched modified alkylolamides possess abundant hydroxyl and carboxyl functional groups, which contribute to improved foam stability; and polycarboxylate superplasticizers allow the concrete foaming agent to form a dense adsorption layer and network structure within the concrete during foaming, effectively enhancing the stability of the generated foam. Therefore, the concrete foaming agent provided by this invention has a simple composition, does not contain harmful environmental components, is environmentally friendly, and exhibits excellent foaming performance, high foam stability, and wide applicability. Detailed Implementation

[0027] The raw materials of the concrete foaming agent provided by this invention include a composite foaming component, a hyperbranched modified alkylolamide, a polycarboxylic acid water-reducing agent, and water. The composite foaming component includes a surfactant and a modified plant protein. The modified plant protein is obtained by modifying plant protein with an alkaline substance in the presence of a solvent. The hyperbranched modified alkylolamide is obtained by melt polymerization of cyclic fatty acids, alkylolamines, and branched monomers. The branched monomer is a multifunctional compound containing at least one of hydroxyl, carboxyl, and amino groups, with a functionality of 2 or more, preferably 2 to 10, such as 2, 3, 4, 5, 6, 8, 10, or any value between them. The functionality of the branched monomer refers to the number of hydroxyl, carboxyl, and amino groups contained in the molecular structure of a branched monomer.

[0028] In this invention, the content of the composite foaming component is preferably 20-40 parts by weight, such as 20, 25, 30, 35, 40 parts by weight or any value between them; the hyperbranched modified alkylolamide is preferably 3-7 parts by weight, such as 3, 4, 5, 6, 7 parts by weight or any value between them; the content of the polycarboxylate superplasticizer is preferably 10-15 parts by weight, such as 10, 11, 12, 13, 14, 15 parts by weight or any value between them; and the content of water is preferably 40-70 parts by weight, such as 40, 45, 50, 55, 60, 65, 70 parts by weight or any value between them. Controlling the content of each component in the concrete foaming agent within the above-mentioned preferred ranges is more conducive to leveraging the synergistic effect between the composite foaming component, the hyperbranched modified alkylolamide, and the polycarboxylate superplasticizer, which can further improve the foaming performance and foam stabilization performance of the concrete foaming agent.

[0029] In this invention, the preferred mass ratio of the surfactant to the modified plant protein is (1-1.5):1, such as 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, or any value between them. Controlling the mass ratio of the surfactant to the modified plant protein within the above-mentioned preferred range is more conducive to their synergistic effect in effectively reducing the surface tension of the liquid, thereby improving the foaming performance of the concrete foaming agent and producing abundant foam.

[0030] In this invention, the preferred method for preparing the modified plant protein includes: reacting the plant protein with an alkaline substance in the presence of a solvent to form a modification reaction; and concentrating the resulting reaction solution to obtain the modified plant protein. In the above-mentioned preparation process of the modified plant protein, the plant protein or alkaline substance can be mixed with a solvent first, and then another remaining substance can be added for the modification reaction; alternatively, the plant protein and the alkaline substance can be added to the solvent simultaneously and then mixed for the modification reaction. Preferably, the alkaline substance is first mixed with a solvent to form an alkaline solution, and then the plant protein is added to the alkaline solution for the modification reaction. The solvent can be a conventional choice in the art, preferably water.

[0031] In this invention, the alkaline substance preferably exists in the form of an alkaline solution, i.e., the alkaline substance is mixed with a solvent to obtain an alkaline solution, and the solvent is preferably water. The concentration of the alkaline substance in the alkaline solution is preferably 0.05–0.1 mol / L, such as 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, or any value between them. The mass ratio of the plant protein to the alkaline solution is preferably 1:(10–50), such as 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, or any value between them. Controlling the concentration of the alkaline substance and / or the mass ratio of the plant protein to the alkaline solution within the above-mentioned preferred range allows the modified plant protein obtained under these conditions to better interact with surfactants, thereby further improving the foaming effect of the concrete foaming agent.

[0032] This invention does not specifically limit the type of plant protein, and can use any conventional choice in the art. Specific examples include, but are not limited to, at least one of tea seed protein, soy protein, pea protein, and brown rice protein. This invention also does not specifically limit the type of alkaline substance, and can use any conventional choice in the art. Specific examples include, but are not limited to, at least one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0033] In this invention, the preferred temperature for the modification reaction is 30–50°C, such as 30°C, 35°C, 40°C, 45°C, 50°C, or any value between them; the preferred time is 8–10 hours, such as 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, or any value between them. Controlling the temperature and time of the modification reaction within the above-mentioned preferred ranges is more conducive to the modification of plant proteins by alkaline substances, thereby improving the foaming properties of the modified plant proteins. The preferred temperature for the concentration treatment is 40–60°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, or any value between them; the preferred time is 3–5 hours, such as 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or any value between them.

[0034] In one specific embodiment, the method for preparing the modified plant protein includes: mixing the plant protein with an alkaline solution and carrying out a modification reaction at 30-50°C for 8-10 hours; filtering after the reaction is completed; and concentrating the filtrate at 40-60°C for 3-5 hours to obtain the modified plant protein.

[0035] In this invention, the melt polymerization is preferably carried out in the presence of a catalyst. The mass ratio of the cyclic fatty acid to the alcohol amide is preferably 1:(1-3), such as 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, or any value between them. The mass ratio of the cyclic fatty acid to the branched monomer is preferably 1:(0.8-1.0), such as 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1.0, or any value between them. This is more conducive to obtaining a polymer with a certain degree of branching and improving the stability of the foam. The mass ratio of the cyclic fatty acid to the catalyst is preferably 1:(0.5-0.8), such as 1:0.5, 1:0.6, 1:0.7, 1:0.8, or any value between them.

[0036] In this invention, the temperature of the melt polymerization reaction is preferably 160-180°C, such as 160°C, 165°C, 170°C, 175°C, 180°C or any value between them; the time is preferably 6-8h, such as 6h, 6.5h, 7h, 7.5h, 8h or any value between them.

[0037] In this invention, the cyclic fatty acid is preferably a compound having an R-COOH structure, wherein R is C4 to C5. 12 Specific examples of the cycloalkyl group include, but are not limited to, at least one of cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Specific examples of the cyclic fatty acid include, but are not limited to, at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, cycloheptanecarboxylic acid, cyclobutanecarboxylic acid, and cyclooctanecarboxylic acid.

[0038] In this invention, the alkanolamine is preferably characterized by (R1). n -N-(R2-OH) m A class of compounds with the structure, wherein n can be 0 or 1, m can be 2 or 3, n+m=3, R1 is a hydrogen atom or a methyl group, and R2 is a C1-C5 alkylene group, specifically including but not limited to at least one of methylene, ethylene, n-propylene, isopropylene, n-butylene, isobutylene, n-pentylene, and neopentylene. Specific examples of the alkanolamine include but are not limited to at least one of triethanolamine, diethanolamine, triisopropanolamine, and diisopropanolamine.

[0039] In this invention, specific examples of the branched monomers include, but are not limited to, at least one of chitosan, pentaerythritol, and sorbitol.

[0040] In this invention, specific examples of the catalyst include, but are not limited to, at least one of: dipotassium hydrogen phosphate, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and dibutyltin dilaurate.

[0041] In this invention, the surfactant can be a conventional choice in the art, such as at least one of anionic surfactants, cationic surfactants, and amphoteric surfactants. Specific examples include, but are not limited to, at least one of potassium cocoate soap, lauramide propyl dimethyl tertiary amine, erucamide propyl dimethyl tertiary amine, oleamide propyl hydroxysulfonate betaine, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium fatty acid methyl ester sulfonate, and sodium α-alkenyl sulfonate.

[0042] In this invention, the number-average molecular weight Mn of the polycarboxylate superplasticizer is preferably 30,000 to 50,000 mol / L, such as 30,000 mol / L, 35,000 mol / L, 40,000 mol / L, 45,000 mol / L, 50,000 mol / L, or any value between them. The polycarboxylate superplasticizer is preferably a TPEG-MA foam-stabilizing polycarboxylate superplasticizer and / or an EPEG-MAA foam-stabilizing polycarboxylate superplasticizer. The ratio of methyl allyl polyoxyethylene ether to methacrylamide block in the TPEG-MA foam-stabilizing polycarboxylate superplasticizer is preferably (4-5):1, such as 4:1, 4.2:1, 4.5:1, 4.8:1, 5:1, or any value between them. The preferred ratio of allyl polyoxyethylene ether to methacrylic acid block in the EPEG-MAA foam-stabilizing polycarboxylate superplasticizer is (4-6):1, such as 4:1, 4.5:1, 5:1, 5.5:1, 6:1 or any value between them.

[0043] In this invention, the preparation method of the concrete foaming agent includes the following steps: mixing the composite foaming component, hyperbranched modified alkylolamide, polycarboxylate superplasticizer, and water evenly to obtain the concrete foaming agent. The preparation process of the above concrete foaming agent does not specifically limit the mixing order; at least one of the composite foaming component, hyperbranched modified alkylolamide, and polycarboxylate superplasticizer can be mixed with water under heating conditions first, and then the remaining raw materials can be added and mixed under heating conditions. In a preferred embodiment, the mixing method includes first mixing the composite foaming component, polycarboxylate superplasticizer, and water at 60–90°C and 50–180 r / min, stirring for 2–10 min, then adding the hyperbranched modified alkylolamide and continuing stirring for 2–10 min, and finally cooling to room temperature to obtain the concrete foaming agent.

[0044] The present invention will be described in detail below through specific embodiments.

[0045] Example 1

[0046] 1.1 Preparation of modified plant protein: 1g of plant protein (soy protein) was placed in a 500mL beaker, and 20g of sodium hydroxide alkaline solution (concentration of 0.05mol / L) was added and mixed. After reacting at 30℃ for 10h, the mixture was filtered. The filtrate was concentrated in an oven at 40℃ for 5h to obtain modified plant protein A1.

[0047] 1.2 Preparation of hyperbranched modified alkylolamide: Cyclohexanecarboxylic acid, triethanolamine, chitosan and dipotassium hydrogen phosphate were added to a four-necked flask equipped with a stirrer in a mass ratio of 1:1:0.8:0.5. The mixture was melt-polymerized at 160°C for 8 hours. After the reaction was completed, the product was washed, filtered and vacuum dried to obtain hyperbranched modified alkylolamide B1.

[0048] 1.3 Preparation of concrete foaming agent: Weigh 10 parts by weight of potassium cocoate soap, 10 parts by weight of modified plant protein A1, 10 parts by weight of TPEG-MA foam-stabilizing polycarboxylate superplasticizer (Mn = 30000 mol / L, methyl allyl polyoxyethylene ether to methacrylamide block ratio of 4:1) and 20 parts by weight of water, heat in a 60℃ water bath, stir slowly at 50 r / min for 10 min, then add 3 parts by weight of hyperbranched modified alkylolamide B1, continue stirring for 10 min after addition, then let stand and cool to room temperature to obtain concrete foaming agent.

[0049] Example 2

[0050] 2.1 Preparation of modified plant protein: 3g of plant protein (tea cake protein) was placed in a 500mL beaker, and 60g of potassium hydroxide alkaline solution (concentration of 0.07mol / L) was added and mixed. After reacting at 40℃ for 9h, the mixture was filtered. The filtrate was concentrated in an oven at 50℃ for 4h to obtain modified plant protein A2.

[0051] 2.2 Preparation of hyperbranched modified alkylolamide: Cyclopentane carboxylic acid, diethanolamine, pentaerythritol and trifluoromethanesulfonic acid were added to a four-necked flask equipped with a stirrer in a mass ratio of 1:1.5:0.9:0.7. The mixture was melt-polymerized at 170°C for 7 hours. After the reaction was completed, the product was washed, filtered and vacuum dried to obtain hyperbranched modified alkylolamide B2.

[0052] 2.3 Preparation of concrete foaming agent: Weigh 15 parts by weight of lauramidopropyl dimethyl tertiary amine, 10 parts by weight of modified plant protein A2, 12 parts by weight of TPEG-MA foam-stabilizing polycarboxylate superplasticizer (Mn = 50000 mol / L, methyl allyl polyoxyethylene ether to methacrylamide block ratio of 5:1) and 60 parts by weight of water. Heat in an 80℃ water bath and stir slowly at 150 r / min for 4 min. Then add 5 parts by weight of hyperbranched modified alkylolamide B2 and continue stirring for 4 min. Then let stand and cool to room temperature to obtain concrete foaming agent.

[0053] Example 3

[0054] 3.1 Preparation of modified plant protein: 2g of plant protein (pea protein) was placed in a 500mL beaker, and 100g of sodium hydroxide alkaline solution (concentration of 0.1mol / L) was added and mixed. After reacting at 50℃ for 8h, the mixture was filtered. The filtrate was concentrated in an oven at 60℃ for 3h to obtain modified plant protein A3.

[0055] 3.2 Preparation of hyperbranched modified alkylolamide: Cycloheptane carboxylic acid, triethanolamine, sorbitol and dipotassium hydrogen phosphate were added to a four-necked flask equipped with a stirrer in a mass ratio of 1:2:1.0:0.8. The mixture was melt-polymerized at 180°C for 6 hours. After the reaction was completed, the product was washed, filtered and vacuum dried to obtain hyperbranched modified alkylolamide B3.

[0056] 3.3 Preparation of concrete foaming agent: Weigh 20 parts by weight of erucamide propyl dimethyl tertiary amine, 15 parts by weight of modified plant protein A3, 15 parts by weight of EPEG-MAA foam-stabilizing polycarboxylate superplasticizer (Mn = 50000 mol / L, allyl polyoxyethylene ether to methacrylic acid block ratio is 5.5:1) and 70 parts by weight of water. Heat in a water bath at 60℃ and stir slowly at 180 r / min for 2 min. Then add 7 parts by weight of hyperbranched modified alkylolamide B3 and continue stirring for 2 min. After standing and cooling to room temperature, the concrete foaming agent can be obtained.

[0057] Comparative Example 1

[0058] Commercially available concrete foaming agent, purchased from Sasol, brand name MARLINAT 6104.

[0059] Comparative Example 2

[0060] Preparation of reference concrete foaming agent: Weigh 10 parts by weight of potassium cocoate soap, 10 parts by weight of soybean protein, 10 parts by weight of TPEG-MA foam-stabilizing polycarboxylate superplasticizer (Mn = 30000 mol / L, methyl allyl polyoxyethylene ether to methacrylamide block ratio of 4:1) and 20 parts by weight of water, heat in a 60℃ water bath, stir slowly at 50 r / min for 10 min, then add 3 parts by weight of hyperbranched modified alkylolamide B1, continue stirring for 10 min after addition, then let stand and cool to room temperature to obtain the reference concrete foaming agent.

[0061] Comparative Example 3

[0062] Weigh 20 parts by weight of modified plant protein A1, 10 parts by weight of TPEG-MA foam-stabilizing polycarboxylate superplasticizer (Mn = 30000 mol / L, methyl allyl polyoxyethylene ether to methacrylamide block ratio of 4:1) and 20 parts by weight of water, heat in a 60℃ water bath, stir slowly at 50 r / min for 10 min, then add 3 parts by weight of hyperbranched modified alkylolamide B1, continue stirring for 10 min after addition, then let stand and cool to room temperature to obtain the reference concrete foaming agent.

[0063] Comparative Example 4

[0064] Weigh 10 parts by weight of potassium cocoate soap, 10 parts by weight of modified plant protein A1 and 20 parts by weight of water, heat in a 60°C water bath, stir slowly at 50 r / min for 10 min, then add 13 parts by weight of hyperbranched modified alkylolamide B1, continue stirring for 10 min after adding, then let stand and cool to room temperature to obtain concrete foaming agent.

[0065] Comparative Example 5

[0066] 5.1 Preparation of alkylolamide: Cyclohexane carboxylic acid, triethanolamine and dipotassium hydrogen phosphate were added to a four-necked flask equipped with a stirrer in a mass ratio of 1:1:0.8. The mixture was melt-polymerized at 160°C for 8 hours. After the reaction was completed, the product was washed, filtered and dried under vacuum to obtain alkylolamide DB1.

[0067] 5.2 Preparation of concrete foaming agent: Weigh 10 parts by weight of potassium cocoate soap, 10 parts by weight of modified plant protein A1, 10 parts by weight of foam-stabilizing polycarboxylate superplasticizer TPEG-MA (Mn = 30000mol / L, methyl allyl polyoxyethylene ether to methacrylamide block ratio of 4:1) and 20 parts by weight of water, heat in a 60℃ water bath, stir slowly at 50r / min for 10min, then add 3 parts by weight of alkylolamide DB1, continue stirring for 10min after addition, then let stand and cool to room temperature to obtain the reference concrete foaming agent.

[0068] Test case

[0069] The performance of the concrete foaming agents in the above examples and comparative examples was tested according to the method in JCT 2199-2013 "Foaming Agents for Foamed Concrete". The results are shown in Table 1.

[0070] Table 1

[0071]

[0072] As shown in Table 1, compared with commercially available concrete foaming agents (Comparative Example 1), the concrete foaming agents provided in Examples 1-3 of this invention have significantly improved foaming ratios, lower 1-hour settlement distances, and lower 1-hour bleeding rates, demonstrating excellent foaming performance. The comparison between Example 1 and Comparative Examples 2-4 shows that using unmodified plant protein or unbranched alkylolamides, or lacking any one of surfactants or polycarboxylate superplasticizers, results in a decrease in the foaming ratio of the concrete foaming agent, an increase in the 1-hour settlement distance and 1-hour bleeding rate, and a deterioration in the foaming effect.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A concrete foaming agent, characterized in that, The raw materials of the concrete foaming agent include a composite foaming component, hyperbranched modified alkylolamide, polycarboxylic acid water-reducing agent, and water; the composite foaming component includes a surfactant and modified plant protein; The modified plant protein is obtained by reacting plant protein with an alkaline substance in the presence of a solvent; the hyperbranched modified alkylolamide is obtained by melt polymerization of cyclic fatty acids, alkylolamines and branched monomers; the branched monomers have a functionality of 2 or higher.

2. The concrete foaming agent according to claim 1, characterized in that, The composite foaming component comprises 20-40 parts by weight, the hyperbranched modified alkylolamide comprises 3-7 parts by weight, the polycarboxylate superplasticizer comprises 10-15 parts by weight, and the water comprises 40-70 parts by weight. The mass ratio of the surfactant to the modified plant protein is (1~1.5):

1.

3. The concrete foaming agent according to claim 1, characterized in that, In the preparation process of the modified plant protein, the alkaline substance exists in the form of an alkaline solution; The concentration of alkaline substances in the alkaline solution is 0.05~0.1 mol / L; The mass ratio of the plant protein to the alkaline solution is 1:(10~50).

4. The concrete foaming agent according to claim 3, characterized in that, The plant protein is selected from at least one of tea seed protein, soy protein, pea protein, and brown rice protein; The alkaline substance is selected from at least one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

5. The concrete foaming agent according to claim 1, characterized in that, The modification reaction is carried out at a temperature of 30-50°C for 8-10 hours.

6. The concrete foaming agent according to claim 1, characterized in that, The melt polymerization reaction is carried out in the presence of a catalyst; The mass ratio of the cyclic fatty acid, alkyl alcohol amine, branched monomer, and catalyst is 1:(1~3):(0.8~1.0):(0.5~0.8).

7. The concrete foaming agent according to claim 6, characterized in that, The cyclic fatty acid is selected from at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, cycloheptanecarboxylic acid, and cyclooctanecarboxylic acid; The alkyl alcoholamine is selected from at least one of triethanolamine, diethanolamine, triisopropanolamine, and diisopropanolamine; The branched monomer is selected from at least one of chitosan, pentaerythritol, and sorbitol; The catalyst is selected from at least one of dipotassium hydrogen phosphate, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and dibutyltin dilaurate; The melt polymerization reaction is carried out at a temperature of 160-180°C for 6-8 hours.

8. The concrete foaming agent according to claim 1, characterized in that, The surfactant is selected from at least one of potassium cocoate soap, lauramide propyl dimethyl tertiary amine, erucamide propyl dimethyl tertiary amine, oleamide propyl hydroxysulfonyl betaine, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium fatty acid methyl ester sulfonate, and sodium α-alkenyl sulfonate. The number average molecular weight of the polycarboxylate superplasticizer is 30,000~50,000 g / mol.

9. A method for preparing the concrete foaming agent according to any one of claims 1 to 8, characterized in that, The method includes the following steps: mixing the composite foaming component, hyperbranched modified alkylolamide, polycarboxylate superplasticizer and water evenly to obtain the concrete foaming agent.

10. The application of the concrete foaming agent according to any one of claims 1 to 8 in building materials.

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