Composite lightweight concrete air-entraining agent and preparation method thereof

Abstract

The application relates to the field of concrete additives, in particular to a composite light-weight concrete air entraining agent and a preparation method thereof, raw materials are as follows in parts by weight: 10-30 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 10-20 parts of foam stabilizer, 40-60 parts of dispersant, 30-50 parts of sodium alpha-alkenyl sulfonate, 5-10 parts of sodium gluconate and 180-220 parts of water. By introducing a polyoxypropylene-polyoxyethylene block group (PO-EO) between the hydrophilic group and the hydrophobic group of the traditional surfactant, the hydrophobic chain length is prolonged from the molecular structure, which is helpful to form micelles, improve the molecular hydrophilic performance, generate the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate with excellent surface performance and air entraining performance; and by utilizing the interaction between anions and non-ions and introducing a large number of uniform, tiny and stable air bubbles, the air entraining performance and the foam stabilizing and foaming performance of the air entraining agent are improved through the synergistic effect.

Description

Technical Field

[0001] This invention relates to the field of concrete additives, and in particular to a composite lightweight concrete air-entraining agent and its preparation method. Background Technology

[0002] Lightweight concrete, as a new type of building material, has been widely used in geotechnical engineering in recent years due to its excellent properties. However, in actual engineering applications, lightweight concrete is not only subjected to various loads, but also to various natural factors in the environment (such as cold climate and seawater freeze-thaw erosion). Especially under harsh environmental conditions, it may suffer damage or even destruction due to poor durability.

[0003] Adding an air-entraining agent to concrete introduces a large number of uniformly distributed micro-closed pores. Under low-temperature conditions, the water entering the pores turns into ice, which has a certain buffering and reduction effect on the expansion stress generated by the concrete, thereby significantly improving the freeze-thaw resistance and durability of the concrete.

[0004] Existing air-entraining agents mainly include rosin resins, alkylbenzene sulfonates, fatty alcohol sulfonates, saponins, protein salts, and petroleum sulfonate hydrochloride. Rosin thermopolymer air-entraining agents have a high water-reducing rate, resulting in less concrete strength loss at the same dosage, but their water solubility is poor. Alkylbenzene sulfonate air-entraining agents have a very fast foaming speed, producing large and abundant foam, but their foam stability is poor; after the bubbles are formed, small bubbles quickly merge into larger bubbles and may disappear completely within minutes. Saponin and fatty alcohol sulfonate air-entraining agents have good air-entraining properties, but their foaming ability is poor.

[0005] Therefore, it is necessary to further optimize the preparation process of air-entraining agents and carry out research on air-entraining agents specifically for lightweight concrete. Summary of the Invention

[0006] To address the shortcomings of existing air-entraining agents, this invention provides a composite lightweight concrete air-entraining agent. The raw materials, by weight, include: 10-30 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 10-20 parts of foam stabilizer, 40-60 parts of dispersant, 30-50 parts of sodium α-olefin sulfonate, 5-10 parts of sodium gluconate, and 180-220 parts of water.

[0007] Furthermore, the preparation method of the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is as follows: by weight, 50-60 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and solvent are added to a container, stirred and dissolved, and then 5-10 parts of hydride are slowly added, and stirring is continued until all bubbles disappear; then, the temperature is adjusted to 40-60℃, and 3-5 parts of sulfonate are added dropwise. After the addition is completed, the reaction is kept at a constant temperature for 2-5 hours, the solvent is removed by rotary evaporation, and the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is obtained after purification.

[0008] Furthermore, the purification steps include dissolution, extraction, rotary evaporation, and recrystallization.

[0009] Furthermore, the solvent is one of dimethyl sulfoxide, tetrahydrofuran, isopropyl acetate, and dimethylformamide.

[0010] Furthermore, the solvent comprises 80-120 parts by weight.

[0011] Furthermore, the hydride is one of sodium hydride, potassium hydride, cuprous hydride, and lithium aluminum hydride.

[0012] Furthermore, the sulfonate is one of 1,3-propanesulfonate lactone, cyclopropyl sulfinate, methyl ethanedisulfonate, and methanedisulfonate.

[0013] Furthermore, the foam stabilizer is one of coconut oil fatty acid diethanolamide, N,N-di(hydroxyethyl)cocamide, laurylamidopropylamine oxide, and isobutyl diethanolamine.

[0014] Furthermore, the dispersant is one of carboxymethyl cellulose, polyvinyl alcohol, maleic anhydride, polyvinylpyrrolidone, or sulfonated polystyrene.

[0015] Furthermore, the sodium α-alkenylsulfonate is one of the sodium α-alkenylsulfonates with carbon numbers of C12, C14, C16, C18, and C20.

[0016] The present invention also provides a method for preparing the above-mentioned composite lightweight concrete air-entraining agent, wherein the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is mixed with a foam stabilizer, a dispersant, sodium α-alkenyl sulfonate, sodium gluconate and water in a certain proportion, stirred evenly, heated in a water bath at 20-30°C, and reacted for 1-3 hours to obtain the product.

[0017] Compared with the prior art, the composite lightweight concrete air-entraining agent provided by the present invention has the following beneficial effects:

[0018] 1. This invention introduces polyoxypropylene-polyoxyethylene block groups (PO-EO) between the hydrophilic and hydrophobic groups of traditional surfactants, thereby extending the hydrophobic chain length from a molecular structure perspective. This facilitates the formation of micelles, improves the hydrophilicity of the molecules, and generates fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate with excellent surface properties and air-entraining properties.

[0019] 2. This invention employs anionic / nonionic compounding, utilizing the interaction between anionic and nonionic molecules, and introducing a large number of uniform, tiny, and stable bubbles. Through a synergistic effect, it improves the gas-entraining performance and foam-stabilizing and foaming performance of the gas-entraining agent.

[0020] 3. The air-entraining agent of the present invention has a molecular structure similar to that of polycarboxylate superplasticizer and has good compatibility with polycarboxylate superplasticizer, which is beneficial to the needs of concrete compound production; in addition, the present invention adopts atmospheric pressure production, has low equipment requirements, is easy to operate, and is conducive to industrial production. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a composite lightweight concrete air-entraining agent, the raw materials of which, by weight, include: 10-30 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 10-20 parts of foam stabilizer, 40-60 parts of dispersant, 30-50 parts of sodium α-olefin sulfonate, 5-10 parts of sodium gluconate, and 180-220 parts of water.

[0023] The present invention also provides a method for preparing the above-mentioned composite lightweight concrete air-entraining agent, wherein the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is mixed with a foam stabilizer, a dispersant, sodium α-olefin sulfonate, sodium gluconate and water in a certain proportion, stirred evenly, heated in a water bath at 20-30°C, and reacted for 1-3 hours to obtain the product.

[0024] The present invention provides the following raw material compositions for embodiments and comparative examples, as shown in Table 1:

[0025] Table 1

[0026] Fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate 20 10 30 foam stabilizer 15 10 20 dispersant 40 40 60 Sodium α-Alkenylsulfonate 40 30 50 Sodium gluconate 8 5 10 water 200 180 220

[0027] The present invention provides the following preparation methods for embodiments and comparative examples:

[0028] Example 1

[0029] (1) Add 60 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and 110 parts of tetrahydrofuran to a four-necked flask, stir to dissolve, then slowly add 8 parts of sodium hydride, and continue stirring until all bubbles disappear; then, adjust the temperature to 45°C, and add 3 parts of 1,3-propanesulfonic acid lactone dropwise using a constant pressure titration funnel. After the addition is complete, react at a constant temperature for 3 hours, remove the solvent tetrahydrofuran by rotary evaporation, and then dissolve, extract, rotary evaporate and recrystallize to obtain the purified fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate.

[0030] (2) Mix 20 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 15 parts of coconut oil fatty acid diethanolamide, 40 parts of polyvinylpyrrolidone, 40 parts of sodium α-alkenyl sulfonate with carbon number C16, 8 parts of sodium gluconate, and 200 parts of water and stir evenly. Heat in a water bath at 25°C for 2 hours to obtain a composite lightweight concrete air-entraining agent.

[0031] Example 2

[0032] (1) Add 55 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and 100 parts of dimethyl sulfoxide to a four-necked flask, stir to dissolve, then slowly add 5 parts of potassium hydride, and continue stirring until all bubbles disappear; then, adjust the temperature to 40°C, and add 4 parts of cyclopropyl sulfinate dropwise using a constant pressure titration funnel. After the addition is complete, react at a constant temperature for 2 hours, remove the solvent dimethyl sulfoxide by rotary evaporation, and then dissolve, extract, rotary evaporate and recrystallize to obtain the purified fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate.

[0033] (2) Mix 10 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 10 parts of N,N-di(hydroxyethyl)cocoamide, 40 parts of polyvinyl alcohol, 30 parts of sodium α-olefin sulfonate with carbon number C18, 5 parts of sodium gluconate, and 180 parts of water and stir evenly. Heat in a water bath at 20°C for 3 hours to obtain a composite lightweight concrete air-entraining agent.

[0034] Example 3

[0035] (1) Add 50 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and 90 parts of dimethylformamide to a four-necked flask, stir to dissolve, then slowly add 5 parts of lithium aluminum hydride, and continue stirring until all bubbles disappear; then, adjust the temperature to 60°C, and add 5 parts of methane disulfonate dropwise using a constant pressure titration funnel. After the addition is complete, react at a constant temperature for 5 hours, remove the solvent dimethylformamide by rotary evaporation, and then dissolve, extract, rotary evaporate and recrystallize to obtain the purified fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate.

[0036] (2) Mix 30 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 20 parts of isobutyl diethanolamine, 60 parts of maleic anhydride, 50 parts of sodium α-alkenyl sulfonate with carbon number C20, 10 parts of sodium gluconate, and 220 parts of water and stir evenly. Heat in a water bath at 30°C for 3 hours to obtain a composite lightweight concrete air-entraining agent.

[0037] Comparative Example 1

[0038] Unlike Example 1, the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate in step (2) was replaced with water by mass, while the other raw materials and preparation methods were the same as in Example 1.

[0039] Comparative Example 2

[0040] Unlike Example 1, the sodium α-alkenyl sulfonate with carbon number C16 in step (2) was replaced with water by mass, while the other raw materials and preparation methods were the same as in Example 1.

[0041] Comparative Example 3

[0042] HMS-206 air-entraining agent from Hangzhou Jinsen Building Materials Co., Ltd. is available commercially.

[0043] Performance testing

[0044] Referring to the test methods for concrete mixture performance in GB / T 8076-2008 "Concrete Admixtures", the workability of hardened concrete obtained from the above examples and comparative examples was tested. Specific concrete mix proportions are shown in Table 2, and the test results for cement and concrete performance are shown in Table 3.

[0045] Table 2 Concrete Mix Proportions

[0046] 360 800 1140 175 0.15 0.02

[0047] Table 3 Concrete Performance Tests

[0048]

[0049] As can be seen from Table 3, the composite lightweight concrete air-entraining agent prepared by the method provided by the present invention, compared with the existing air-entraining agents, utilizes the interaction between anionic and nonionic molecules and introduces a large number of uniform, tiny, and stable bubbles, which effectively improves the air-entraining performance and foaming performance of the air-entraining agent in lightweight concrete. While reducing the bulk density of concrete, it can also maintain good concrete dispersion and strength performance, which is more conducive to the needs of concrete compound production.

[0050] The comparison results between Example 1 and Comparative Example 1 show that when fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is not added to the air-entraining agent, its air-entraining performance is reduced, the air content of the concrete decreases after being added to the concrete, and the strength of the concrete is also reduced.

[0051] The comparison results of Example 1 and Comparative Example 2 show that when sodium α-alkenyl sulfonate is not added to the air-entraining agent, its air-entraining performance is significantly reduced, resulting in the inability to effectively reduce the density of concrete after being added to it, thus failing to meet the usage requirements.

[0052] It should be noted that the specific parameters or reagents in the above embodiments are specific or preferred embodiments under the concept of the present invention, and not limitations thereof; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite lightweight concrete air-entraining agent, characterized in that: The raw materials, by weight, include: 10-30 parts of fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate, 10-20 parts of foam stabilizer, 40-60 parts of dispersant, 30-50 parts of sodium α-olefin sulfonate, 5-10 parts of sodium gluconate, and 180-220 parts of water. The preparation method of the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is as follows: by weight, 50-60 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and solvent are added to a container, stirred and dissolved, and then 5-10 parts of hydride are slowly added while stirring continuously until all bubbles disappear; then, the temperature is adjusted to 40-60℃, and 3-5 parts of sulfonate are added dropwise. After the addition is completed, the reaction is kept at a constant temperature for 2-5 hours, the solvent is removed by rotary evaporation, and the fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is obtained after purification. The hydride is one of sodium hydride, potassium hydride, cuprous hydride, and lithium aluminum hydride; The sulfonate is one of 1,3-propanesulfonate lactone, cyclopropyl sulfinate, and methanedisulfonate methylene ester; The foam stabilizer is one of coconut oil fatty acid diethanolamide, N,N-di(hydroxyethyl)cocamide, laurylamidopropylamine oxide and isobutyl diethanolamine; The dispersant is one of carboxymethyl cellulose, polyvinyl alcohol, maleic anhydride, polyvinylpyrrolidone, or sulfonated polystyrene.

2. The composite lightweight concrete air-entraining agent according to claim 1, characterized in that: The solvent is one of dimethyl sulfoxide, tetrahydrofuran, isopropyl acetate, and dimethylformamide.

3. The composite lightweight concrete air-entraining agent according to claim 1, characterized in that: The solvent is in the form of 80-120 parts by weight.

4. The composite lightweight concrete air-entraining agent according to claim 1, characterized in that: The sodium α-alkenylsulfonate is one of the sodium α-alkenylsulfonates with carbon numbers of C12, C14, C16, C18, and C20.

5. The method for preparing the composite lightweight concrete air-entraining agent according to any one of claims 1-4, characterized in that: The fatty alcohol polyoxypropylene polyoxyethylene ether sulfonate is mixed with foam stabilizer, dispersant, sodium α-olefin sulfonate, sodium gluconate and water in a certain proportion, stirred evenly, heated in a water bath at 20-30°C for 1-3 hours to obtain the product.

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