A high-adaptability and high-foam-stable concrete air-entraining agent and its preparation method

Abstract

The present invention provides a highly adaptable and highly stable foam type concrete air entraining agent, which comprises, by weight, 100 parts of branched alkyl polyether sodium sulfate anionic surfactant A, 8-40 parts of alkylbenzene sulfonic acid sodium salt anionic surfactant B, and 25-34 parts of polymer C, wherein polymer C is formed by free radical copolymerization of an unsaturated polyether macromonomer and an amide monomer, and the molar ratio of the unsaturated polyether macromonomer to the amide monomer is 1:(1-3). The highly adaptable and highly stable foam type concrete air entraining agent of the present application has good temperature adaptability, good clay adaptability, excellent foam stabilization performance, good frost resistance, and can improve concrete workability.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a high-adaptability and high-foam-stable concrete air-entraining agent and a preparation method thereof. Background Art

[0002] Bubbles in concrete originate primarily from two sources: air contained within the concrete material and air introduced during the mixing or pumping process. In fresh concrete, bubble generation and stable existence are two separate processes. Bubbles in fresh concrete are inherently unstable because their presence increases the gas-liquid interface area of ​​the concrete system, thereby increasing the interfacial free energy. From a thermodynamic perspective, bubbles tend to fuse, reducing the interfacial area and lowering the interfacial free energy. As concrete transitions from a plastic state to a hardened state, numerous bubbles continuously fuse, rupture, or escape from the system, significantly reducing the bubble content in the hardened concrete structure. Consequently, all bubbles have a lifespan. From the perspective of bubble instability, there are three physical mechanisms that may cause bubbles in fresh concrete to burst: (1) The gas in smaller bubbles with higher internal pressure gradually diffuses into larger pores with lower internal pressure, or diffuses into the solution surrounding the foam; (2) Due to the action of capillary flow, the thin film between adjacent bubbles breaks, causing adjacent bubbles to merge. For example, the vibration and compaction of fresh concrete may cause bubbles to contact each other and merge into larger bubbles. This situation often occurs slowly and can also occur in stable concrete; (3) The rapid flow of water in the liquid phase between bubbles causes the bubbles to burst quickly.

[0003] To increase the stability of bubbles in concrete, concrete air-entraining agents (AEAs) are often added. AEA molecules can self-assemble at the air-liquid interface of already formed bubbles, stabilizing them. This reduces bleeding and segregation in the mixture, improves workability, and significantly enhances the frost resistance and durability of hardened concrete. Overseas, particularly in Japan, nearly all concrete, including high-strength and high-performance concrete (HPC), incorporates AEAs. However, their use in concrete projects in my country is less widespread, accounting for only a few percent of the total concrete volume. This is primarily due to concerns that AEAs reduce concrete strength, a lack of high-performance, affordable AEAs, ineffective AEAs due to improper use, and insufficient attention to improving concrete's impermeability and durability.

[0004] Patent CN110104986A discloses a "method for preparing a novel composite concrete air-entraining agent." The novel composite concrete air-entraining agent described in this invention comprises 5%-15% dodecyl dimethamine oxide, 5%-15% sodium ethoxylated alkyl sulfate, 5%-10% sodium rosinate, 5%-15% coconut oil diethanolamide, and the balance water. This invention exhibits excellent compatibility with other concrete admixtures, requires minimal dosage, and exhibits superior compounding effectiveness compared to trigonal saponin-based air-entraining agents. It effectively reduces the surface tension of the solution and produces closed, independent bubbles. It boasts a high foaming rate, small bubble diameter, and long foam stability, significantly improving concrete workability and enhancing concrete flow and slump retention. The dodecyl dimethamine oxide in this invention is a zwitterionic surfactant. When used in cement concrete systems, the material adaptability is poor. When the sand and gravel material contains a high amount of mud / stone powder, it will undergo electrostatic adsorption with the clay / stone powder, causing it to fail (lack of air entraining ability). At the same time, this invention contains coconut diethanolamide, which will cause uneven stratification when compounded with polycarboxylic acid water reducer. Summary of the Invention

[0005] Common problems encountered by air-entraining agents in the prior art during use include: (1) the declining quality of concrete raw materials (poor grading of manufactured sand, high mud / stone powder content, high carbon content in admixtures, etc.), which leads to difficulty in air entrainment and unstable bubbles; (2) the contradiction between high air content and high frost resistance and high strength in hydraulic concrete, marine concrete, bridges in cold regions, highways, etc., which requires air-entraining agents to have both excellent air entrainment and foam stabilization capabilities. In response to the above problems, the present invention provides a highly adaptable and highly foam-stable air-entraining agent with good storage properties at low temperatures (-5°C), good adaptability to materials such as sand and gravel, and the ability to significantly improve the stability of bubbles inside concrete, thereby improving the workability and durability of concrete, and a preparation method thereof.

[0006] A highly adaptable and highly foam-stable concrete air-entraining agent, comprising, by weight, 100 parts of a branched alkyl polyether sodium sulfate anionic surfactant A, 8-40 parts of an alkylbenzene sulfonate sodium salt anionic surfactant B, and 25-34 parts of a polymer C. The highly adaptable and highly foam-stable concrete air-entraining agent of the present invention can be used in combination with other concrete admixtures, such as concrete water reducers, concrete retarders, concrete defoamers, and concrete thickeners.

[0007] The structural formula of the branched alkyl polyether sodium sulfate anionic surfactant A is: Wherein, a is 0 or 1; m and n are both integers, and p is an integer from 1 to 3; when a is 0, 1≤m≤6, 2≤n≤12, 7≤m+n≤13; when a is 1, 1≤m, n≤11, 6≤m+n≤12;

[0008] The hydrophobic structure and the position of the hydrophilic group of the surfactant have a great influence on the performance of the surfactant. Compared with the linear alkyl sulfate (such as sodium lauryl sulfate, sodium lauryl polyoxyethylene ether sulfate) air-entraining agent commonly used in concrete, the branched alkyl polyether sulfate sodium salt anionic surfactant of the present invention has a branched structure and a steric hindrance greater than that of the linear structure. Therefore, its intercalation adsorption effect with clay is weaker and has good material adaptability. Secondly, the branched structure has a stronger ability to reduce surface tension than the linear structure, so it has excellent air-entraining capacity. At the same time, the hydrophilic group -OSO3-Na in the molecular structure of the branched alkyl sulfate + The hydrophilic group is located closer to the center of the hydrophobic group than at the end, which is one of the key reasons for its excellent foaming ability. Furthermore, the presence of polyoxyethylene segments in the structure increases the surfactant's low-temperature stability (below 0°C). This means that the surfactant will not precipitate or stratify at low temperatures, making it suitable for winter use.

[0009] The above-mentioned sodium alkylbenzenesulfonate anionic surfactant B is sodium dodecylbenzenesulfonate; sodium dodecylbenzenesulfonate can form an insoluble calcium salt with a cement slurry solution with a high calcium ion concentration, and adsorb on the liquid film between cement particles and bubbles. This can prevent the liquid film between bubbles from thinning and rupturing, causing small bubbles to merge into large bubbles, thereby improving the stability of the bubbles.

[0010] The weight-average molecular weight of the polymer C is 100,000-200,000, and the polymer C is formed by free radical copolymerization of an unsaturated polyether macromonomer and an amide monomer, wherein the unsaturated polyether macromonomer is represented by X and the amide monomer is represented by Y; the molar ratio of the unsaturated polyether macromonomer X to the amide monomer Y is 1:(1-3).

[0011] The structural formula of the above unsaturated polyether macromonomer X is:

[0012] Wherein, R1 represents H or CH3, and Z is -C2H4-, d is an integer from 25 to 90.

[0013] The unsaturated polyether macromonomer X is an unsaturated polyether macromonomer with a molecular weight of 1200-4000.

[0014] The structural formula of the above-mentioned amide monomer Y is:

[0015] Wherein, R2 represents H or CH3; R3 is C e H 2e+1 or (CH2) f OCg H 2g+1 , wherein e is an integer from 0 to 4, f is an integer from 1 to 3, g is an integer from 0 to 4; R4 is C h H 2h+1 or (CH2) i OC j H 2j+1 , wherein h is an integer from 0 to 4, i is an integer from 1 to 3, and j is an integer from 0 to 4; when R3 is (CH2) f OC g H 2g+1 When R4 is (CH2) i OC j H 2j+1 When R3 is H.

[0016] Polymer C is a polymer with a weight-average molecular weight of 100,000-200,000, formed by free radical copolymerization of unsaturated polyether macromonomer X and amide monomer Y. It enhances bubble stability, improves concrete workability, and enhances concrete fluidity (resistance to clay). Unsaturated polyether macromonomer X exhibits strong intercalation adsorption on clay, effectively preventing air-entraining agent molecules from entering the clay interlayers and reducing ineffective adsorption of air-entraining agent molecules on the clay. Amide monomer Y not only contains double bonds, but its side chains are also significantly less hydrophilic than those of polycarboxylate superplasticizers, effectively preventing water molecules from entering the clay interlayers. This increases the free water content in the system, reduces clay swelling, and thus mitigates the damage to concrete properties caused by clay. Polymer C has a specific molecular weight. A higher molecular weight means more adsorption sites, and the polymer's adsorption capacity on clay increases, effectively preventing ineffective adsorption of air-entraining agent molecules on the clay, thereby improving concrete fluidity. The long hydrophilic side chains in the polymer C molecular structure can adsorb and immobilize free water molecules. This swelling effect increases its apparent volume and the viscosity of the mixing water. Simultaneously, the side chains of the polymer C molecules attract each other, leading to entanglement and the formation of a network structure, which inhibits the migration of free water and increases the viscosity of the entire system. The interactions between polymer C molecules and water, as well as between molecules, are the primary reasons for its ability to improve concrete workability and bubble stability. While a high molecular weight of polymer C can prevent the ineffective adsorption of air-entraining agent molecules, it can also affect the flowability of concrete. A low molecular weight can't effectively prevent the ineffective adsorption of air-entraining agent molecules on clay, and also weakens the interactions between polymer C molecules and water, as well as between molecules.

[0017] Preferably, the structural formula of the unsaturated polyether macromonomer is:

[0018] Wherein, R1 represents H or CH3, and Z is -C2H4-, d is 25 or 52 or 53 or 65 or 66 or 89 or 90.

[0019] Preferably, the structural formula of the above-mentioned amide monomer is:

[0020] Wherein, R2 represents H or CH3; R3 is C e H 2e+1 or (CH2) f OC g H 2g+1 , wherein e is an integer from 0 to 4, f is 1 or 3, g is 1 or 4; R4 is C h H 2h+1 or (CH2) i OC j H 2j+1 , where h is 0 or 1 or 3, i is 1 or 2, j is 0 or 2 or 3; when R3 is (CH2) f OC g H 2g+1 When R4 is (CH2) i OC j H 2j+1 When R3 is H.

[0021] The branched alkyl polyether sulfate sodium salt anionic surfactant A is an aqueous solution with a solid content of 30%, the alkylbenzene sulfonic acid sodium salt anionic surfactant B is a powder, and the polymer C is an aqueous solution with a solid content of 15%.

[0022] The highly adaptable and highly foam-stable concrete air-entraining agent has a solid content of 15-25%. Its preparation method comprises weighing branched alkyl polyether sulfate sodium salt anionic surfactant A, alkylbenzene sulfonate sodium salt anionic surfactant B, and polymer C according to the aforementioned weight ratios, physically and mechanically mixing the three different surfactants, and stirring until uniformly mixed.

[0023] The preparation of the above-mentioned polymer C includes the following steps: (1) adding unsaturated polyether macromonomer X, amide monomer Y and deionized water to a reactor equipped with a thermometer, a stirrer and a dropping funnel, starting stirring, and heating to 50°C; (2) preparing an initiator into a solution with a mass concentration of 1.0% to 2.0%, and preparing a chain transfer agent into a solution with a mass concentration of 0.1%, and slowly adding the prepared initiator and chain transfer agent solutions dropwise to the reactor over 2 hours and 2.5 hours, respectively. After the addition is completed, the temperature is raised to 70-80°C, and the reaction is continued at this temperature for 4-6 hours to obtain a polymer C with a solid content of 15%.

[0024] The free radical polymerization reaction in step (2) is carried out at 70-80°C for 4-6 hours. The reaction temperature is determined by the decomposition temperature of the initiator. Excessively high or low temperatures will change the half-life of the initiator, affecting the polymerization reaction rate and the relative molecular weight of the polymer product, thereby changing the overall properties of the polymer product.

[0025] The above-mentioned initiator is selected from a water-soluble azo initiator or a persulfate initiator; the above-mentioned water-soluble azo initiator is selected from at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid, and azobisisopropylimidazoline; the above-mentioned persulfate initiator is selected from at least one of sodium persulfate, potassium persulfate, and ammonium persulfate.

[0026] The initiator is used in an amount of 0.5% to 2.0% of the total weight of the reactants, the unsaturated polyether macromonomer X and the amide monomer Y. Excessive amounts of initiator will induce more free radicals, accelerating the reaction rate and reducing the molecular weight of the product; while insufficient amounts of initiator will induce fewer free radicals, slowing the reaction rate or even stopping the polymerization.

[0027] The chain transfer agent is selected from at least one of dodecanethiol, hexadecanethiol, mercaptoethanol, thioglycolic acid, 2-mercaptopropionic acid, and 3-mercaptopropionic acid.

[0028] The amount of the chain transfer agent is 1.5% to 3.0% of the total molar number of the reactants unsaturated polyether macromonomer X and amide monomer Y. Too much or too little chain transfer agent will make the molecular weight of the product too small or too large, causing the product to lose its proper function.

[0029] The initiator and chain transfer agent solutions were added dropwise for 2 hours and 2.5 hours, respectively. The solvent for these solutions was water. The concentration of the aqueous initiator and chain transfer agent solutions is not critical; as long as the solution is added within the specified time, it will suffice. Higher concentrations require slower addition, while lower concentrations require faster addition. High concentrations result in a smaller solution volume, making it difficult to control the addition rate. Therefore, the mass concentrations of the initiator and chain transfer agent, respectively, were controlled within the range of 1.0% to 2.0% and 0.1%.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The highly adaptable and highly foam-stable concrete air-entraining agent of this application has good temperature adaptability and can be stably stored at -5°C or above without stratification or precipitation.

[0032] 2. The highly adaptable and highly foam-stable concrete air-entraining agent of the present invention has good adaptability to clay. In a cementitious system containing clay, the polymer C of the present invention can prevent the ineffective adsorption of air-entraining agent molecules (branched alkyl polyether sulfate sodium salt anionic surfactant A and alkylbenzene sulfonate sodium salt anionic surfactant B) on the clay, thereby increasing the effective content of the present invention in the system and avoiding failure.

[0033] 3. The highly adaptable and highly foam-stable concrete air-entraining agent of the present application has excellent foam-stabilizing performance. The proportion of tiny bubbles with a diameter of less than 150 μm introduced into fresh concrete reaches more than 60%, and the change over time is very small. After 1 hour, the proportion of tiny bubbles with a diameter of less than 150 μm can still reach more than 55%.

[0034] 4. The highly adaptable and highly stable air-entraining concrete air-entraining agent of the present application can improve the workability of concrete; without affecting the strength of concrete, it can appropriately increase the viscosity of the cementitious system and at the same time introduce a large number of uniform, tiny, closed and stable bubbles, thereby improving the workability of concrete and avoiding segregation, bleeding, aggregate settlement and other phenomena.

[0035] 5. The highly adaptable and highly stable concrete air-entraining agent of the present invention has excellent frost resistance. After 300 freeze-thaw cycles (quick freezing) of the concrete incorporating the present invention, the relative dynamic elastic modulus reaches more than 95%, and the mass loss rate is less than 0.65%. After 108 freeze-thaw cycles (salt freezing) of the concrete incorporating the present invention, the relative dynamic elastic modulus reaches more than 98.5%, and the spalling mass is less than 0.55 kg / m 3 the following. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In the examples of the present invention, the weight average molecular weight Mw of polymer C is measured using a gel permeation chromatograph (miniDAWN Tristar laser light scattering detector) from Wyatt Technology Corporation.

[0038] The surfactant codes, names and molecular formulas involved in the following examples and comparative examples are as shown in Table 1 Branched alkyl polyether sodium sulfate and Table 2 Monomers used for polymer C.

[0039] Table 1: Branched alkyl polyether sodium sulfate

[0040]

[0041]

[0042] Table 2: Monomer structures used in polymer C

[0043]

[0044]

[0045]

[0046] The codes related to initiators and chain transfer agents are shown in Table 3 below:

[0047] Table 3

[0048]

[0049] The monomer codes and reaction conditions involved in polymer C are shown in Table 4 below:

[0050] Table 4

[0051]

[0052] The component codes and mass ratios used in each synthesis example and comparative example are shown in Table 5 below:

[0053] Table 5

[0054]

[0055]

[0056] The specific amounts of the components used in each synthesis example and comparative example, as well as the specific amounts, molecular weights, and other information of the monomers used in polymer C, are shown in Table 6 below:

[0057] Table 6

[0058]

[0059] Example 1:

[0060] In a reactor equipped with a thermometer, agitator, and a dropping funnel, 189.6 g of X-1, 10.1 g of Y-1, and 1154 g of deionized water were added, stirring was initiated, and the temperature was raised to 50°C. 3.99 g of I-1 was prepared into a 1.0% solution, and 0.003 g of K-1 was prepared into a 0.1% solution. The prepared initiator and chain transfer agent solutions were slowly added dropwise to the reactor over 2 hours and 2.5 hours, respectively. After the additions were complete, the temperature was raised to 70-80°C and the reaction was continued at this temperature for 4-6 hours to obtain polymer C-1 with a weight-average molecular weight of 198,000 and a solids content of 15%. 4000 g of A-1, 1600 g of B, and 1332 g of C-1 were physically and mechanically mixed and stirred to obtain an air-entraining agent solution with a solids content of 15%.

[0061] The preparation methods of the air-entraining agents of the examples and comparative examples were all obtained by referring to the preparation method of Example 1.

[0062] Comparative Example 1: an air-entraining agent solution with a solid content of 25% prepared by physically mixing and stirring sodium lauryl polyoxyethylene ether sulfate (AES), B, and C-6 in a mass ratio of 100:8.75:33.4; Comparative Example 2 (excluding component C): an air-entraining agent solution with a solid content of 25% prepared by physically mixing and stirring A-6 and B in a mass ratio of 100:8.75; Comparative Example 3 (excluding component B): an air-entraining agent solution with a solid content of 25% prepared by physically mixing and stirring A-6 and C-6 in a mass ratio of 100:25.9; Comparative Example 4 (excluding component A): an air-entraining agent solution with a solid content of 25% prepared by physically mixing and stirring B and C-6 in a mass ratio of 38.75:33.4 An air-entraining agent solution with a solid content of 25% was prepared by physical mixing and stirring; Comparative Example 5: A-6, B, and C-17 (the difference from Example 6 is that the molecular weight of polymer C is different, and the molecular weight of C-17 is 56,000) were physically mixed and stirred in a mass ratio of 100:8.75:33.4 to prepare an air-entraining agent solution with a solid content of 25%; Comparative Example 6: A-6, B, and C-18 (the difference from Example 6 is that the molecular weight of polymer C is different, and the molecular weight of C-18 is 302,000) were physically mixed and stirred in a mass ratio of 100:8.75:33.4 to prepare an air-entraining agent solution with a solid content of 25%.

[0063] Test example:

[0064] The air content and 1-hour change in air content of the high-foam-stabilizing air-entraining agent concrete described in this invention were measured according to the method described in 6.5.4 of GB / T 8076-2008, the water bleeding rate was measured according to the method described in 6.5.3, and the compressive strength was measured according to the method described in 6.6.1. The concrete frost resistance test (quick freezing method) was conducted according to the method described in 4.2 of GB / T 50082-2009. The concrete frost resistance test (salt freezing method) was conducted according to the method described in 4.3 of GB / T 50082-2009. The air bubble distribution of fresh concrete was measured using an AVA3000 fresh concrete pore structure analyzer from German, Denmark.

[0065] The present invention uses the mix ratio in Table 7 to test the concrete air content and its change over time after 1 hour, the initial slump / fluidity and 1-hour slump / fluidity, the bleeding rate, the 28-day compressive strength, and the bubble distribution of the fresh concrete.

[0066] Table 7

[0067]

[0068]

[0069] The performance test results are shown in Table 8, Table 9, and Table 10;

[0070] Table 8

[0071]

[0072] Table 9

[0073]

[0074]

[0075] Table 10

[0076] Dosage / 10,000 Initial gas content / % Gas content in 1h / % Example 1 1.60 5.8 5.5 Example 2 2.33 5.8 5.6 Example 3 1.82 5.9 5.4 Example 4 1.33 5.8 5.3 Example 5 0.88 5.8 5.3 Example 6 0.72 5.7 5.3 Example 7 1.40 5.7 5.3 Example 8 1.32 5.9 5.4 Example 9 1.12 5.8 5.4 Example 10 1.52 5.6 5.2 Example 11 0.96 5.9 5.4 Example 12 1.20 5.7 5.3 Example 13 0.76 5.8 5.3 Example 14 0.96 5.8 5.4 Example 15 1.08 5.9 5.5 Example 16 1.56 5.7 5.4 Comparative Example 1 1.80 5.6 4.9 Comparative Example 2 1.28 5.6 4.0 Comparative Example 3 1.03 5.7 4.6 Comparative Example 4 1.68 5.6 4.8 Comparative Example 5 1.00 5.7 4.3 Comparative Example 6 0.88 5.8 5.5

[0077] Note: The sand used in Table 10 is manufactured sand from Nanjing Hengji Concrete Co., Ltd., with Mx = 2.9 and a mud content of 6.0%.

[0078] The frost resistance of concrete was tested using the mix ratio in Table 11, and the performance test results are shown in Table 12. PCE is a polycarboxylate water reducer, a self-made product of Jiangsu Subote New Materials Co., Ltd.

[0079] Table 11

[0080]

[0081] Table 12

[0082]

[0083] It can be seen from Tables 8, 9, 10, and 12 that: (1) In natural sand with a low mud content, the examples effectively improve the workability of concrete, with the 1-hour water bleeding rate being 0. (2) The bubbles in the concrete mixed with the examples are highly stable. When the initial air content is 5.0-6.0%, the 1-hour air content loss rate is less than 10%. In the fresh concrete (initial), the proportion of micro-bubbles with a diameter of less than 150 μm is more than 60%, and the change over time is small. After 1 hour, the proportion of micro-bubbles with a diameter of less than 150 μm in the fresh concrete can still reach more than 55%, effectively ensuring the stability of the concrete state as well as the workability, strength, and durability of the concrete. (3) The 28-day compressive strength ratio of the concrete mixed with the examples is greater than 98%. (4) In the machine-made sand with a high mud content, the embodiment can preferentially adsorb active sites on the surface of the machine-made sand, effectively preventing the ineffective adsorption of air-entraining agent molecules (component A and component B) on the clay. Compared with the dosage in Table 7, with the same initial air content, the dosage of the embodiment in the machine-made sand is about 1-1.2 times that of the natural sand, and the dosage increase is very small. The air content loss rate in 1 hour is also less than 10%, which is comparable to the air content loss rate in natural sand. This shows that the present invention has excellent clay adaptability and still has excellent air entrainment and foam stabilization capabilities in concrete with a high mud content. (5) The concrete quick freezing test was carried out 300 times. After quick freezing, the relative dynamic elastic modulus of the blank group concrete was only 78.8%, which was lower than 80%, and the internal damage of the concrete was serious. After quick freezing 300 times, the relative dynamic elastic modulus of the concrete mixed with the embodiment could reach more than 95%. The mass loss rate of the blank group concrete reached 1.98%, while the mass loss rate of the concrete mixed with the embodiment was less than 0.65%. The concrete salt freezing test was carried out 108 times. After salt freezing, the relative dynamic elastic modulus of the blank group concrete was 91.5%, while the relative dynamic elastic modulus of the concrete mixed with the embodiment was above 98.5%. The spalling mass of the blank group concrete reached 0.93kg / m 3 , while the spalling mass of concrete in the examples was 0.55kg / m 3The following illustrates that the concrete mixed with the present invention has excellent frost resistance, and the present invention can effectively improve the durability of concrete. (6) Comparative Example 1 Compared with Example 6, the component A in Comparative Example 1 is AES (straight-chain surfactant), and the dosage of Comparative Example 1 is higher, about 2.5-2.8 times that of Example 6. In concrete containing natural sand or machine-made sand, the 1h air content loss rate is about 12%. The 1h water bleeding rate is 0.7%, the 28d compressive strength ratio is 97%, and the proportion of tiny bubbles with a diameter of <150μm in the fresh concrete at the initial and 1h times is 57.8% and 53.7%, respectively. After 300 quick freezings, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 1 is 94.8%, and the mass loss rate is 0.72%; after 108 salt freezings, the relative dynamic elastic modulus is 98.12%, and the concrete spalling mass is 0.60kg / m 3 . (7) Compared with Example 6, Comparative Example 2 does not contain component C, has the same initial air content, and its dosage in machine-made sand concrete is 1.5 times that of natural sand. In concrete containing natural sand or machine-made sand, the 1h air content loss rate is 17% and 29%, respectively. The 1h water bleeding rate is 2.8%, the 28d compressive strength ratio is 95.8%, and the proportion of tiny bubbles with a diameter of <150μm in the fresh concrete at the initial and 1h time is only 51.5% and 42.9%. After 300 quick freezings, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 2 is 93.0%, and the mass loss rate is 0.93%; after 108 salt freezings, the relative dynamic elastic modulus is 96.24%, and the concrete spalling mass is 0.78kg / m 3 . (8) Compared with Example 6, Comparative Example 3 does not contain component B. In concrete containing natural sand or machine-made sand, the air content loss rate of the concrete mixed with Comparative Example 3 in 1h is 14% and 19% respectively. The 1h water bleeding rate is 1.9%, the 28d compressive strength ratio is 96.5%, and the proportion of tiny bubbles with a diameter of less than 150μm in the initial and 1h in the fresh concrete is only 56.9% and 51.6%. After 300 quick freezing, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 3 is 94.0%, and the mass loss rate is 0.85%; after 108 salt freezing, the relative dynamic elastic modulus is 96.88%, and the concrete spalling mass is 0.69kg / m 3. (9) Compared with Example 6, Comparative Example 4 does not contain component A. The dosage of Comparative Example 4 is higher, about 2.3-2.6 times that of Example 6. In concrete containing natural sand or machine-made sand, the 1h air content loss rate is about 11% and 14%. The 1h water bleeding rate is 0.8%, the 28d compressive strength ratio is 97.0%, and the proportion of tiny bubbles with a diameter of <150μm in the initial and 1h of the fresh concrete is only 57.5% and 54.8%. After 300 quick freezing, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 4 is 94.5%, and the mass loss rate is 0.87%; after 108 salt freezing, the relative dynamic elastic modulus is 97.67%, and the concrete spalling mass is 0.66kg / m 3 . (10) Compared with Example 6, the molecular weight of component C in Comparative Example 5 is smaller, only 56,000. In concrete containing natural sand or machine-made sand, the air loss rate of the concrete mixed with Comparative Example 5 is about 14% and 25% in 1h. The 1h water bleeding rate is 2.3%, the 28d compressive strength ratio is 96.2%, and the proportion of tiny bubbles with a diameter of less than 150μm in the fresh concrete at the initial and 1h time is only 58.5% and 50.3%. After 300 quick freezings, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 5 is 93.6%, and the mass loss rate is 0.90%; after 108 salt freezings, the relative dynamic elastic modulus is 96.53%, and the concrete spalling mass is 0.73kg / m 3 . (11) Compared with Example 6, the molecular weight of component C in Comparative Example 6 is large, only 302000, which has a greater impact on the fluidity of concrete. The 1h water bleeding rate is 0%, the 28d compressive strength ratio is 98.3%, and the proportion of tiny bubbles with a diameter of less than 150μm in the fresh concrete at the initial and 1h time is only 63.6% and 61.8%. After 300 quick freezings, the relative dynamic elastic modulus of the concrete mixed with Comparative Example 6 is 97.7%, and the mass loss rate is 0.52%; after 108 salt freezings, the relative dynamic elastic modulus is 98.85%, and the concrete spalling mass is 0.48kg / m 3 .

[0084] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A highly adaptable and highly foam-stable concrete air-entraining agent, characterized by: The highly adaptable and highly foam-stable concrete air-entraining agent comprises the following components in parts by weight: 100 parts of branched alkyl polyether sodium sulfate anionic surfactant A, 8-40 parts of alkylbenzenesulfonic acid sodium salt anionic surfactant B, 25-34 parts of polymer C; The structural formula of the branched alkyl polyether sodium sulfate anionic surfactant A is: Wherein, a is 0 or 1; m and n are both integers, and p is an integer from 1 to 3; when a is 0, 1≤m≤6, 2≤n≤12, 7≤m+n≤13; when a is 1, 1≤m, n≤11, 6≤m+n≤12; The alkylbenzenesulfonate sodium salt anionic surfactant B is sodium dodecylbenzenesulfonate; The polymer C is formed by free radical copolymerization of an unsaturated polyether macromonomer and an amide monomer, the molar ratio of the unsaturated polyether macromonomer to the amide monomer is 1:(1-3), and the weight average molecular weight of the polymer C is 100,000-200,000; The structural formula of the unsaturated polyether macromonomer is: Wherein, R1 represents H or CH3, and Z is d is an integer from 25 to 90; The structural formula of the amide monomer is: Wherein, R2 represents H or CH3; R3 is C e H 2e+1 or (CH2) f OC g H 2g+1 , wherein e is an integer from 0 to 4, f is an integer from 1 to 3, g is an integer from 0 to 4; R4 is C h H 2h+1 or (CH2) i OC j H 2j+1 , wherein h is an integer from 0 to 4, i is an integer from 1 to 3, and j is an integer from 0 to 4; when R3 is (CH2) f OC g H 2g+1 When R4 is (CH2) i OC j H 2j+1 When R3 is H.

2. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 1, characterized in that: The structural formula of the unsaturated polyether macromonomer is: Wherein, R1 represents H or CH3, and Z is d is 25 or 52 or 53 or 65 or 66 or 89 or 90.

3. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 1, characterized in that: The structural formula of the amide monomer is: Wherein, R2 represents H or CH3; R3 is C e H 2e+1 or (CH2) f OC g H 2g+1 , wherein e is an integer from 0 to 4, f is 1 or 3, g is 1 or 4; R4 is C h H 2h+1 or (CH2) i OC j H 2j+1 , where h is 0 or 1 or 3, i is 1 or 2, j is 0 or 2 or 3; when R3 is (CH2) f OC g H 2g+1 When R4 is (CH2) i OC j H 2j+1 When R3 is H.

4. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 1, characterized in that: The solid content of the high-adaptability and high-foam-stable concrete air-entraining agent is 15-25%.

5. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 1, characterized in that: The branched alkyl polyether sodium sulfate anionic surfactant A is an aqueous solution with a solid content of 30%, the alkylbenzene sulfonic acid sodium salt anionic surfactant B is a powder, and the polymer C is an aqueous solution with a solid content of 15%.

6. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 1, characterized in that: The preparation of the polymer C comprises the following steps: (1) adding an unsaturated polyether macromonomer, an amide monomer and deionized water into a reactor equipped with a thermometer, an agitator and a dropping funnel, starting stirring, and heating to 50° C.; (2) preparing an initiator into a solution with a mass concentration of 1.0% to 2.0%, and preparing a chain transfer agent into a solution with a mass concentration of 0.1%, and slowly dropping the prepared initiator and chain transfer agent solutions into the reactor within 2 hours and 2.5 hours, respectively. After the dropwise addition is completed, heating to 70 to 80° C. and continuing the reaction at this temperature for 4 to 6 hours to obtain a polymer C with a solid content of 15%.

7. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 6, characterized in that: The initiator is selected from a water-soluble azo initiator or a persulfate initiator; the water-soluble azo initiator is selected from at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid, and azobisisopropylimidazoline; the persulfate initiator is selected from at least one of sodium persulfate, potassium persulfate, and ammonium persulfate.

8. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 6, characterized in that: The amount of the initiator used accounts for 0.5% to 2.0% of the total weight of the unsaturated polyether macromonomer and amide monomer.

9. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 6, characterized in that: The chain transfer agent is selected from at least one of dodecanethiol, hexadecanethiol, mercaptoethanol, thioglycolic acid, 2-mercaptopropionic acid, and 3-mercaptopropionic acid.

10. The highly adaptable and highly foam-stable concrete air-entraining agent according to claim 6, characterized in that: The amount of the chain transfer agent used accounts for 1.5% to 3.0% of the total molar number of the unsaturated polyether macromonomer and the amide monomer.

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