High-strength concrete and curing method thereof
By designing the molecular structure of the modified polycarboxylate superplasticizer, phosphoramide anchoring groups and anti-mud zwitterionic monomers are introduced, which solves the problem of insufficient dispersibility and anti-mud properties in high-strength concrete and improves the strength and durability of concrete.
Patent Information
- Application Number
- CN202511628548.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-01-27
AI Technical Summary
Existing high-strength concrete technologies suffer from problems such as a sharp increase in the viscosity of fresh concrete, deterioration of fluidity and pumpability, high risk of early cracking, difficulty in controlling temperature difference cracks, and poor mix proportion stability. Traditional polycarboxylate superplasticizers have insufficient dispersibility and anti-mud properties in low water-cement ratio and high admixture systems, making it difficult to achieve synergistic improvement of multiple functions.
A modified polycarboxylate superplasticizer was prepared by copolymerization using a monomer with phosphoramide anchoring groups and anti-mud zwitterionic structure. The modified polycarboxylate superplasticizer was combined with a methacrylate functional monomer with phosphoramide anchoring groups and an imidazolium zwitterionic monomer with styrene groups to improve dispersibility and anti-mud properties and optimize the hydration process.
It achieves good dispersion and slump retention, improves the compressive strength and durability of concrete, reduces shrinkage and chloride ion permeability, and enhances the structural uniformity and durability of concrete.
Smart Images
Figure CN121405413A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of concrete technology, specifically relating to a high-strength concrete and its curing method. Background Technology
[0002] High-strength concrete, due to its high compressive strength, high modulus of elasticity, and excellent durability, has become the preferred material for new wall materials in super high-rise buildings, long-span bridges, heavy industrial plants, and special structures. Furthermore, it can be used in the furnace support structure of energy-saving boilers, the core pressure-bearing shell of waste heat, waste gas, and waste pressure utilization equipment, and the fabrication of material-bearing tray supports for energy-saving drying equipment. Currently, the mainstream technical approach achieves high strength by increasing the amount of cementitious materials, incorporating ultrafine active admixtures such as silica fume, and using highly efficient water-reducing agents to reduce the water-cement ratio to an extremely low level.
[0003] However, this approach has given rise to a series of new problems that urgently need to be solved: the viscosity of freshly mixed concrete increases sharply, its fluidity and pumpability deteriorate significantly, and construction becomes more difficult; chemical shrinkage and self-drying shrinkage intensify, the risk of early cracking increases sharply, and the structural durability is seriously threatened; the heat of hydration is released in a concentrated manner, the internal temperature of large-volume components rises, and temperature difference cracks are difficult to control; it is sensitive to fluctuations in raw materials, such as the mud content of aggregates, and the mix proportion is unstable, affecting the uniformity of project quality.
[0004] Polycarboxylate superplasticizers, as a core material for achieving low water-cement ratios, have seen their development reflect both the progress and limitations of concrete chemistry. The traditional "comb-shaped" molecular structure of polycarboxylate superplasticizers relies on the adsorption of carboxyl groups in the main chain and the steric hindrance of the polyether side chains. However, their performance is insufficient to meet the new challenges of high-strength concrete, such as limited anchoring ability and the limited adhesion of traditional carboxyl groups to the surface calcium carbonate of cement particles. 2+ Insufficient adsorption strength means that cement and micro powder cannot be fully dispersed in low water-cement ratio, high admixture systems, resulting in persistently high viscosity; Clay resistance defects: Anionic polycarboxylate superplasticizers are easily adsorbed and intercalated by clay minerals in aggregates, leading to a sharp reduction in effective components, a sudden drop in water reduction rate, and an abnormally rapid increase in slump loss; Single function: Conventional modification can usually only achieve single-function improvement, making it difficult to achieve synergistic improvement of multiple functions on the same molecular chain. Summary of the Invention
[0005] To overcome the shortcomings of the existing technology, this invention abandons the traditional single modification approach and innovates from the molecular design source, developing a polycarboxylate superplasticizer modified with strongly anchored phosphoramide groups and anti-mud zwitterionic monomers, providing a high-strength concrete and its curing method. The technical solution to achieve the purpose of this invention is as follows: A high-strength concrete comprising the following components: cement 300~400 kg / m³ 3 Silica fume 100~130 kg / m³3 50~80 kg / m³ of fly ash 3 Sand 700~850 kg / m 3 Crushed stone 850~950 kg / m³ 3 Modified polycarboxylate superplasticizer 5~9 kg / m 3 Water 140~170 kg / m 3 The modified polycarboxylate superplasticizer is copolymerized from methacrylate functional monomers containing phosphoramide anchoring groups, imidazolium zwitterionic monomers containing styrene groups, acrylic monomers, monoethyl fumarate monomers, and allyl polyoxyethylene ether monomers. The molar ratio of the methacrylate functional monomer containing phosphoramide anchoring group, the imidazolium zwitterionic monomer containing styrene group, the acrylic acid monomer, the fumarate monoethyl ester monomer, and the allyl polyoxyethylene ether monomer is (0.1~0.3):(0.05~0.15):(2~4):(0.3~0.7):1.
[0006] The acrylic monomer is acrylic acid or methacrylic acid, and the allyl polyoxyethylene ether monomer is methallyl polyoxyethylene ether or allyl polyoxyethylene ether; the structure of the methacrylate functional monomer containing phosphoramide anchoring groups is shown in Formula 1; the structure of the styrene-containing imidazolium zwitterionic monomer is shown in Formula 2. Equation 1; Equation 2.
[0007] The method for preparing the methacrylate functional monomer containing phosphoramide anchoring groups includes the following steps: Under argon protection, diphenylphosphamide was dissolved in anhydrous toluene by stirring. Glycidyl methacrylate and a trace amount of polymerization inhibitor were added to a constant pressure dropping funnel, followed by the addition of triethylamine to the reaction flask. The system was cooled in an ice-water bath, and the glycidyl methacrylate solution was slowly added dropwise, with the temperature controlled below 10°C. After the addition was complete, the ice bath was removed, and the reaction solution was allowed to rise naturally to room temperature. The reaction was then stirred at 60-70°C. After the reaction was completed, the methacrylate functional monomer containing phosphoramide anchoring groups was purified to obtain the product.
[0008] The molar ratio of diphenylphosphamide to glycidyl methacrylate is 1:(1.05~1.15).
[0009] The method for preparing the styrene-containing imidazolium zwitterionic monomer includes the following steps: Under argon protection, sodium bicarbonate and imidazole were mixed to remove oxygen, followed by the addition of a 1:1 mixture of water and acetone, and the mixture was stirred at room temperature. Then, 4-vinylbenzyl chloride was slowly added dropwise, and the reaction mixture was stirred at 45–65 °C. After the reaction was completed, 1-(4-vinylbenzyl)imidazolium chloride was purified. The 1-(4-vinylbenzyl)imidazolium chloride was transferred to a single-necked flask and degassed under argon protection for 15 min. Then, 0.8 eq of 1,3-propanesulfonate lactone was dissolved in acetonitrile and added to the reaction flask, and the reaction was carried out at 45–65 °C. After the reaction was completed, acetonitrile was removed under reduced pressure, and the resulting solid was added dropwise to acetone with stirring to precipitate. Finally, the precipitate was dissolved in deionized water and freeze-dried to obtain a styrene-containing imidazolium zwitterionic monomer.
[0010] The preparation method of the modified polycarboxylate superplasticizer includes the following steps: S1. Construction of the reaction system: Weigh out the functional monomers of methacrylate containing phosphoramide anchoring groups, zwitterionic monomers of imidazolium containing styrene groups, acrylic acid monomers, monoethyl fumarate monomers, and allyl polyoxyethylene ether monomers by molar ratio. Stir the allyl polyoxyethylene ether monomers in deionized water to remove oxygen and heat to 70~80℃. S2. Monomer solution preparation: The methacrylate functional monomer containing phosphoramide anchoring groups and the imidazolium zwitterionic monomer containing styrene groups are pre-dissolved in ethanol. The pre-dissolved solution is then dissolved in the remaining deionized water along with the acrylic acid monomer and the fumarate monoethyl monomer. The mixture is stirred until homogeneous. 0.1% to 0.2% of the total monomer mass of chain transfer agent is added and mixed until homogeneous to prepare a monomer mixture. 1% to 2% of the total monomer mass of initiator is dissolved in water to prepare a 5% initiator solution. S3. Addition copolymerization reaction: Maintain the reaction system temperature at 70~80℃, start by adding monomer mixture and initiator solution dropwise simultaneously, control the addition time to 3~4 h, maintain a uniform addition rate, maintain the pH value between 5.5 and 6.5 to avoid monomer precipitation; after the addition is complete, continue to keep warm at 70~80℃ until the reaction is complete. S4. Cool the reaction solution to below 40°C and adjust the pH to 6.0~7.0 to obtain the modified polycarboxylate superplasticizer.
[0011] Another object of the present invention is a method for protecting the curing of high-strength concrete, comprising the following steps: S1. Weigh out cement, silica fume, fly ash, sand and crushed stone according to the mix proportion, and mix for 3-5 minutes; S2. Mix the mixture with water, stir for 2-3 minutes, add the modified polycarboxylate superplasticizer, continue stirring for 10-15 minutes, and discharge to obtain high-strength concrete wet material; S3. Pouring and Curing: The mixed high-strength concrete wet material is poured into the mold. Pouring is done in layers, each layer ≤200 mm. The layers are vibrated with an immersion vibrator until the surface is smooth and free of air bubbles. After molding, the concrete is covered with wet burlap and plastic film and left to stand at 20~25℃ for 3~5 h. Then, the temperature is increased to 60℃ at 3~8℃ / h and kept constant for 12~20 h with RH≥95%. The temperature is then decreased to 40℃ at 3~8℃ / h and cooled to room temperature with the mold still in place. After demolding, the concrete is transferred to a standard curing room for 28 days to complete the curing and demolding of the high-strength concrete, thus obtaining the high-strength concrete.
[0012] Beneficial effects
[0013] This invention prepares a modified polycarboxylate superplasticizer through molecular design. By introducing a multi-mechanism synergistic effect between a methacrylate functional monomer containing a phosphoramide anchoring group and a styrene-containing imidazolium zwitterionic monomer, a high-strength concrete is prepared, exhibiting the following beneficial effects: 1. Good dispersibility and slump retention: The phosphoramide groups of the methacrylate functional monomers containing phosphoramide anchoring groups affect the Ca2+ surface of cement particles. 2+ It has better complexing ability than traditional carboxyl groups, which enables the water-reducing agent molecules to be firmly adsorbed and provides a strong initial electrostatic repulsion. The zwitterionic structure of the imidazolium zwitterionic monomer containing styrene groups can preferentially adsorb onto clay particles, "passivating" them, thereby protecting the main water-reducing agent molecules from being consumed by the clay and significantly improving the anti-mud properties. In addition, the ester group of the monoethyl fumarate monomer slowly hydrolyzes under alkaline conditions, continuously releasing dispersible carboxyl groups, which compensate for the consumed water-reducing agent molecules, thereby achieving longer working performance.
[0014] 2. Good mechanical properties: The low water-cement ratio and the excellent dispersibility of cement particles by the water-reducing agent together reduce the capillary and macropores inside the concrete, making the structure more uniform and dense, which helps to improve the compressive strength of the concrete.
[0015] 3. Good durability: The modified polycarboxylate superplasticizer of the present invention prepares a dense concrete matrix by achieving a low water-cement ratio and optimizing the hydration process, which helps to prevent the intrusion of harmful substances such as chloride ions and has good durability.
[0016] In summary, this invention, through molecular design, introduces strongly anchored phosphoramide groups and anti-mud zwitterionic monomers into polycarboxylate superplasticizers, which helps to improve the strength and lifespan of concrete. It is an ideal chemical admixture for preparing high-performance concrete and can be applied in new wall materials and furnace support structures of energy-saving boilers. Attached Figure Description
[0017] Figure 1 Synthetic routes for methacrylate functional monomers containing phosphoramide anchoring groups.
[0018] Figure 2 Synthetic route for imidazolium zwitterionic monomers containing styrene groups.
[0019] Figure 3 The 1H NMR spectrum of a methacrylate functional monomer containing a phosphoramide anchoring group.
[0020] Figure 4 The image shows the 1H NMR spectrum of a styrene-containing imidazolium zwitterion monomer.
[0021] Figure 5 The infrared spectrum of modified polycarboxylate superplasticizer 1. Detailed Implementation
[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0023] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.
[0024] Unless otherwise specified, all raw materials used in the preparation examples, embodiments and comparative examples of this invention are commercially available raw materials, and the raw materials used in each parallel experiment are the same.
[0025] The raw materials and equipment used in the preparation examples, embodiments, and comparative examples are described below, where eq represents molar equivalents: Phosphamide-anchored methacrylate functional monomers: prepared in-house, as follows: Under argon protection, in a 250 mL dry three-necked flask equipped with a magnetic stirrer, reflux condenser, constant-pressure dropping funnel, and thermometer, 1.0 eq of diphenylphosphamide and 80 mL of anhydrous toluene were added and stirred to dissolve. 1.1 eq of glycidyl methacrylate and a trace amount of hydroquinone as a polymerization inhibitor were added to the constant-pressure dropping funnel, followed by 0.05 eq of triethylamine. The system was cooled to 0–5 °C in an ice-water bath, and then the glycidyl methacrylate solution was slowly added dropwise, controlling the temperature below 10 °C. After the addition was complete, the ice bath was removed, and the reaction solution was allowed to rise naturally to room temperature before being stirred at 60–70 °C for 20 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was transferred to a separatory funnel, and then... The organic phase was washed with dilute hydrochloric acid and saturated brine, dried over anhydrous sodium sulfate, filtered, and then toluene was removed by rotary evaporation under reduced pressure below 40°C. The final product was purified by silica gel column chromatography to obtain a methacrylate functional monomer containing a phosphoramide anchoring group, with the structure shown below: .
[0026] Phosphamide-anchored methacrylate functional monomer 2: Prepared in-house, the preparation method differs from that of the phosphoramide-anchored methacrylate functional monomer in that diphenylphosphamide is replaced with 1,1-diphenylethane-1-amine, while other conditions remain unchanged, to obtain phosphoramide-anchored methacrylate functional monomer 2, with the structure shown below: .
[0027] 2-Hydroxybutyl methacrylate: Commercially available.
[0028] Styrene-containing imidazolium zwitterion: prepared in-house, the preparation method is as follows: Under argon protection, 1 eq of sodium bicarbonate and 4 eq of imidazole were added to a 500 mL single-necked flask, and the argon atmosphere was purged for 20 min. Then, 200 mL of a 1:1 mixture of water and acetone was added, and the mixture was stirred at room temperature for 30 min. Next, 1 eq of 4-vinylbenzyl chloride was slowly added dropwise, and the reaction mixture was stirred at 50 °C for 40 min. After the reaction was complete, the mixture was concentrated under reduced pressure to remove acetone, followed by three liquid-liquid extractions with diethyl ether. The combined organic phases were washed with deionized water to remove excess imidazole. The resulting ether layer was rotary evaporated to obtain 0.5 eq of 1-(4-vinylbenzyl)imidazolium chloride. This intermediate was transferred to a 250 mL single-necked flask and degassed under argon protection for 15 min. Then, 0.8 eq of 1,3-propanesulfonate lactone was dissolved in 40 mL of acetonitrile and added to the reaction flask, and the mixture was reacted at 50 °C for 70 min. min; after the reaction was completed, acetonitrile was removed under reduced pressure, and the resulting solid was added dropwise to acetone under stirring to precipitate. Finally, the precipitate was dissolved in deionized water and freeze-dried to obtain a styrene-containing imidazolium zwitterionic monomer, the structure of which is shown in the following formula: .
[0029] Methacryloxyethyltrimethylammonium chloride: Commercially available.
[0030] Sodium 2-ethanesulfonate methacrylate: Commercially available.
[0031] Acrylic monomer: Acrylic acid, commercially available.
[0032] Monoethyl fumarate monomer: Monoethyl fumarate, commercially available.
[0033] Allyl polyoxyethylene ether monomer: methyl allyl alcohol polyoxyethylene ether, hydroxyl value 23.0~25.0 mg KOH / g, commercially available.
[0034] Cement: Silicate cement, PII 52.5R, purchased from China Resources Cement.
[0035] Fly ash: purchased from Wuhan Lianhekang Biotechnology Co., Ltd.
[0036] Sand: River sand, medium sand (3.0~2.3), purchased from Macheng Chuhe Sand and Gravel State-owned Management Co., Ltd.
[0037] Silica fume: raw ash, SiO2 content 94%, purchased from Sichuan Evande, 940UU.
[0038] Crushed stone: with a particle size of 5~10 mm, purchased from Xinxin Mining Co., Ltd., Xian'an District, Xianning City.
[0039] Common polycarboxylate superplasticizer: Polycarboxylate high-efficiency superplasticizer (40%), commercially available.
[0040] Preparation Example Preparation Example 1 Modified polycarboxylate superplasticizer 1: Self-made, preparation method as follows: S1. Construction of the reaction system: Take the methacrylate functional monomer containing phosphoramide anchoring group, the imidazolium zwitterionic monomer containing styrene group, the acrylic monomer, the fumarate monoethyl ester monomer, and the allyl polyoxyethylene ether monomer in a molar ratio of 0.2:0.1:3:0.5:1. Stir the allyl polyoxyethylene ether monomer and 80% of the total water volume of deionized water evenly, purge with high-purity nitrogen for 30 min to completely remove oxygen, and heat to 75℃. S2. Monomer solution preparation: The methacrylate functional monomer containing phosphoramide anchoring groups and the imidazolium zwitterionic monomer containing styrene groups are pre-dissolved in 95% ethanol. The pre-dissolved solution is then dissolved in the remaining deionized water along with the acrylic acid monomer and the fumarate monoethyl monomer. The mixture is stirred until homogeneous. 0.15% of the total monomer mass of mercaptopropionic acid, a chain transfer agent, is added and mixed until homogeneous to prepare a monomer mixture. 1.5% of the total monomer mass of ammonium persulfate, an initiator, is dissolved in water to prepare a 5% initiator solution. S3. Droplet addition copolymerization reaction: Maintain the reaction system temperature at 75℃, and simultaneously add the monomer mixture and initiator solution dropwise. Control the dropwise addition time to 3~4 h, maintain a uniform dropwise addition rate, monitor the pH value of the reaction system in real time, and maintain the pH value between 5.5 and 6.5 by adding 10% sodium hydroxide solution to avoid monomer precipitation; after the dropwise addition is completed, continue to keep the reaction at 75℃ for 1 h to ensure the reaction is complete. S4. Cool the reaction solution to below 40°C, slowly add a 30% sodium hydroxide solution, and adjust the pH to 6.0~7.0 to obtain modified polycarboxylate superplasticizer 1.
[0041] Preparation Example 2 Modified polycarboxylate superplasticizer 2: prepared in-house. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the molar ratio of methacrylate functional monomer containing phosphoramide anchoring group, imidazolium zwitterionic monomer containing styrene group, acrylic monomer, monoethyl fumarate monomer, and allyl polyoxyethylene ether monomer is 0.1:0.05:2:0.3:1, while other conditions remain unchanged, thus obtaining modified polycarboxylate superplasticizer 2.
[0042] Preparation Example 3 Modified polycarboxylate superplasticizer 3: prepared in-house. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the molar ratio of methacrylate functional monomer containing phosphoramide anchoring group, imidazolium zwitterionic monomer containing styrene group, acrylic monomer, monoethyl fumarate monomer, and allyl polyoxyethylene ether monomer is 0.3:0.15:4:0.7:1, while other conditions remain unchanged, thus obtaining modified polycarboxylate superplasticizer 3.
[0043] Preparation Example 4 Modified polycarboxylate superplasticizer 4: self-made. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the methacrylate functional monomer containing phosphoramide anchoring groups is replaced with methacrylate functional monomer 2 without phosphoramide anchoring groups. All other conditions remain unchanged to obtain modified polycarboxylate superplasticizer 4.
[0044] Preparation Example 5 Modified polycarboxylate superplasticizer 5: self-made. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the methacrylate functional monomer containing the phosphoramide anchoring group is replaced with 2-hydroxybutyl methacrylate. All other conditions remain unchanged to obtain modified polycarboxylate superplasticizer 5.
[0045] Preparation Example 6 Modified polycarboxylate superplasticizer 6: self-made. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the styrene-containing imidazolium zwitterionic monomer is replaced with methacryloyloxyethyltrimethylammonium chloride, while other conditions remain unchanged, thus obtaining modified polycarboxylate superplasticizer 6.
[0046] Preparation Example 7 Modified polycarboxylate superplasticizer 7: self-made. The preparation method is the same as that of modified polycarboxylate superplasticizer 1, except that the styrene-containing imidazolium zwitterionic monomer is replaced with sodium 2-ethanesulfonate methacrylate. All other conditions remain unchanged to obtain modified polycarboxylate superplasticizer 7.
[0047] Table 1. Formulations (molar ratio) of modified polycarboxylate superplasticizers in Preparation Examples 1-7
[0048] Examples 1-5 and Comparative Examples 1-5 A method for curing high-strength concrete includes the following steps: S1. Weigh out cement, silica fume, fly ash, sand and crushed stone according to the mix proportion, and mix for 4 minutes; S2. Mix the mixture with water, stir for 3 minutes, add the modified polycarboxylate superplasticizer, continue stirring for 12 minutes, and discharge to obtain high-strength concrete wet material; S3. Pouring and Curing: The mixed high-strength concrete wet material is poured into the mold. Pouring is done in layers, each layer is 200 mm, and the concrete is vibrated with an immersion vibrator until the surface is smooth and free of air bubbles. After molding, the concrete is covered with wet burlap and plastic film and left to stand at 20℃ for 4 hours. Then the temperature is increased to 60℃ at 5℃ / h and kept constant for 15 hours (RH≥95%). The temperature is then decreased to 40℃ at 5℃ / h and cooled to room temperature with the mold in place. After demolding, the concrete is transferred to a standard curing room for 28 days to complete the curing and demolding of the high-strength concrete, thus obtaining the high-strength concrete.
[0049] Table 2. High-strength concrete formulations for Examples 1-5 and Comparative Examples 1-5 (kg / m³) 3 )
[0050] The following are the test methods for performance parameters involved in this invention: 1. Proton NMR spectroscopy: The functional monomers of methacrylate containing phosphoramide anchoring groups and zwitterionic monomers containing styrene groups were characterized by nuclear magnetic resonance spectroscopy (Bruker AM-600, Advance 600).
[0051] 2. Fourier transform infrared spectroscopy (FT-IR): The modified polycarboxylate superplasticizer 1 was analyzed by FT-IR using a Thermo Nicolet IS10 Fourier transform infrared spectrometer.
[0052] 3. Spreadability test: Take another batch of concrete from the same batch for the spreadability test. The sample will not enter the steam curing process. After mixing, the concrete will be left to stand for 60 minutes and tested in accordance with the national standard GB / T 50080-2016.
[0053] 4. Shrinkage test: Concrete specimens were made into prisms with dimensions of 100 mm × 100 mm × 400 mm. The test method was carried out in accordance with GB / T 50082-2009. The shrinkage rate was calculated after 7 days, 28 days and 365 days after being taken out of the curing room.
[0054] 5. Compressive strength test: Concrete specimens were made into 100 mm cubes and the compressive strength was tested for 28 days in accordance with the national standard GB / T 50081-2019.
[0055] 6. Chloride ion penetration resistance test: Concrete is made into a cylindrical component with a diameter of 100 mm and a height of 50 mm. After molding, it is covered with plastic film and moved to a standard curing room for testing according to the RCM method of GB / T 50082-2009.
[0056] Table 3 Performance test results of Examples 1-5 and Comparative Examples 1-5
[0057] As shown in Table 3, in terms of spreadability, Example 1, which used a methacrylate functional monomer with a phosphoramide anchoring group and a styrene-containing imidazolium zwitterionic monomer, achieved good spreadability. Compared with Comparative Example 2, Comparative Example 1, which used a monomer without a phosphoramide group, performed better than Comparative Example 2, which used a common ester monomer. After replacing the imidazolium zwitterionic monomer with a styrene-containing monomer, the spreadability of Comparative Examples 3 and 4 decreased, indicating that zwitterionic monomers have the best overall performance in terms of anti-interference and dispersion stability.
[0058] Regarding shrinkage, Example 1 exhibits a low shrinkage rate, which is attributed to the highly efficient water-reducing effect of the modified polycarboxylate superplasticizer 1. In contrast, the shrinkage rate of performance-reducing agents or ordinary superplasticizers is significantly increased.
[0059] In terms of compressive strength, Example 1 showed high 28-day strength, demonstrating the advantages of modified polycarboxylate superplasticizer 1 in achieving a low water-cement ratio and optimizing the interfacial transition zone; commercially available polycarboxylate superplasticizers had the lowest strength because they could not achieve the same low water-cement ratio and had insufficient ability to optimize the microstructure.
[0060] Regarding resistance to chloride ion penetration, Example 1 exhibits a low diffusion coefficient, indicating that its internal structure is the most compact and has the fewest harmful pores.
[0061] In summary, methacrylate functional monomers with phosphoramide anchoring groups and styrene-containing imidazolium zwitterionic monomers exhibit a significant positive synergistic effect in polycarboxylate superplasticizer molecules. The former provides strong adsorption and high water reduction rate, while the latter ensures dispersion stability and anti-sludge properties. Furthermore, both methacrylate functional monomers with phosphoramide anchoring groups and styrene-containing imidazolium zwitterionic monomers significantly outperformed ordinary commercial monomers and commercially available superplasticizers in all comparative examples, demonstrating that molecular structure design is crucial for improving concrete performance.
[0062] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A high-strength concrete, characterized in that, Includes the following components: cement 300~400 kg / m³ 3 Silica fume 100~130kg / m³ 3 50~80 kg / m³ of fly ash 3 Sand 700~850 kg / m 3 Crushed stone 850~950 kg / m³ 3 Modified polycarboxylate superplasticizer 5~9 kg / m 3 Water 140~170 kg / m 3 The modified polycarboxylate superplasticizer is copolymerized from a methacrylate functional monomer containing a phosphoramide anchoring group, a styrene-containing imidazolium zwitterionic monomer, an acrylic monomer, a fumarate monoethyl monomer, and an allyl polyoxyethylene ether monomer. The structural formula of the methacrylate functional monomer containing the phosphoramide anchoring group is shown in Formula 1, and the structural formula of the styrene-containing imidazolium zwitterionic monomer is shown in Formula 2. Formula 1; Formula 2; The molar ratio of the methacrylate functional monomer containing phosphoramide anchoring group, the imidazolium zwitterionic monomer containing styrene group, the acrylic acid monomer, the fumarate monoethyl ester monomer, and the allyl polyoxyethylene ether monomer is (0.1~0.3):(0.05~0.15):(2~4):(0.3~0.7):
1.
2. The high-strength concrete as described in claim 1, characterized in that, The acrylic monomer is at least one of acrylic acid or methacrylic acid; the allyl polyoxyethylene ether monomer is at least one of methyl allyl polyoxyethylene ether or allyl polyoxyethylene ether; the degree of polymerization of the polyoxyethylene in the methyl allyl polyoxyethylene ether or allyl polyoxyethylene ether is 9 to 54.
3. The high-strength concrete as described in claim 1, characterized in that, The method for preparing the methacrylate functional monomer containing phosphoramide anchoring groups includes the following steps: Under argon protection, diphenylphosphamide was dissolved in anhydrous toluene by stirring. Glycidyl methacrylate and a polymerization inhibitor were added to a constant-pressure dropping funnel, followed by the addition of triethylamine to the reaction flask. The system was cooled in an ice-water bath, and the glycidyl methacrylate solution was slowly added dropwise, with the temperature controlled below 10°C. After the addition was complete, the reaction solution was allowed to rise naturally to room temperature, and then stirred at 60-70°C. After the reaction was completed, the methacrylate functional monomer containing phosphoramide anchoring groups was purified to obtain the product.
4. The high-strength concrete as described in claim 1, characterized in that, The method for preparing the styrene-containing imidazolium zwitterionic monomer includes the following steps: Under argon protection, sodium bicarbonate and imidazole were mixed to remove oxygen, followed by the addition of solvent and stirring at room temperature. 4-Vinylbenzyl chloride was then slowly added dropwise and stirred at 45-65°C. After the reaction was completed, 1-(4-vinylbenzyl)imidazolium chloride was obtained by purification. The 1-(4-vinylbenzyl)imidazolium chloride was transferred to a single-necked flask and degassed under argon protection. Subsequently, 1,3-propanesulfonate lactone was dissolved in acetonitrile and added to the reaction flask, and the reaction was carried out at 45-65°C. After the reaction was completed, styrene-containing imidazolium zwitterionic monomer was obtained by purification.
5. The high-strength concrete as described in claim 1, characterized in that, The preparation method of the modified polycarboxylate superplasticizer includes the following steps: S1. Construction of the reaction system: Weigh out the functional monomers of methacrylate containing phosphoramide anchoring groups, zwitterionic monomers of imidazolium containing styrene groups, acrylic acid monomers, monoethyl fumarate monomers, and allyl polyoxyethylene ether monomers by molar ratio. Stir the allyl polyoxyethylene ether monomers in deionized water to remove oxygen and heat to 70~80℃. S2. Monomer solution preparation: The methacrylate functional monomer containing phosphoramide anchoring groups and the imidazolium zwitterionic monomer containing styrene groups are pre-dissolved in ethanol. The pre-dissolved solution is then dissolved in the remaining deionized water along with the acrylic acid monomer and the fumarate monoethyl monomer. The mixture is stirred until homogeneous. 0.1% to 0.2% of the total monomer mass of chain transfer agent is added and mixed until homogeneous to prepare a monomer mixture. 1% to 2% of the total monomer mass of initiator is dissolved in water to prepare an initiator solution. S3. Addition copolymerization reaction: Maintain the reaction system temperature at 70~80℃, and start adding the monomer mixture and initiator solution dropwise at the same time, keeping the addition at a uniform rate, and maintaining the pH value between 5.5 and 6.5 to avoid monomer precipitation; after the addition is complete, continue to keep warm at 70~80℃ until the reaction is complete. S4. Cool the reaction solution to below 40°C and adjust the pH to 6.0~7.0 to obtain the modified polycarboxylate superplasticizer.
6. The curing method for high-strength concrete as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Weigh out cement, silica fume, fly ash, sand and crushed stone according to the mix proportion, and mix them together; S2. Mix the mixture with water, stir, add the modified polycarboxylate superplasticizer, continue stirring, and discharge to obtain high-strength concrete wet material; S3. Pouring and Curing: The mixed high-strength concrete wet material is poured into the mold. When pouring and filling the mold, layered pouring is adopted, and immersion vibration is used until the surface is covered with slurry and free of air bubbles. After molding, it is covered with wet burlap and plastic film and left to stand at 20~25℃ for 3~5 hours. Then, the temperature is increased to 60℃ at 3~8℃ / h and kept constant for 12~20 hours with RH≥95%. After cooling to below 40℃ at 3~8℃ / h, it is cooled to room temperature with the mold on. After demolding, it is transferred to the standard curing room for 28 days to complete the curing and demolding of the high-strength concrete, and the high-strength concrete is obtained.