An antibacterial long-acting gel polysaccharide-poly-carboxylic acid type water reducing agent for concrete and a preparation method thereof
Through the synergistic effect of components such as gel polysaccharide-polycarboxylate water-reducing agent and antibacterial synergist, the shortcomings of concrete water-reducing agents in antibacterial performance and preparation process have been solved, realizing a concrete admixture with long-lasting antibacterial effect and stable performance, which is suitable for concrete engineering in complex environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-03-20
- Publication Date
- 2026-05-29
Smart Images
Figure CN122102560A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of concrete admixture technology, specifically to an antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete and its preparation method. Background Technology
[0002] Concrete, as the most widely used basic material in the construction engineering field, directly affects the stability, safety, and service life of engineering structures. Water-reducing agents, as key admixtures for concrete, can effectively reduce the amount of mixing water, improve the workability of concrete, and enhance its strength, density, and durability. They have become an indispensable component in modern concrete preparation. As engineering construction moves towards complex environments and long-term service, the problem of microbial erosion faced by concrete during its service life is becoming increasingly prominent. Harmful microorganisms in soil and water can proliferate on and inside the concrete surface, and their metabolic products can corrode the cementitious materials in the concrete, destroy the integrity of the internal structure, and lead to a decrease in concrete strength, cracking, and leakage, seriously shortening the service life of the project. Therefore, developing composite water-reducing agents with excellent water-reducing properties and long-term antibacterial functions to achieve the synergistic effect of water reduction, strengthening, and antibacterial protection has become an important development direction in the field of concrete admixtures, meeting the needs of various projects for multifunctional and high-performance concrete materials.
[0003] Traditional concrete water-reducing agents primarily focus on basic functions such as increasing water reduction rate and improving workability, lacking targeted antibacterial design. This makes them ill-suited to resist structural damage caused by microbial erosion. Some water-reducing agent products that attempt to add antibacterial components suffer from several technical defects: Firstly, the compatibility between antibacterial components and the main components of the water-reducing agent is poor, easily leading to stratification and sedimentation. This not only affects the dispersion and stability of the water-reducing agent but also causes fluctuations in concrete workability. Secondly, the antibacterial components have a single mode of action, easily being lost or ineffective during concrete mixing and hardening, making it difficult to achieve long-term antibacterial effects and fundamentally failing to solve the problem of long-term microbial erosion. Furthermore, traditional preparation processes lack precise control over the reaction conditions of each component, resulting in insufficient integration of antibacterial components with the main components. This reduces antibacterial efficiency and may affect the mechanical properties and durability of concrete due to uneven component distribution. Additionally, some traditional antibacterial agents may adversely affect the internal hydration reaction of concrete, further limiting their widespread application in engineering projects. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an antibacterial, long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete and its preparation method. This water-reducing agent uses gel polysaccharide and polycarboxylate water-reducing agent as its core components, combined with antibacterial synergists, compatibility regulators, and dispersants to construct a composite system. Each component works synergistically. The preparation process involves precise raw material compounding, pretreatment, step-by-step temperature and pH adjustment, composite reaction under nitrogen protection, and subsequent cooling and filtration, ensuring stable product performance. The product combines excellent water-reducing properties with long-lasting antibacterial capabilities, improving concrete workability, inhibiting harmful microbial erosion, and extending concrete service life. Furthermore, the components exhibit good compatibility and uniform dispersion. The preparation process is controllable and standardized, making it suitable for various concrete projects requiring durability and antibacterial properties, providing a reliable solution for the multi-functional upgrading of concrete materials.
[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On the one hand, an antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete, the water-reducing agent comprising the following raw materials in parts by weight: 3-8 parts gel polysaccharide, 80-88 parts polycarboxylate water-reducing agent, 0.5-2 parts antibacterial synergist, 1-3 parts compatibility modifier, and 2-5 parts dispersant;
[0006] The gel polysaccharide is one or more of xanthan gum, gellan gum, guar gum, and konjac glucomannan. When there are two or more, it is a mixture of any two or more in equal proportions.
[0007] The polycarboxylate superplasticizer is one or two of ether-based and ester-based polycarboxylate superplasticizers. When there are two types, they are mixed in equal proportions, and the solid content is 30%-50%.
[0008] The antibacterial synergist is one or more of nano zinc oxide, chitosan quaternary ammonium salt, and polyhexamethylene biguanide hydrochloride; when there are two or more, it is a mixture of any two or more in equal proportions. The compatibility modifier is one or more of glycerol, propylene glycol, and polypropylene glycol; when there are two or more, it is a mixture of any two or more in equal proportions. The dispersing agent is one or two of polyethylene glycol and sodium dodecylbenzenesulfonate, and when there are two, they are a mixture in equal proportions.
[0009] Furthermore, the degree of molecular chain branching of the gel polysaccharide is 1.8-2.5, and the viscosity in an aqueous solution with a mass concentration of 5% at 25°C is 800 mPa·s-1500 mPa·s; the degree of molecular chain branching of xanthan gum is 1.8-2.0, that of gellan gum is 2.2-2.5, that of guar gum is 2.0-2.3, and that of konjac glucomannan is 2.1-2.4.
[0010] Furthermore, the polyoxyethylene ether side chain length of the ether-based polycarboxylate superplasticizer is 20-40 ethylene oxide units, the ester hydrolysis rate of the ester-based polycarboxylate superplasticizer is 0.05 mmol / (g·h)-0.1 mmol / (g·h), and the hydrolysis rate detection conditions are 25℃ and pH=7; the molecular weight of the polyethylene glycol is 2000-6000, and the critical micelle concentration of sodium dodecylbenzenesulfonate is 1.0 mmol / L-1.5 mmol / L.
[0011] Furthermore, the nano-zinc oxide has a particle size of 20nm-50nm and a specific surface area of 50m² / g-80m² / g; the chitosan quaternary ammonium salt has a degree of substitution of 0.6-0.8 and a molecular weight of 50000Da-100000Da; the polyhexamethylene biguanide hydrochloride has a purity of ≥99%; the hydroxyl value of glycerol is 300mgKOH / g-500mgKOH / g; the viscosity of propylene glycol at 25℃ is 50mPa·s-80mPa·s; and the molecular weight of polypropylene glycol is 2000-4000.
[0012] On the other hand, a method for preparing an antibacterial, long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete is provided, the specific steps of which are as follows: S1. Accurate weighing and compounding of raw materials: Weigh 3-8 parts of gel polysaccharide, 80-88 parts of polycarboxylate superplasticizer, 0.5-2 parts of antibacterial synergist, 1-3 parts of compatibility regulator, and 2-5 parts of dispersant according to the weight ratio. The selection and compounding ratio of each component are consistent with the component requirements of the superplasticizer. The components to be compounded should be mixed evenly separately for later use. S2, Preparation of mixed dispersion of gel polysaccharide and antibacterial synergist: Weigh the compounded gel polysaccharide and antibacterial synergist together and add them to deionized water. Stir continuously with a stirring device to prepare a mixed dispersion. S3, Adjusting pH and adding compatibility regulator in reaction system: Weigh the compounded polycarboxylate superplasticizer and add it to the reactor. Start the temperature control device to raise the temperature. Adjust the pH value of the system with acid and base reagents. After the temperature and pH value are stable, add the weighed compounded compatibility regulator and continue to stir and mix. S4, Mixed dispersion drop addition and composite reaction: The mixed dispersion prepared in step S2 is slowly injected into the reaction vessel treated in step S3 through a drop addition device, the stirring rate is increased, nitrogen gas is introduced into the reaction vessel, and the set temperature and pH value are maintained for heat preservation reaction; S5, Addition of dispersing agent, cooling and filtration: Add the weighed dispersing agent to the system after the compound reaction is completed, stir and mix evenly, cool the system, and filter it through a filter screen after cooling to the set temperature to obtain the water-reducing agent.
[0013] Furthermore, before the antibacterial synergist is compounded and mixed, it needs to be pretreated by ultrasonic dispersion at a power of 300W for 10 minutes; the compounding and mixing of the gel polysaccharide and the polycarboxylate water-reducing agent are carried out by mechanical stirring at a speed of 500r / min-1500r / min for 5min-10min.
[0014] Furthermore, the deionized water has a conductivity ≤10μS / cm and a pH value of 6.5-7.5; the stirring is carried out in a container equipped with an anchor stirrer, the stirring rate is controlled at 200r / min-300r / min, the stirring time is 30min-60min, and the stirring ambient temperature is controlled at 25℃-30℃; the mass concentration of the prepared mixed dispersion is 3%-10%, and the particle size of the solid particles is ≤50μm.
[0015] Furthermore, after the polycarboxylate superplasticizer is added to the reaction vessel, the temperature is increased to 60℃-80℃ at a rate of 2℃ / min-5℃ / min and held at that temperature for 3min-5min. Then, the pH value of the system is adjusted to 6-8 using a 5%-10% citric acid or sodium hydroxide aqueous solution, and the fluctuation range is maintained at ≤±0.2. The compatibility regulator is added after the pH value stabilizes, and stirring is continued for 10min-15min after addition.
[0016] Furthermore, the mixed dispersion is added dropwise through a constant pressure dropping funnel at a rate of 1 mL / min-3 mL / min; after the addition is complete, the stirring rate is increased to 300 r / min-500 r / min; the reaction is carried out under the protection of nitrogen gas with a purity ≥99.9%, maintaining the reaction temperature at 60℃-80℃, the pH value at 6-8, and the reaction time at 2h-4h; when the composite reaction is a grafting reaction, before adding the mixed dispersion, ammonium persulfate at 0.1%-0.3% of the mass of the polycarboxylate superplasticizer should be added to the reaction system as an initiator.
[0017] Furthermore, the dispersing agent is added dropwise through a constant pressure dropping funnel at a rate of 2 mL / min-3 mL / min. After the addition is complete, the mixture is stirred for 15 min-30 min at a stirring rate of 300 r / min-500 r / min. Subsequently, the reaction system is cooled by circulating cold water at 5℃-10℃ through a jacket or by natural cooling at a rate of 5℃ / h-10℃ / h to 25℃±5℃. Finally, the mixture is filtered using a filter screen of 200 mesh or higher at a filtration pressure of 0.1 MPa-0.2 MPa to obtain the water-reducing agent product. Beneficial effects
[0018] Compared with existing technologies, this antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete and its preparation method have the following beneficial effects: I. This invention constructs a multi-component synergistic system by rationally selecting gel polysaccharides and polycarboxylate-based water-reducing agents as core components, combined with antibacterial synergists, compatibility modifiers, and dispersing agents. The gel polysaccharides and antibacterial synergists form a complementary effect, endowing the water-reducing agent with long-lasting antibacterial ability, inhibiting the reproduction of harmful microorganisms inside concrete, avoiding the erosion of concrete structure by microbial metabolites, and extending the service life of concrete. The compatibility modifier can optimize the fusion state between the components, eliminate the repulsion between components, and ensure the uniformity and stability of the entire system. The dispersing agent can enhance the dispersion effect of the water-reducing agent in concrete, improve the workability of concrete, and maintain good fluidity of concrete during mixing, pouring, and setting, avoiding problems such as segregation and bleeding, thus achieving simultaneous improvement of antibacterial function and workability.
[0019] II. This invention optimizes the preparation process by employing a series of technological measures, including raw material pretreatment, stepwise reaction, precise temperature and pH control, and nitrogen protection. These measures ensure that all components react fully and achieve optimal performance. Targeted treatment of raw materials before compounding enhances component activity, laying a solid foundation for subsequent reactions. Stepwise addition of components and strict control of reaction conditions prevent excessively high local concentrations or incomplete reactions, ensuring uniform and stable product performance. The nitrogen-protected reaction reduces interference from the external environment and improves product structural stability. Subsequent cooling and filtration processes effectively remove impurities from the system, improving product purity. The entire preparation process is standardized and controllable, ensuring the long-lasting antibacterial effect and reliability of the water-reducing agent while improving production efficiency and reducing the risk of performance fluctuations during application. This provides high-quality admixtures with stable performance and comprehensive functions for various concrete projects.
[0020] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.
[0022] Figure 1A flowchart illustrating the preparation method of an antibacterial, long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete; Figure 2 This is a flowchart for quality inspection and finished product filtration. Detailed Implementation
[0023] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below. Example
[0024] Basic preparation and performance testing of antibacterial long-acting gel polysaccharide-polycarboxylate water-reducing agent.
[0025] Raw material preparation:
[0026] Xanthan gum was selected as the gel polysaccharide, with a molecular chain branching degree of 1.9 and a viscosity of 1000 mPa·s in a 5% aqueous solution at 25°C. Five portions were accurately weighed. The polycarboxylate-based water-reducing agent was an ether with a solid content of 40% and a polyoxyethylene ether side chain length of 30 ethylene oxide units. Eighty-five portions were accurately weighed. The antibacterial synergist was nano-zinc oxide with a particle size of 30 nm and a specific surface area of 60 m² / g. One portion was accurately weighed. The compatibility modifier was glycerol with a hydroxyl value of 400 mg / g potassium hydroxide. Two portions were accurately weighed. The dispersing agent was polyethylene glycol with a molecular weight of 4000. Three portions were accurately weighed. All raw materials underwent purity testing and met the preparation requirements.
[0027] Preparation process, such as Figure 1 As shown: S1, Precise weighing and compounding of raw materials:
[0028] The antibacterial synergist was first pretreated with ultrasonic dispersion at 300 watts for 10 minutes to ensure uniform dispersion. The gel polysaccharide was mechanically stirred at 1000 rpm for 8 minutes. The polycarboxylate superplasticizer was mechanically stirred at 1200 rpm for 7 minutes. Each component was then mixed separately and thoroughly for later use.
[0029] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist:
[0030] Pretreated xanthan gum and nano-zinc oxide were added together to deionized water with a conductivity of 8 μS / cm and a pH of 7.0. A container equipped with an anchor stirrer was used, and the stirring environment temperature was controlled at 28 degrees Celsius. The mixture was stirred continuously at a speed of 250 rpm for 45 minutes to prepare a mixed dispersion with a mass concentration of 6% and a solid particle size of 35 micrometers.
[0031] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator:
[0032] The compounded polycarboxylate superplasticizer was added to the reactor, and the temperature control device was activated to raise the temperature to 70 degrees Celsius at a rate of 3 degrees Celsius per minute, and held at this temperature for 4 minutes. The pH of the system was adjusted to 7.0 using an 8% citric acid aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the pH stabilized, the compounded glycerol was added, and stirring was continued for 12 minutes to ensure that the compatibility regulator and the polycarboxylate superplasticizer were fully mixed.
[0033] S4, Mixed dispersion droplet addition to composite reaction: The prepared mixed dispersion was slowly injected into the reactor at a rate of 2 ml per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring speed was increased to 400 rpm, and 99.9% pure nitrogen gas was introduced into the reactor. The reaction temperature was maintained at 70°C and the pH at 7.0, and the reaction was carried out at this temperature for 3 hours. If it is a grafting reaction, ammonium persulfate at 0.2% of the mass of the polycarboxylate superplasticizer was added to the reaction system as an initiator before the addition of the mixed dispersion.
[0034] S5, Dispersant addition, cooling and filtration:
[0035] The compounded polyethylene glycol was added dropwise to the composite reaction system at a rate of 2.5 mL per minute using a constant-pressure dropping funnel. After the addition was complete, mixing continued for 20 minutes at a stirring rate of 400 rpm. Subsequently, the mixture was cooled to 25°C using 8°C cold water circulating in a jacket at a rate of 8°C per hour. Finally, the mixture was filtered through a 250-mesh filter at a filtration pressure of 0.15 MPa to obtain the antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent product, such as... Figure 2 As shown.
[0036] Performance testing: Dispersion performance test: The fluidity of the paste was tested using the paste fluidity test method at a dosage of 0.5%. The initial fluidity reached 290 mm, and the fluidity remained at 275 mm after 1 hour, demonstrating excellent dispersion performance and plasticity retention effect, which is far superior to the fluidity retention ability of ordinary polycarboxylate superplasticizers.
[0037] Antibacterial performance test: The plate count method was used to test the antibacterial rate of this water-reducing agent against Escherichia coli and Staphylococcus aureus. After 24 hours, the antibacterial rate against Escherichia coli was 99.3%, and the antibacterial rate against Staphylococcus aureus was 99.1%. After 72 hours, the antibacterial rate remained above 98.5%, demonstrating a significant and long-lasting antibacterial effect.
[0038] Long-term effectiveness test: Concrete test blocks with the added water-reducing agent were cured for 180 days in an environment with 95% humidity and 25 degrees Celsius, and the number of bacteria inside the test blocks was tested periodically. After 180 days of curing, the number of bacteria inside the test blocks remained at a low level. Compared with the blank concrete test blocks without the added water-reducing agent, the number of bacteria was reduced by more than 99%, indicating that the product has a good long-term antibacterial effect.
[0039] Compatibility test: The water-reducing agent was tested for compatibility with different brands of cement, and the flowability of the cement paste was tested at different water-cement ratios. The results showed that the water-reducing agent had good compatibility with all types of cement, with a flowability deviation of no more than 5%, and no stratification or bleeding. Example
[0040] Optimization of gel polysaccharide types and performance comparison.
[0041] Raw material preparation: Four types of gelatinizing polysaccharides were selected: xanthan gum (molecular chain branching degree 1.8, viscosity of 850 mPa·s in a 5% aqueous solution at 25°C), gellan gum (molecular chain branching degree 2.3, viscosity 1300 mPa·s), guar gum (molecular chain branching degree 2.1, viscosity 1100 mPa·s), and konjac glucomannan (molecular chain branching degree 2.2, viscosity 1200 mPa·s). Five portions of each type were accurately weighed. For the polycarboxylate-based water-reducing agent, ethers were uniformly selected, with a solid content of 35% and a polyoxyethylene ether side chain length of 25 ethylene oxide units; 84 portions were accurately weighed. For the antibacterial synergist, nano-zinc oxide with a particle size of 25 nm and a specific surface area of 55 m² / g was uniformly selected; 1.2 portions were accurately weighed. For the compatibility modifier, propylene glycol with a viscosity of 65 mPa·s at 25°C was uniformly selected; 2 portions were accurately weighed. The dispersing agent used is uniformly polyethylene glycol with a molecular weight of 3000, and 3.8 parts are accurately weighed. All raw materials are of consistent specifications to ensure that the single variable is the type of gel polysaccharide.
[0042] Preparation process: S1, Precise weighing and compounding of raw materials: All antibacterial synergists underwent ultrasonic dispersion pretreatment at 300 watts for 10 minutes. The four types of gel polysaccharides were mechanically stirred at 900 rpm for 9 minutes. The polycarboxylate-based water-reducing agent was mechanically stirred at 1100 rpm for 8 minutes. Each component was then individually mixed thoroughly and set aside.
[0043] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist: Four pretreated and compounded gel polysaccharides were added to deionized water along with nano-zinc oxide. The deionized water had a conductivity of 7 μS / cm and a pH of 7.2. Containers equipped with anchor stirrers were used, and the stirring environment was maintained at 27°C. The mixture was stirred continuously at 230 rpm for 50 minutes to prepare four mixed dispersions with a mass concentration of 5% and a solid particle size of 40 μm.
[0044] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator: The four equal parts of the compounded polycarboxylate superplasticizer were added to four separate reactors. The temperature control devices were activated, and the temperature was increased to 68°C at a rate of 3.5°C per minute, then held at this temperature for 4 minutes. The pH of each system was adjusted to 7.2 using a 7% sodium hydroxide aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the pH stabilized, the compounded propylene glycol was added to each reactor, and stirring was continued for 13 minutes to ensure thorough mixing.
[0045] S4, Mixed dispersion droplet addition to composite reaction: Four mixed dispersions were slowly injected into their respective reaction vessels at a rate of 1.8 mL per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring speed was increased to 380 rpm, and 99.9% pure nitrogen gas was introduced into each reaction vessel to maintain the reaction temperature at 68°C and the pH at 7.2 for 3 hours. For grafting reactions, ammonium persulfate was added as an initiator at 0.18% of the mass of the polycarboxylate superplasticizer before adding the mixed dispersions.
[0046] S5, Dispersant addition, cooling and filtration: The four equal portions of compounded polyethylene glycol were added dropwise at a rate of 2.3 mL per minute to four separate systems that had completed the compounding reaction using a constant-pressure dropping funnel. After the addition was complete, each system was stirred at 380 rpm for 22 minutes. The mixture was then allowed to cool naturally to 24°C at a rate of 7°C per hour. Finally, the mixture was filtered through a 220-mesh filter at a filtration pressure of 0.14 MPa to obtain four different water-reducing agent products containing different gel polysaccharides.
[0047] Performance testing: Basic performance tests: Dispersion performance, antibacterial performance, and viscosity were tested on the four products. Dispersion performance was assessed using a paste flowability test at a dosage of 0.5%. Antibacterial performance was tested using the plate count method to determine the antibacterial rate against *E. coli* after 24 hours. Viscosity was measured at 25°C using a 5% (w / w) aqueous solution.
[0048] Comparative Testing: The performance comparison of the water-reducing agents corresponding to the four types of gel polysaccharides is as follows: Types of gel polysaccharides Degree of branching of molecular chain Viscosity (mPa·s) Initial paste fluidity (mm) 1-hour paste flowability (mm) 24-hour antibacterial rate (%) Xanthan Gum 1.8 850 280 260 98.8 Gel 2.3 1300 275 255 99.4 Guar gum 2.1 1100 285 265 99.0 Konjac glucomannan 2.2 1200 282 263 99.2
[0049] Results Analysis: The comparative data shows that the product corresponding to gellan gum has the highest antibacterial rate, but its viscosity is relatively high and the flowability of the paste is slightly low. The product corresponding to guar gum exhibits the best dispersibility. Considering dispersibility, antibacterial properties, and viscosity characteristics, guar gum, as a gelling polysaccharide, offers the best overall performance, ensuring good dispersibility, high antibacterial rate, and moderate viscosity, making it more suitable for practical applications. Example
[0050] Optimization of antibacterial synergists and performance comparison.
[0051] Raw material preparation: Three antibacterial synergists were selected: nano-zinc oxide (particle size 40 nm, specific surface area 70 m² / g), chitosan quaternary ammonium salt (degree of substitution 0.7, molecular weight 80,000 Daltons), and polyhexamethylene biguanide hydrochloride (purity 99.5%). One part of each synergist was precisely weighed. Guar gum was uniformly selected as the gelling polysaccharide, with a molecular chain branching degree of 2.2 and a viscosity of 1150 mPa·s for a 5% aqueous solution at 25°C. Five parts were precisely weighed. Ester-based water-reducing agents were uniformly selected as esters, with a solid content of 45% and an ester group hydrolysis rate of 0.07 mmol / g / h. 86 parts were precisely weighed. Polypropylene glycol (molecular weight 3000) was uniformly selected as the compatibility modifier. 2.5 parts were precisely weighed. Sodium dodecylbenzenesulfonate (CMS) was uniformly selected as the dispersant, with a critical micelle concentration of 1.2 mmol / L. 3.5 parts were precisely weighed. All raw materials were of consistent specifications to ensure that the single variable was the type of antibacterial synergist.
[0052] Preparation process: S1, Precise weighing and compounding of raw materials: All three antibacterial synergists underwent ultrasonic dispersion pretreatment at 300 watts for 10 minutes. Guar gum was mechanically stirred for 8 minutes at 850 rpm. The polycarboxylate superplasticizer was mechanically stirred for 7 minutes at 1200 rpm. Each component was then mixed separately and thoroughly before use.
[0053] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist: Three pretreated and compounded antibacterial synergists were added to deionized water along with guar gum. The deionized water had a conductivity of 9 μS / cm and a pH of 6.8. Containers equipped with anchor stirrers were used, and the stirring environment temperature was controlled at 29°C. The mixture was stirred continuously at 260 rpm for 40 minutes to prepare three mixed dispersions with a mass concentration of 7% and a solid particle size of 38 μm.
[0054] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator: The three equal parts of the compounded polycarboxylate superplasticizer were added to three separate reactors. The temperature control devices were activated, and the temperature was increased to 72°C at a rate of 4°C per minute, then held at this temperature for 3 minutes. The pH of each system was adjusted to 6.8 using a 9% citric acid aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the pH stabilized, the compounded polypropylene glycol was added to each reactor, and stirring was continued for 14 minutes to ensure thorough mixing.
[0055] S4, Mixed dispersion droplet addition to composite reaction: The three mixed dispersions were slowly injected into their respective reaction vessels at a rate of 2.2 mL per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring speed was increased to 420 rpm, and 99.9% pure nitrogen gas was introduced into each reaction vessel to maintain the reaction temperature at 72°C and the pH at 6.8 for 2.5 hours. For grafting reactions, ammonium persulfate was added as an initiator at 0.22% of the mass of the polycarboxylate superplasticizer before adding the mixed dispersions.
[0056] S5, Dispersant addition, cooling and filtration: The three equal portions of sodium dodecylbenzenesulfonate were added dropwise at a rate of 2.6 mL per minute to each of the three systems that had completed the compounding reaction using a constant-pressure dropping funnel. After the addition was complete, the mixture was stirred at 420 rpm for 18 minutes. The mixture was then cooled to 26°C by circulating 7°C cold water through a jacket at a rate of 9°C per hour. Finally, the mixture was filtered through a 280-mesh filter at a filtration pressure of 0.17 MPa to obtain three water-reducing agent products with different antibacterial synergists.
[0057] Performance testing: Basic performance tests: The three products were tested for antibacterial properties, long-lasting antibacterial properties, and dispersibility. Antibacterial properties were tested for antibacterial rates against *Escherichia coli* and *Staphylococcus aureus* at 24, 72, and 168 hours. Dispersibility was tested for the fluidity of the paste at a dosage of 0.5%.
[0058] Comparative Testing: The performance comparison of water-reducing agent products corresponding to the three antibacterial synergists is as follows: Types of antibacterial synergists 24-hour antibacterial rate (%) 72-hour antibacterial rate (%) Antibacterial rate after 168 hours (%) Initial paste fluidity (mm) 1-hour pulp flowability (mm) Nano zinc oxide 99.0 98.3 97.5 283 264 Chitosan Quaternary Ammonium Salt 98.7 97.8 96.6 285 266 Polyhexamethylene biguanide hydrochloride 99.5 99.2 98.8 281 262 Results Analysis: Comparative data shows that the product corresponding to polyhexamethylene biguanide hydrochloride exhibited the highest antibacterial rate across all time periods, demonstrating the best long-lasting antibacterial performance. The product corresponding to chitosan quaternary ammonium salt showed slightly better dispersibility but slightly weaker long-lasting antibacterial effect. The product corresponding to nano-zinc oxide had moderate overall performance. Considering both antibacterial effect and long-lasting effect, polyhexamethylene biguanide hydrochloride, as an antibacterial synergist, demonstrated the best antibacterial performance and long-lasting effect, better meeting the long-term antibacterial requirements of concrete. Example
[0059] Optimization and performance comparison of polycarboxylate superplasticizers.
[0060] Raw material preparation: Three types of polycarboxylate superplasticizers were selected: ethers (30% solids content, 20 ethylene oxide units for the polyoxyethylene ether side chain), esters (50% solids content, ester hydrolysis rate of 0.09 mmol / g / h), and a mixture of ethers and esters in equal proportions (40% solids content, 35 ethylene oxide units for the polyoxyethylene ether side chain, 0.06 mmol / g / h). Eighty-five portions of each type of superplasticizer were accurately weighed. Konjac glucomannan was uniformly selected as the gel polysaccharide, with a molecular chain branching degree of 2.3 and a viscosity of 1250 mPa·s for a 5% aqueous solution at 25°C; six portions were accurately weighed. Chitosan quaternary ammonium salt was uniformly selected as the antibacterial synergist, with a degree of substitution of 0.65 and a molecular weight of 70,000 Daltons; 1.5 portions were accurately weighed. Glycerin was uniformly selected as the compatibility modifier, with a hydroxyl value of 450 mg / g potassium hydroxide; 1.8 portions were accurately weighed. The dispersing agent is a uniform mixture of polyethylene glycol and sodium dodecylbenzenesulfonate in equal proportions (polyethylene glycol molecular weight 5000, sodium dodecylbenzenesulfonate critical micelle concentration 1.3 mmol / L), with 4 parts accurately weighed. All raw materials are of consistent specifications to ensure that the single variable is a polycarboxylate-based water-reducing agent.
[0061] Preparation process: S1, Precise weighing and compounding of raw materials: The antibacterial synergist was pretreated by ultrasonic dispersion at 300 watts for 10 minutes. Konjac glucomannan was mechanically stirred for 7 minutes at 1000 rpm. The three polycarboxylate-based water-reducing agents were each mechanically stirred for 6 minutes at 1300 rpm. Each component was mixed separately and thoroughly before use.
[0062] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist: Pretreated and compounded konjac glucomannan and chitosan quaternary ammonium salt were added together to deionized water with a conductivity of 6 μS / cm and a pH of 7.3. A container equipped with an anchor stirrer was used, and the stirring environment temperature was controlled at 26 degrees Celsius. The mixture was stirred continuously at a speed of 240 rpm for 55 minutes to prepare a mixed dispersion with a mass concentration of 8% and a solid particle size of 32 micrometers. This dispersion was then divided into three equal portions for later use.
[0063] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator: Three polycarboxylate superplasticizers were added to three separate reactors. The temperature control devices were activated, and the temperature was increased to 75°C at a rate of 2.5°C per minute, then held at this temperature for 5 minutes. The pH of each system was adjusted to 7.5 using a 6% citric acid aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the pH stabilized, the compounded glycerol was added to each reactor, and stirring was continued for 12 minutes to ensure thorough mixing.
[0064] S4, Mixed dispersion droplet addition to composite reaction: The three equal portions of the mixed dispersion were slowly injected into their respective reaction vessels at a rate of 2.5 mL per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring speed was increased to 450 rpm, and 99.9% pure nitrogen gas was introduced into each reaction vessel to maintain the reaction temperature at 75°C and the pH at 7.5 for 3.5 hours. For grafting reactions, ammonium persulfate (0.25% by weight of the polycarboxylate superplasticizer) was added as an initiator to each reaction system before the addition of the mixed dispersion.
[0065] S5, Dispersant addition, cooling and filtration: The three equal parts of the compounded dispersant were added dropwise at a rate of 2.8 mL per minute to three separate systems that had completed the compounding reaction using a constant-pressure dropping funnel. After the addition was complete, each system was stirred at 450 rpm for 25 minutes. The mixture was then cooled to 23°C by circulating 9°C cold water through a jacket at a rate of 6°C per hour. Finally, the mixture was filtered through a 300-mesh filter at a filtration pressure of 0.19 MPa to obtain three different polycarboxylate superplasticizer products.
[0066] Performance testing: Basic performance tests: Dispersion performance, concrete mechanical properties, and compatibility were tested on the three products. Dispersion performance was tested by measuring the flowability and time loss of the cement paste at a dosage of 0.5%. Mechanical properties were tested by measuring the 28-day compressive strength of concrete with the added water-reducing agent. Compatibility was tested by assessing the compatibility with three different types of cement.
[0067] Comparative Testing: The performance comparison of the three polycarboxylate superplasticizers is as follows:
[0068] Polycarboxylate superplasticizers Initial paste fluidity (mm) Flowability loss (mm) over 1 hour 28-day compressive strength (MPa) Cement compatibility pass rate (%) ethers 290 20 46.8 95 esters 282 15 48.5 90 Mixture of ethers and esters 295 12 50.2 98
[0069] Results Analysis: Comparative data shows that the polycarboxylate superplasticizer with an equal ratio of ether and ester components exhibits the highest initial paste fluidity, the smallest fluidity loss over time, the highest 28-day compressive strength in concrete, and the highest compatibility rate with different cements. The ether-based polycarboxylate superplasticizer shows good cement compatibility, but slightly greater fluidity loss. The ester-based polycarboxylate superplasticizer shows good mechanical properties, but slightly poorer compatibility. Overall, the polycarboxylate superplasticizer with an equal ratio of ether and ester components provides the best comprehensive performance, combining good dispersibility, plasticity retention, mechanical strengthening effect, and compatibility.
[0070] Example 5:
[0071] Preparation process parameters optimization and performance comparison.
[0072] Raw material preparation:
[0073] Guar gum was selected as the gelling polysaccharide, with a molecular chain branching degree of 2.1. A 5% aqueous solution at 25°C had a viscosity of 1050 mPa·s, and 5 parts were accurately weighed. A polycarboxylate-based water-reducing agent was selected as a mixture of ethers and esters in equal proportions, with a solid content of 40%, and 84 parts were accurately weighed. A polyhexamethylene biguanide hydrochloride was selected as the antibacterial synergist, with a purity of 99.2%, and 1 part was accurately weighed. A compatibility modifier was selected as a mixture of propylene glycol and polypropylene glycol in equal proportions (propylene glycol viscosity at 25°C 60 mPa·s, polypropylene glycol molecular weight 2500), and 2 parts were accurately weighed. Polyethylene glycol with a molecular weight of 4000 was selected as the dispersing agent, and 4 parts were accurately weighed. All raw material specifications were fixed; only the preparation process parameters were optimized.
[0074] Preparation process:
[0075] S1, Precise weighing and compounding of raw materials:
[0076] The antibacterial synergist was pretreated by ultrasonic dispersion at 300 watts for 10 minutes. Guar gum was mechanically stirred for 8 minutes at 950 rpm. The polycarboxylate superplasticizer was mechanically stirred for 7 minutes at 1200 rpm. Each component was then mixed separately and thoroughly for later use.
[0077] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist:
[0078] Pretreated and compounded guar gum and polyhexamethylene biguanide hydrochloride were added together to deionized water with a conductivity of 8 μS / cm and a pH of 7.1. A container equipped with an anchor stirrer was used, and the stirring environment temperature was controlled at 28 degrees Celsius. The mixture was stirred continuously at a speed of 250 rpm for 45 minutes to prepare a mixed dispersion with a mass concentration of 6% and a solid particle size of 36 micrometers. This dispersion was then divided into three equal portions for later use.
[0079] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator:
[0080] The three equal parts of the compounded polycarboxylate superplasticizer were added to three separate reactors, with three sets of process parameters set: Group 1: heating rate 3°C / min, reaction temperature 65°C, pH 6.5; Group 2: heating rate 4°C / min, reaction temperature 70°C, pH 7.0; Group 3: heating rate 5°C / min, reaction temperature 75°C, pH 7.5. All reactors were held at this temperature for 4 minutes. The pH of each system was adjusted to the set value using an 8% citric acid or sodium hydroxide aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the temperature and pH stabilized, the compounded compatibility adjuster was added to each reactor, and stirring was continued for 13 minutes to ensure thorough mixing.
[0081] S4, Mixed dispersion droplet addition to composite reaction:
[0082] The three equal portions of the mixed dispersion were slowly injected into their respective reaction vessels at a rate of 2 ml per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring rate was 350 rpm for the first group and the reaction time was 3.5 hours; the stirring rate was 400 rpm for the second group and the reaction time was 3 hours; and the stirring rate was 450 rpm for the third group and the reaction time was 2.5 hours. Nitrogen gas of 99.9% purity was purged into the reaction vessels to maintain the set reaction temperature and pH value for each group. If it was a grafting reaction, ammonium persulfate (0.2% by weight of the polycarboxylate superplasticizer) was added as an initiator to each reaction system before the addition of the mixed dispersion.
[0083] S5, Dispersant addition, cooling and filtration:
[0084] The three equal portions of compounded polyethylene glycol were added dropwise at a rate of 2.4 mL per minute to three separate systems that had completed the compounding reaction using a constant-pressure dropping funnel. After the addition was complete, each system was mixed for 20 minutes at the corresponding stirring rate. Subsequently, the mixture was circulated with 8°C cold water through a jacket, with cooling rates of 6°C per hour for the first group, 8°C per hour for the second group, and 10°C per hour for the third group, all cooled to 25°C. Finally, the mixture was filtered through a 250-mesh filter at a filtration pressure of 0.16 MPa to obtain three water-reducing agent products with different process parameters.
[0085] Performance testing:
[0086] Basic performance tests: Dispersion performance, antibacterial performance, and stability tests were conducted on the three products. Dispersion performance was tested on the flowability of the paste at a dosage of 0.5%. Antibacterial performance was tested on the antibacterial rate against Staphylococcus aureus after 24 hours. Stability was tested on the performance retention rate of the products after 3 months of sealed storage.
[0087] Comparative Testing: The performance comparison of water-reducing agent products corresponding to three process parameters is as follows: Process parameter group Neat paste fluidity (mm) 24-hour antibacterial rate (%) 3-month performance retention rate (%) Product uniformity (%) Group 1 278 98.5 95.2 92 Group 2 292 99.3 98.6 97 Group 3 285 99.0 96.8 94 Results Analysis: The comparative data shows that the product corresponding to the second set of process parameters (heating rate 4°C / min, reaction temperature 70°C, pH 7.0, stirring rate 400 rpm, reaction time 3 hours, cooling rate 8°C / hour) exhibits the highest pulp fluidity, the highest antibacterial rate, the highest 3-month performance retention rate, and the best product uniformity. The first set of process parameters has a lower reaction temperature and a longer reaction time, resulting in slightly inferior product performance. The third set of process parameters has a higher reaction temperature and a shorter reaction time, leading to slightly lower product stability compared to the second set. Overall, the second set of process parameters represents the optimal preparation process, maximizing the overall performance of the product.
[0088] Example 6:
[0089] Verification of performance in actual concrete applications.
[0090] Raw material preparation:
[0091] The gelling polysaccharide used is guar gum, with a molecular chain branching degree of 2.1. A 5% aqueous solution at 25°C has a viscosity of 1050 mPa·s, and 5 parts are accurately weighed. The polycarboxylate superplasticizer is a mixture of ethers and esters in equal proportions, with a solid content of 40%. The polyoxyethylene ether side chain length is 30 ethylene oxide units, and the ester hydrolysis rate is 0.07 mmol / g / h, and 85 parts are accurately weighed. The antibacterial synergist is polyhexamethylene biguanide hydrochloride, with a purity of 99.5%, and 1 part is accurately weighed. The compatibility modifier is a mixture of propylene glycol and polypropylene glycol in equal proportions, and 2 parts are accurately weighed. The dispersing agent is polyethylene glycol, with a molecular weight of 4000, and 3 parts are accurately weighed. The concrete raw materials are P.O42.5 ordinary Portland cement, medium sand (fineness modulus 2.6), continuously graded crushed stone ranging from 5 mm to 25 mm, and drinking water. The concrete mix proportions are: 320 kg of cement per cubic meter, 36% sand, and 0.48 water-cement ratio.
[0092] Preparation of water-reducing agent:
[0093] S1, Precise weighing and compounding of raw materials:
[0094] The antibacterial synergist was pretreated by ultrasonic dispersion at 300 watts for 10 minutes. Guar gum was mechanically stirred for 8 minutes at 950 rpm. The polycarboxylate superplasticizer was mechanically stirred for 7 minutes at 1200 rpm. Each component was then mixed separately and thoroughly for later use.
[0095] S2, Preparation of a mixed dispersion of gelatin polysaccharide and antibacterial synergist:
[0096] Pretreated and compounded guar gum and polyhexamethylene biguanide hydrochloride were added together to deionized water with a conductivity of 8 μS / cm and a pH of 7.1. A container equipped with an anchor stirrer was used, and the stirring environment temperature was controlled at 28 degrees Celsius. The mixture was stirred continuously at a speed of 250 rpm for 45 minutes to prepare a mixed dispersion with a mass concentration of 6% and a solid particle size of 36 micrometers.
[0097] S3, temperature adjustment and pH adjustment of the reaction system, and addition of a compatibility regulator:
[0098] Add the compounded polycarboxylate superplasticizer to the reactor, start the temperature control device, and raise the temperature to 70 degrees Celsius at a rate of 4 degrees Celsius per minute, then hold the temperature for 4 minutes. Adjust the pH of the system to 7.0 using an 8% citric acid aqueous solution, maintaining a fluctuation range not exceeding 0.2. After the pH stabilizes, add the compounded compatibility adjuster and continue stirring for 13 minutes to ensure thorough mixing.
[0099] S4, Mixed dispersion droplet addition to composite reaction:
[0100] The prepared mixed dispersion was slowly injected into the reactor at a rate of 2 ml per minute using a constant-pressure dropping funnel. After the addition was complete, the stirring speed was increased to 400 rpm, and 99.9% pure nitrogen gas was introduced into the reactor. The reaction temperature was maintained at 70°C and the pH at 7.0, and the reaction was carried out at this temperature for 3 hours. If it is a grafting reaction, ammonium persulfate at 0.2% of the mass of the polycarboxylate superplasticizer was added to the reaction system as an initiator before the addition of the mixed dispersion.
[0101] S5, Dispersant addition, cooling and filtration:
[0102] The compounded polyethylene glycol was added dropwise to the composite reaction system at a rate of 2.4 mL per minute using a constant-pressure dropping funnel. After the addition was complete, mixing continued for 20 minutes with a stirring speed of 400 rpm. Subsequently, the mixture was cooled to 25°C by circulating 8°C cold water through a jacket at a rate of 8°C per hour. Finally, the mixture was filtered through a 250-mesh filter at a filtration pressure of 0.16 MPa to obtain the water-reducing agent product.
[0103] Concrete preparation and performance testing:
[0104] Concrete preparation: According to the mix proportion, first put cement, sand, and gravel into the mixer and dry mix for 2 minutes. Then add half of the water and continue mixing for 3 minutes. Next, add 0.5% water-reducing agent and the remaining water, and mix for 5 minutes to form a homogeneous concrete mixture. At the same time, prepare a blank control group concrete without water-reducing agent.
[0105] Workability testing: The slump, spread, and loss over time of the concrete mixture were tested. The slump was measured using a standard slump cone test, and the spread was measured using the steel plate diffusion method.
[0106] Mechanical property testing:
[0107] The concrete mixture was made into 100 mm x 100 mm x 100 mm cube specimens, which were cured under standard curing conditions for 3 days, 7 days, 28 days and 90 days respectively, and their compressive strength was tested using a pressure testing machine.
[0108] Antibacterial performance test: Concrete test blocks cured for 28 days were cut into small pieces of 50 mm x 50 mm x 50 mm and placed in a mixed culture medium containing Escherichia coli and Staphylococcus aureus. The blocks were incubated at a constant temperature of 25 degrees Celsius for 7 days, 14 days and 28 days. The number of bacteria on the surface and inside of the test blocks was then tested.
[0109] Comparative testing: The performance of concrete with added water-reducing agent and the blank control group are compared as follows: Performance indicators Blank control group Add water-reducing agent group Performance improvement (%) Slump (mm) 120 225 87.5 Expansion (mm) 350 580 65.7 28-day compressive strength (MPa) 42.5 51.8 21.9 90-day compressive strength (MPa) 46.8 56.5 20.7 28-day surface antibacterial rate (%) none 99.2 / 28-day internal antibacterial rate (%) none 98.8 / Results Analysis: Comparative data shows that the concrete with the added water-reducing agent of this invention exhibits significantly improved slump and spread compared to the blank control group, resulting in a substantial improvement in workability and meeting the construction requirements for pumped concrete. The 28-day and 90-day compressive strengths are both significantly increased, enhancing mechanical properties. Simultaneously, the concrete specimens show excellent antibacterial properties on both the surface and interior. While the blank control group concrete showed no antibacterial effect, the concrete with the added water-reducing agent effectively inhibited bacterial growth, and the antibacterial effect is long-lasting. This indicates that the water-reducing agent of this invention, in practical concrete applications, not only improves concrete workability and mechanical strength but also imparts long-lasting antibacterial properties, demonstrating significant practical application value.
[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A long-lasting antibacterial gel polysaccharide-polycarboxylate superplasticizer suitable for concrete, characterized in that, The water-reducing agent contains the following raw materials in parts by weight: 3-8 parts of gel polysaccharide, 80-88 parts of polycarboxylate water-reducing agent, 0.5-2 parts of antibacterial synergist, 1-3 parts of compatibility modifier, and 2-5 parts of dispersing agent; The gel polysaccharide is one or more of xanthan gum, gellan gum, guar gum, and konjac glucomannan. When there are two or more, it is a mixture of any two or more in equal proportions. The polycarboxylate superplasticizer is one or two of ether-based and ester-based polycarboxylate superplasticizers. When there are two types, they are mixed in equal proportions, and the solid content is 30%-50%. The antibacterial synergist is one or more of nano zinc oxide, chitosan quaternary ammonium salt, and polyhexamethylene biguanide hydrochloride; when there are two or more, it is a mixture of any two or more in equal proportions. The compatibility modifier is one or more of glycerol, propylene glycol, and polypropylene glycol; when there are two or more, it is a mixture of any two or more in equal proportions. The dispersing agent is one or two of polyethylene glycol and sodium dodecylbenzenesulfonate, and when there are two, they are a mixture in equal proportions.
2. The antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete according to claim 1, characterized in that, The degree of molecular chain branching of the gel polysaccharide is 1.8-2.5, and the viscosity in an aqueous solution with a mass concentration of 5% at 25°C is 800 mPa·s-1500 mPa·s; the degree of molecular chain branching of xanthan gum is 1.8-2.0, that of gellan gum is 2.2-2.5, that of guar gum is 2.0-2.3, and that of konjac glucomannan is 2.1-2.
4.
3. The antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete according to claim 1, characterized in that, The polyoxyethylene ether side chain length of the ether-based polycarboxylate superplasticizer is 20-40 ethylene oxide units, and the ester hydrolysis rate of the ester-based polycarboxylate superplasticizer is 0.05 mmol / (g·h)-0.1 mmol / (g·h), with the hydrolysis rate detection conditions being 25℃ and pH=7; the molecular weight of the polyethylene glycol is 2000-6000, and the critical micelle concentration of sodium dodecylbenzenesulfonate is 1.0 mmol / L-1.5 mmol / L.
4. The antibacterial long-lasting gel polysaccharide-polycarboxylate water-reducing agent suitable for concrete according to claim 1, characterized in that, The nano zinc oxide has a particle size of 20nm-50nm and a specific surface area of 50m² / g-80m² / g; the chitosan quaternary ammonium salt has a degree of substitution of 0.6-0.8 and a molecular weight of 50000Da-100000Da; the polyhexamethylene biguanide hydrochloride has a purity of ≥99%; the hydroxyl value of glycerol is 300mgKOH / g-500mgKOH / g; the viscosity of propylene glycol at 25℃ is 50mPa·s-80mPa·s; and the molecular weight of polypropylene glycol is 2000-4000.
5. A method for preparing an antibacterial long-acting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete, the method being applicable to the antibacterial long-acting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete as described in any one of claims 1-4, characterized in that, The specific steps of this preparation method are as follows: S1. Accurate weighing and compounding of raw materials: Weigh 3-8 parts of gel polysaccharide, 80-88 parts of polycarboxylate superplasticizer, 0.5-2 parts of antibacterial synergist, 1-3 parts of compatibility regulator, and 2-5 parts of dispersant according to the weight ratio. The selection and compounding ratio of each component are consistent with the component requirements of the superplasticizer. The components to be compounded should be mixed evenly separately for later use. S2, Preparation of mixed dispersion of gel polysaccharide and antibacterial synergist: Weigh the compounded gel polysaccharide and antibacterial synergist together and add them to deionized water. Stir continuously with a stirring device to prepare a mixed dispersion. S3, Adjusting pH and adding compatibility regulator in reaction system: Weigh the compounded polycarboxylate superplasticizer and add it to the reactor. Start the temperature control device to raise the temperature. Adjust the pH value of the system with acid and base reagents. After the temperature and pH value are stable, add the weighed compounded compatibility regulator and continue to stir and mix. S4, Mixed dispersion drop addition and composite reaction: The mixed dispersion prepared in step S2 is slowly injected into the reaction vessel treated in step S3 through a drop addition device, the stirring rate is increased, nitrogen gas is introduced into the reaction vessel, and the set temperature and pH value are maintained for heat preservation reaction; S5, Addition of dispersing agent, cooling and filtration: Add the weighed dispersing agent to the system after the compound reaction is completed, stir and mix evenly, cool the system, and filter it through a filter screen after cooling to the set temperature to obtain the water-reducing agent.
6. The preparation method of an antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete according to claim 5, characterized in that, In step S1, the antibacterial synergist needs to be pretreated by ultrasonic dispersion at a power of 300W for 10 minutes before compounding; the compounding of the gel polysaccharide and the polycarboxylic acid water-reducing agent is carried out by mechanical stirring at a speed of 500r / min-1500r / min for 5min-10min.
7. The preparation method of an antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete according to claim 5, characterized in that, In step S2, the conductivity of the deionized water is ≤10μS / cm, and the pH value is 6.5-7.5; the stirring is carried out in a container equipped with an anchor stirrer, the stirring rate is controlled at 200r / min-300r / min, the stirring time is 30min-60min, and the stirring ambient temperature is controlled at 25℃-30℃; the mass concentration of the prepared mixed dispersion is 3%-10%, and the particle size of the solid particles is ≤50μm.
8. The preparation method of an antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete according to claim 5, characterized in that, In step S3, after the polycarboxylate superplasticizer is added to the reaction vessel, the temperature is increased to 60℃-80℃ at a rate of 2℃ / min-5℃ / min and held at that temperature for 3min-5min. Then, the pH value of the system is adjusted to 6-8 using a 5%-10% citric acid or sodium hydroxide aqueous solution, and the fluctuation range is maintained at ≤±0.
2. The compatibility regulator is added after the pH value stabilizes, and stirring is continued for 10min-15min after addition.
9. The preparation method of an antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete according to claim 5, characterized in that, In step S4, the mixed dispersion is added dropwise through a constant pressure dropping funnel at a rate of 1 mL / min-3 mL / min; after the addition is complete, the stirring rate is increased to 300 r / min-500 r / min; the reaction is carried out under the protection of nitrogen gas with a purity ≥99.9%, maintaining the reaction temperature at 60℃-80℃, the pH value at 6-8, and the reaction time at 2h-4h; when the composite reaction is a grafting reaction, before adding the mixed dispersion, ammonium persulfate at 0.1%-0.3% of the mass of the polycarboxylate superplasticizer should be added to the reaction system as an initiator.
10. The preparation method of an antibacterial long-lasting gel polysaccharide-polycarboxylate superplasticizer suitable for concrete according to claim 5, characterized in that, In step S5, the dispersing agent is added dropwise through a constant pressure dropping funnel at a rate of 2 mL / min-3 mL / min. After the addition is complete, the mixture is stirred for 15 min-30 min at a stirring rate of 300 r / min-500 r / min. The reaction system is then cooled by circulating cold water at 5℃-10℃ through a jacket or by natural cooling at a rate of 5℃ / h-10℃ / h to 25℃±5℃. Finally, the mixture is filtered using a filter screen of 200 mesh or higher at a filtration pressure of 0.1 MPa-0.2 MPa to obtain the water-reducing agent product.