Preparation method of concrete anti-mud agent

Abstract

The invention relates to the technical field of concrete admixtures, and discloses a preparation method of a concrete anti-mud agent, the preparation takes a hyperbranched cationic polymer (component A) loaded with a repairing agent precursor as an inner core, takes a polycarboxylate superplasticizer (component B) as a shell, and forms a core-shell structure through composite assembly. The preparation method comprises the following steps: respectively preparing the component A and the component B, and then mixing and assembling the component A and the component B under specific process conditions. Through the core-shell structure, time sequence separation of functions is realized: in the plastic concrete, the positively charged core preferentially adsorbs clay minerals, so that the polycarboxylic acid water reducing agent of the shell is released in situ, the technical problem that the polycarboxylic acid water reducing agent loses efficacy due to clay adsorption is solved, and the working performance of the concrete is ensured; in hardened concrete, the repairing agent precursor fixedly sealed in the inner core can be passively released when microcracks are generated, the cracks are filled and healed, the concrete is endowed with a self-repairing function, the durability of the structure is remarkably improved, and the service life of the structure is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of concrete admixture technology, specifically to a method for preparing a concrete anti-mud agent. Background Technology

[0002] Concrete, as the most widely used material in infrastructure construction, directly affects the safety and durability of engineering structures. With the increasing demands for concrete performance in modern engineering, high-performance water-reducing agents, such as polycarboxylate superplasticizers, are widely used to achieve high fluidity and high strength in concrete with low water-cement ratios. However, in practical engineering, the widely used natural sand and gravel aggregates often inevitably contain a certain amount of clay minerals, especially montmorillonite. These clay minerals have a huge specific surface area and negative charge characteristics, which can strongly adsorb polycarboxylate superplasticizer molecules, leading to a significant loss of the effective components of the superplasticizer. This, in turn, causes a sharp deterioration in the workability of the concrete mixture, rapid loss of fluidity, seriously affecting construction quality and increasing material costs.

[0003] On the other hand, during long-term service, concrete inevitably develops microcracks due to factors such as drying shrinkage, temperature changes, and external loads. These microcracks provide channels for the intrusion of harmful media such as water and chloride ions, accelerating steel corrosion and the deterioration of the concrete matrix, thereby significantly reducing the overall durability and service life of the structure.

[0004] Currently, the two technical problems mentioned above are typically addressed using independent technical approaches. For example, a single function can be achieved by introducing specific cationic polymers as clay inhibitors or by incorporating microcapsules loaded with repair agents. However, incorporating multiple functional admixtures separately into the concrete system not only increases the complexity and cost of the formulation but may also lead to compatibility issues between the components. Therefore, developing a single, highly efficient composite admixture that can simultaneously solve the clay interference problem and impart self-healing capabilities to the material is a pressing technical challenge in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a concrete anti-mud agent. The anti-mud agent prepared by this method can effectively deal with the adverse effects of clay minerals in concrete and can endow hardened concrete with a certain damage repair ability.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for preparing a concrete anti-mud agent, the method comprising the following steps:

[0007] (a) Prepare a hyperbranched cationic polymer loaded with a repair agent precursor as component A;

[0008] (b) A polycarboxylate superplasticizer containing environmentally responsive dissociable functional groups in the polymer chain is prepared as component B;

[0009] (c) The components A and B are combined and assembled in an aqueous solution to form a core-shell composite with component A as the core and component B as the shell.

[0010] In one embodiment of the present invention, in step (c), the following components are assembled in parts by weight:

[0011] Component A is 1 part; component B is 8-25 parts.

[0012] In one embodiment of the present invention, the composite assembly in step (c) is completed by low-speed stirring for 1-2 hours within a temperature range of 20-40°C.

[0013] In one embodiment of the present invention, in step (a), component A is composed of a hyperbranched cationic polymer matrix and a repair agent precursor, wherein the weight ratio of the hyperbranched cationic polymer matrix to the repair agent precursor is (5-15):1.

[0014] In one embodiment of the present invention, the hyperbranched cationic polymer matrix is ​​prepared by reacting triethylenetetramine with epichlorohydrin, wherein the amount of epichlorohydrin used is 1.3-1.7 moles for every 1 mole of triethylenetetramine. The repair agent precursor is at least one of basic silicate, bisphenol A epoxy resin prepolymer, or polymeric MDI.

[0015] In one embodiment of the present invention, in step (b), component B is copolymerized from the following monomer raw materials: polyethylene glycol monoether (meth)acrylate monomers; unsaturated carboxylic acid monomers; and acrylate monomers containing ester bonds. The environmentally responsive dissociable functional group in component B is an ester bond that is sensitive to alkaline environments with a pH greater than 12 and undergoes hydrolysis.

[0016] In one embodiment of the present invention, in the copolymerization reaction of component B, the molar amounts of each monomer raw material are as follows: for every 1 mole of polyethylene glycol monoether (meth)acrylate monomer, the amount of unsaturated carboxylic acid monomer is 2.5-4.5 moles, and the amount of acrylate monomer with ester bond is 0.3-0.8 moles.

[0017] The working mechanism and beneficial effects of this invention are as follows:

[0018] This invention, through the above-described preparation method, yields a composite with a core-shell structure. This composite exhibits multi-stage functionality after the addition of admixtures to fresh concrete mixture.

[0019] In the first stage (fresh concrete stage), the composite releases component B (polycarboxylate superplasticizer) as the shell through two pathways.

[0020] Approach 1: When the composite encounters negatively charged clay mineral particles in the mixture, component A (hyperbranched cationic polymer), which acts as the core, will preferentially bind to the clay minerals due to its stronger binding ability. This process causes the physically adsorbed component B to detach from the surface of the composite and be released into the cement paste.

[0021] Approach Two: For composites not in direct contact with clay, as cement hydration progresses, the pH of the mixing water rises above 12. This highly alkaline environment triggers the hydrolytic breakage of ester bonds in the molecular chain of component B, thereby disrupting its molecular structure and promoting its release from the surface of component A. This dual release mechanism ensures that component B can be effectively released under different conditions, thus enabling it to disperse cement particles and reduce the adsorption and deactivation effect of the clay on the water-reducing agent.

[0022] In the second stage (hardened concrete stage), component A, which has completed its bonding with clay, is fixed as a stable composite within the matrix formed by hydration products. The internally loaded repair agent precursor is in an unreacted, stable state. When microcracks develop in the hardened concrete matrix due to external loads or its own shrinkage, and these cracks extend to the location of the composite, the stress field at the crack tip can disrupt the cage-like structure of component A or the coating layer of its loaded repair agent precursor. This causes the repair agent precursor to be released into the crack, where it chemically reacts with moisture that has seeped into the crack or substances such as calcium hydroxide in the cement paste matrix, generating an insoluble solid product. This product fills and seals the microcracks, thereby preventing further crack propagation and improving the durability of the hardened concrete.

[0023] In summary, the preparation method provided by this invention can produce an admixture with two functions. In the fresh concrete stage, this admixture effectively solves the problem of clay interference through its unique structure and release mechanism; in the long-term service stage of hardened concrete, its latent components can provide repair functions when micro-damage occurs in the structure.

[0024] This invention provides a method for preparing a concrete anti-mud agent. It has the following beneficial effects:

[0025] 1. The preparation method provided by this invention can obtain a concrete anti-mud agent with excellent resistance to clay mineral interference. This anti-mud agent utilizes its core-shell structure, so that the component A with a high positive charge acts as the core and preferentially combines with the negatively charged clay minerals in the concrete, thereby replacing and releasing the outer component B, i.e., the polycarboxylate superplasticizer. At the same time, the highly alkaline environment during the cement hydration process will also trigger the hydrolysis of the ester bonds on the molecular chain of component B, further promoting its release. This dual release mechanism can ensure that the superplasticizer components are fully released, avoiding performance loss caused by clay adsorption, thereby ensuring the workability in concrete with high clay content.

[0026] 2. The anti-mud agent prepared by this invention can endow hardened concrete with self-healing function, thereby improving its structural durability and service life. The repair agent precursor loaded inside component A is stably sealed in the cement stone matrix after the concrete hardens. When the expansion path of microcracks touches and destroys the structure of component A, the repair agent precursor inside it is released into the crack and reacts with the infiltrated water or substances in the cement matrix to generate insoluble products. These products can fill and heal the cracks, thereby effectively preventing further damage.

[0027] 3. Through precise molecular design and structural assembly, this invention achieves the temporal separation and synergistic effect of anti-clay function and self-healing function. The anti-clay function mainly acts in the plastic flow stage of concrete, while the self-healing function lies dormant in the long-term service stage after hardening and is only triggered when the structure is damaged. This technical solution that integrates immediate and long-term functions avoids potential interference between different functional components, enabling each component to play its role at a preset time point, and ultimately improving material utilization efficiency and final product performance. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to comparative examples and test cases. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0030] Triethylenetetramine, CAS No.: 112-24-3;

[0031] Epichlorohydrin, CAS No.: 106-89-8;

[0032] Bisphenol A epoxy resin prepolymer, CAS No.: 25722-66-1;

[0033] Polymerized MDI, CAS No.: 9016-87-9;

[0034] Polyethylene glycol monomethyl ether methacrylate, CAS No.: 32171-39-4;

[0035] Acrylic acid, CAS No.: 79-10-7;

[0036] 2-Hydroxyethyl acrylate, CAS No.: 818-61-1;

[0037] Ammonium persulfate, CAS No.: 7727-54-0;

[0038] Mercaptoacetic acid, CAS No.: 68-11-1;

[0039] Montmorillonite, CAS No.: 1318-93-0.

[0040] Examples 1-3:

[0041] Example 1:

[0042] Preparation of component A1:

[0043] (1) Preparation of hyperbranched cationic polymer precursor:

[0044] To a four-necked flask equipped with a stirrer, thermometer, and reflux condenser, add 146.23 g (1.0 mol) of triethylenetetramine and 300 g of deionized water, and stir until completely dissolved. Heat the mixture to 60 °C, and then begin dropwise addition of 120.28 g (1.3 mol) of epichlorohydrin. During the addition, control the temperature of the reaction system to not exceed 70 °C. After the addition is complete, continue the reaction at 70 °C for 4 hours. After the reaction is complete, cool the system to room temperature to obtain an aqueous solution of the hyperbranched cationic polymer precursor.

[0045] (2) Loaded repair agent precursor:

[0046] Based on the polymer matrix solution obtained in step (1) above, take 5 parts of polymer matrix by dry weight and add 1 part of basic silicate (industrial water glass, solid content 40%) as a repair agent precursor. Stir the mixture at low speed for 30 minutes at room temperature to ensure uniform loading of the repair agent precursor, and finally obtain component A1.

[0047] Preparation of component B1:

[0048] 1000 g of deionized water, 2000 g (1.0 mol) of polyethylene glycol monomethyl ether methacrylate (molecular weight 2000), 180.16 g (2.5 mol) of acrylic acid, and 34.84 g (0.3 mol) of 2-hydroxyethyl acrylate were added to a reaction vessel. Stirring was started, and after the monomers were completely dissolved, the system was heated to 70°C. An ammonium persulfate initiator solution (15 g of ammonium persulfate dissolved in 100 g of water) and a chain transfer agent solution (12 g of mercaptoacetic acid dissolved in 50 g of water) were added dropwise over 3 hours using a dropping funnel at a uniform rate. After the addition was complete, the reaction temperature was raised to 75°C and maintained for 1 hour. The mixture was then cooled to room temperature to obtain component B1.

[0049] Preparation of core-shell complexes:

[0050] Weigh out 1 part of component A1 by dry weight and place it in a container equipped with a mixer. Under constant temperature water bath conditions of 20°C, start low-speed mixing and slowly add 8 parts of component B1. Continue mixing for 1 hour to complete the composite assembly process, ultimately obtaining the target product: concrete anti-sludge agent.

[0051] Example 2:

[0052] Preparation of component A2:

[0053] (1) Preparation of hyperbranched cationic polymer precursor:

[0054] 146.23 g (1.0 mol) of triethylenetetramine and 320 g of deionized water were added to the reaction apparatus, and the temperature was raised to 60 °C. 138.78 g (1.5 mol) of epichlorohydrin was then added dropwise, with the reaction temperature controlled to not exceed 75 °C. After the addition was complete, the reaction was continued at 75 °C for 4 hours. After cooling, the hyperbranched cationic polymer precursor was obtained.

[0055] (2) Loaded repair agent precursor:

[0056] Based on dry matter weight, take 10 parts of the above polymer matrix and add 1 part of bisphenol A epoxy resin prepolymer (epoxy value 0.51) as a precursor for the repair agent. Stir at low speed at room temperature for 30 minutes to ensure uniform loading, thus obtaining component A2.

[0057] Preparation of component B2:

[0058] 1200 g of deionized water, 2000 g (1.0 mol) of polyethylene glycol monomethyl ether methacrylate (molecular weight 2000), 252.22 g (3.5 mol) of acrylic acid, and 58.06 g (0.5 mol) of 2-hydroxyethyl acrylate were added to a reactor. The temperature was raised to 70°C, and ammonium persulfate solution and mercaptoacetic acid solution were added dropwise simultaneously over 3 hours. After the addition was complete, the mixture was kept at 75°C for 1 hour, and after cooling, component B2 was obtained.

[0059] The core-shell composite was prepared by taking 1 part of component A2 by dry weight and slowly adding 16.5 parts of component B2 under constant temperature conditions of 30°C. Low-speed stirring was then started and continued for 1.5 hours to complete the composite assembly, resulting in the concrete anti-sludge agent of this embodiment.

[0060] Example 3:

[0061] Preparation of component A3:

[0062] (1) Preparation of hyperbranched cationic polymer precursor: 146.23 g (1.0 mol) of triethylenetetramine and 350 g of deionized water were added to the reaction apparatus, and the temperature was raised to 60 °C. 157.28 g (1.7 mol) of epichlorohydrin was added dropwise, and the reaction temperature was controlled not to exceed 80 °C. After the addition was complete, the reaction was continued at 80 °C for 4 hours. After cooling, the hyperbranched cationic polymer precursor was obtained.

[0063] (2) Loading the repair agent precursor: Take 15 parts of the above polymer matrix by dry matter weight and add 1 part of polymeric MDI as the repair agent precursor. Stir at low speed at room temperature for 30 minutes to make it uniformly loaded, and obtain component A3.

[0064] Preparation of component B3:

[0065] 1400 g of deionized water, 2000 g (1.0 mol) of polyethylene glycol monomethyl ether methacrylate (molecular weight 2000), 324.29 g (4.5 mol) of acrylic acid, and 92.9 g (0.8 mol) of 2-hydroxyethyl acrylate were added to a reactor. The temperature was raised to 70°C, and ammonium persulfate solution and mercaptoacetic acid solution were added dropwise simultaneously over 3 hours. After the addition was complete, the mixture was kept at 75°C for 1 hour, and after cooling, component B3 was obtained.

[0066] Preparation of core-shell complexes:

[0067] Based on dry matter weight, take 1 part of component A3 and slowly add 25 parts of component B3 under constant temperature conditions of 40°C. Start low-speed stirring and continue stirring for 2 hours to complete the composite assembly, thus obtaining the concrete anti-sludge agent of this embodiment.

[0068] Comparative Examples 1-3:

[0069] Comparative Example 1:

[0070] This comparative example prepared a sample containing only polycarboxylate superplasticizer. Its composition is exactly the same as component B2 prepared in Example 2. This comparative example does not contain any component A, nor does it involve any composite assembly steps.

[0071] Comparative Example 2:

[0072] Compared to Example 2, this comparative example differs in that bisphenol A epoxy resin prepolymer, which serves as a precursor for the repair agent, is not added during the preparation of component A. In other words, component A in this comparative example consists solely of a hyperbranched cationic polymer matrix. All other raw materials, proportions, and preparation steps are identical to those in Example 2.

[0073] Comparative Example 3:

[0074] Compared to Example 2, this comparative example differs in that the core-shell composite preparation steps are not performed. Instead, separately prepared components A2 and B2 are directly physically blended before use (e.g., before adding cement paste in subsequent performance tests). The preparation methods and raw material ratios of components A2 and B2 are exactly the same as in Example 2.

[0075] Test Example 1-2:

[0076] Test Example 1: Evaluation of Clay Resistance

[0077] This test case aims to evaluate the performance of the samples prepared by the above examples and comparative examples in a clay-containing cement paste system.

[0078] Raw materials and formula:

[0079] Cement: P·O42.5 ordinary Portland cement.

[0080] Clay: Industrial montmorillonite powder, with a specific surface area greater than 750 m² 2 / g.

[0081] Water: Deionized water.

[0082] The standard formula for cement paste is a water-cement ratio (W / C) of 0.29.

[0083] Clay content: The amount of montmorillonite powder is 5% of the weight of cement.

[0084] Admixture dosage: The dosage of the samples prepared in Examples 1-3 and Comparative Examples 1 and 3 was calculated based on dry matter (solid content) and was 1.0% of the total weight of cement and montmorillonite.

[0085] Experimental steps:

[0086] (1) Weigh out the cement and montmorillonite powder according to the formula, put them in a mixing pot, and dry mix at low speed for 60 seconds to make them evenly mixed.

[0087] (2) Weigh the required amount of the sample to be tested (from Examples 1-3 or Comparative Examples 1 and 3) according to the formula, mix it with the required amount of deionized water, stir evenly to form a mixing solution to be used.

[0088] (3) Start the mixer and pour all the mixing liquid into the mixing pot within 5 seconds. Then stir at low speed for 120 seconds and then stir at high speed for 120 seconds.

[0089] (4) After mixing, immediately pour the prepared cement paste into a clean, moist truncated cone mold (according to GB / T8077-2012 standard) and smooth the top surface.

[0090] (5) Lift the top cone mold vertically upwards. After the slurry stops flowing, use a steel ruler to measure the expansion diameter in two mutually perpendicular directions, take the average value, and record it as the initial flowability.

[0091] (6) Immediately seal the remaining paste with plastic wrap and let it stand in an environment of (20±2)℃ for 60 minutes.

[0092] (7) After the settling period, stir the paste at low speed for 30 seconds on a mixer, and then measure its fluidity again and record it as the 1-hour fluidity.

[0093] Experimental results:

[0094] Table 1. Results of Cement Paste Flowability Test

[0095]

[0096] Analysis of Test Example 1 Results:

[0097] Test data show that in a cement paste system containing 5% montmorillonite, the samples prepared using Examples 1, 2, and 3 exhibited significantly higher initial and 1-hour flowability than the samples prepared using Comparative Examples 1 and 3. This result indicates that the product obtained by the preparation method of the present invention can more effectively disperse cement particles in clay-containing systems and better maintain the fluidity of the paste.

[0098] The sample in Comparative Example 1, consisting solely of component B (polycarboxylate superplasticizer), exhibited extremely low fluidity in the clay-containing system. This was because the polycarboxylate superplasticizer molecules were heavily adsorbed by the layered structure of montmorillonite, preventing them from effectively adsorbing onto the surface of cement particles and exerting a dispersing effect. The sample in Comparative Example 3, a simple physical mixture of components A and B, performed better than Comparative Example 1, but still far inferior to the sample in the examples. This indicates that without the prior formation of a stable core-shell structure, component A's protective effect on component B is limited; some component B is adsorbed and rendered ineffective by the clay before component A interacts with it.

[0099] The product prepared in this embodiment of the invention has a predetermined core-shell structure. When added to cement paste, component A (hyperbranched cationic polymer), acting as the core, preferentially and firmly binds to the negatively charged montmorillonite particles due to the high positive charge inherent in its structure. This binding process disrupts the interfacial stability of the composite, thereby releasing component B (polycarboxylate superplasticizer), which is physically coated on the outer layer, into the paste environment. Since component A acts as a clay trap, the released component B is prevented from being adsorbed by the clay, thus fully exerting its function of dispersing cement particles, ultimately resulting in a significant improvement and maintenance of the paste's fluidity on a macroscopic scale.

[0100] Test Example 2: Self-Healing Performance Evaluation

[0101] This test case aims to evaluate the effect of applying the products of the examples and comparative examples on the recovery of the mechanical properties of hardened mortar after pre-damage when applied to mortar specimens.

[0102] Raw materials and formula:

[0103] Cement: P·O42.5 ordinary Portland cement.

[0104] Sand: Standard sand (ISO 679).

[0105] Water: Deionized water.

[0106] The standard formula for cement mortar is: water-cement ratio of 0.5 and cement-sand ratio of 1:3.

[0107] Admixture dosage: The dosage of the samples prepared in Examples 1-3 and Comparative Example 2 was calculated based on dry matter (solid content) and was 1.0% of the cement weight.

[0108] Experimental steps:

[0109] (1) According to the cement mortar reference formula, weigh out cement, standard sand, water and test samples from Examples 1-3 or Comparative Example 2 respectively.

[0110] (2) Dry mix cement and sand evenly, then add an aqueous solution containing the sample to be tested, and stir according to the method of GB / T17671-1999 to prepare shaped mortar.

[0111] (3) Pour the mortar into a prism mold of 40mm×40mm×160mm and compact it.

[0112] (4) After the molded specimen is cured in an environment of (20±1)℃ and relative humidity of not less than 95% for 24 hours, it is demolded and then transferred to clean water at (20±2)℃ to continue curing for 28 days.

[0113] (5) Take half of the specimens from each sample group and test their initial flexural strength (f0) using a universal testing machine.

[0114] (6) The other half of the specimens in each sample group were preloaded. A bending load was applied to them at a loading rate of 0.5 MPa / s, and the load was immediately unloaded after reaching 70% of the average initial flexural strength of the corresponding group. This step was intended to generate microcracks inside the specimens.

[0115] (7) The damaged specimen that has undergone pre-loading treatment is placed in clean water at (20±2)℃ for another 28 days to allow it to be repaired.

[0116] (8) After curing, the repaired specimen was taken out and its flexural strength (f1) was tested.

[0117] (9) Calculate the strength recovery rate (η) of each group of specimens according to the formula: η(%)=(f1 / f0)×100%.

[0118] Experimental results:

[0119] Table 2. Test results of flexural strength and strength recovery rate of mortar

[0120] sample Initial flexural strength (MPa) Flexural strength after repair (MPa) Strength recovery rate (%) Example 1 8.21 7.15 87.1 Example 2 8.35 7.64 91.5 Example 3 8.28 7.42 89.6 Comparative Example 2 8.19 5.49 67.0

[0121] Analysis of Test Example 2 Results:

[0122] Experimental results show that the mortar specimens incorporating the products of Examples 1, 2, and 3 exhibit significantly higher flexural strength recovery rates after undergoing pre-load damage and a curing period compared to the specimens incorporating the product of Comparative Example 2. This data demonstrates that the products prepared in this invention can impart damage repair capabilities to cement-based materials.

[0123] This functionality stems from the pre-designed internal structure of the product. Within a hardened cementitious matrix, the product of this invention is dispersed as composite microparticles. When a mortar specimen develops microcracks due to external loads, the crack propagation path passes through these composite microparticles. The stress field at the crack tip is sufficient to disrupt the microparticle structure, causing the internally loaded repair agent precursor to be released and enter the newly formed crack space. Upon contact with capillary water present in the crack or alkaline substances in the cement matrix, a chemical reaction occurs, generating an insoluble solid product.

[0124] These newly generated solid products can fill and cement the walls of cracks, thereby structurally repairing the discontinuities caused by damage and restoring the mechanical properties of the specimens. In contrast, although the product of Comparative Example 2 also contains hyperbranched cationic polymers, it does not contain a repair agent precursor. Therefore, when cracks pass through these repair agent-free particles, there is no repair material available for release, and the cracks cannot be effectively chemically filled and healed. Its limited strength recovery is mainly attributed to the self-healing effect of cement, i.e., the continuous hydration of a small number of unhydrated cement particles on the crack surface. This effect contributes far less than the target chemical repair mechanism, resulting in a final strength recovery rate much lower than that of the example samples.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a concrete anti-mud agent, characterized in that, Includes the following steps: (a) Prepare a hyperbranched cationic polymer loaded with a repair agent precursor as component A; (b) A polycarboxylate superplasticizer containing environmentally responsive dissociable functional groups in the polymer chain is prepared as component B; (c) The components A and B are combined and assembled in an aqueous solution to form a core-shell composite with component A as the core and component B as the shell.

2. The method for preparing a concrete anti-mud agent according to claim 1, characterized in that, In step c, the following components are assembled in parts by weight: Component A: 1 part; Component B: 8-25 parts.

3. The method for preparing a concrete anti-mud agent according to claim 1, characterized in that, The composite assembly in step c is completed at a temperature range of 20-40℃ by low-speed stirring for 1-2 hours.

4. The method for preparing a concrete anti-mud agent according to claim 3, characterized in that, In step a, component A is prepared from the following parts by weight of raw materials: Hyperbranched cationic polymer matrix: 5-15 parts; Repair agent precursor: 1 part.

5. The method for preparing a concrete anti-mud agent according to claim 4, characterized in that, The hyperbranched cationic polymer matrix is ​​prepared by reacting triethylenetetramine with epichlorohydrin, wherein the amount of epichlorohydrin used is 1.3-1.7 moles for every 1 mole of triethylenetetramine.

6. The method for preparing a concrete anti-mud agent according to claim 4, characterized in that, The repair agent precursor is at least one of basic silicate, bisphenol A epoxy resin prepolymer, or polymeric MDI.

7. The method for preparing a concrete anti-mud agent according to claim 1, characterized in that, The environmentally responsive dissociable functional group in component B is an ester bond that is sensitive to alkaline environments with a pH value greater than 12 and undergoes hydrolysis.

8. The method for preparing a concrete anti-mud agent according to claim 1, characterized in that, In step b, component B is copolymerized from the following monomer raw materials: Polyethylene glycol monoether (meth)acrylate monomers; Unsaturated carboxylic acid monomers; Acrylate monomers containing ester bonds.

9. A method for preparing a concrete anti-mud agent according to claim 8, characterized in that, The molar ratios of the various monomer raw materials are as follows: For every 1 mole of polyethylene glycol monoether (meth)acrylate monomer, the amount of unsaturated carboxylic acid monomer is 2.5-4.5 moles, and the amount of acrylate monomer with ester bond is 0.3-0.8 moles.

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