Intelligent self-sensing and self-repairing sleeve grouting material as well as preparation method and application method thereof

Abstract

The invention belongs to the technical field of grouting materials, and particularly relates to an intelligent self-sensing and self-repairing sleeve grouting material as well as a preparation method and an application method thereof. The grouting material comprises the following components in parts by weight: a basic cementing material system: 100 parts of P.O52.5 Portland cement, 8-12 parts of sulphoaluminate cement, 15-25 parts of superfine slag powder and 8-12 parts of nano silica fume; the intelligent sensing component system is prepared from 0.8 to 1.5 parts of carboxyl functionalized multi-walled carbon nanotubes, 0.3 to 0.6 part of graphene oxide hydrosol and 0.05 to 0.1 part of a polyacrylamide dispersing agent; the self-repairing component system comprises the following components in parts by weight: 8-12 parts of epoxy resin microcapsules, 3-5 parts of cyanoacrylate microcapsules, 0.01-0.05 part of microbial spores and 0.5-1.0 part of a microbial nutrient solution; the aggregate system comprises the following components in parts by weight: 150-180 parts of quartz sand of 20-40 meshes, 120-150 parts of quartz sand of 40-80 meshes and 50-80 parts of quartz sand of 80-120 meshes; the additive system comprises 3.5 to 4.5 parts of polycarboxylic acid water reducing agent, 10 to 15 parts of UEA expanding agent, 1.2 to 2.0 parts of lithium carbonate early strength agent, 0.5 to 1.2 parts of sodium gluconate retarder, 0.3 to 0.6 part of nano TiO2 photocatalyst and 0.2 to 0.4 part of organic silicon defoaming agent. The invention provides an intelligent self-sensing and self-repairing sleeve grouting material as well as a preparation method and an application method thereof.

Description

Technical Field

[0001] This invention belongs to the field of grouting material technology, and specifically relates to an intelligent self-sensing and self-repairing sleeve grouting material and its preparation and application methods. Background Technology

[0002] Prefabricated construction, as an important development direction of building industrialization, has been vigorously promoted. Rebar sleeve grouting connection technology is one of the most critical connection methods in prefabricated concrete structures, and its connection quality directly affects structural safety. The sleeve grouting material needs to possess properties such as high fluidity, early strength, micro-expansion, and high strength to ensure a reliable connection between the rebar and the sleeve.

[0003] In recent years, with the expansion of prefabricated building construction, the performance requirements for sleeve grouting materials have been continuously increasing, especially in terms of quality monitoring, durability assurance, and intelligent construction. However, traditional grouting materials mainly focus on mechanical and construction performance, and have significant shortcomings in intelligent sensing, self-healing, and digital management.

[0004] 1. The problem of not being able to monitor grouting quality in real time: Traditional grouting materials cannot provide real-time information on the grout fullness, density, and presence of voids or defects inside the sleeve during the grouting process and after solidification, making it difficult to detect potential quality issues in a timely manner. Construction acceptance relies mainly on experience-based judgment and random sampling, which cannot achieve full inspection and creates blind spots in quality control.

[0005] 2. The problem of inability to continuously monitor service status: Grouting materials bear various loads throughout the entire life cycle of a building, but there is a lack of effective means to monitor their internal stress and strain state, making it impossible to predict potential structural safety risks. Especially under extreme conditions such as earthquakes and wind loads, the stress state of connection nodes cannot be monitored in real time.

[0006] 3. The problem of insufficient self-healing ability of microcracks: Grouting materials are prone to developing microcracks under shrinkage, temperature stress, and load conditions. These cracks can lead to reduced durability, steel corrosion, and strength loss. Traditional materials can only be passively repaired or replaced once they crack, lacking active self-healing capabilities, resulting in high maintenance costs and reduced service life.

[0007] 4. The problem of the lack of a quality traceability system: The entire process, from material production, transportation, and storage to on-site construction and maintenance, lacks a complete data recording and traceability mechanism. Once a quality problem occurs, it is difficult to quickly locate the problematic link, the division of responsibility is unclear, and the efficiency of problem-solving is affected.

[0008] 5. The problem of low visibility in construction: Grouting is a concealed project, and construction workers cannot visually judge the flow state and filling status of the grouting material. Relying on experience can easily lead to defects such as incomplete grouting and the presence of air bubbles. Summary of the Invention

[0009] In order to solve the above-mentioned problems in the existing technology, the purpose of this invention is to provide an intelligent self-sensing and self-repairing sleeve grouting material and its preparation and application methods.

[0010] The technical solution adopted in this invention is as follows: A smart self-sensing and self-healing sleeve grouting material, comprising the following components by weight: Basic cementitious material system: 100 parts P.O52.5 silicate cement, 8-12 parts sulfoaluminate cement, 15-25 parts ultrafine slag powder, and 8-12 parts nano silica fume; Intelligent sensing component system: 0.8-1.5 parts of carboxyl-functionalized multi-walled carbon nanotubes, 0.3-0.6 parts of graphene oxide hydrosol, and 0.05-0.1 parts of polyacrylamide dispersant; Self-healing component system: 8-12 epoxy resin microcapsules, 3-5 cyanoacrylate microcapsules, 0.01-0.05 microbial spores, and 0.5-1.0 microbial nutrient solution; Aggregate system: 20-40 mesh quartz sand 150-180, 40-80 mesh quartz sand 120-150, 80-120 mesh quartz sand 50-80; Additive system: polycarboxylate superplasticizer 3.5-4.5, UEA expansion agent 10-15, lithium carbonate early strength agent 1.2-2.0, sodium gluconate retarder 0.5-1.2, nano TiO2 photocatalyst 0.3-0.6, organosilicon defoamer 0.2-0.4.

[0011] As a preferred embodiment of the present invention, the P.O52.5 silicate cement has a strength grade of 52.5 and a specific surface area of ​​350-380 m². 2 / kg; sulfoaluminate cement strength grade 42.5, C3A content ≥40%; ultrafine slag powder specific surface area ≥500m² 2 / kg, activity index ≥95%; SiO2 content in nano silica fume ≥96%, specific surface area ≥20000m² 2 / kg.

[0012] As a preferred embodiment of the present invention, the carboxyl-functionalized multi-walled carbon nanotubes have an outer diameter of 8-15 nm, a length of 5-20 μm, and a carboxyl content of 2-5%; the graphene oxide hydrosol has a sheet thickness of 0.8-1.2 nm and a concentration of 5 mg / mL; and the polyacrylamide dispersant has a molecular weight of 3-5 million and a degree of hydrolysis of 25-30%.

[0013] As a preferred embodiment of the present invention, the epoxy resin microcapsules have a particle size of 80-150 μm, the shell material is polyurea with a wall thickness of 2-5 μm, and the core material is epoxy resin E-51; the cyanoacrylate microcapsules have a particle size of 50-100 μm, the shell material is gelatin-gum arabic, and the core material is ethyl α-cyanoacrylate; the microbial spores are Bacillus spp. with a survival rate of ≥85% and a size of 1-2 μm; the microbial nutrient solution is calcium lactate and yeast extract in dry powder form.

[0014] As a preferred embodiment of the present invention, the polycarboxylate superplasticizer has a solid content of 40%, a water reduction rate of ≥35%, and an air content of <3%; the UEA expanding agent has a 7-day restricted expansion rate of ≥0.025%, and its main component is calcium sulfoaluminate; the lithium carbonate early strength agent has a Li2CO3 purity of ≥99% and a particle size of <10μm; the sodium gluconate retarder has a purity of ≥98% and extends the retarding time by 2-3 hours; the nano-TiO2 photocatalyst is anatase type, with a particle size of 20-30nm and a specific surface area of ​​≥150m². 2 / kg; the silicone defoamer is a polyether-modified silicone with a defoaming speed of <10s.

[0015] As a preferred embodiment of the present invention, the grouting material of the present invention further includes an intelligent sensing system component; the intelligent sensing system component includes a flexible electrode sheet, an NFC passive chip and a strain-sensitive RFID tag, the flexible electrode sheet is embedded in the inner wall of the sleeve and in close contact with the grouting material, the NFC chip obtains energy from the electromagnetic field emitted by the reader, and the RFID tag stores information including material batch, production date and formula number and can sense strain changes.

[0016] A method for preparing an intelligent self-sensing and self-healing sleeve grouting material includes the following steps: S1: Nanomaterial dispersion: Pre-dispersion: Weigh 0.8-1.5 parts of carboxyl-functionalized multi-walled carbon nanotubes and 0.3-0.6 parts of graphene oxide hydrosol with a concentration of 5 mg / mL; add the carbon nanotubes to the graphene oxide solution and stir mechanically for 10 minutes; add 0.05-0.1 parts of polyacrylamide dispersant and continue stirring for 5 minutes. Ultrasonic dispersion: Transfer the above mixture to an ultrasonic dispersion device; ultrasonic power: 500-800W, frequency: 20-25kHz; dispersion time: 30 minutes; temperature controlled at 25-35°C during ultrasonication; High-shear stirring: After ultrasonication, the mixture is transferred to a high-shear mixer; shear rate: 3000-5000 rpm; stirring time: 2 hours; a uniform and stable dispersion of nanomaterials is obtained. Quality inspection: Take a small amount of the dispersion and drop it onto filter paper to observe whether there are agglomerates; measure the zeta potential; observe the uniformity of dispersion under a microscope; S2: Microcapsule preparation: Preparation of epoxy resin microcapsules; preparation of cyanoacrylate microcapsules; preparation of microbial spores; S3: Dry Mixture Preparation: Premixing of cementitious materials: Weigh out the following according to the proportions: 100 parts of P.O52.5 cement, 8-12 parts of sulfoaluminate cement, 15-25 parts of ultrafine slag powder, and 8-12 parts of nano silica fume; put them into a planetary mixer and dry mix at low speed for 10 minutes; ensure uniform color. Aggregate addition: Weigh out three sizes of quartz sand according to the proportion; add them to the mixer in batches: first coarse sand, then medium sand, and finally fine sand; mix for 3 minutes after each batch is added, for a total mixing time of 15 minutes; Microcapsule addition: 8-12 parts epoxy resin microcapsules + 3-5 parts cyanoacrylate microcapsules; premix with a small amount of fine sand; add to the main mixer and mix at low speed for 5 minutes; Microbial spore addition: 0.01-0.05 parts spore powder, 0.5-1.0 parts nutrient solution; add simultaneously with the microcapsules and mix thoroughly; Additives: Weigh the following according to the formula: polycarboxylate superplasticizer, UEA expanding agent, lithium carbonate, sodium gluconate, nano TiO2, and defoamer; mix the liquid additives with the nanomaterial dispersion; mix the powdered additives with the main material; continue stirring for 10 minutes to ensure uniformity; Quality inspection and packaging: Sampling and testing of flowability, gas content, and condensation time; packaging after passing the test; affixing RFID tags and recording production information.

[0017] As a preferred embodiment of the present invention, step S2 specifically includes: S21: Preparation of epoxy resin microcapsules: Emulsion preparation: Oil phase: 40g epoxy resin E-51, 0.5g isocyanate curing agent; Aqueous phase: 100mL distilled water, 5g polyvinyl alcohol, 0.5g sodium dodecyl sulfate; The oil phase is added dropwise to the aqueous phase and stirred at high speed to form an O / W emulsion; The oil droplet size is controlled at 80-150μm; Wall material formation: Slowly add 8g of diethylenetriamine to the emulsion; reaction temperature: 50-60°C, time: 2-3 hours; reduce stirring speed to 500-800 rpm to maintain emulsion stability; Post-processing: Cool to room temperature; filter and collect microcapsules; wash repeatedly with deionized water and ethanol to remove surface residues; vacuum dry at 40-50°C for 12 hours; microscopic examination: particle size 80-150μm, wall thickness 2-5μm, good sphericity; S22: Preparation of cyanoacrylate microcapsules: Coagulation: Dissolve 10g of gelatin in 150mL of water and stir at 50°C to dissolve; add 10g of gum arabic and adjust the pH to 4.0-4.5; add 30g of ethyl α-cyanoacrylate dropwise and stir at high speed to form an emulsion; Wall material curing: Add 3g of glutaraldehyde dropwise to cure the gelatin-gum arabic coagulation layer; reaction temperature: 40-45°C, time: 3-4 hours; adjust pH to 7.0-8.0 and terminate the reaction; Post-treatment: Same washing and drying procedures as epoxy resin microcapsules; Microscopic inspection: Particle size 50-100μm; S23: Microbial spore preparation: Bacterial culture: Bacillus was inoculated onto nutrient agar medium; culture conditions: 30°C, 72 hours, to promote spore formation; Spore collection: Rinse the surface of the culture medium with sterile water and collect the spore suspension; centrifuge at 5000 rpm for 10 minutes to remove vegetative cells and impurities; wash repeatedly 2-3 times. Spray drying: Mix the spore suspension with the nutrient solution; Spray drying conditions: inlet air temperature 150-180°C, outlet air temperature 80-90°C; Obtain dry powder containing spores, with a spore survival rate ≥85%.

[0018] As a preferred embodiment of the present invention, the preparation method of the present invention further includes the following steps: S4: Intelligent Sensing System Integration S41: Flexible electrode sheet pre-embedding: Electrode grooves are reserved at symmetrical positions on the inner wall of the sleeve; the flexible electrode sheet is cut to a suitable size; it is fixed in the electrode groove with conductive adhesive; the lead wire is led out through the reserved hole in the sleeve wall and connected to the external measurement circuit; the electrode surface is coated with a thin layer of epoxy resin for protection to avoid damage during grouting; S42: NFC chip installation: The NFC chip is fixed to the outer wall of the sleeve; the position is chosen to be easily readable; it is fixed with waterproof sealant to ensure long-term reliable operation; S43: RFID Tag Binding: Strain-sensitive RFID tags are affixed to the sleeve surface or concrete component; the following information is written to the tag using an RFID writer: material batch number, production date and expiration date, formula number, quality inspection data, and manufacturer information; corresponding records are established in the cloud platform database. S44: System Testing: Test the electrode resistance before grouting; test the chip function using an NFC reader; read the tag information using an RFID reader to confirm data accuracy.

[0019] A method for applying an intelligent self-sensing and self-healing sleeve grouting material includes the following steps: Y1: Construction preparation: Check that the sleeve is clean and free of debris; clean the ends of the reinforcing bars, removing oil and rust; prepare grouting equipment: mixer, grouting pump or grouting funnel; prepare monitoring equipment: resistance meter, NFC reader, mobile terminal; Y2: Material mixing: Measure by weight, dry mix: water = 1:0.11-0.13; first pour water into the mixing bucket, then add the dry mix; mix at low speed for 1 minute, then at high speed for 5-8 minutes; observe the fluidity during mixing, and adjust the water amount slightly if necessary; after mixing, let stand for 1-2 minutes to defoam. Y3: Initial resistance measurement: Connect the resistance meter to the electrode leads; measure and record the initial resistance R0; upload the data to the cloud platform and bind it to the sleeve; Y4: Grouting operation: Bottom injection method is adopted; Pump grouting: Pressure is controlled at 0.2-0.4MPa, flow rate is 50-100mL / s; Gravity grouting: The height of the grouting funnel is 1.5-2.0m from the grouting port, and it flows naturally; During grouting: monitor resistance changes in real time; observe whether grout overflows from the vent holes; display grouting progress on the mobile terminal; Y5: Grouting process monitoring principle: Before grouting: There is almost no conductive path between the electrodes, and the resistance is extremely high; Grouting begins: The grout contacts the lower electrode, and the resistance begins to decrease; Grouting proceeds: The grout gradually fills the sleeve, the conductive path increases, and the resistance continues to decrease; Grouting is completed: The grout reaches the upper electrode, and the resistance drops to a stable minimum value; Criterion: When R drops to 0.1R0 or reaches the preset threshold and remains stable for more than 30 seconds, the grouting is considered complete; Y6: Grouting completion confirmation: Grout overflows from the vent hole; resistance reaches a stable minimum value; system prompts grouting completion; grouting port and vent hole are sealed; Y7: Maintenance and Monitoring Standard maintenance conditions: temperature 20±2°C, relative humidity ≥95%; Continuous monitoring: Resistance changes with hydration reaction; NFC chip records temperature and humidity curves; RFID tag senses for abnormal strain; Data is automatically uploaded to the cloud platform, forming a complete maintenance record; Y8: Service life monitoring: After the structure is put into use, monitor the following regularly or in real time: resistance changes; temperature changes; strain accumulation; The system will automatically issue a warning when the following anomalies are detected: sudden change in resistance; strain exceeding the design value; abnormal temperature. Maintenance personnel conduct inspections and take appropriate actions based on the early warning information.

[0020] The beneficial effects of this invention are as follows: 1. This invention enables real-time monitoring of grouting quality, improving detection efficiency and reducing detection costs. By incorporating conductive nanomaterials (carbon nanotubes, graphene) into the grouting material to construct a conductive network, this invention utilizes the piezoresistive effect to achieve strain self-sensing. During the grouting process and service life, the grout density and internal stress-strain state can be monitored in real time by measuring resistance changes, achieving a detection accuracy of ±5με and an error of <3%. Compared to traditional ultrasonic testing, efficiency is improved by more than 80%, and the cost of detecting a single node is reduced to less than 50 yuan, enabling rapid detection of all nodes.

[0021] 2. This invention enables in-service health monitoring and provides early warnings for structural safety. Through an embedded sensing system (flexible electrodes, NFC chip, RFID tag), this invention achieves long-term health monitoring of sleeve connection nodes. It can collect data such as strain, temperature, and humidity in real time, with a strain monitoring range of ±2000με, and transmit the data wirelessly to a cloud platform. When abnormal strain is detected (such as instantaneous large strain caused by an earthquake or cumulative damage caused by fatigue load), the system automatically issues an early warning, providing a basis for maintenance decisions and ensuring structural safety.

[0022] 3. This invention endows materials with self-healing capabilities, extending their service life and reducing maintenance costs. This invention achieves active repair of microcracks by introducing self-healing components (microencapsulated repair agent + microbial mineralization) into the grouting material. When cracks with a width of 0.05-0.8 mm occur, the microcapsules rupture, releasing the repair agent (epoxy resin, cyanoacrylate), which fills and seals the crack; simultaneously, microorganisms metabolize at the crack, producing calcium carbonate deposition, forming a dual repair mechanism. For cracks <0.3 mm wide, the self-healing rate is ≥80% after 7 days; for cracks 0.3-0.8 mm wide, the repair rate is ≥60% after 28 days; and the strength recovery rate after self-healing is ≥85%. Compared to traditional repair methods, this saves over 90% of maintenance costs.

[0023] 4. This invention establishes a full lifecycle quality traceability system for rapid problem identification. By binding RFID tags to each batch of materials, this invention records information throughout the entire process from production to construction (raw material batch, production time, transportation route, storage environment, construction personnel, construction time, environmental parameters, etc.), and utilizes blockchain technology to ensure data immutability. When a problem occurs, scanning the RFID tag allows for complete historical tracing within 2 minutes, quickly pinpointing the problematic stage and clarifying responsibility. Compared to traditional investigation methods, problem identification time is reduced from weeks to minutes, improving efficiency by over 99%.

[0024] 5. This invention enhances construction visibility and reduces operational error rates. Through real-time resistance monitoring and an IoT sensing system, construction personnel can view grouting progress, fullness, and resistance change curves in real time on mobile terminals (phones, tablets). The system automatically determines whether grouting is complete and whether defects exist, providing operational guidance (such as "flow rate too fast, please reduce pressure," "air bubbles detected, need to be replenished," etc.), transforming hidden works into "transparent" works. Compared to traditional experience-based operations, the error rate is reduced by more than 70%, and the grouting quality pass rate increases from 92% to over 99%.

[0025] 6. This invention can achieve the following comprehensive benefits: quality inspection efficiency is increased by 80%, and inspection costs are reduced by 75%; service life safety early warning capabilities are improved, avoiding major structural failure accidents; material service life is extended by 30-50%, and maintenance costs are reduced by 90%; the time for tracing quality problems is shortened from several weeks to several minutes, and efficiency is increased by 99%; the construction error rate is reduced by 70%, and the first-pass rate is increased from 92% to 99%; the overall project quality is improved, and the social benefits are significant. Attached Figure Description

[0026] Figure 1 This is a flow chart of the nanomaterial dispersion process; Figure 2 This is a schematic diagram of the epoxy resin microcapsule structure; Figure 3 This is a schematic diagram of the intelligent sleeve structure; Figure 4 This is the circuit schematic of the sensing system; Figure 5 Here are SEM images and schematic diagrams of carbon nanotube conductive networks; Figure 6 This is a schematic diagram of the piezoresistive effect principle; Figure 7 It is a resistance-time curve of the grouting process; Figure 8 This is a diagram illustrating the self-healing process. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0029] I. Overall Concept of Technical Solution This invention proposes a multifunctional grouting material technology solution integrating "intelligent sensing + autonomous repair + IoT monitoring". The core innovation lies in: 1. Materials level: By introducing functionalized nanomaterials and self-healing components into traditional grouting materials, the materials are endowed with intrinsic sensing and self-healing capabilities.

[0030] 2. Sensing level: Integrates flexible electrodes and wireless sensor chips to achieve signal acquisition and wireless transmission.

[0031] 3. System level: Build an IoT monitoring platform to achieve intelligent management such as data analysis, early warning, and traceability.

[0032] The three levels work together to form a complete intelligent grouting material system.

[0033] II. Material Composition and Proportioning The intelligent self-sensing and self-repairing sleeve grouting material of the present invention is composed of the following components in parts by weight: 2.1 Basic Cementitious Material System Table 1 is a table of basic cementitious material systems.

[0034]

[0035] Design Principles: Ordinary Portland cement serves as the primary cementitious material, providing stable strength development and long-term durability. Sulfoaluminate cement hydrates rapidly, and when blended with ordinary cement, it achieves early strength without sacrificing later-stage strength. Ultrafine slag powder and nano-silica fume possess high pozzolanic activity, reacting with the hydration product Ca(OH)₂ to form CSH gel, refining the pore structure. The extremely small particle size of nano-silica fume (0.1-0.2 μm) allows it to fill the spaces between cement particles, significantly improving density.

[0036] 2.2 Intelligent Sensing Component System Table 2 is a table of intelligent sensing component systems.

[0037]

[0038] Design principle: Carbon nanotubes have excellent electrical conductivity (conductivity > 10). 4In addition to improving the S / m (strength and mechanical properties), carbon nanotubes can form a three-dimensional conductive network when incorporated into cement-based materials. When the material is subjected to strain, the contact distance and number of contact points between carbon nanotubes change, leading to a change in overall resistance, i.e., the piezoresistive effect. Carboxyl functionalization can introduce hydrophilic groups onto the surface of carbon nanotubes, improving their dispersibility in aqueous phases and preventing aggregation. Graphene oxide has a large number of oxygen-containing functional groups, which can further stabilize the carbon nanotube dispersion system through electrostatic adsorption. Polyacrylamide is a polymeric dispersant; its long chains form an adsorption layer on the surface of nanomaterials, providing a steric hindrance effect.

[0039] Piezoresistive effect principle: The relationship between the material resistance R and the strain ε can be expressed as: ΔR / R0=K·ε.

[0040] Where: ΔR = R - R0 (resistance change); R0 (initial resistance); K (piezoresistive sensitivity coefficient, K≈100-150 in this invention); ε (strain).

[0041] By measuring the change in resistance, the strain state of the material can be deduced.

[0042] 2.3 Self-healing component system Table 3 shows the self-healing component system.

[0043]

[0044] Design principles: Chemical Repair Mechanism (Microcapsules): Epoxy resin microcapsules are prepared using in-situ polymerization. The polyurea shell material possesses good mechanical strength and chemical stability. When cracks occur, stress concentration at the crack tip leads to microcapsule rupture, releasing the epoxy resin core material. Epoxy resin has low viscosity (0.1-0.5 Pa·s) and good flowability, allowing it to penetrate cracks through capillary action. Epoxy resin reacts with Ca(OH)₂ in the matrix or cross-links and cures with a curing agent (premixed in adjacent microcapsules). Cyanoacrylate undergoes anionic polymerization immediately upon contact with moisture and alkaline environments (pH>12), forming a high-strength polymer within 1-2 hours. The dual microcapsule system is complementary: epoxy resin has high strength after curing but a long curing time (24h), while cyanoacrylate cures quickly but has slightly lower long-term strength.

[0045] Bioremediation mechanism (microbial mineralization): Bacillus spores can be preserved for a long time in a dry state and germinate upon contact with water and nutrients. In the moist microenvironment formed in the cracks, the spores germinate into vegetative cells. During cell metabolism, nutrients such as calcium lactate are consumed, producing CO2 and NH3. Metabolic products increase the local pH and carbonate concentration, reacting with calcium in the environment. 2+The minerals combine to form CaCO3 precipitate. CaCO3 crystals precipitate on the crack walls and inside the cracks, gradually filling them. Biomineralization is an ongoing process that repairs continuously forming microcracks.

[0046] Synergistic effect of chemical and biological remediation: Chemical remediation rapidly seals cracks and prevents the intrusion of harmful substances (1-3 days). Biological remediation continuously strengthens and improves the strength and density of the remediated area (7-28 days). The dual remediation approach enhances reliability, effectively repairing cracks of varying widths.

[0047] 2.4 Aggregate System Table 4 shows the aggregate system.

[0048]

[0049] Design Principles: Three-graded silica sand is used, designed according to Fuller's continuous gradation curve to achieve optimal dense packing. The volume ratio of coarse, medium, and fine sand is approximately 5:4:2, ensuring sufficient coarse aggregate to support the framework and adequate fine aggregate to fill the pores. The silica sand has high hardness and good chemical stability, and will not react harmfully with cement. Strict particle size control is maintained to avoid excessively coarse (affecting flowability) or excessively fine (increasing water consumption).

[0050] 2.5 Admixture System Table 5 shows the admixture system.

[0051]

[0052] Design Principle: Polycarboxylate superplasticizers adsorb onto the surface of cement particles through the carboxyl groups on their molecular chains, providing electrostatic repulsion and steric hindrance, thus dispersing the particles and releasing the trapped moisture, achieving high fluidity at low water-cement ratios. The main component of UEA expansive agent, calcium sulfoaluminate, reacts with water to form ettringite (3CaO·Al₂O₃·3CaSO₄·32H₂O), expanding in volume by approximately 2.5 times, compensating for material shrinkage and autogenous shrinkage. Lithium carbonate contains Li... + It can promote the rapid hydration of C3S (tricalcium silicate) and refine Ca(OH)2 crystals, thereby improving early strength. Sodium gluconate forms a complex film on the surface of cement particles, delaying the hydration reaction, balancing the effect of the early strength agent, and ensuring sufficient construction time. Nano-TiO2 generates electron-hole pairs under ultraviolet light irradiation, decomposing organic pollutants and achieving a self-cleaning function. Organosilicon defoamer reduces the surface tension of the liquid phase, causing bubbles to break down quickly and preventing the formation of pores after hardening that would affect strength.

[0053] 2.6 Intelligent Sensing System Components Table 6 shows the components of the intelligent sensing system.

[0054]

[0055] Design Principle: Flexible electrode sheets are embedded in the inner wall of the sleeve, making close contact with the grouting material. The overall conductivity of the material is obtained by measuring the resistance between the two electrodes. The silver nanowire conductive film is flexible, can be bent to fit the inner wall of the sleeve, and has strong corrosion resistance. The NFC chip obtains energy from the electromagnetic field emitted by the reader, requiring no battery and allowing for long-term operation. The RFID tag stores information such as material batch, production date, and formula number, and can sense strain changes.

[0056] III. Detailed Explanation of Preparation Method The preparation method of the present invention includes steps such as nanomaterial dispersion, microcapsule preparation, dry mixing formulation, intelligent sensing system integration, and field application.

[0057] 3.1 Dispersion of nanomaterials (see...) Figure 1 ) Step 1-1: Pre-dispersion: Weigh 0.8-1.5 parts of carboxyl-functionalized multi-walled carbon nanotubes and 0.3-0.6 parts of graphene oxide hydrosol (concentration 5 mg / mL); add the carbon nanotubes to the graphene oxide solution and stir mechanically for 10 minutes; add 0.05-0.1 parts of polyacrylamide dispersant (dissolved in a small amount of deionized water) and continue stirring for 5 minutes.

[0058] Steps 1-2: Ultrasonic dispersion: Transfer the above mixture to an ultrasonic dispersion device; ultrasonic power: 500-800W, frequency: 20-25kHz; dispersion time: 30 minutes (pause for 1 minute every 5 minutes to avoid overheating); temperature is controlled at 25-35°C during ultrasonication (using ice water bath or circulating cooling).

[0059] Steps 1-3: High-shear stirring: After sonication, transfer to a high-shear mixer; shear speed: 3000-5000 rpm; stirring time: 2 hours; to obtain a uniform and stable nanomaterial dispersion.

[0060] Steps 1-4: Quality inspection: Take a small amount of the dispersion and drop it onto filter paper to observe whether there are agglomerates (pass standard: no visible agglomerates); measure the Zeta potential (the absolute value should be ≥35mV, indicating that the dispersion is stable); observe the uniformity of the dispersion under a microscope.

[0061] Key control points: Ultrasonic power should not be too high, otherwise it may damage the carbon nanotube structure; temperature control is very important, as excessive temperature will cause the dispersant to degrade; the dispersion should be used within 24 hours to avoid long-term storage that may lead to re-agglomeration.

[0062] 3.2 Microcapsule preparation (see...) Figure 2 ) Preparation of epoxy resin microcapsules (in-situ polymerization method): Step 2-1: Emulsion preparation: Oil phase: epoxy resin E-51 (40g) + isocyanate curing agent (0.5g, as wall material monomer); Aqueous phase: distilled water (100mL) + polyvinyl alcohol (5g, emulsifier) ​​+ sodium dodecyl sulfate (0.5g, co-emulsifier); add the oil phase dropwise to the aqueous phase and stir at high speed (8000-10000rpm) to form an O / W emulsion; control the oil droplet size to 80-150μm.

[0063] Step 2-2: Wall material formation: Slowly add diethylenetriamine (8g, which reacts with isocyanate to form polyurea wall material) to the emulsion; reaction temperature: 50-60°C, time: 2-3 hours; reduce stirring speed to 500-800 rpm to maintain emulsion stability.

[0064] Steps 2-3: Post-processing: Cool to room temperature; filter and collect microcapsules; wash repeatedly with deionized water and ethanol to remove surface residues; vacuum dry (40-50°C, 12 hours); microscopic examination: particle size 80-150μm, wall thickness 2-5μm, good sphericity.

[0065] Preparation of cyanoacrylate microcapsules (complex coagulation method): Steps 2-4: Coagulation: Dissolve 10g of gelatin in 150mL of water and stir at 50°C to dissolve; add 10g of gum arabic and adjust the pH to 4.0-4.5 (so that the gelatin and gum arabic have opposite charges and coagulation occurs); add 30g of ethyl α-cyanoacrylate and stir at high speed (6000-8000rpm) to form an emulsion.

[0066] Steps 2-5: Wall material curing: Add glutaraldehyde (3g, crosslinking agent) dropwise to cure the gelatin-gum arabic cohesive layer; reaction temperature: 40-45°C, time: 3-4 hours; adjust pH to 7.0-8.0 and terminate the reaction.

[0067] Steps 2-6: Post-treatment: Same washing and drying procedures as epoxy resin microcapsules; Microscopic inspection: Particle size 50-100μm.

[0068] Microbial spore preparation: Steps 2-7: Culture of the strain: Bacillus was inoculated into nutrient agar medium; culture conditions: 30°C, 72 hours, to promote spore formation.

[0069] Steps 2-8: Spore collection: Rinse the surface of the culture medium with sterile water and collect the spore suspension; centrifuge (5000 rpm, 10 minutes) to remove vegetative cells and impurities; wash repeatedly 2-3 times.

[0070] Steps 2-9: Spray drying: Mix the spore suspension with the nutrient solution (calcium lactate + yeast extract); Spray drying conditions: inlet air temperature 150-180°C, outlet air temperature 80-90°C; Obtain dry powder containing spores, with a spore survival rate ≥85%.

[0071] 3.3 Dry Mixture Preparation Step 3-1: Premixing of cementitious materials: Weigh out the following according to the proportions: 100 parts of P.O52.5 cement, 8-12 parts of sulfoaluminate cement, 15-25 parts of ultrafine slag powder, and 8-12 parts of nano silica fume; put them into a planetary mixer and dry mix at low speed (50-80 rpm) for 10 minutes; ensure that the color is uniform (grayish-white).

[0072] Step 3-2: Aggregate addition: Weigh out three sizes of quartz sand according to the ratio (total 320-410 parts); add them to the mixer in batches: first coarse sand, then medium sand, and finally fine sand; mix for 3 minutes after each batch is added, for a total mixing time of 15 minutes.

[0073] Step 3-3: Microcapsule addition: 8-12 parts epoxy resin microcapsules + 3-5 parts cyanoacrylate microcapsules; premix with a small amount of fine sand (to prevent microcapsule breakage); add to the main mixer and mix at low speed (30-50 rpm) for 5 minutes (avoid vigorous mixing to prevent damage to the microcapsules).

[0074] Steps 3-4: Adding microbial spores: 0.01-0.05 parts spore powder + 0.5-1.0 parts nutrient solution; add simultaneously with the microcapsules and mix evenly.

[0075] Steps 3-5: Adding admixtures: Weigh out the following according to the formula: polycarboxylate superplasticizer, UEA expansion agent, lithium carbonate, sodium gluconate, nano TiO2, and defoamer; mix the liquid admixtures (superplasticizer and defoamer) with the nanomaterial dispersion; mix the powdered admixtures with the main material; continue stirring for 10 minutes to ensure uniformity.

[0076] Steps 3-6: Quality Inspection and Packaging: Sampling and testing of flowability, gas content, and condensation time; packaging after passing the tests (using composite moisture-proof bags, 25kg / bag or 40kg / bag); affixing RFID tags and entering production information (batch, date, formula, quality inspection data, etc.).

[0077] Key control points: The mixing speed of microcapsules should not be too high, otherwise they will break; the order of adding additives affects the dispersion effect, and the water-reducing agent should be added last; the finished product should be sealed and stored to avoid moisture absorption and failure.

[0078] 3.4 Intelligent Sensing System Integration (see...) Figure 3 and Figure 4 ) Step 4-1: Embedding of flexible electrode sheet: Reserve electrode grooves (1-2mm deep) at symmetrical positions (180°) on the inner wall of the sleeve; cut the flexible electrode sheet (silver nanowire conductive film) to a suitable size (50×100mm); fix it in the electrode groove with conductive adhesive; lead wires are led out through the reserved holes in the sleeve wall and connected to the external measurement circuit; coat the electrode surface with a thin layer of epoxy resin (thickness <0.5mm) for protection to avoid damage during grouting.

[0079] Step 4-2: NFC chip installation: The NFC chip (with temperature and humidity sensor) is fixed to the outer wall of the sleeve; the position is chosen to be easily readable (1.2-1.5m from the ground); it is fixed with waterproof sealant to ensure long-term reliable operation.

[0080] Step 4-3: RFID Tag Binding: Affix strain-sensitive RFID tags to the sleeve surface or concrete component; use an RFID writer to write the following information into the tag: material batch number, production date and expiration date, formula number, quality inspection data (flowability, strength, etc.), and manufacturer information; establish corresponding records in the cloud platform database.

[0081] Step 4-4: System Testing: Before grouting, test the resistance of the electrode sheets (they should be open circuit or high resistance, >10MΩ); test the chip function with an NFC reader (it should be able to read temperature and humidity under normal circumstances); read the tag information with an RFID reader to confirm the data is accurate.

[0082] 3.5 Field Application Step 5-1: Construction preparation: Check that the sleeve is clean and free of debris; clean the ends of the reinforcing bars, removing oil stains and rust; prepare grouting equipment: mixer, grouting pump or grouting funnel; prepare monitoring equipment: resistance meter, NFC reader, mobile terminal (with monitoring APP installed).

[0083] Step 5-2: Material mixing: Measure according to the dry mix: water = 1:0.11-0.13 (by weight); first pour the water into the mixing bucket, then add the dry mix (to prevent dust from flying); mix at low speed for 1 minute, then mix at high speed for 5-8 minutes; observe the fluidity during mixing, and adjust the water volume slightly (±5%) if necessary; after mixing, let stand for 1-2 minutes to defoam.

[0084] Step 5-3: Initial resistance measurement: Connect the resistance meter to the electrode leads; measure and record the initial resistance R0 (typical value: tens to hundreds of kΩ, depending on the carbon nanotube doping and dispersion state); upload the data to the cloud platform and bind it to the sleeve; Step 5-4: Grouting operation: Bottom injection method is adopted (injected from the grouting port at the lower end of the sleeve); Pump grouting: the pressure is controlled at 0.2-0.4MPa, and the flow rate is 50-100mL / s; Gravity grouting: the height of the grouting funnel is 1.5-2.0m away from the grouting port, and it flows naturally; During the grouting process: real-time monitoring of resistance changes (data is collected every 10 seconds), observation of whether there is grout overflow from the vent hole, and the grouting progress is displayed on the mobile terminal (the fullness is estimated based on the resistance change).

[0085] Step 5-5: Monitoring principle of grouting process: Before grouting: There is almost no conductive path between the electrodes, and the resistance is extremely high; Grouting begins: The grout contacts the lower electrode, and the resistance begins to decrease; Grouting proceeds: The grout gradually fills the sleeve, the conductive path increases, and the resistance continues to decrease; Grouting is completed: The grout reaches the upper electrode, and the resistance drops to a stable minimum value (Rmin); Criterion: When R drops to 0.1R0 or reaches the preset threshold (determined based on historical data), and remains stable for more than 30 seconds, it is determined that the grouting is full.

[0086] Steps 5-6: Confirmation of grouting completion: Grout overflows from the vent hole; resistance reaches a stable minimum value; system prompts "grouting complete"; seal the grouting port and vent hole.

[0087] Steps 5-7: Maintenance and Monitoring: Standard maintenance conditions: temperature 20±2°C, relative humidity ≥95%; continuous monitoring: resistance changes with hydration reaction (initially slightly increases, then tends to stabilize), NFC chip records temperature and humidity curves, RFID tag senses for abnormal strain (such as impact during demolding); data is automatically uploaded to the cloud platform to form a complete maintenance record.

[0088] Steps 5-8: Service life monitoring: After the structure is put into use, monitor regularly or in real time: resistance changes (reflecting strain state), temperature changes (reflecting environmental and load effects), and strain accumulation (RFID tag); when the following abnormalities are detected, the system will automatically issue an early warning: sudden change in resistance (may indicate crack formation), strain exceeding the design value, and abnormal temperature (such as fire); maintenance personnel will conduct inspections and take appropriate measures based on the early warning information.

[0089] IV. In-depth analysis of working principle 4.1 Self-sensing principle (see Figure 5 and Figure 6 ) Mechanism of conductive network formation: When the carbon nanotube content exceeds the percolation threshold (approximately 0.5-1.0 wt%), a three-dimensional conductive network forms in the cement-based material. The conductive pathways include: intrinsic conductivity of the carbon nanotubes; contact conductivity or tunneling conductivity between carbon nanotubes; and ionic conductivity from the aqueous solution within the pores (with a relatively small contribution).

[0090] Piezoresistive effect mechanism: When a material is subjected to compressive or tensile stress: Compressive stress: The distance between carbon nanotubes decreases, the number of contact points increases, the contact resistance decreases, and the overall resistance decreases (ΔR < 0). Tensile stress: The distance between carbon nanotubes increases, some contacts break, the tunneling distance increases, and the overall resistance increases (ΔR > 0). The resistance change rate has a good linear relationship with strain: ΔR / R0=K·ε; In this invention, the piezoresistive sensitivity coefficient K≈100-150, that is: when the strain is 100με, the resistance changes by about 1-1.5%; when the strain is 1000με, the resistance changes by about 10-15%.

[0091] Principle of grout fullness monitoring: Typical characteristics of resistance change curves during grouting (see...) Figure 7 ): First stage (0-t1): No contact with the electrode, R≈∞ (open circuit); Second stage (t1-t2): The slurry contacts the lower electrode, and R drops rapidly; Third stage (t2-t3): The slurry gradually fills the electrode, and R continues to drop, but at a slower rate; Fourth stage (t3-): The slurry contacts the upper electrode, and R drops to the minimum value Rmin and stabilizes.

[0092] The empirical formula for the relationship between fullness η and resistance is: η=(R0-R) / (R0-Rmin)×100%; when η≥95% and remains stable, the grouting is considered full.

[0093] Service life strain monitoring: After the structure is put into use, the sleeve connection node bears various loads: dead load: self-weight, floor load; live load: people, equipment, wind load; accidental load: earthquake, impact; The resistance reflects the strain status in real time: Normal operating condition: the resistance fluctuates slightly around the reference value (<5%); Overload condition: the resistance changes significantly (>10%), triggering an early warning; Fatigue damage: the resistance drifts slowly, indicating cumulative damage; Crack formation: the resistance changes abruptly (±20-50%), indicating local cracks.

[0094] 4.2 Self-healing principle (see...) Figure 8 ) Chemical repair process: Crack formation: Shrinkage stress, load, and temperature changes cause the substrate to crack.

[0095] Microcapsule rupture: Stress concentration occurs at the crack tip (stress intensity factor KI exceeds the fracture toughness of the microcapsule wall material), leading to wall material rupture. Repair agent release: Epoxy resin and cyanoacrylate flow out from the ruptured microcapsules. Capillary penetration: Low-viscosity repair agent (0.1-0.5 Pa·s) penetrates the crack through capillary action, reaching depths of several millimeters. Curing reaction: Epoxy resin reacts with Ca(OH)₂ or a curing agent, curing in 24-48 hours; cyanoacrylate reacts with water and alkali (OH⁻). - It polymerizes immediately and cures in 1-2 hours. Crack sealing: The cured polymer fills the crack and bonds both sides of the crack.

[0096] Bioremediation process: 1. Spore germination: The cracks create a moist environment, allowing the spores to absorb water, swell, and germinate into vegetative cells. 2. Metabolic alkali production: Bacteria consume nutrients such as calcium lactate, producing CO2 and NH3 through metabolism.

[0097] C3H5O3 - +2O2→2CO3 2- +H + +H2O (lactic acid oxidation); NH2-CO-NH2+H2O→2NH3+CO2 (Urea hydrolysis, if added); pH increases: NH3 dissolves in water to form NH4. + and OH - The local pH level rose to 9-10.

[0098] 3. Calcium carbonate precipitation: Ca 2+ +CO3 2- →CaCO3↓; CaCO3 crystals (calcite, aragonite) precipitate on the crack walls and inside the crack.

[0099] 4. Continuous mineralization: As long as there are nutrients and water, bacteria continue to metabolize, and mineralization continues (up to several weeks to several months).

[0100] 5. Crack filling: CaCO3 gradually fills the cracks, restoring strength and density.

[0101] Quantification of repair effect: Repair effect evaluation indicators: 1. Crack width recovery rate = (width before repair - width after repair) / width before repair × 100%.

[0102] 2. Strength recovery rate = (Strength after repair / Strength before cracking) × 100%.

[0103] 3. Permeability recovery rate = (permeability coefficient before repair - permeability coefficient after repair) / permeability coefficient before repair × 100%.

[0104] Repair effects of this invention: Crack width <0.3mm: 7-day repair rate ≥80%, 28-day repair rate ≥95%; Crack width 0.3-0.8mm: 28-day repair rate ≥60%; Strength recovery rate ≥85%; Permeability recovery rate ≥90%.

[0105] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A smart self-sensing and self-healing sleeve grouting material, characterized in that: Includes the following components by weight: Basic cementitious material system: 100 parts P.O52.5 silicate cement, 8-12 parts sulfoaluminate cement, 15-25 parts ultrafine slag powder, and 8-12 parts nano silica fume; Intelligent sensing component system: 0.8-1.5 parts of carboxyl-functionalized multi-walled carbon nanotubes, 0.3-0.6 parts of graphene oxide hydrosol, and 0.05-0.1 parts of polyacrylamide dispersant; Self-healing component system: 8-12 epoxy resin microcapsules, 3-5 cyanoacrylate microcapsules, 0.01-0.05 microbial spores, and 0.5-1.0 microbial nutrient solution; Aggregate system: 20-40 mesh quartz sand 150-180, 40-80 mesh quartz sand 120-150, 80-120 mesh quartz sand 50-80; Additive system: polycarboxylate superplasticizer 3.5-4.5, UEA expansion agent 10-15, lithium carbonate early strength agent 1.2-2.0, sodium gluconate retarder 0.5-1.2, nano TiO2 photocatalyst 0.3-0.6, organosilicon defoamer 0.2-0.

4.

2. The intelligent self-sensing and self-healing sleeve grouting material according to claim 1, characterized in that: P.O52.5 silicate cement has a strength grade of 52.5 and a specific surface area of ​​350-380 m². 2 / kg; sulfoaluminate cement strength grade 42.5, C3A content ≥40%; ultrafine slag powder specific surface area ≥500m² 2 / kg, activity index ≥95%; SiO2 content in nano silica fume ≥96%, specific surface area ≥20000m² 2 / kg.

3. The intelligent self-sensing and self-healing sleeve grouting material according to claim 1, characterized in that: The outer diameter of the carboxyl-functionalized multi-walled carbon nanotubes is 8-15 nm, the length is 5-20 μm, and the carboxyl content is 2-5%; the thickness of the sheets in the graphene oxide hydrosol is 0.8-1.2 nm, and the concentration is 5 mg / mL; the molecular weight of the polyacrylamide dispersant is 3 million-5 million, and the degree of hydrolysis is 25-30%.

4. The intelligent self-sensing and self-repairing sleeve grouting material according to claim 1, characterized in that: The epoxy resin microcapsules have a particle size of 80-150μm, a shell material of polyurea with a wall thickness of 2-5μm, and a core material of epoxy resin E-51; the cyanoacrylate microcapsules have a particle size of 50-100μm, a shell material of gelatin-gum arabic, and a core material of ethyl α-cyanoacrylate; the microbial spores are Bacillus spp. with a survival rate of ≥85% and a size of 1-2μm; the microbial nutrient solution is calcium lactate and yeast extract in dry powder form.

5. The intelligent self-sensing and self-healing sleeve grouting material according to claim 1, characterized in that: The polycarboxylate superplasticizer has a solid content of 40%, a water reduction rate of ≥35%, and an air content of <3%; the UEA expanding agent has a 7-day restricted expansion rate of ≥0.025%, and its main component is calcium sulfoaluminate; the lithium carbonate early strength agent has a Li2CO3 purity of ≥99% and a particle size of <10μm; the sodium gluconate retarder has a purity of ≥98% and extends the retarding time by 2-3 hours. The nano-TiO2 photocatalyst is anatase type, with a particle size of 20-30 nm and a specific surface area ≥150 m². 2 / kg; the silicone defoamer is a polyether-modified silicone with a defoaming speed of <10s.

6. The intelligent self-sensing and self-repairing sleeve grouting material according to claim 1, characterized in that: It also includes intelligent sensing system components; the intelligent sensing system components include flexible electrode sheets, NFC passive chips and strain-sensitive RFID tags. The flexible electrode sheets are embedded in the inner wall of the sleeve and are in close contact with the grouting material. The NFC chip obtains energy from the electromagnetic field emitted by the reader. The RFID tag stores information including material batch, production date and formula number and can sense strain changes.

7. A method for preparing an intelligent self-sensing and self-repairing sleeve grouting material, used to prepare the intelligent self-sensing and self-repairing sleeve grouting material as described in claim 6, characterized in that: Includes the following steps: S1: Nanomaterial dispersion: Pre-dispersion: Weigh 0.8-1.5 parts of carboxyl-functionalized multi-walled carbon nanotubes and 0.3-0.6 parts of graphene oxide hydrosol with a concentration of 5 mg / mL; add the carbon nanotubes to the graphene oxide solution and stir mechanically for 10 minutes; add 0.05-0.1 parts of polyacrylamide dispersant and continue stirring for 5 minutes. Ultrasonic dispersion: Transfer the above mixture to an ultrasonic dispersion device; ultrasonic power: 500-800W, frequency: 20-25kHz; dispersion time: 30 minutes; temperature controlled at 25-35°C during ultrasonication; High-shear stirring: After ultrasonication, the mixture is transferred to a high-shear mixer; shear rate: 3000-5000 rpm; stirring time: 2 hours; a uniform and stable dispersion of nanomaterials is obtained. Quality inspection: Take a small amount of the dispersion and drop it onto filter paper to observe whether there are agglomerates; measure the zeta potential; observe the uniformity of dispersion under a microscope; S2: Microcapsule preparation: Preparation of epoxy resin microcapsules; preparation of cyanoacrylate microcapsules; preparation of microbial spores; S3: Dry Mixture Preparation: Premixing of cementitious materials: Weigh out the following according to the proportions: 100 parts of P.O52.5 cement, 8-12 parts of sulfoaluminate cement, 15-25 parts of ultrafine slag powder, and 8-12 parts of nano silica fume; put them into a planetary mixer and dry mix at low speed for 10 minutes; ensure uniform color. Aggregate addition: Weigh out three sizes of quartz sand according to the proportion; add them to the mixer in batches: first coarse sand, then medium sand, and finally fine sand; mix for 3 minutes after each batch is added, for a total mixing time of 15 minutes; Microcapsule addition: 8-12 parts epoxy resin microcapsules + 3-5 parts cyanoacrylate microcapsules; premix with a small amount of fine sand; add to the main mixer and mix at low speed for 5 minutes; Microbial spore addition: 0.01-0.05 parts spore powder, 0.5-1.0 parts nutrient solution; add simultaneously with the microcapsules and mix thoroughly; Additives: Weigh the following according to the formula: polycarboxylate superplasticizer, UEA expanding agent, lithium carbonate, sodium gluconate, nano TiO2, and defoamer; mix the liquid additives with the nanomaterial dispersion; mix the powdered additives with the main material; Continue stirring for 10 minutes to ensure it is thoroughly mixed; Quality inspection and packaging: Sampling and testing of flowability, gas content, and condensation time; packaging after passing the test; affixing RFID tags and recording production information.

8. The preparation method of an intelligent self-sensing and self-repairing sleeve grouting material according to claim 7, characterized in that: Step S2 specifically includes: S21: Preparation of epoxy resin microcapsules: Emulsion preparation: Oil phase: 40g epoxy resin E-51, 0.5g isocyanate curing agent; Aqueous phase: 100mL distilled water, 5g polyvinyl alcohol, 0.5g sodium dodecyl sulfate; The oil phase is added dropwise to the aqueous phase and stirred at high speed to form an O / W emulsion; The oil droplet size is controlled at 80-150μm; Wall material formation: Slowly add 8g of diethylenetriamine to the emulsion; reaction temperature: 50-60°C, time: 2-3 hours; reduce stirring speed to 500-800 rpm to maintain emulsion stability; Post-processing: Cool to room temperature; filter and collect microcapsules; wash repeatedly with deionized water and ethanol to remove surface residues; vacuum dry at 40-50°C for 12 hours; microscopic examination: particle size 80-150μm, wall thickness 2-5μm, good sphericity; S22: Preparation of cyanoacrylate microcapsules: Coagulation: Dissolve 10g of gelatin in 150mL of water and stir at 50°C to dissolve; add 10g of gum arabic and adjust the pH to 4.0-4.5; add 30g of ethyl α-cyanoacrylate dropwise and stir at high speed to form an emulsion; Wall material curing: Add 3g of glutaraldehyde dropwise to cure the gelatin-gum arabic coagulation layer; reaction temperature: 40-45°C, time: 3-4 hours; adjust pH to 7.0-8.0 and terminate the reaction; Post-treatment: Same washing and drying procedures as epoxy resin microcapsules; Microscopic inspection: Particle size 50-100μm; S23: Microbial spore preparation: Bacterial culture: Bacillus was inoculated onto nutrient agar medium; culture conditions: 30°C, 72 hours, to promote spore formation; Spore collection: Rinse the surface of the culture medium with sterile water and collect the spore suspension; centrifuge at 5000 rpm for 10 minutes to remove vegetative cells and impurities; wash repeatedly 2-3 times. Spray drying: Mix the spore suspension with the nutrient solution; Spray drying conditions: inlet air temperature 150-180°C, outlet air temperature 80-90°C; Obtain dry powder containing spores, with a spore survival rate ≥85%.

9. The preparation method of an intelligent self-sensing and self-repairing sleeve grouting material according to claim 7, characterized in that: It also includes the following steps: S4: Intelligent Sensing System Integration S41: Flexible electrode sheet pre-embedding: Electrode grooves are reserved at symmetrical positions on the inner wall of the sleeve; the flexible electrode sheet is cut to a suitable size; it is fixed in the electrode groove with conductive adhesive; the lead wire is led out through the reserved hole in the sleeve wall and connected to the external measurement circuit; the electrode surface is coated with a thin layer of epoxy resin for protection to avoid damage during grouting; S42: NFC chip installation: The NFC chip is fixed to the outer wall of the sleeve; the position is chosen to be easily readable; it is fixed with waterproof sealant to ensure long-term reliable operation; S43: RFID Tag Binding: Strain-sensitive RFID tags are affixed to the sleeve surface or concrete component; the following information is written to the tag using an RFID writer: material batch number, production date and expiration date, formula number, quality inspection data, and manufacturer information; corresponding records are established in the cloud platform database. S44: System Testing: Test the electrode resistance before grouting; test the chip function using an NFC reader; read the tag information using an RFID reader to confirm data accuracy.

10. A method for applying an intelligent self-sensing and self-repairing sleeve grouting material, using the intelligent self-sensing and self-repairing sleeve grouting material as described in claim 6, characterized in that: Includes the following steps: Y1: Construction preparation: Check that the sleeve is clean and free of debris; clean the ends of the reinforcing bars, removing oil and rust; prepare grouting equipment: mixer, grouting pump or grouting funnel; prepare monitoring equipment: resistance meter, NFC reader, mobile terminal; Y2: Material mixing: Measure by weight, dry mix: water = 1:0.11-0.13; first pour the water into the mixing bucket, then add the dry mix; Stir at low speed for 1 minute, then at high speed for 5-8 minutes; observe the fluidity during stirring and adjust the water volume slightly if necessary; after stirring, let stand for 1-2 minutes to defoam. Y3: Initial resistance measurement: Connect the resistance meter to the electrode leads; measure and record the initial resistance R0; upload the data to the cloud platform and bind it to the sleeve; Y4: Grouting operation: Bottom injection method is adopted; Pump grouting: Pressure is controlled at 0.2-0.4MPa, flow rate is 50-100mL / s; Gravity grouting: The height of the grouting funnel is 1.5-2.0m from the grouting port, and it flows naturally; During grouting: monitor resistance changes in real time; observe whether grout overflows from the vent holes; display grouting progress on the mobile terminal; Y5: Grouting process monitoring principle: Before grouting: There is almost no conductive path between the electrodes, and the resistance is extremely high; When grouting begins: The grout contacts the lower electrode, and the resistance begins to decrease. Grouting proceeds: The grout gradually fills the sleeve, increasing the conductive path and causing the resistance to continuously decrease; Grouting complete: The grout reaches the upper electrode and the resistance drops to a stable minimum value; Criterion: When R drops to 0.1R0 or reaches the preset threshold and remains stable for more than 30 seconds, the grouting is considered complete; Y6: Grouting completion confirmation: Grout overflows from the vent hole; resistance reaches a stable minimum value; system prompts grouting completion; grouting port and vent hole are sealed; Y7: Maintenance and Monitoring Standard maintenance conditions: temperature 20±2°C, relative humidity ≥95%; Continuous monitoring: Resistance changes with hydration reaction; NFC chip records temperature and humidity curves; RFID tag senses for abnormal strain; Data is automatically uploaded to the cloud platform, forming a complete maintenance record; Y8: Service life monitoring: After the structure is put into use, monitor the following regularly or in real time: resistance changes; temperature changes; strain accumulation; The system will automatically issue a warning when the following anomaly is detected: sudden change in resistance; Strain exceeding design value; abnormal temperature; Maintenance personnel conduct inspections and take appropriate actions based on the early warning information.

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