Method for inhibiting corrosion of rusted reinforcing steel bars in concrete structure

Abstract

The invention discloses a method for inhibiting rust of rusted steel bars in a concrete structure, and aims to solve the problems that in the prior art, a safe, environment-friendly and long-acting steel bar corrosion inhibitor convenient to construct is lacked, and a long-acting steel bar corrosion prevention method formed by compounding materials such as an efficient anti-corrosion coating is lacked. Through three innovations of organic silicon modification, a nano-composite technology and a self-crosslinking system, the core problems of poor weather resistance, high VOC (Volatile Organic Compounds), insufficient dispersion stability and the like of the traditional acrylic emulsion are solved, and the acrylic emulsion is particularly suitable for severe environments with high ultraviolet rays, high humidity and the like, so that long-period corrosion prevention is realized, and the service performance of concrete is improved.

Description

Technical Field

[0001] This invention relates to the field of rust prevention technology for steel bars in concrete structures, and specifically to a method for preventing rust on steel bars in concrete structures. Background Technology

[0002] When steel reinforcement within concrete corrodes, it leads to damage to the concrete cross-sectional dimensions, a reduction in the effective cross-section of the reinforcement, a decrease in the yield strength of the reinforcement, and degradation of the bond between the concrete and the reinforcement. This results in a decrease in the load-bearing capacity of the concrete member, which declines rapidly as corrosion progresses, severely impacting the safety, usability, and durability of the building. Current research has identified the following main causes of steel reinforcement corrosion within concrete:

[0003] 1. Carbonation: Carbon dioxide in concrete ( Carbonation penetrates into the concrete, lowering its pH value and damaging the iron oxide layer on the reinforcing steel. The carbonation process reduces the alkalinity of the concrete, weakening its ability to protect the reinforcing steel; this is especially true for carbon dioxide (C₂O₃). High concentrations of certain substances can cause the steel reinforcement inside the concrete to begin to corrode.

[0004] 2. Chloride ion intrusion: Chloride ions from de-icing salt and marine environments are particularly corrosive. Chloride ions can penetrate into the internal steel bars through cracks and pores in the concrete protective layer. Chloride ions can damage the protective layer on the surface of the steel bars, leading to localized corrosion and pitting.

[0005] 3. Oxygen corrosion: The oxide film formed on the surface of the steel bar can protect it from corrosion. However, if there are a large number of oxygen molecules inside the concrete, the surface of the steel bar can be further oxidized, leading to steel bar corrosion. Moreover, the increase in the oxygen content in the concrete will accelerate the oxidation process of the steel bar.

[0006] 4. Environmental factors: In coastal areas and industrial zones with high humidity, high salinity and high levels of corrosive chemicals, the rate and extent of steel reinforcement corrosion in concrete will be accelerated.

[0007] The main technical principle of traditional steel reinforcement corrosion inhibitors is based on inhibiting electrochemical corrosion reactions, delaying or preventing corrosion by interfering with the anodic or cathodic processes of steel reinforcement corrosion. Their mechanism of action and effects can be summarized as follows:

[0008] (1) Anodic rust inhibitors (such as nitrites and chromates) block the dissolution of iron ions in the anodic region by promoting the formation of a passivation film on the surface of the reinforcing steel. For example, nitrites (such as calcium nitrite) react with iron in an alkaline environment to form a dense passivation film of iron oxide or iron hydroxide, which covers the surface of the reinforcing steel and prevents contact between oxygen and water. Such rust inhibitors need to be effective in a highly alkaline environment of concrete (pH≥11.5), but as the concrete carbonizes or chloride ions invade, causing the pH to drop, the passivation film is easily damaged, and the protective effect is significantly reduced.

[0009] (2) Cathodic corrosion inhibitors (such as phosphates and silicates) slow down the electrochemical corrosion current by inhibiting the oxygen reduction reaction in the cathodic region. For example, phosphates can react with Ca in the pore fluid of concrete. 2+ The formation of insoluble calcium phosphate precipitate covers the cathode area and reduces the oxygen diffusion rate, thereby lowering the corrosion rate. This type of rust inhibitor is highly adaptable to environments with high chloride ion concentrations, but it requires a high degree of concrete density; if cracks or pores are present, the protective effect will be significantly reduced.

[0010] (3) Hybrid rust inhibitors: Some traditional rust inhibitors combine anodic and cathodic inhibition mechanisms, such as the compound system of nitrite and phosphate, which protects the anode through a passivation film and inhibits the cathodic process through precipitation reaction. Such formulations can improve adaptability to complex corrosive environments (such as alternating wet and dry or high-chlorine environments), but they have the problems of complex composition and high cost.

[0011] Traditional steel reinforcement corrosion inhibitors are characterized by significant short-term protective effects, especially in uncarbonized concrete with low chloride ion concentrations. Traditional corrosion inhibitors (especially nitrite-based ones) can effectively delay the onset of corrosion, with experiments showing they can reduce steel weight loss by more than 50%. However, when the chloride ion concentration exceeds a critical value (typically 0.4% to 1.0% of the cement mass), anodic corrosion inhibitors cannot prevent corrosion. When concrete carbonization causes a pH drop, the passivation film stability decreases sharply, and the corrosion-inhibiting effect fails. Furthermore, nitrites are carcinogenic, posing a threat to human health and the environment during construction. In addition, some corrosion inhibitors (such as nitrites) may accelerate concrete setting or introduce additional salts, leading to increased porosity and consequently reducing the concrete's density and impermeability.

[0012] Current research includes studies such as CN201110271404.0, "Organic Composite Nano-diameter Fiber Serpentine Fiber Reinforced Concrete Corrosion Inhibitor, Preparation Method and Application." This corrosion inhibitor is prepared by high-speed mixing and homogenization of an organic corrosion inhibitor and inorganic nano-diameter serpentine fibers. The mass ratio of the organic corrosion inhibitor to the inorganic nano-diameter serpentine fibers is 1-1.5:2.0-2.5. This research has improved the corrosion limit of steel reinforcement to a certain extent, enhanced the impermeability of the reinforced concrete cover, and improved the performance of the interface between the concrete and steel reinforcement. However, the components contain organophosphonates (potentially toxic), posing environmental and construction safety concerns. Furthermore, it is an internal admixture design, requiring mixing with concrete, resulting in a single application method and a relatively large addition amount (1-1.5:2.0-2.5), leading to high costs.

[0013] Therefore, it is essential to continue developing safe, environmentally friendly, long-lasting, and convenient steel reinforcement rust inhibitors, and to further combine them with high-efficiency anti-corrosion coatings and other materials to form new methods for long-lasting steel reinforcement corrosion protection. Summary of the Invention

[0014] To address the shortcomings of existing technologies, such as the lack of safe, environmentally friendly, long-lasting, and convenient steel reinforcement rust inhibitors and the lack of efficient anti-corrosion coatings that can be compounded to form long-lasting steel reinforcement corrosion prevention methods, this invention provides a method for preventing rust on steel reinforcement within concrete structures. This invention solves the core problems of traditional acrylic emulsions, such as poor weather resistance, high VOCs, and insufficient dispersion stability, through three major innovations: organosilicon modification, nanocomposite technology, and self-crosslinking system. It is particularly suitable for harsh environments such as high ultraviolet radiation and high humidity, so as to achieve long-term corrosion prevention and improve the service performance of concrete.

[0015] The technical solution of the present invention is as follows:

[0016] The passivation film on the surface of reinforcing bars is the main barrier preventing corrosion of reinforcing bars within concrete. Ultimately, the cause of steel bar corrosion stems from changes in the composition and structure of this passivation film. Therefore, this invention employs a penetrating material to inhibit electrochemical corrosion reactions caused by chloride ions, oxygen, and water vapor present in the reinforcing bars and concrete, thereby improving the passivating environment on the surface of the reinforcing bars within the concrete and protecting the passivation film. Simultaneously, a composite anti-corrosion system is used, consisting of "penetrating silane concrete reinforcing bar corrosion inhibitor + epoxy-modified cement mortar + inorganic hybrid waterborne epoxy coating + waterborne highly dispersed pure acrylic polymer," to achieve long-term corrosion protection and improve the service performance of the concrete.

[0017] The objective of this invention is achieved through the following technical solution:

[0018] A method for preventing corrosion of reinforcing steel bars in concrete structures includes the following steps:

[0019] S1. Preparation of penetrating silane concrete rebar corrosion inhibitor:

[0020] S1-1. Weigh out the following components according to the mass ratio: 12-18% silane coupling agent, 2-4% nano-silica and graphene oxide composite, 3-6% sodium molybdate-sodium tungstate composite corrosion inhibitor, 5-8% bio-based penetration enhancer (Cyrene), 4-7% polyether-modified siloxane, 0.8-1.5% polycarboxylic acid dispersant, with the balance being deionized water.

[0021] S1-2. First, put the remaining components, except for nano-silica and graphene oxide composite, into a stainless steel reactor equipped with an anchor stirrer. Control the stirring speed to 50-100 r / min and premix at room temperature for 15-20 min until the material is evenly dispersed. During this period, add 60-70% of the total amount of deionized water in batches.

[0022] S1-2. Simultaneously, the nano-silica and graphene oxide composite and the remaining deionized water are treated in an ultrasonic dispersion device at a frequency of 20-40kHz for 20-30 minutes to form a stable nano-dispersion. Then, the mixture is slowly pumped into the reaction vessel, the stirring speed is increased to 150-200r / min, and dispersion is continued for 30-45 minutes.

[0023] S1-3. The pH is adjusted to 6.5-7.5 by monitoring the system with an online pH meter and stirring at low speed for 10 minutes. Finally, the mixture is filtered through a polypropylene microporous membrane filter with a pore size of 0.45μm to remove undispersed particles and impurities.

[0024] S2. Preparation of epoxy-modified cement mortar:

[0025] S2-1. Prepare the following proportions by mass: 15-20% bisphenol A epoxy resin (E-51), 5-8% nitrile rubber modified epoxy resin, 0.5-1.5% aminated graphene (accelerator), 25-30% cationic epoxy emulsion (E-44), 10-15% ultrafine silica fume (800 mesh), 2-4% nano silica (50nm), 0.3-0.8% polycarboxylate superplasticizer, and 1-3% bentonite / fumed silica. (Environmentally friendly thixotropic agent), 20-25% ultrafine sulfoaluminate cement, and the remainder is deionized water;

[0026] S2-2. Add bisphenol A epoxy resin (E-51) and nitrile rubber modified epoxy resin into a jacketed stainless steel reactor (500L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to raise the temperature to 40-50℃, and stir at 80-120r / min for 10-15min until completely miscible. Add cationic epoxy emulsion (E-44), maintain the temperature and continue stirring at 150-200r / min for 20min to form a uniform resin base liquid.

[0027] S2-3. Add the aminated graphene and 10% deionized water to an ultrasonic disperser (500W power, 40kHz frequency) and sonicate for 20-30 minutes until no obvious agglomeration occurs. Simultaneously, pre-disperse the nano-silica and polycarboxylate superplasticizer in a high-speed disperser (2000-3000r / min) for 15 minutes to form a nano-slurry. Combine the nano-slurry with the graphene dispersion and slowly add it to the reaction vessel at a rate of 50mL / min using a peristaltic pump. Turn on the high-shear emulsification head (3000-4000r / min) and disperse for 30 minutes.

[0028] S2-4. After screening the ultrafine silica fume and ultrafine sulfoaluminate cement through an 80-mesh vibrating screen, add them to the reactor in three batches (5 minutes apart each time). At the same time, add an environmentally friendly thixotropic agent, reduce the stirring speed to 100-150 r / min, and use a vacuum system (vacuum degree -0.06MPa) to remove the powder to avoid dust. Continue mixing for 45-60 minutes until the slurry has uniform fluidity.

[0029] S2-5. Add the remaining deionized water in two batches (add 60% initially, check viscosity until...). Add the remaining amount later), switch to a screw mixer (60-80 r / min) for low-speed homogenization, and monitor the particle distribution (D50≤10μm, D90≤30μm) with an online particle size analyzer. If it does not meet the requirements, transfer it to a sand mill (1500 r / min) for circulating grinding for 20-30 min.

[0030] S2-6. Detect the pH value of the slurry (target range 7.5-8.5), finely adjust it with 5% NaOH solution or 3% acetic acid solution, and finally sterilize and remove impurities through a 0.22μm polytetrafluoroethylene membrane filter. Then, it is transported to a stainless steel storage tank lined with polyethylene by a gear pump, filled with nitrogen (purity ≥99.9%) and sealed for storage.

[0031] S3. Preparation of inorganic hybrid waterborne epoxy coatings:

[0032] S3-1. Accurately weigh each component according to the following mass ratio: 35-45% epoxy resin emulsion (modified), 3-5% fluorinated reduced graphene oxide. Hybrid nanofillers, 2-4% silane coupling agent (KH-560), 5-8% bio-based self-emulsifying agent (Cyrene), 10-15% inorganic silica sol (nano) ), 1-3% sodium molybdate-sodium tungstate composite corrosion inhibitor, 0.5-1.5% polyether-modified polysiloxane leveling agent, 0.5-1% rare earth-modified cerium oxide ( The remainder is deionized water (sterilized by a 0.22μm filter membrane).

[0033] S3-2. Place the epoxy resin emulsion, silane coupling agent (KH-560), and bio-based self-emulsifier (Cyrene) into a jacketed stainless steel reactor (1000L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to 50-60℃ and stir at 80-120r / min for 15-20min until completely miscible to form a stable emulsion system. The silane coupling agent reacts with the epoxy resin emulsion through its epoxy groups to enhance the interfacial bonding between the inorganic filler and the organic resin.

[0034] S3-3, Fluoride-reduced graphene oxide The hybrid nanofiller and 10% deionized water were added to an ultrasonic disperser (power 800W, frequency 40kHz) and ultrasonically treated for 30-40 minutes until no obvious agglomeration was observed.

[0035] S3-4. Simultaneously, the inorganic silica sol and polyether-modified polysiloxane leveling agent are pre-dispersed for 15 minutes in a high-shear emulsifier (4000-6000 r / min) to form a nano-slurry. This slurry is then combined with the graphene dispersion and slowly added to the reactor at a rate of 100 mL / min using a peristaltic pump. The high-shear emulsification head is then turned on (5000-6000 r / min) and dispersed for 30 minutes. This step ensures the nano-slurry is properly dispersed. Fluorinated reduced graphene oxide Distribute evenly to avoid clumping;

[0036] S3-5. Dissolve the sodium molybdate-sodium tungstate composite corrosion inhibitor in 5% deionized water to form a solution, add it to the reaction vessel, and stir at 150-200 r / min for 10 min; then add rare earth modified cerium oxide ( A vacuum system (vacuum degree -0.08MPa) is used to extract the powder to avoid dust. The mixture is continuously mixed for 20-30 minutes until it is evenly dispersed. Sodium molybdate and sodium tungstate work synergistically to form a dense passivation film. Rare earth modified cerium oxide further enhances the corrosion resistance.

[0037] S3-6. Add the remaining deionized water in three batches (add 40% initially, check viscosity until...). Add the remaining amount later), switch to a screw mixer (60-80 r / min) for low-speed homogenization, and monitor the particle distribution (D50≤8μm, D90≤25μm) with an online particle size analyzer. If it does not meet the requirements, transfer it to a sand mill (zirconia beads, diameter 0.4-0.8mm, filling rate 75%, speed 1800 r / min) for 20-30 minutes of circulating grinding.

[0038] S4, Water-based highly dispersible pure acrylic polymer:

[0039] S4-1. Weigh each component precisely according to the following mass ratio: 40-50% methyl methacrylate (MMA), 20-30% butyl acrylate (BA), 2-4% acrylic acid (AA), 3-5% γ-methacryloyloxypropyltrimethoxysilane (KH-570), 1-3% nano zinc oxide (nZnO), 2-3% diacetone acrylamide (DAAM), 0.5-1.5% polycarboxylate dispersant, 0.5-1% composite light stabilizer, and the balance is deionized water (treated with ion exchange resin).

[0040] S4-2. Add 40% of the total amount of deionized water and all of the polycarboxylate dispersant into a stainless steel emulsifying tank (500L volume) with an anchor stirrer. Stir at 200-300 r / min. Add methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA) and silane coupling agent KH-570 monomer in sequence. Stir continuously for 30 min to form a uniform pre-emulsion. The silane groups of KH-570 can participate in the crosslinking reaction in the future to improve the water resistance of the coating.

[0041] S4-3. Mix nano zinc oxide with 10% deionized water, add 0.2% (based on nZnO mass) of polycarboxylic acid dispersant (such as sodium polyacrylate), and circulate and grind for 40-60 minutes using a sand mill (zirconia bead diameter 0.6-1.0 mm, filling rate 70%, speed 2000 r / min) until the particle size D90 ≤ 100 nm. Monitor the particle size distribution in real time using a laser particle size analyzer.

[0042] S4-4. Add the remaining deionized water and 0.3% ammonium persulfate initiator to the jacketed polymerization reactor (volume 1000L, equipped with turbine stirrer), heat to 80-85℃, add 15% of the total amount of pre-emulsion as seed, keep the reaction at the temperature for 30 minutes to form seed emulsion.

[0043] S4-5. Add the remaining preemulsion and nano zinc oxide dispersion separately to the reactor using a peristaltic pump, controlling the dropping rate to maintain the reaction temperature at 82-85℃. The dropping time for the preemulsion is 3-3.5 hours, and the dropping time for the nano zinc oxide dispersion is extended by 0.5 hours to ensure uniform distribution. When the preemulsion has been added to 50%, start adding diacetone acrylamide (DAAM) aqueous solution (DAAM dissolved in 5% deionized water) simultaneously for 2 hours. After the preemulsion is added, keep the reaction at the temperature for 1 hour, and continue the reaction for another hour to reduce residual monomers.

[0044] S4-6. Cool down to below 40℃, add a composite light stabilizer (a combination of hindered amines and benzotriazoles), and adjust the pH to 8-9 with 25% ammonia to enhance the stability of the system. Finally, filter through a 100-mesh filter and place in a storage tank to stand for 24 hours to remove bubbles.

[0045] S5. On-site construction:

[0046] S5-1. Remove laitance and loose material from the concrete surface;

[0047] S5-2. Use power tools to grind the concrete substrate as a whole to fully expose the pores on the surface of the concrete substrate, and meet the requirements of SSPC-SP13; the roughness grade of the overall grinding of the concrete substrate is ICRI-CSP2.

[0048] S5-3. Apply a penetrating concrete-internal steel reinforcement corrosion inhibitor, 2-4 coats, each coat using 180-230 ml / m². 2 The painting interval is 15 minutes.

[0049] S5-4. After the rust-inhibiting material for steel bars is sprayed and dried for 48 hours, an epoxy mortar coating with a dry film thickness of 1000μm is roller-coated or sprayed. After surface drying, an inorganic hybrid waterborne epoxy coating with a dry film thickness of 150μm is roller-coated or sprayed. Finally, a waterborne highly dispersed pure acrylic polymer with a dry film thickness of 80μm is sprayed to achieve long-term protection of steel bars.

[0050] S6. Effect Verification: After 10 years of operation in the treated area, check the steel reinforcement corrosion. If no rust is found by visual inspection and the appearance quality is good, it indicates that the effect is excellent.

[0051] In this invention:

[0052] The penetrating silane concrete rebar corrosion inhibitor described in S1 is shown in Table 1:

[0053] Table 1. Formulation of Components for Rebar Corrosion Inhibitor

[0054]

[0055] Furthermore, the silane coupling agent described in S1-1 is selected from KH-560 compound.

[0056] Furthermore, the pH adjustment described in S1-3 uses a 5% (w / w) dilute hydrochloric acid or sodium hydroxide solution.

[0057] The epoxy-modified cement mortar described in S2 is shown in Table 2:

[0058] Table 2. Component Formulation of Reinforcing Steel Corrosion Inhibitor

[0059]

[0060] Furthermore, the bisphenol A epoxy resin mentioned in S2-1 is selected from E-51; the cationic epoxy emulsion is selected from E-44; the ultrafine silica fume is selected from 800 mesh; and the nano silica has a particle size of 50 nm.

[0061] The inorganic hybrid waterborne epoxy coatings described in S3 are shown in Table 3:

[0062] Table 3 Inorganic Hybrid Waterborne Epoxy Coatings

[0063]

[0064] Furthermore, the silane coupling agent described in S3-1 is selected from KH-560; the inorganic silica sol is selected from nano-sized... Rare earth modified cerium oxide, selected from .

[0065] The water-based, highly dispersible pure acrylic polymer described in S4 is shown in Table 4:

[0066] Table 4 Waterborne Highly Dispersible Pure Acrylic Polymers

[0067]

[0068] Furthermore, the polycarboxylic acid dispersant described in S4-1 is selected from sodium polyacrylate.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] 1. This invention discloses a method for preventing corrosion of reinforcing steel bars in concrete structures. The penetrating silane concrete reinforcing steel corrosion inhibitor completely eliminates nitrites and organophosphonates, employing green corrosion inhibitors such as molybdates / tungstates and bio-based solvents, thus avoiding the environmental toxicity problems of traditional organophosphonates. It adopts a "gradient silane compound + nano-graphene oxide" technical route, where the silane coupling agent enhances interfacial adhesion through chemical bonding, and the nanocomposite fills microscopic pores, synergistically improving the physical-chemical dual barrier performance. Nano-silica / graphene oxide fills the pores of the silane film, and the conductivity of graphene oxide inhibits electrochemical corrosion. Graphene oxide also has conductive and anti-corrosion functions, overcoming the limitations of single physical barriers and significantly reducing chloride ion permeability. To ensure long-term protective effects, the silane coupling agent forms covalent bonds with the reinforcing steel matrix, and vinyl silane enhances flexibility, resulting in more stable chemical bonding and resistance to 60 wet-dry cycles without detachment. To further enhance ease of application, a low-viscosity water-based system is selected to support various application methods, making it particularly suitable for complex surface repair. This overcomes the application limitations of internally mixed rust inhibitors, supporting spraying, brushing, and dipping. (Low viscosity...) Adaptable to complex surfaces. This technology is suitable for the repair of existing structures, with a penetration depth of 50-100 μm. Compared with traditional steel reinforcement rust inhibitors, this technology has significant breakthroughs in environmental protection, construction flexibility, and long-term protective performance, and is especially suitable for new construction and repair projects in highly corrosive environments.

[0071] 2. The present invention provides a method for preventing corrosion of reinforcing steel bars in concrete structures. Based on the anti-corrosion requirements of steel bar corrosion inhibitors, a novel high-efficiency epoxy-modified cement mortar has been developed. By introducing nanocomposite technology, a dual-curing system, and environmentally friendly additives, the mechanical properties, durability, and ease of construction of traditional epoxy mortar are significantly improved. The specific component design is as follows:

[0072] Epoxy resin provides long-term adhesion through chemical cross-linking; sulfoaluminate cement rapidly hydrates to form ettringite, achieving rapid construction with "initial setting in 1 hour and final setting in 3 hours," resulting in improved early strength; graphene promotes interfacial bonding between epoxy resin and cement hydration products, enhancing flexural strength; nano-silica + silica fume form a "micron-nano" scale filling network, significantly reducing total porosity and chloride ion penetration depth; utilizing the stability of cationic emulsions ensures... It remains stable in an alkaline environment, avoiding bonding failure caused by emulsion demulsification in traditional acrylic emulsions; the water-based epoxy system, combined with deionized water, has a VOC content far lower than that of traditional solvent-based epoxy mortars (traditional...). ); through bentonite and gas phase By adjusting rheological properties, this technology supports airless spraying, increasing efficiency by 3 times and making it suitable for complex applications such as tunnels and bridges. In summary, this technology solves the core problems of traditional epoxy mortars, such as insufficient strength, slow curing, and poor environmental performance, through three major innovations: a dual-curing system, nanocomposite technology, and environmentally friendly processes. It is especially suitable for harsh environments with high corrosion and high loads.

[0073] 3. The method for preventing rust on reinforcing steel bars in concrete structures described in this invention, based on the anti-corrosion requirements of reinforcing steel bar rust inhibitors, develops an inorganic hybrid waterborne epoxy coating. By introducing nano-hybrid technology, rare earth modification, and self-healing function, the coating's corrosion resistance, ease of application, and environmental adaptability are significantly improved. The specific formula and innovations are as follows:

[0074] Fluorinated reduced graphene oxide sheets are used to create a "maze effect," which extends the diffusion path of corrosive media. Nanoparticles release Generate on metal surface Passivation film blocks the electrochemical corrosion path; Released upon contact with water at microcracks in the coating. ,and Reaction generation Precipitation fills defects and inhibits further corrosion; polyether-modified polysiloxane reduces the system viscosity to Supports airless spraying (atomized particle size) This product can be applied by brushing to cover complex metal surfaces (such as threads and welds); it uses water as a solvent, and the bio-based Cyrene is biodegradable, complying with green environmental protection regulations. This formula overcomes the bottlenecks of traditional water-based epoxy coatings, such as insufficient corrosion resistance and high VOC emissions, through two core technologies: nano-hybrid fillers and rare earth self-healing. It combines highly effective protection with green construction characteristics.

[0075] 4. The method for preventing rust on reinforcing steel bars in concrete structures described in this invention, based on the anti-corrosion requirements of steel bar rust inhibitors, develops a water-based, highly dispersible pure acrylic polymer. Through nanocomposite technology, organosilicon modification, and functional monomer design, it achieves a balance between high efficiency, environmental friendliness, and long-lasting weather resistance. The specific functions of the components are as follows:

[0076] Nanocomposite Enhancement of Weather Resistance: Nano zinc oxide shields 290-400nm ultraviolet rays through a dual mechanism of ultraviolet absorption (UVA) and reflection (UVR); KH-570 hydrolyzes to form a Si-O-Si cross-linked structure with a contact angle >110°, significantly improving water resistance; the carboxyl groups of acrylic acid (AA) achieve stable dispersion of nanoparticles through the synergistic effect of electrostatic repulsion and steric hindrance; at pH=8-9, carboxylate ionization enhances dispersion stability, avoiding the demulsification problem caused by electrolyte sensitivity in traditional emulsions; using water as a solvent, no film-forming aids are added, complying with safety and environmental regulations. The DAAM / ADH cross-linked system achieves local repair at microcracks through hydrogen bond recombination, extending coating life. Attached Figure Description

[0077] Figure 1 This is a construction drawing of a penetrating silane concrete steel reinforcement corrosion inhibitor, as described in an embodiment of the present invention, for a method of preventing corrosion of steel reinforcement in concrete structures.

[0078] Figure 2 This is a primer application drawing for a method of preventing rust on steel bars in concrete structures, as described in an embodiment of the present invention.

[0079] Figure 3 This is an intermediate paint application drawing for a method of preventing rust on reinforcing steel bars in concrete structures, as described in an embodiment of the present invention.

[0080] Figure 4 This is a topcoat application drawing for a method of preventing rust on reinforcing steel bars in a concrete structure, as described in an embodiment of the present invention.

[0081] Figure 5 This is a construction drawing of a method for preventing corrosion of steel bars in concrete structures, as described in an embodiment of the present invention. Detailed Implementation

[0082] The specific embodiments of the present invention will be further described below with reference to examples.

[0083] Example 1:

[0084] A method for preventing corrosion of reinforcing steel bars in concrete structures includes the following steps:

[0085] S1. Preparation of penetrating silane concrete rebar corrosion inhibitor:

[0086] S1-1. Weigh out the following components according to the mass ratio: 12% silane coupling agent (KH-560 compound), 4% nano silica and graphene oxide composite, 3% sodium molybdate-sodium tungstate composite corrosion inhibitor, 8% bio-based penetration aid (Cyrene), 4% polyether modified siloxane, 1.5% polycarboxylic acid dispersant, and the balance being deionized water.

[0087] S1-2. First, put the remaining components, except for nano-silica and graphene oxide composite, into a stainless steel reactor equipped with an anchor stirrer. Control the stirring speed to 50 r / min and premix at room temperature for 20 min until the materials are evenly dispersed. During this period, add 60% of the total amount of deionized water in batches.

[0088] S1-2. Simultaneously, the nano-silica and graphene oxide composite and the remaining deionized water are treated in an ultrasonic dispersion device at a frequency of 20kHz for 30 minutes to form a stable nano-dispersion. Then, the mixture is slowly pumped into the reaction vessel, the stirring speed is increased to 150r / min, and dispersion is continued for 45 minutes.

[0089] S1-3. The pH is adjusted to 6.5-7.5 by monitoring the system with an online pH meter and stirring at low speed for 10 minutes. Finally, the mixture is filtered through a polypropylene microporous membrane filter with a pore size of 0.45μm to remove undispersed particles and impurities.

[0090] According to GB / T 50082-2009, the chloride ion diffusion coefficient was determined to evaluate the inhibitory effect of the rust inhibitor on chloride ion penetration. Chloride ion diffusion coefficient The Rp value was measured by linear scanning. It has excellent rust-inhibiting properties;

[0091] S2. Preparation of epoxy-modified cement mortar:

[0092] S2-1. Prepare the following proportions by mass: 15% bisphenol A epoxy resin (E-51), 8% nitrile rubber modified epoxy resin, 0.5% aminated graphene (accelerator), 30% cationic epoxy emulsion (E-44), 10% ultrafine silica fume (800 mesh), 4% nano silica (50nm), 0.3% polycarboxylate superplasticizer, and 3% bentonite / fumed silica. (Environmentally friendly thixotropic agent), 20% ultrafine sulfoaluminate cement, and the remainder is deionized water;

[0093] S2-2. Add bisphenol A epoxy resin (E-51) and nitrile rubber modified epoxy resin into a jacketed stainless steel reactor (500L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to raise the temperature to 40℃, stir at 120r / min for 10min until completely miscible, add cationic epoxy emulsion (E-44), maintain the temperature and continue stirring at 200r / min for 20min to form a uniform resin base liquid.

[0094] S2-3. Add the aminated graphene and 10% deionized water to an ultrasonic disperser (500W power, 40kHz frequency) and sonicate for 20-30 minutes until no obvious agglomeration occurs. Simultaneously, pre-disperse the nano-silica and polycarboxylate superplasticizer in a high-speed disperser (2000r / min) for 15 minutes to form a nano-slurry. Combine the nano-slurry with the graphene dispersion and slowly add it to the reaction vessel at a rate of 50mL / min using a peristaltic pump. Turn on the high-shear emulsification head (4000r / min) and disperse for 30 minutes.

[0095] S2-4. After screening the ultrafine silica fume and ultrafine sulfoaluminate cement through an 80-mesh vibrating screen, add them to the reactor in three batches (5 minutes apart each time). At the same time, add an environmentally friendly thixotropic agent, reduce the stirring speed to 100 r / min, and use a vacuum system (vacuum degree -0.06MPa) to remove the powder to avoid dust. Continue mixing for 60 minutes until the slurry has uniform fluidity.

[0096] S2-5. Add the remaining deionized water in two batches (add 60% initially, check viscosity until...). Add the remaining amount later, then switch to a screw mixer (80 r / min) for low-speed homogenization, while monitoring particle distribution using an online particle size analyzer. If it does not meet the requirements, it is introduced into a sand mill (speed 1500 r / min) for 20 minutes of circulating grinding;

[0097] S2-6. Detect the pH value of the slurry (target range 7.5-8.5), finely adjust it with 5% NaOH solution or 3% acetic acid solution, and finally sterilize and remove impurities through a 0.22μm polytetrafluoroethylene membrane filter. Then, it is transported to a stainless steel storage tank lined with polyethylene by a gear pump, filled with nitrogen (purity ≥99.9%) and sealed for storage.

[0098] Samples were prepared and their mechanical properties were tested. The results showed that the compressive strength after 28 days was ≥65MPa and the bond strength was ≥3.5MPa, indicating excellent performance.

[0099] S3. Preparation of inorganic hybrid waterborne epoxy coatings:

[0100] S3-1. Accurately weigh each component according to the following mass ratio: 35% epoxy resin emulsion (modified), 5% fluorinated reduced graphene oxide. Hybrid nanofillers, 2% silane coupling agent (KH-560), 8% bio-based self-emulsifying agent (Cyrene), 10% inorganic silica sol (nano) ), 3% sodium molybdate-sodium tungstate composite corrosion inhibitor, 0.5% polyether-modified polysiloxane leveling agent, 1% rare earth-modified cerium oxide ( The remainder is deionized water (sterilized by a 0.22μm filter membrane).

[0101] S3-2. Place the epoxy resin emulsion, silane coupling agent (KH-560), and bio-based self-emulsifier (Cyrene) into a jacketed stainless steel reactor (1000L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to 50℃ and stir at 120r / min for 15min until completely miscible to form a stable emulsion system. The silane coupling agent reacts with the epoxy resin emulsion through its epoxy groups to enhance the interfacial bonding between the inorganic filler and the organic resin.

[0102] S3-3, Fluoride-reduced graphene oxide Hybrid nanofillers and 10% deionized water were added to an ultrasonic disperser (power 800W, frequency 40kHz) and ultrasonically treated for 30 minutes until no obvious agglomeration was observed.

[0103] S3-4. Simultaneously, the inorganic silica sol and polyether-modified polysiloxane leveling agent are pre-dispersed in a high-shear emulsifier (4000 r / min) for 15 min to form a nano-slurry. This slurry is then combined with the graphene dispersion and slowly added to the reactor at a rate of 100 mL / min using a peristaltic pump. The high-shear emulsification head is then turned on (6000 r / min) and dispersed for 30 min. This step ensures the nano-slurry is properly dispersed. Fluorinated reduced graphene oxide Distribute evenly to avoid clumping;

[0104] S3-5. Dissolve the sodium molybdate-sodium tungstate composite corrosion inhibitor in 5% deionized water to form a solution, add it to the reaction vessel, and stir at 150 r / min for 10 min; then add rare earth modified cerium oxide ( A vacuum system (vacuum degree -0.08MPa) is used to extract the powder to avoid dust. The mixture is continuously mixed for 30 minutes until it is evenly dispersed. Sodium molybdate and sodium tungstate work synergistically to form a dense passivation film. Rare earth modified cerium oxide further enhances the corrosion resistance.

[0105] S3-6. Add the remaining deionized water in three batches (add 40% initially, check viscosity until...). Add the remaining amount later, then switch to a screw mixer (80 r / min) for low-speed homogenization, while monitoring particle distribution using an online particle size analyzer. If it does not meet the requirements, it is introduced into a sand mill (zirconia beads, diameter 0.4-0.8mm, filling rate 75%, speed 1800r / min) for 20-30min of circulating grinding;

[0106] The pH value of the slurry was tested (target range 7.0-8.0), and fine-tuned using 5% NaOH solution or 3% acetic acid solution. Finally, it was sterilized and impurities removed by a 0.22μm polytetrafluoroethylene membrane filter, and then transported to a stainless steel storage tank lined with polyethylene by a gear pump. The tank was filled with nitrogen (purity ≥99.9%) and sealed for storage.

[0107] The mechanical properties of the prepared samples were tested. The adhesion exceeded 12 MPa, and no obvious blistering or peeling failures were observed after 1500 h of salt spray testing, demonstrating good resistance to corrosive media.

[0108] S4, Water-based highly dispersible pure acrylic polymer:

[0109] S4-1. Weigh each component precisely according to the following mass ratio: 40% methyl methacrylate (MMA), 30% butyl acrylate (BA), 2% acrylic acid (AA), 5% γ-methacryloyloxypropyltrimethoxysilane (KH-570), 1% nano zinc oxide (nZnO), 3% diacetone acrylamide (DAAM), 0.5% polycarboxylate dispersant, 1% composite light stabilizer, and the balance is deionized water (treated with ion exchange resin).

[0110] S4-2. Add 40% of the total amount of deionized water and all of the polycarboxylate dispersant into a stainless steel emulsification tank (500L volume) with an anchor stirrer. Stir at 200r / min, then add methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA) and silane coupling agent KH-570 monomer in sequence. Stir continuously for 30min to form a uniform pre-emulsion. The silane groups of KH-570 can participate in the crosslinking reaction in the future to improve the water resistance of the coating.

[0111] S4-3. Mix nano zinc oxide with 10% deionized water, add 0.2% (based on nZnO mass) of dispersant (such as sodium polyacrylate), and circulate and grind for 40 minutes using a sand mill (zirconia bead diameter 0.6-1.0 mm, filling rate 70%, speed 2000 r / min) until the particle size D90 ≤ 100 nm. Monitor the particle size distribution in real time using a laser particle size analyzer.

[0112] S4-4. Add the remaining deionized water and 0.3% ammonium persulfate initiator to the jacketed polymerization reactor (volume 1000L, equipped with turbine stirrer), heat to 80℃, add 15% of the total amount of pre-emulsion as seed, keep the reaction at the temperature for 30min to form seed emulsion.

[0113] S4-5. The remaining preemulsion and nano zinc oxide dispersion are added dropwise to the reactor separately using a peristaltic pump. The dropping rate is controlled to maintain the reaction temperature at 82℃. The preemulsion is added over 3 hours, and the nano zinc oxide dispersion is added over an additional 0.5 hours to ensure uniform distribution. When the preemulsion has been added to 50%, diacetone acrylamide (DAAM) aqueous solution (DAAM dissolved in 5% deionized water) is added simultaneously over 2 hours. After the preemulsion is added, the reaction is maintained at this temperature for 1 hour, and then the reaction continues for another hour to reduce residual monomers.

[0114] S4-6. Cool down to below 40℃, add a composite light stabilizer (a combination of hindered amines and benzotriazoles), and adjust the pH to 8-9 with 25% ammonia to enhance the stability of the system. Finally, filter through a 100-mesh filter and place in a storage tank to stand for 24 hours to remove bubbles.

[0115] Mechanical properties, resistance to media, and aging resistance tests were conducted in accordance with standards such as GB50393;

[0116] The results showed that its adhesion was ≥10MPa, its acid resistance was 100d without blistering failure, and its ΔE was <1.5 after 2000 hours of QUV aging.

[0117] S5. On-site construction, the construction process is as follows: Figures 1-5 As shown, the process includes applying the rust inhibitor, primer, intermediate coat, and topcoat, as detailed below:

[0118] S5-1. Remove laitance and loose material from the concrete surface;

[0119] S5-2. Use power tools to grind the concrete substrate as a whole to fully expose the pores on the surface of the concrete substrate, and meet the requirements of SSPC-SP13; the roughness grade of the overall grinding of the concrete substrate is ICRI-CSP2.

[0120] S5-3. Apply a penetrating concrete-penetrating steel reinforcement corrosion inhibitor in two coats, with each coat containing 230 ml / m². 2 The painting interval is approximately 15 minutes.

[0121] S5-4. After the rust-inhibiting material for steel bars is sprayed and dried for 48 hours, an epoxy mortar coating with a dry film thickness of 1000μm is roller-coated or sprayed. After surface drying, an inorganic hybrid waterborne epoxy coating with a dry film thickness of 150μm is roller-coated or sprayed. Finally, a waterborne highly dispersed pure acrylic polymer with a dry film thickness of 80μm is sprayed to achieve long-term protection of steel bars.

[0122] 6. Effect verification: After 10 years of operation in the test area, the steel reinforcement corrosion was checked and no rust was found by visual inspection, and the appearance quality was good.

[0123] Example 2:

[0124] A method for preventing corrosion of reinforcing steel bars in concrete structures includes the following steps:

[0125] S1. Preparation of penetrating silane concrete rebar corrosion inhibitor:

[0126] S1-1. Weigh out the following components according to the mass ratio: 18% silane coupling agent (KH-560 compound), 2% nano silica and graphene oxide composite, 6% sodium molybdate-sodium tungstate composite corrosion inhibitor, 5% bio-based penetration aid (Cyrene), 7% polyether modified siloxane, 0.8% polycarboxylic acid dispersant, and the balance being deionized water.

[0127] S1-2. First, put the remaining components, except for nano-silica and graphene oxide composite, into a stainless steel reactor equipped with an anchor stirrer. Control the stirring speed to 100 r / min and premix at room temperature for 15 min until the materials are evenly dispersed. During this period, add 70% of the total amount of deionized water in batches.

[0128] S1-2. Simultaneously, the nano-silica and graphene oxide composite and the remaining deionized water are treated in an ultrasonic dispersion device at a frequency of 40kHz for 20 minutes to form a stable nano-dispersion. Then, the mixture is slowly pumped into the reaction vessel, the stirring speed is increased to 200r / min, and dispersion is continued for 30 minutes.

[0129] S1-3. The pH is adjusted to 6.5-7.5 by monitoring the system with an online pH meter and stirring at low speed for 10 minutes. Finally, the mixture is filtered through a polypropylene microporous membrane filter with a pore size of 0.45μm to remove undispersed particles and impurities.

[0130] According to GB / T 50082-2009, the chloride ion diffusion coefficient was determined to evaluate the inhibitory effect of the rust inhibitor on chloride ion penetration. Chloride ion diffusion coefficient The Rp value was measured by linear scanning. It has excellent rust-inhibiting properties;

[0131] S2. Preparation of epoxy-modified cement mortar:

[0132] S2-1. Prepare the following proportions by mass: 20% bisphenol A epoxy resin (E-51), 5% nitrile rubber modified epoxy resin, 1.5% aminated graphene (accelerator), 25% cationic epoxy emulsion (E-44), 10% ultrafine silica fume (800 mesh), 4% nano silica (50nm), 0.3% polycarboxylate superplasticizer, and 3% bentonite / fumed silica. (Environmentally friendly thixotropic agent), 20% ultrafine sulfoaluminate cement, and the remainder is deionized water;

[0133] S2-2. Add bisphenol A epoxy resin (E-51) and nitrile rubber modified epoxy resin into a jacketed stainless steel reactor (500L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to raise the temperature to 50℃, stir at 80r / min for 15min until completely miscible, add cationic epoxy emulsion (E-44), maintain the temperature and continue stirring at 200r / min for 20min to form a uniform resin base liquid.

[0134] S2-3. Add the aminated graphene and 10% deionized water to an ultrasonic disperser (500W power, 40kHz frequency) and sonicate for 20-30 minutes until no obvious agglomeration occurs. Simultaneously, pre-disperse the nano-silica and polycarboxylate superplasticizer in a high-speed disperser (3000r / min) for 15 minutes to form a nano-slurry. Combine the nano-slurry with the graphene dispersion and slowly add it to the reaction vessel at a rate of 50mL / min using a peristaltic pump. Turn on the high-shear emulsification head (3000r / min) and disperse for 30 minutes.

[0135] S2-4. After screening the ultrafine silica fume and ultrafine sulfoaluminate cement through an 80-mesh vibrating screen, add them to the reactor in three batches (5 minutes apart each time). At the same time, add an environmentally friendly thixotropic agent, reduce the stirring speed to 150 r / min, and use a vacuum system (vacuum degree -0.06MPa) to remove the powder to avoid dust. Continue mixing for 45 minutes until the slurry has uniform fluidity.

[0136] S2-5. Add the remaining deionized water in two batches (add 60% initially, check viscosity until...). Add the remaining amount later, then switch to a screw mixer (60 r / min) for low-speed homogenization, while monitoring particle distribution using an online particle size analyzer. If it does not meet the requirements, it is introduced into a sand mill (speed 1500 r / min) for 20 minutes of circulating grinding;

[0137] S2-6. Detect the pH value of the slurry (target range 7.5-8.5), finely adjust it with 5% NaOH solution or 3% acetic acid solution, and finally sterilize and remove impurities through a 0.22μm polytetrafluoroethylene membrane filter. Then, it is transported to a stainless steel storage tank lined with polyethylene by a gear pump, filled with nitrogen (purity ≥99.9%) and sealed for storage.

[0138] Samples were prepared and their mechanical properties were tested. The results showed that the compressive strength after 28 days was ≥65MPa and the bond strength was ≥3.5MPa, indicating excellent performance.

[0139] S3. Preparation of inorganic hybrid waterborne epoxy coatings:

[0140] S3-1. Accurately weigh each component according to the following mass ratio: 45% epoxy resin emulsion (modified), 3% fluorinated reduced graphene oxide. Hybrid nanofillers, 4% silane coupling agent (KH-560), 5% bio-based self-emulsifying agent (Cyrene), and 10% inorganic silica sol (nano) ), 3% sodium molybdate-sodium tungstate composite corrosion inhibitor, 0.5% polyether-modified polysiloxane leveling agent, 1% rare earth-modified cerium oxide ( The remainder is deionized water (sterilized by a 0.22μm filter membrane).

[0141] S3-2. Place the epoxy resin emulsion, silane coupling agent (KH-560), and bio-based self-emulsifier (Cyrene) into a jacketed stainless steel reactor (1000L volume, equipped with an anchor stirrer and temperature sensor). Turn on the electric heating to 60℃ and stir at 80r / min for 20min until completely miscible to form a stable emulsion system. The silane coupling agent reacts with the epoxy resin emulsion through its epoxy groups to enhance the interfacial bonding between the inorganic filler and the organic resin.

[0142] S3-3, Fluoride-reduced graphene oxide Hybrid nanofillers and 10% deionized water were added to an ultrasonic disperser (power 800W, frequency 40kHz) and ultrasonically treated for 40 minutes until no obvious agglomeration was observed.

[0143] S3-4. Simultaneously, the inorganic silica sol and polyether-modified polysiloxane leveling agent are pre-dispersed in a high-shear emulsifier (6000 r / min) for 15 min to form a nano-slurry. This slurry is then combined with the graphene dispersion and slowly added to the reactor at a rate of 100 mL / min using a peristaltic pump. The high-shear emulsification head is then turned on (5000 r / min) and dispersed for 30 min. This step ensures the nano-slurry is properly dispersed. Fluorinated reduced graphene oxide Distribute evenly to avoid clumping;

[0144] S3-5. Dissolve the sodium molybdate-sodium tungstate composite corrosion inhibitor in 5% deionized water to form a solution, add it to the reaction vessel, and stir at 200 r / min for 10 min; then add rare earth modified cerium oxide ( A vacuum system (vacuum degree -0.08MPa) is used to extract the powder to avoid dust. The mixture is continuously mixed for 20 minutes until it is evenly dispersed. Sodium molybdate and sodium tungstate work together to form a dense passivation film. Rare earth modified cerium oxide further enhances the corrosion resistance.

[0145] S3-6. Add the remaining deionized water in three batches (add 40% initially, check viscosity until...). Add the remaining amount later, then switch to a screw mixer (60 r / min) for low-speed homogenization, while monitoring particle distribution using an online particle size analyzer. If it does not meet the requirements, it is introduced into a sand mill (zirconia beads, diameter 0.4-0.8mm, filling rate 75%, speed 1800r / min) for 20-30min of circulating grinding;

[0146] The pH value of the slurry was tested (target range 7.0-8.0), and fine-tuned using 5% NaOH solution or 3% acetic acid solution. Finally, it was sterilized and impurities removed by a 0.22μm polytetrafluoroethylene membrane filter, and then transported to a stainless steel storage tank lined with polyethylene by a gear pump. The tank was filled with nitrogen (purity ≥99.9%) and sealed for storage.

[0147] The mechanical properties of the prepared samples were tested. The adhesion exceeded 12 MPa, and no obvious blistering or peeling failures were observed after 1500 h of salt spray testing, demonstrating good resistance to corrosive media.

[0148] S4, Water-based highly dispersible pure acrylic polymer:

[0149] S4-1. Weigh each component precisely according to the following mass ratio: 50% methyl methacrylate (MMA), 20% butyl acrylate (BA), 4% acrylic acid (AA), 3% γ-methacryloyloxypropyltrimethoxysilane (KH-570), 1% nano zinc oxide (nZnO), 3% diacetone acrylamide (DAAM), 0.5% polycarboxylic acid dispersant, 1% composite light stabilizer, and the balance is deionized water (treated with ion exchange resin).

[0150] S4-2. Add 40% of the total amount of deionized water and all of the polycarboxylate dispersant into a stainless steel emulsifying tank (500L volume) with an anchor stirrer. Stir at 300r / min. Add methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA) and silane coupling agent KH-570 monomer in sequence. Stir continuously for 30min to form a uniform pre-emulsion. The silane groups of KH-570 can participate in the crosslinking reaction in the future to improve the water resistance of the coating.

[0151] S4-3. Mix nano zinc oxide with 10% deionized water, add 0.2% (based on nZnO mass) of dispersant (such as sodium polyacrylate), and circulate and grind for 60 minutes using a sand mill (zirconia bead diameter 0.6-1.0 mm, filling rate 70%, speed 2000 r / min) until the particle size D90 ≤ 100 nm. Monitor the particle size distribution in real time using a laser particle size analyzer.

[0152] S4-4. Add the remaining deionized water and 0.3% ammonium persulfate initiator to the jacketed polymerization reactor (volume 1000L, equipped with turbine stirrer), heat to 85℃, add 15% of the total amount of pre-emulsion as seed, keep the reaction at the temperature for 30min to form seed emulsion.

[0153] S4-5. The remaining preemulsion and nano zinc oxide dispersion are added dropwise to the reactor separately using a peristaltic pump. The dropping rate is controlled to maintain the reaction temperature at 85℃. The dropping time of the preemulsion is 3.5h, and the dropping time of the nano zinc oxide dispersion is extended by 0.5h to ensure uniform distribution. When the preemulsion is added to 50%, diacetone acrylamide (DAAM) aqueous solution (DAAM dissolved in 5% deionized water) is added dropwise simultaneously for 2h. After the preemulsion is added, the reaction is kept at the temperature for 1h, and then the reaction is continued for another 1h to reduce residual monomers.

[0154] S4-6. Cool down to below 40℃, add a composite light stabilizer (a combination of hindered amines and benzotriazoles), and adjust the pH to 8-9 with 25% ammonia to enhance the stability of the system. Finally, filter through a 100-mesh filter and place in a storage tank to stand for 24 hours to remove bubbles.

[0155] Mechanical properties, resistance to media, and aging resistance tests were conducted in accordance with standards such as GB50393;

[0156] The results showed that its adhesion was ≥10MPa, its acid resistance was 100d without blistering failure, and its ΔE was <1.5 after 2000 hours of QUV aging.

[0157] S5. On-site construction:

[0158] S5-1. Remove laitance and loose material from the concrete surface;

[0159] S5-2. Use power tools to grind the concrete substrate as a whole to fully expose the pores on the surface of the concrete substrate, and meet the requirements of SSPC-SP13; the roughness grade of the overall grinding of the concrete substrate is ICRI-CSP2.

[0160] S5-3. Apply a penetrating concrete-internal steel reinforcement corrosion inhibitor in four coats, with each coat using 180ml / m². 2 The painting interval is approximately 15 minutes.

[0161] S5-4. After the rust-inhibiting material for steel bars is sprayed and dried for 48 hours, an epoxy mortar coating with a dry film thickness of 1000μm is roller-coated or sprayed. After surface drying, an inorganic hybrid waterborne epoxy coating with a dry film thickness of 150μm is roller-coated or sprayed. Finally, a waterborne highly dispersed pure acrylic polymer with a dry film thickness of 80μm is sprayed to achieve long-term protection of steel bars.

[0162] 6. Effect verification: After 10 years of operation in the test area, the steel reinforcement corrosion was checked and no rust was found by visual inspection, and the appearance quality was good.

[0163] Comparative Example

[0164] A control test was conducted on a localized area of ​​a concrete project at a petrochemical terminal. No protection was provided for the reinforcing steel. Ten years later, the concrete was removed, and the surface of the reinforcing steel was inspected for corrosion. It was found that the steel had been severely corroded, with reddish-brown rust deposits and pitting depth of 0.1 mm.

[0165] Results and Discussion:

[0166] By comparing the examples and comparative examples, it can be seen that after 10 years of operation, the steel reinforcement corrosion in the test area showed no rust reappearance and good appearance quality. In contrast, no protection was applied to the steel reinforcement. After 10 years, the concrete was removed, and the steel reinforcement surface was inspected for severe corrosion, with reddish-brown rust deposits and pitting depth of 0.1 mm. This method demonstrates a long-lasting and significant effect in preventing rust on steel reinforcement within concrete structures, offering excellent economic benefits. It effectively solves the problem of steel reinforcement corrosion in existing engineering structures, preventing potential safety hazards to structural durability.

[0167] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preventing corrosion of reinforcing steel bars in concrete structures, characterized in that, Includes the following steps: S1. Preparation of penetrating silane concrete rebar corrosion inhibitor: S1-1. Weigh out the following components according to the mass ratio: 12-18% silane coupling agent, 2-4% nano-silica and graphene oxide composite, 3-6% sodium molybdate-sodium tungstate composite corrosion inhibitor, 5-8% bio-based penetration aid, 4-7% polyether-modified siloxane, 0.8-1.5% polycarboxylic acid dispersant, and the balance being deionized water. S1-2. First, put the remaining components, except for nano-silica and graphene oxide composite, into a stainless steel reactor equipped with an anchor stirrer. Control the stirring speed to 50-100 r / min and premix at room temperature for 15-20 min until the material is evenly dispersed. During this period, add 60-70% of the total amount of deionized water in batches. S1-2. Simultaneously, the nano-silica and graphene oxide composite and the remaining deionized water are treated in an ultrasonic dispersion device at a frequency of 20-40kHz for 20-30 minutes to form a stable nano-dispersion. Then, the mixture is slowly pumped into the reaction vessel, the stirring speed is increased to 150-200r / min, and dispersion is continued for 30-45 minutes. S1-3. The pH is adjusted to 6.5-7.5 by monitoring the system with an online pH meter and stirring at low speed for 10 minutes. Finally, the mixture is filtered through a polypropylene microporous membrane filter with a pore size of 0.45μm to remove undispersed particles and impurities. S2. Preparation of epoxy-modified cement mortar: S2-1. Prepare the following proportions by mass: 15-20% bisphenol A epoxy resin, 5-8% nitrile rubber modified epoxy resin, 0.5-1.5% aminated graphene, 25-30% cationic epoxy emulsion, 10-15% ultrafine silica fume, 2-4% nano silica, 0.3-0.8% polycarboxylate superplasticizer, and 1-3% bentonite / fumed silica. 20-25% ultrafine sulfoaluminate cement, with the balance being deionized water; S2-2. Add bisphenol A epoxy resin and nitrile rubber modified epoxy resin into a jacketed stainless steel reactor with a volume of 500L. Equipped with an anchor stirrer and a temperature sensor, turn on the electric heating to raise the temperature to 40-50℃, and stir at 80-120r / min for 10-15min until completely miscible. Add cationic epoxy emulsion, maintain the temperature and continue stirring at 150-200r / min for 20min to form a uniform resin base liquid. S2-3. Add the aminated graphene and 10% deionized water to an ultrasonic disperser at a power of 500W and a frequency of 40kHz, and sonicate for 20-30 minutes until no obvious agglomeration occurs. Simultaneously, pre-disperse the nano-silica and polycarboxylate superplasticizer in a high-speed disperser for 15 minutes at a speed of 2000-3000 r / min to form a nano-slurry. Combine the slurry with the graphene dispersion and slowly add it to the reaction vessel at a rate of 50 mL / min using a peristaltic pump. Turn on the high-shear emulsification head and disperse for 30 minutes at a speed of 3000-4000 r / min. S2-4. After sieving the ultrafine silica fume and ultrafine sulfoaluminate cement through an 80-mesh vibrating screen, add them to the reactor in three batches, with a 5-minute interval between each batch. At the same time, add an environmentally friendly thixotropic agent, reduce the stirring speed to 100-150 r / min, use a vacuum system with a vacuum degree of -0.06 MPa to remove powder and avoid dust generation, and continue mixing for 45-60 minutes until the slurry has uniform fluidity. S2-5. Add the remaining deionized water in two batches, adding 60% initially and checking the viscosity until... Add the remaining amount, then switch to a screw mixer for low-speed homogenization at 60-80 r / min. At the same time, monitor the particle distribution using an online particle size analyzer. D50≤10μm, D90≤30μm. If the particle size distribution does not meet the requirements, transfer the mixture to a sand mill for 20-30 min of circulating grinding at 1500 r / min. S2-6. Detect the pH value of the slurry, with a target range of 7.5-8.

5. Fine-tune it using 5% NaOH solution or 3% acetic acid solution. Finally, sterilize and remove impurities by passing it through a 0.22μm polytetrafluoroethylene membrane filter, and then transport it to a stainless steel storage tank lined with polyethylene through a gear pump. Fill the tank with nitrogen gas with a purity of ≥99.9% and seal it for storage. S3. Preparation of inorganic hybrid waterborne epoxy coatings: S3-1. Accurately weigh each component according to the following mass ratio: 35-45% epoxy resin emulsion, 3-5% fluorinated reduced graphene oxide. Hybrid nanofiller, 2-4% KH-560 silane coupling agent, 5-8% bio-based self-emulsifying agent, 10-15% inorganic silica sol, 1-3% sodium molybdate-sodium tungstate composite corrosion inhibitor, 0.5-1.5% polyether-modified polysiloxane leveling agent, 0.5-1% rare earth-modified cerium oxide, and the balance being deionized water sterilized through a 0.22μm filter membrane; S3-2. Place the epoxy resin emulsion, KH-560 silane coupling agent, and bio-based self-emulsifier into a jacketed stainless steel reactor with a volume of 1000L. Equipped with an anchor-type stirrer and a temperature sensor, turn on the electric heating to 50-60℃ and stir at a speed of 80-120r / min for 15-20min until completely miscible to form a stable emulsion system. The silane coupling agent reacts with the epoxy resin emulsion through its epoxy groups to enhance the interfacial bonding between the inorganic filler and the organic resin. S3-3, Fluoride-reduced graphene oxide The hybrid nanofiller and 10% deionized water were added to an ultrasonic disperser at a power of 800W and a frequency of 40kHz, and ultrasonically treated for 30-40 minutes until there was no obvious agglomeration. S3-4. Simultaneously, the inorganic silica sol and polyether-modified polysiloxane leveling agent are pre-dispersed for 15 minutes in a high-shear emulsifier at a speed of 4000-6000 r / min to form a nano-slurry. This slurry is then combined with the graphene dispersion and slowly added to the reactor at a rate of 100 mL / min using a peristaltic pump. The high-shear emulsification head is then turned on, and the dispersion is carried out at a speed of 5000-6000 r / min for 30 minutes. This step ensures the nano-slurry is properly dispersed. Fluorinated reduced graphene oxide Distribute evenly to avoid clumping; S3-5. Dissolve the sodium molybdate-sodium tungstate composite corrosion inhibitor in 5% deionized water to form a solution. Add the solution to the reactor and stir at 150-200 r / min for 10 min. Then add rare earth modified cerium oxide and use a vacuum system to remove the powder to avoid dust generation. The vacuum degree is -0.08 MPa. Continue mixing for 20-30 min until uniformly dispersed. Sodium molybdate and sodium tungstate work synergistically to form a dense passivation film, and rare earth modified cerium oxide further enhances the corrosion resistance. S3-6. Add the remaining deionized water in three batches, starting with 40% added initially, and check the viscosity until... Add the remaining amount, switch to a screw mixer at 60-80 r / min for low-speed homogenization, and monitor the particle distribution using an online particle size analyzer. The particle size distribution should be D50≤8μm and D90≤25μm. If the particle size distribution does not meet the requirements, transfer the mixture to a sand mill with zirconia beads of 0.4-0.8 mm in diameter and a filling rate of 75%. Grind the mixture at 1800 r / min for 20-30 minutes. S4, Water-based highly dispersible pure acrylic polymer: S4-1. Weigh each component precisely according to the following mass ratio: 40-50% methyl methacrylate, 20-30% butyl acrylate, 2-4% acrylic acid, 3-5% γ-methacryloyloxypropyltrimethoxysilane, 1-3% nano zinc oxide, 2-3% diacetone acrylamide, 0.5-1.5% polycarboxylic acid dispersant, 0.5-1% composite light stabilizer, and the balance is deionized water treated with ion exchange resin. S4-2. Add 40% of the total amount of deionized water and all of the polycarboxylate dispersant to a 500L stainless steel emulsification kettle equipped with an anchor stirrer. Stir at 200-300r / min, then add methyl methacrylate, butyl acrylate, acrylic acid and silane coupling agent KH-570 monomer in sequence. Continue stirring for 30min to form a uniform pre-emulsion. S4-3. Mix nano zinc oxide with 10% deionized water, add 0.2% polycarboxylic acid dispersant based on the mass of nZnO, and use a sand mill with zirconium oxide beads of 0.6-1.0 mm diameter, a filling rate of 70%, a rotation speed of 2000 r / min, and circulate and grind for 40-60 min until the particle size D90≤100nm. Monitor the particle size distribution in real time using a laser particle size analyzer. S4-4. Add the remaining deionized water and 0.3% ammonium persulfate initiator to a 1000L polymerization reactor equipped with a turbine stirrer and jacket. Heat to 80-85℃, add 15% of the total amount of pre-emulsion as seed, and keep the reaction at the temperature for 30 minutes to form seed emulsion. S4-5. Add the remaining preemulsion and nano zinc oxide dispersion separately to the reactor using a peristaltic pump, controlling the dropping rate to maintain the reaction temperature at 82-85℃. The dropping time for the preemulsion is 3-3.5 hours, and the dropping time for the nano zinc oxide dispersion is extended by 0.5 hours to ensure uniform distribution. When the preemulsion reaches 50%, start adding diacetone acrylamide aqueous solution simultaneously for 2 hours. After the preemulsion is added, keep the reaction at the temperature for 1 hour, and continue the reaction for another hour to reduce residual monomers. S4-6. Cool down to below 40℃, add composite light stabilizer, and adjust pH to 8-9 with 25% ammonia to enhance system stability. Finally, filter through a 100-mesh filter and pour into a storage tank to stand for 24 hours to degas. S5. On-site construction: S5-1. Remove laitance and loose material from the concrete surface; S5-2. Use power tools to grind the concrete substrate as a whole to fully expose the pores on the surface of the concrete substrate, and meet the requirements of SSPC-SP13; the roughness grade of the overall grinding of the concrete substrate is ICRI-CSP2. S5-3. Apply a penetrating concrete-internal steel reinforcement corrosion inhibitor, 2-4 coats, each coat using 180-230 ml / m². 2 The painting interval is 15 minutes. S5-4. After the rust-inhibiting material for steel bars is sprayed and dried for 48 hours, an epoxy mortar coating with a dry film thickness of 1000μm is roller-coated or sprayed. After surface drying, an inorganic hybrid waterborne epoxy coating with a dry film thickness of 150μm is roller-coated or sprayed. Finally, a waterborne highly dispersed pure acrylic polymer with a dry film thickness of 80μm is sprayed to achieve long-term protection of steel bars. S6. Effect Verification: After 10 years of operation in the treated area, check the steel reinforcement corrosion. If no rust is found by visual inspection and the appearance quality is good, it indicates that the effect is excellent.

2. The method for preventing corrosion of reinforcing steel bars in concrete structures according to claim 1, characterized in that, The silane coupling agent described in S1-1 is selected from KH-560 compound.

3. The method for preventing corrosion of reinforcing steel bars in concrete structures according to claim 1, characterized in that, The pH adjustment described in S1-3 uses a 5% (w / w) dilute hydrochloric acid or sodium hydroxide solution.

4. The method for preventing corrosion of reinforcing steel bars in concrete structures according to claim 1, characterized in that, The bisphenol A epoxy resin described in S2-1 is selected from model E-51; the cationic epoxy emulsion is selected from model E-44; the ultrafine silica fume is selected from 800 mesh; and the nano silica has a particle size of 50 nm.

5. A method for preventing corrosion of reinforcing steel bars in concrete structures according to claim 1, characterized in that, The silane coupling agent described in S3-1 is selected from KH-560; the inorganic silica sol is selected from nano-sized... ; Rare earth modified cerium oxide, selected from .

6. A method for preventing corrosion of reinforcing steel bars in concrete structures according to claim 1, characterized in that, The polycarboxylic acid dispersant described in S4-1 is selected from sodium polyacrylate.

Images