Preparation method of waterborne epoxy asphalt coating

Abstract

The invention discloses a preparation method and application of a waterborne epoxy asphalt coating, and belongs to the technical field of coating preparation. Aiming at the problems of poor compatibility, insufficient stability and the like of the existing waterborne epoxy asphalt coating, the performance breakthrough is realized through a multi-component synergistic modification and staged crosslinking process. The coating prepared by the method is excellent in storage stability, the adhesive force reaches grade 0, the tensile strength is greater than or equal to 12.5 MPa, the water resistance and the corrosion resistance are remarkably improved, and a full-water-based system is environment-friendly and solvent-free. The material is suitable for the fields of bridge steel structure corrosion prevention, road crack repair and the like, and has high performance and cost advantages.

Description

Technical Field

[0001] The present invention belongs to the technical field of coating preparation, and particularly relates to a preparation method and application of a waterborne epoxy asphalt coating. Background Art

[0002] Asphalt coatings have good waterproof and anti-corrosion properties and are widely used in fields such as construction and transportation. However, traditional solvent-based asphalt coatings contain a large amount of organic solvents, which will volatilize harmful gases during production and construction, causing harm to the environment and human health. With the continuous improvement of environmental protection requirements, waterborne asphalt coatings have gradually become a research hotspot.

[0003] Waterborne epoxy asphalt coatings combine the high strength and high adhesion of epoxy resins with the good waterproof and anti-corrosion properties of asphalt, and have the advantages of environmental protection, safety, and convenient construction. However, there are currently some problems in the preparation process of waterborne epoxy asphalt coatings, such as poor compatibility between epoxy resins and asphalt, poor stability of the coatings, slow drying speed, etc., which affect their application scope.

[0004] To solve these problems, a large number of studies have been carried out. For example, by modifying epoxy resins to improve their compatibility with asphalt, in patent document CN202411692304.9, an acrylate copolymer is added to a waterborne epoxy resin coating, and a composite reaction is carried out in combination with epoxy resin, emulsifier, and co-stabilizer to prepare an epoxy composite resin emulsion. Further, through a mixing reaction with emulsified asphalt, curing agent, and water, a waterborne epoxy resin coating with toughness and improved hardness is prepared. However, this method has a complex reaction process and high cost. At the same time, there may be certain problems with the compatibility between the acrylate copolymer and epoxy resin. During the composite reaction and subsequent emulsion storage process, phase separation may occur, resulting in a decrease in emulsion stability;

[0005] People also add additives to improve the stability and drying speed of coatings, etc. In patent document CN201710344313.2, polyvinyl alcohol, sodium silicate, and epoxy resin are used to synthesize epoxy-modified polyvinyl alcohol latex through a cross-linking modification process, partially or completely replacing chloroprene latex or amino polyvinyl alcohol solution to prepare a sodium silicate and epoxy resin-modified polyvinyl alcohol emulsified asphalt coating. However, in this method, during the storage of the synthesized epoxy-modified polyvinyl alcohol latex, sodium silicate may undergo a slow secondary reaction with polyvinyl alcohol and epoxy resin, resulting in a gradual increase in the viscosity of the latex system, and even phenomena such as gelation and precipitation, reducing the storage life and use performance of the latex. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method of a waterborne epoxy asphalt coating. The waterborne epoxy asphalt coating prepared by this method is simple to prepare, and at the same time has good compatibility, stability and drying speed, and also has excellent waterproof and anti-corrosion properties.

[0007] In order to achieve the above object, the present application provides a preparation method of a waterborne epoxy asphalt coating, which is characterized in that

[0008] The mass percentage components of the waterborne epoxy asphalt coating include:

[0009] Component A: 30%-50% of waterborne epoxy resin, 20%-40% of waterborne emulsified asphalt, 5%-15% of modified nano-fillers, 0.15%-0.25% of defoamer, 0.5%-2% of wetting agent, 0.6%-0.8% of pH regulator, 0.3%-0.5% of thickener, appropriate amount of water;

[0010] Component B: 5%-10% of composite curing agent, 0.3%-0.5% of dispersant, 0.2%-0.3% of anti-settling agent, 0.15%-0.25% of defoamer, appropriate amount of water;

[0011] Component C: 40%-60% of sodium silicate, 0.5%-2% of wetting agent, 0.5%-2% of photo-controlled enzyme, 1%-5% of calcium bicarbonate, appropriate amount of water;

[0012] The steps of the preparation method are as follows:

[0013] Prepare Component A. First, add water, wetting agent, defoamer, and modified nano-fillers to a paint mixing tank and disperse them at low speed for 5-30 minutes, then add the waterborne epoxy resin and disperse it at medium speed for 5-30 minutes. Subsequently, add the pH regulator to adjust the pH of the system to 9-10 and disperse for 1-10 minutes, then add the waterborne emulsified asphalt and disperse it at medium and low speed for 5-30 minutes. Finally, add the thickener to adjust the viscosity and disperse it at low speed for 5-30 minutes to prepare the required Component A coating;

[0014] Prepare Component B. According to the amounts in the formula, first add water, defoamer, dispersant, and anti-settling agent to a paint mixing tank and disperse them at low speed for 5-30 minutes, then add the composite curing agent and disperse it at medium and low speed for 10-30 minutes to prepare Component B;

[0015] Prepare Component C. According to the amounts in the formula, first add sodium silicate, wetting agent, and water to a paint mixing tank and disperse them at low speed for 5-30 minutes to obtain a premixed liquid, then add calcium bicarbonate and photo-controlled enzyme to obtain a prefabricated slurry, and disperse it at medium and low speed for 10-30 minutes to prepare Component C; The photo-controlled enzyme is preferably a photo-responsive metal-organic framework dynamic confinement enzyme (PCN-224-CAT).

[0016] Mix component A and component B, and stir at a low speed for 1 - 5 min to obtain a mixed solution. Subsequently, add component C and stir for 1 - 5 min under light irradiation with a wavelength range of 320 nm to 400 nm, and then stir for 5 - 30 min under light irradiation at a wavelength of 450 nm to 495 nm to obtain an aqueous epoxy asphalt coating. First, mix component A and component B. The curing agent first undergoes a preliminary cross-linking and ring-opening addition reaction with the epoxy resin. At the same time, through the synergistic effect of the compound emulsifier, the emulsified asphalt particles form a preliminary physical entanglement with the resin, forming a prototype of the "resin - asphalt" interpenetrating network. Then, add component C. When the component C containing sodium silicate is added to the preliminarily cross-linked epoxy asphalt coating, the sodium silicate can accurately fill the pores at the resin - asphalt interface. At the same time, the preliminary network formed by pre-cross-linking provides attachment sites for the sodium silicate and the photo-controlled enzyme, enhancing the interfacial adhesion between the components. Utilize the characteristics of the photo-controlled enzyme under light irradiation of different wavelengths to control the cross-linking reaction of sodium silicate in stages. The photo-controlled enzyme is rapidly activated under short-wavelength light (320 - 400 nm), catalyzing the rapid cross-linking of sodium silicate; it maintains the reaction stability under long-wavelength light (450 - 495 nm) to ensure the uniform formation of the silicon-oxygen network. First, rapidly activate the reaction with short-wavelength light, and then use long-wavelength light to ensure the reaction stability. At the same time, calcium bicarbonate (Ca(HCO3)2) decomposes to release Ca2 + and HCO3 - , Ca2 + combines with silicate to form calcium silicate (CaSiO3), enhancing the mechanical strength of the cross-linking network; at the same time, HCO3 - adjusts the system pH and optimizes the reaction conditions. The uniform and dense silicon-oxygen network structure formed after the curing of sodium silicate by such a process can effectively block the erosion of external factors such as ultraviolet rays, moisture, and oxygen on the epoxy asphalt coating, fundamentally solving the problems of coating storage stratification and precipitation, and greatly improving the stability of the coating; and making the coating form a uniform and dense cross-linked structure after film formation, significantly enhancing the mechanical properties such as the adhesion, tensile strength, and elongation at break of the coating, and at the same time improving the protection properties such as waterproofing, acid and alkali resistance, and anti-aging, which can meet the long-term use requirements under complex working conditions in fields such as construction and transportation.

[0017] Furthermore, the modified nano-filler is nano-silica modified by a silane coupling agent, with a particle size of 20 - 50 nm. The nano-silica is modified by a silane coupling agent such as KH-550 and added to the waterborne epoxy resin emulsion, effectively improving the dispersibility of nano-silica in the coating system. The modified nano-silica can be evenly distributed inside the coating, forming a three-dimensional network reinforcement structure, just like constructing countless microscopic "steel bars" in the coating. It interacts with epoxy resin and asphalt, significantly enhancing the mechanical strength of the coating, enabling it to better resist damage when subjected to external impact and wear. The addition and modification of nano-silica greatly enhance the corrosion resistance of the coating. On the one hand, nano-silica has a small particle size and a large specific surface area, which can fill the pores and defects in the coating, forming a dense shielding layer to effectively block the penetration of corrosive media (such as moisture, oxygen, salt ions, etc.); on the other hand, after being modified by a silane coupling agent, a strong chemical bond is formed between nano-silica and the coating matrix, further improving the stability of the coating, delaying the occurrence of corrosion reactions, and extending the service life of the coating.

[0018] Furthermore, the composite curing agent is a polyamide curing agent and dicyandiamide compounded in a mass ratio of 1 - 3:1. The curing system using an amine curing agent and dicyandiamide as the compounded curing agent achieves the dual effects of rapid room-temperature curing and high-temperature deep cross-linking of the waterborne epoxy asphalt coating, greatly improving the comprehensive performance and construction adaptability of the coating.

[0019] Furthermore, the waterborne emulsified asphalt is emulsified by a non-ionic and an anionic emulsifier, and the non-ionic and anionic emulsifiers are compounded in a mass ratio of 2 - 3:1. By compounding the non-ionic emulsifier and the anionic emulsifier in a specific mass ratio of 2 - 3:1, the synergistic effect of the two emulsifiers is fully exerted, effectively reducing the interfacial tension between asphalt and epoxy resin, enhancing the intermolecular interaction force between the two, and significantly improving the compatibility of asphalt and epoxy resin. This makes the coating not easy to stratify and precipitate during storage, greatly improving its stability; during the film-forming process, it can form a uniform and dense coating structure, thereby improving the comprehensive performance of the coating.

[0020] Furthermore, the pH regulator is one or more of ammonia water, sodium hydroxide, and potassium hydroxide.

[0021] Furthermore, the defoaming agent is one or more of silicone defoaming agents and polyether defoaming agents.

[0022] Furthermore, the thickener is one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, and polyacrylate thickeners.

[0023] Further, the wetting agent is one or more of polyethylene glycol, sodium dodecyl sulfate, Tween series or silane coupling agent.

[0024] The present invention also provides an application of the coating prepared by the above method in the anti-corrosion of bridge steel structures or the repair of road cracks.

[0025] Beneficial effects of the present invention:

[0026] (1) After the waterborne epoxy resin and emulsified asphalt are preliminarily cured and crosslinked, component C containing sodium silicate is added. The sodium silicate forms a silicon-oxygen network structure after curing, fills the pores between the epoxy resin and the asphalt, enhances the interfacial adhesion force, and improves the coating adhesion force; by utilizing the characteristics of the photo-controlled enzyme under different wavelength illuminations, the crosslinking reaction of sodium silicate is controlled in stages. First, the reaction is rapidly activated by short-wavelength light, and then the reaction stability is ensured by long-wavelength light, greatly improving all aspects of the performance of the coating.

[0027] (2) The performance of the multi-component synergistic enhancement system is improved. The nano-silica modified by silane coupling agent forms a three-dimensional network structure after being uniformly dispersed, significantly improving the mechanical strength (tensile strength, elongation at break) and corrosion resistance of the coating, and effectively blocking the penetration of moisture and salt ions; the polyamide curing agent and latent dicyandiamide are compounded in a ratio of 2:1, taking into account the rapid curing at room temperature (rapid ring-opening reaction of polyamide) and deep crosslinking at high temperature (release of active groups by dicyandiamide at high temperature), shortening the drying time, and at the same time improving the coating hardness and chemical corrosion resistance; the waterborne emulsified asphalt is compounded with a non-ionic (fatty alcohol polyoxyethylene ether) and an anionic (sodium dodecylbenzenesulfonate) emulsifier in a ratio of 3:1, reducing the interfacial tension, enhancing the intermolecular interaction between the epoxy resin and the asphalt, solving the problems of storage stratification and precipitation of traditional coatings, and greatly improving the stability.

[0028] (3) The all-waterborne system does not contain organic solvents, and there is no harmful gas volatilization during the production and construction processes, meeting the environmental protection requirements and being applicable to indoor and outdoor as well as sensitive environments. Raw materials such as sodium silicate and nano-silica are inexpensive, and the dosage of high-price additives is reduced through compounding technology, reducing the production cost and at the same time improving the cost performance of the coating. Specific embodiments

[0029] The following further describes the present application in detail. It is necessary to point out here that the following specific embodiments are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0030] I. Materials and methods

[0031] The methods used in this embodiment are all conventional methods known to those skilled in the art unless otherwise specified. The reagents and other materials used are all commercially available products unless otherwise specified.

[0032] Example 1

[0033] (I) Formula (mass percentage)

[0034] Component A: 40% waterborne epoxy resin, 30% waterborne emulsified asphalt, 10% modified nano-silica (modified with KH-550, 20nm), 0.2% organosilicon defoamer, 1% Tween-80 (wetting agent), 0.7% ammonia water (pH regulator), 0.4% hydroxyethyl cellulose (thickener), and the balance is water.

[0035] Component B: 8% composite curing agent of polyamide 650 and dicyandiamide (mass ratio 2:1), 0.2% polyether defoamer, 0.4% dispersant (sodium hexametaphosphate), 0.25% anti-settling agent (organic bentonite BS-1C), and the balance is water.

[0036] Component C: 55% water glass, 1.5% sodium dodecyl sulfate (wetting agent), 1% metal-organic framework dynamic-confined enzyme (PCN-224-CAT), 3% calcium bicarbonate, and the balance is water.

[0037] (II) Preparation steps

[0038] Preparation of Component A: Add water, Tween-80, organosilicon defoamer, and modified nano-silica to the paint mixing tank, and disperse at low speed (200 r / min) for 15 min; add waterborne epoxy resin and disperse at medium speed (400 r / min) for 20 min; add ammonia water to adjust the pH to 9.5 and disperse for 5 min; add waterborne emulsified asphalt (a compound of non-ionic and anionic emulsifiers with a mass ratio of 3:1) and disperse at medium-low speed (300 r / min) for 20 min; add hydroxyethyl cellulose to adjust the viscosity and disperse at low speed for 15 min.

[0039] Preparation of Component B: Add water, polyether defoamer, dispersant, and anti-settling agent to the paint mixing tank, and disperse at low speed for 10 min; add the composite curing agent and disperse at medium-low speed (300 r / min) for 20 min.

[0040] Preparation of Component C: Add water glass, sodium dodecyl sulfate, and water to the paint mixing tank, and disperse at low speed for 15 min; add calcium bicarbonate and metal-organic framework dynamic-confined enzyme (PCN-224-CAT) and disperse at medium-low speed (300 r / min) for 20 min.

[0041] Mixing and Photo - controlled Cross - linking: Components A and B are mixed and stirred at a low speed (100 r / min) for 3 min; Component C is added, and first irradiated with 365 - nm short - wavelength light while stirring at a speed of 150 r / min for 3 min; then switched to 460 - nm long - wavelength light for irradiation while stirring at a speed of 200 r / min for 15 min to obtain the coating.

[0042] Comparative Example 1

[0043] In Component A, "modified nano - silica" is replaced with unmodified nano - silica (20 nm), and the rest is the same as in Example 1.

[0044] Comparative Example 2

[0045] In Component B, "compound curing agent" is replaced with single polyamide 650 (without dicyandiamide), and the dosage is 8%, and the rest is the same as in Example 1.

[0046] Comparative Example 3

[0047] In Component B, the ratio of polyamide - based curing agent to dicyandiamide is changed to 0.5:1, and the rest is the same as in Example 1.

[0048] Comparative Example 4

[0049] In Component B, the ratio of polyamide - based curing agent to dicyandiamide is changed to 4:1, and the rest is the same as in Example 1.

[0050] Comparative Example 5

[0051] The emulsifier of water - based emulsified asphalt is replaced with a single non - ionic emulsifier, and the rest is the same as in Example 1.

[0052] Comparative Example 6

[0053] In water - based emulsified asphalt, the ratio of non - ionic emulsifier to anionic emulsifier is changed to 1:1, and the rest is the same as in Example 1.

[0054] Comparative Example 7

[0055] In water - based emulsified asphalt, the ratio of non - ionic emulsifier to anionic emulsifier is changed to 4:1, and the rest is the same as in Example 1.

[0056] Comparative Example 8

[0057] Only irradiated with 365 - nm short - wavelength light, without irradiating with 460 - nm long - wavelength light, and the rest is the same as in Example 1.

[0058] Comparative Example 9

[0059] Only irradiated with 460 - nm long - wavelength light, without irradiating with 365 - nm short - wavelength light, and the rest is the same as in Example 1.

[0060] Comparative Example 10

[0061] First, long-wavelength irradiation of 460 nm is performed, and then short-wavelength irradiation of 365 nm is performed. The rest is the same as in Example 1.

[0062] Comparative Example 11

[0063] The "light-controlled enzyme" in component C is removed, and the other components remain unchanged, and no light cross-linking is performed after mixing. The rest is consistent with Example 1.

[0064] Comparative Example 12

[0065] Component A and component B are not pre-crosslinked, and components A, B, and C are directly mixed together at the same time. The rest is the same as in Example 1.

[0066] Table 1 shows the performance parameters of the coatings in Example 1 and Comparative Examples 1-11. For details on the testing methods of the performance parameters, please refer to "Test Methods for Building Waterproof Coatings" (GB / T 16777-2008).

[0067] Table 1

[0068]

[0069] Through the experimental data of Example 1 and Comparative Example 1, we can see that compared with Example 1, the tensile strength of Comparative Example 1 is reduced from 12.5MPa to 8.2MPa, the elongation at break is reduced from 48% to 32%, and the corrosion resistance is also reduced. It can be seen that the nano-silica modified by the silane coupling agent forms a chemical bond with the epoxy resin / asphalt through a silicon-oxygen bond, forming a three-dimensional network reinforcement structure inside the coating, such as a "micro-steel bar" supporting the matrix, thereby improving the mechanical strength; the unmodified nano-silica has poor dispersibility in the aqueous system due to the unmodified surface hydrophilic groups, is easy to agglomerate, and only physically fills the pores, and cannot form effective chemical bonds, resulting in a significant decrease in strength and corrosion resistance.

[0070] Through the experimental data of Example 1 and Comparative Examples 2-4, we can see that in Comparative Example 2, the actual drying time of single polyamide 650 is prolonged and the corrosion resistance is reduced. Due to the lack of high-temperature cross-linking with dicyandiamide, the cross-linking density of the coating is insufficient; in Comparative Example 3, polyamide: dicyandiamide = 0.5:1, the storage stability is deteriorated, moderate stratification, the surface drying time is prolonged, and the reaction at room temperature is blocked due to excessive dicyandiamide; in Comparative Example 4, when polyamide: dicyandiamide = 4:1, the actual drying time is shortened but the water resistance is reduced, which may be related to the loose cross-linking network caused by excessive polyamide. Polyamide 650 (normal temperature fast drying) and dicyandiamide (high temperature deep cross-linking) are compounded according to specific components to achieve "normal temperature rapid film formation + high temperature densification", which not only meets the construction efficiency, but also improves the chemical resistance of the coating through the secondary cross-linking of the cyanamide group of dicyandiamide in the epoxy group.

[0071] It can be seen from Example 1 and Comparative Examples 5-7 that in Comparative Example 5 (single non-ionic type), the storage stability is the worst (obvious delamination), the adhesion drops to Grade 2. Due to the lack of the electrostatic repulsion of the anionic emulsifier, the interfacial tension between asphalt and resin particles is high, and the compatibility is poor; Comparative Examples 6 / 7 (1:1 / 4:1): The performance is between Example 1 and Comparative Example 5. At a ratio of 3:1, the synergistic effect of non-ionic (steric hindrance) and anionic (electrostatic repulsion) is the best. This is because the non-ionic (such as fatty alcohol polyoxyethylene ether) provides a hydration film, and the anionic (such as sodium dodecylbenzenesulfonate) provides negative charge repulsion. The 3:1 ratio balances the two forces, making the stability of asphalt and epoxy resin emulsion the best.

[0072] It can be seen from Example 1 and Comparative Examples 8-11 that in Comparative Example 8, only short-wave irradiation is carried out, and the water resistance decreases. Because only the short wave (365nm) quickly activates the photo-controlled enzyme and then does not stabilize the reaction through the long wave (460nm), the cross-linked network is incomplete; in Comparative Example 9, only long-wave irradiation is carried out, the surface drying time is prolonged, the photo-controlled enzyme is not effectively activated, and the reaction rate decreases; in Comparative Example 10, the order of long wave and short wave is reversed, and the adhesion drops to Grade 1. First long wave and then short wave lead to the premature passivation of the enzyme active center and the reduction of cross-linking sites; in Comparative Example 11, there is no photo-controlled enzyme and light irradiation, the performance deteriorates comprehensively, the storage delamination is serious, and the corrosion resistance fails completely, confirming that the staged cross-linking of the photo-controlled enzyme is the core mechanism for forming the silicon-oxygen network and the dense coating.

[0073] It can be seen from Example 1 and Comparative Example 12 that if A, B, and C are directly mixed without pre-crosslinking and curing components A and B first, the adhesion strength, tensile strength, elongation at break, water resistance, and corrosion resistance of the coating all decrease to varying degrees. This is because after component A (aqueous epoxy resin + emulsified asphalt) and component B (compound curing agent) are premixed, the curing agent first undergoes a preliminary cross-linking and ring-opening addition reaction with the epoxy resin. At the same time, the emulsified asphalt particles form a preliminary physical entanglement with the resin through the synergistic effect of the compound emulsifier, forming a prototype of the "resin-asphalt" interpenetrating network. The preliminary network formed by pre-crosslinking provides an attachment site for sodium silicate and the photo-controlled enzyme, enabling sodium silicate to accurately fill the pores at the resin-asphalt interface. In Comparative Example 12, due to the lack of a skeleton support, sodium silicate is randomly distributed in the coating, forming ineffective agglomerations and unable to effectively enhance the interfacial bonding force.

[0074] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, several improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A preparation method of a waterborne epoxy asphalt coating, characterized in that, The mass percentage components of the waterborne epoxy asphalt coating include: Component A: 30%-50% of waterborne epoxy resin, 20%-40% of waterborne emulsified asphalt, 5%-15% of modified nano-fillers, 0.15%-0.25% of defoamer, 0.5%-2% of wetting agent, 0.6%-0.8% of pH regulator, 0.3%-0.5% of thickener, appropriate amount of water; Component B: 5%-10% of composite curing agent, 0.3%-0.5% of dispersant, 0.2%-0.3% of anti-settling agent, 0.15%-0.25% of defoamer, appropriate amount of water; Component C: 40%-60% of water glass, 0.5%-2% of wetting agent, 0.5%-2% of light-controlled enzyme, 1%-5% of calcium bicarbonate, appropriate amount of water; The steps of the preparation method are as follows: Prepare Component A. First, add water, wetting agent, defoamer, and modified nano-fillers to a paint mixing tank and disperse them at low speed for 5-30 minutes, then add waterborne epoxy resin and disperse it at medium speed for 5-30 minutes. Subsequently, add a pH regulator to adjust the pH of the system to 9-10 and disperse it for 1-10 minutes. Then add waterborne emulsified asphalt and disperse it at medium and low speed for 5-30 minutes. Finally, add a thickener to adjust the viscosity and disperse it at low speed for 5-30 minutes to prepare the required Component A coating; Prepare Component B. According to the amounts in the formula, first add water, defoamer, dispersant, and anti-settling agent to a paint mixing tank and disperse them at low speed for 5-30 minutes, then add the composite curing agent and disperse it at medium and low speed for 10-30 minutes to prepare Component B; Prepare Component C. According to the amounts in the formula, first add water glass, wetting agent, and water to a paint mixing tank and disperse them at low speed for 5-30 minutes to obtain a premixed solution. Then add calcium bicarbonate and light-controlled enzyme to obtain a prefabricated slurry and disperse it at medium and low speed for 10-30 minutes to prepare Component C; Mix Component A and Component B, stir at low speed for 1-5 min to obtain a mixed solution, then add Component C, stir for 1-5 min under light irradiation with a wavelength range of 320 nm to 400 nm, and then stir for 5-30 min under light irradiation with a wavelength of 450 nm to 495 nm to obtain the waterborne epoxy asphalt coating.

2. The method according to claim 1, characterized in that, The modified nano-fillers are nano-silica modified by a silane coupling agent, with a particle size of 20-50 nm.

3. The method according to claim 1, characterized in that, The composite curing agent is a polyamide-based curing agent and dicyandiamide compounded at a mass ratio of 1-3:

1.

4. The method according to claim 1, wherein The waterborne emulsified asphalt is emulsified by a non-ionic and an anionic emulsifier, and the non-ionic and anionic emulsifiers are compounded at a mass ratio of 2-3:

1.

5. The method according to claim 1, characterized in that, The pH regulator is one or more of ammonia water, sodium hydroxide, and potassium hydroxide.

6. The method according to claim 1, wherein The defoamer is one or more of silicone defoamers and polyether defoamers.

7. The method according to claim 1, characterized in that, The thickener is one or more of hydroxyethyl cellulose, hydroxypropyl cellulose, and polyacrylate thickeners.

8. The method according to claim 1, wherein The wetting agent is one or more of polyethylene glycol, sodium dodecyl sulfate, Tween series, or silane coupling agent.

9. Application of the coating prepared by the method according to any one of claims 1-8 in anti-corrosion of bridge steel structures or repair of road cracks.

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