A protective coating for the surface of cement concrete structural members, its preparation method, coating layer, and coating application method thereof.

Abstract

This application relates to the field of concrete protective materials technology, specifically disclosing a protective coating for the surface of cement concrete components, its preparation method, coating layer, and coating application method. This application employs a primer with organosilane as the core component, an intermediate coat with water-based epoxy resin as the core component, and a topcoat with water-based paint base as the core component. Through the three-layer structure of primer, intermediate coat, and topcoat, the protective coating of this application can protect concrete from the inside out in all directions, significantly improving the durability of concrete and thus fully achieving long-lasting protection. This helps overcome the defect that inorganic ions such as chloride ions easily exacerbate concrete corrosion and reduces the corrosion of concrete in coastal engineering environments.

Description

Technical Field

[0001] This application relates to the field of concrete protective materials technology, and more specifically, it relates to a protective coating for the surface of cement concrete components, its preparation method, coating, and coating application method. Background Technology

[0002] Cement concrete structures are multiphase, porous structures. Because they are often exposed to the elements, they are easily affected by external factors such as air, water, and de-icing salt, leading to deterioration of both their internal structure and appearance. For cement concrete structures located near marine environments, they must also withstand the additional damage caused by tidal cycles, temperature stress from diurnal temperature variations, and salt spray carried by sea breezes, significantly shortening their service life. To meet stringent construction requirements, surface protection is necessary for cement concrete structures.

[0003] Currently, coastal engineering concrete generally adopts salt-resistant dense concrete technology, and in necessary parts, it is also surface-impregnated with high-concentration organic solvent-based silane impregnation materials for protection. One related technology is a surface protective agent for cement concrete components, which is prepared by the following method: (1) Polyboron siloxane is put into a high-temperature mixer and the temperature is adjusted to 175°C. After the polyboron siloxane is completely melted, calcined kaolin, clay and heavy metal powder are evenly dispersed in the polyboron siloxane to obtain a blend. The blend is calcined at high temperature, crushed and added to diatomaceous earth slurry. After uniform stirring, magnesium chloride is added and stirred evenly to obtain a silane adsorbent; (2) Isooctyltriethoxysilane, cage-type silsesquioxane and silane adsorbent are evenly mixed for 2 hours to obtain an intermediate; (3) Silane coupling agent KH-550 and water are added to the intermediate and mixed evenly to obtain a preform; (4) Hydrochloric acid polymerization inhibitor is added to the preform and reacted for 6 hours; the hydrochloric acid solution is removed by heating and sodium hydroxide is added to obtain the protective agent. The protective agent can be sprayed or brushed onto the surface or damaged parts of the cement concrete component to complete the protective treatment of the component.

[0004] Regarding the aforementioned technologies, the inventors believe that although the measures in these technologies can achieve surface protection of concrete components, the protection approach of this method is relatively singular, the actual protective effect is limited, and the chloride ions introduced by the components such as magnesium chloride and hydrochloric acid polymerization inhibitors will exacerbate the corrosion of concrete, which is not conducive to improving the durability of concrete components. Summary of the Invention

[0005] The protective methods in related technologies are relatively singular, with limited actual protective effects. Moreover, the chloride ions introduced during construction can exacerbate concrete corrosion, which is detrimental to improving the durability of concrete components. To overcome this deficiency, this application provides a protective coating for the surface of cement concrete components, its preparation method, the coating itself, and its application method.

[0006] In a first aspect, this application provides a protective coating for the surface of cement concrete components, employing the following technical solution: A protective coating for the surface of cement concrete components, comprising a primer, an intermediate coat, and a topcoat, wherein the primer comprises the following components in parts by weight: 12-15 parts of organosilane, 1.2-1.3 parts of calcined activated diatomaceous earth, 0.5-0.7 parts of slag powder, 0.8-0.9 parts of redispersible latex powder, 2.5-2.7 parts of modified nanoparticles, 0.55-0.60 parts of warm wheel adhesive, and 80-85 parts of water; wherein the modified nanoparticles are nano-silica with polycarboxylic acid segments grafted onto their surface; the intermediate coat comprises water-based epoxy resin, a curing agent, and a diluent; and the topcoat comprises water-based paint base, pigments, fillers, additives, and water.

[0007] By adopting the above technical solution, the polycarboxylic acid segments on the surface of the modified nanoparticles in the silane adhesive can adsorb onto both the calcium-containing mineral phase on the concrete surface and the calcined activated diatomaceous earth and slag powder, thus fixing the calcined activated diatomaceous earth and slag powder and providing a large number of adhesion sites for organosilanes. The warm-rolled adhesive significantly improves the viscosity of the primer, strengthening the bond between the primer and the concrete surface. The redispersible latex powder has excellent extensibility and strength properties, reducing shrinkage deformation after the primer film forms. Under the synergistic effect of the modified nanoparticles, warm-rolled adhesive, and redispersible latex powder, the organosilane can fully adhere to the concrete surface and form a strong protective film after the primer cures. This film does not introduce additional chloride ions into the concrete surface, and the slag powder in it also has the ability to solidify chloride ions, effectively limiting chloride ion penetration. Based on this, this application also uses an intermediate paint with waterborne epoxy resin as the core component and a topcoat with waterborne paint base material as the core component. Waterborne epoxy resin imparts excellent flexibility to the intermediate coat, enabling it to adapt to minor deformations on the concrete surface and helping to ensure the durability of the protective effect. The topcoat provides an aesthetically pleasing appearance to the concrete surface while improving resistance to natural factors such as ultraviolet radiation and acid rain. The three-layer structure consisting of primer, intermediate coat, and topcoat provides comprehensive protection for concrete from the inside out, significantly improving its durability and achieving long-lasting protection through synergistic effects. By using the protective coating for cement concrete components of this application, the defects of inorganic ions such as chloride ions easily aggravating concrete corrosion can be overcome, effectively reducing the corrosion of concrete in coastal engineering environments. In addition, the utilization of slag in this application achieves the rational disposal of waste, and the protective coatings of this application are all water-based solvents, with no volatile organic compound emissions, fully meeting environmental protection requirements.

[0008] Preferably, the calcined activated diatomaceous earth is prepared according to the following method:

[0009] (1) After grinding and sieving the raw diatomaceous earth, it is added to water along with sodium hexametaphosphate. After ultrasonic treatment, it is diluted with water, allowed to stand and separate into layers, and the upper slurry is taken. After standing and separating into layers again, the upper suspension is removed, and the bottom mud is taken for filtration and washing. After drying the filter cake, refined diatomaceous earth is obtained.

[0010] (2) The diatomaceous earth concentrate is calcined, cooled, and then washed with an alkaline solution, followed by an acidic solution, and finally washed with water and dried to obtain calcined activated diatomaceous earth.

[0011] By adopting the above technical solution, this application first sorts the raw diatomaceous earth, utilizing the difference in particle suspension and settling velocity to remove impurities such as solidified clay minerals, quartz, and stone chips from the raw diatomaceous earth, obtaining refined diatomaceous earth. After calcination, the residual organic matter in the refined diatomaceous earth is removed, and then some oxide impurities are removed by alkali washing and acid washing, resulting in calcined activated diatomaceous earth with a high specific surface area. This provides more attachment sites for organosilanes, which helps to fully protect against external erosion.

[0012] Preferably, the calcination temperature in the calcination operation is 570-620℃.

[0013] By adopting the above technical solution, this application has optimized the calcination temperature of calcined activated diatomaceous earth, which can effectively increase the specific surface area of ​​calcined activated diatomaceous earth, thereby providing more attachment sites for organosilanes and helping to fully protect against external erosion.

[0014] Preferably, the modified nanoparticles are prepared according to the following method:

[0015] Nano-silica, anhydrous ethanol, water, vinylalkoxysilane, and hydrochloric acid are mixed and heated to obtain a modified silica dispersion. A monomer and an initiator are added to the modified silica dispersion under water bath heating conditions to carry out the reaction. After the reaction is completed, the mixture is naturally cooled, filtered, dried, and then ground to obtain modified nanoparticles. The monomer includes acrylic acid.

[0016] By adopting the above technical solution, this application uses a silane coupling agent to modify nano-silica, grafting vinyl groups onto the surface of nano-silica, and then initiating copolymerization between vinyl groups and monomers under the action of an initiator, forming polycarboxylic acid segments on the surface of nano-silica, thus obtaining modified nanoparticles.

[0017] Preferably, the monomer used in the method for preparing the modified nanoparticles also includes glycidyl acrylate.

[0018] By adopting the above technical solution, glycidyl acrylate can introduce epoxy groups into the polycarboxylic acid segments. These epoxy groups can react with the curing agent during the curing of the intermediate coat, thereby strengthening the bonding force between the primer and the intermediate coat and helping to fully protect against external erosion.

[0019] Preferably, the monomers used in the method for preparing the modified nanoparticles also include unsaturated fatty acids.

[0020] By adopting the above technical solution, unsaturated fatty acids can introduce long-chain alkyl groups into polycarboxylic acid segments, which improves the compatibility between polycarboxylic acid segments and organosilanes and helps to improve the adhesion of organosilanes on concrete surfaces.

[0021] Preferably, in the method for preparing the modified nanoparticles, the unsaturated fatty acid includes linolenic acid.

[0022] By adopting the above technical solution, linolenic acid contains multiple unsaturated bonds. After each of these unsaturated bonds copolymerizes with the monomer, multiple branches can be formed. The formation of the branch structure can improve the adsorption effect of polycarboxylic acid segments on concrete surfaces, as well as calcined activated diatomaceous earth and slag powder, thereby further increasing the attachment sites of organosilanes and helping to improve the adhesion effect of organosilanes on concrete surfaces.

[0023] Secondly, this application provides a method for preparing a protective coating for the surface of cement concrete structural members, using the following technical solution.

[0024] A method for preparing a protective coating for the surface of cement concrete structural members includes the following steps:

[0025] Organosilane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, warm wheel adhesive, and water are added to a reaction vessel and stirred under constant temperature heating to obtain a primer, which is set aside. Component A containing water-based epoxy resin and component B containing curing agent and diluent are mixed evenly, and water is added to adjust to a workable viscosity to obtain an intermediate coat, which is set aside. Water-based paint base, pigments, fillers, additives, and water are mixed evenly to obtain a topcoat, which is set aside.

[0026] By adopting the above technical solution, this application has formulated a primer, intermediate coat, and topcoat, which, when combined, yield a protective coating for the surface of cement concrete components. Through this on-site preparation method, the protective coating for cement concrete components does not introduce additional chloride ions into the concrete surface, effectively reducing cracking caused by chloride ion erosion and contributing to the long-lasting protection of the concrete.

[0027] Thirdly, this application provides a coating, which adopts the following technical solution.

[0028] A coating is made of any of the above-described protective coatings for cement concrete components, wherein the coating comprises, from the inside out, a water-soluble organosilane spraying material layer made of primer, a resin-based polymer film coating material layer made of intermediate paint, and a miscible water-based paint material layer made of topcoat.

[0029] By adopting the above technical solution, this application sequentially uses primer, intermediate coat and topcoat to form a water-soluble organosilane spray material layer, a resin-based polymer film material layer and a miscible water-based paint material layer. The above three-layer structure can protect concrete from the inside out in all directions, significantly improve the durability of concrete, and fully realize the long-lasting protection of concrete through synergistic effect.

[0030] Fourthly, this application provides a coating application method, which adopts the following technical solution.

[0031] A method for applying a protective coating to the surface of cement concrete structural members includes the following steps:

[0032] (1) The concrete structure surface is cleaned and then the damaged parts of the concrete structure surface are repaired with mortar; the raw material components of the mortar include rice husk ash and calcium sulfate whiskers.

[0033] (2) A primer is sprayed onto the surface of the concrete structure and allowed to dry to form a water-soluble organosilane spray material layer.

[0034] (3) Apply intermediate paint to the surface of the concrete structure and let it dry to form a resin-based polymer film material layer.

[0035] (4) Apply topcoat to the concrete structure surface and let it dry to form a layer of water-based paint material.

[0036] By adopting the above technical solution, in areas with severe erosion, where concrete components requiring post-protective treatment typically already have a certain degree of surface damage, this application first uses mortar for repair in the construction method, specifying that the mortar contains rice husk ash and calcium sulfate whiskers. Rice husk ash effectively inhibits mortar carbonation and improves its resistance to sulfate attack, while calcium sulfate whiskers directly reinforce the mortar. Besides physical reinforcement, calcium sulfate whiskers also chemically react with calcium aluminate and calcium hydroxide in the cement paste to generate ettringite and other substances that fill pores, thereby indirectly increasing strength. The synergistic effect of these two components helps prevent protective failure due to mortar peeling, thus improving the protective effect of the coating on the concrete.

[0037] In summary, this application has the following beneficial effects:

[0038] 1. This application employs a primer with organosilane as the core component, an intermediate coat with water-based epoxy resin as the core component, and a topcoat with water-based paint base as the core component. Through the three-layer structure of primer, intermediate coat, and topcoat, the protective coating of this application can protect concrete from the inside out in all directions, significantly improving the durability of concrete, thereby achieving long-lasting protection of concrete through synergistic effects.

[0039] 2. The protective coating for cement concrete components of this application can, to a certain extent, overcome the defect that inorganic ions such as chloride ions easily exacerbate concrete corrosion, thus reducing the corrosion of concrete in coastal engineering environments. Furthermore, the utilization of slag in this application achieves the rational disposal of waste, and all protective coatings in this application use water as a solvent, with no volatile organic compound emissions, fully meeting environmental protection requirements.

[0040] 3. This application introduces epoxy resin into the polycarboxylic acid segments of the modified nanoparticles. The epoxy groups in the polycarboxylic acid segments can react with the curing agent during the curing of the intermediate coat, thereby strengthening the bonding force between the primer and the intermediate coat and helping to fully protect against external erosion.

[0041] 4. In this application, a mortar containing rice husk ash and calcium sulfate whiskers is used to repair concrete components in the construction method. The synergistic effect of rice husk ash and calcium sulfate whiskers helps to avoid the protective failure caused by mortar peeling, thereby improving the protective effect of the coating formed by the protective coating on the concrete. Detailed Implementation

[0042] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0043] Preparation example of calcined activated diatomaceous earth

[0044] The following explanation uses Preparation Example 1 as an example.

[0045] Preparation Example 1

[0046] In this preparation example, calcined activated diatomaceous earth was prepared according to the following method:

[0047] (1) After grinding the raw diatomaceous earth and passing it through an 80-mesh sieve, weigh 20g of the raw diatomaceous earth and mix it with 0.1g of sodium hexametaphosphate. Add the mixture to 60g of water and let it stand for 24 hours. After ultrasonic treatment for 10 minutes, dilute it with water to a solid content of 10%. After standing for 5 minutes, take the upper slurry. After standing for 2 hours again, remove the upper suspension. Take the bottom mud and filter and wash it. After drying the filter cake, you will get refined diatomaceous earth.

[0048] (2) The diatomaceous earth was calcined at 550℃ for 5 hours. After cooling, it was first alkali washed at 45℃ for 1 hour with 3wt% sodium hydroxide solution at a liquid-solid ratio of 3:1. Then it was acid washed with 40wt% sulfuric acid solution at a liquid-solid ratio of 6:1 for 75 minutes. Finally, it was washed with water and dried to obtain calcined activated diatomaceous earth.

[0049] Preparation Example 2

[0050] The difference between this preparation example and Preparation Example 1 is that the calcination temperature is 570°C.

[0051] Preparation Example 3

[0052] The difference between this preparation example and Preparation Example 1 is that the calcination temperature is 600℃.

[0053] Preparation Example 4

[0054] The difference between this preparation example and Preparation Example 1 is that the calcination temperature is 620℃.

[0055] Preparation examples of modified nanoparticles

[0056] The following explanation uses Preparation Example 5 as an example.

[0057] Preparation Example 5

[0058] In this preparation example, the modified nanoparticles were prepared according to the following method:

[0059] 50g of nano-silica, 840g of anhydrous ethanol, 360g of water, and 5g of vinyltriethoxysilane were mixed and the pH was adjusted to 3.5 with 0.1mol / L hydrochloric acid. The mixture was reacted in a water bath at 60℃ for 1 hour to obtain a modified silica dispersion. 150g of acrylic acid monomer and 1g of ammonium persulfate initiator were added to the modified silica and the mixture was reacted at 70℃ for 4 hours. After the reaction was completed, the mixture was allowed to cool naturally. The product was then filtered, dried, and ground to obtain modified nanoparticles.

[0060] Preparation Example 6

[0061] The difference between this preparation example and preparation example 5 is that, in the method for preparing modified nanoparticles, the monomer used also includes glycidyl acrylate, and the amount of glycidyl acrylate used is 10g.

[0062] Preparation Example 7

[0063] The difference between this preparation example and preparation example 6 is that, in the method for preparing modified nanoparticles, the monomer used also includes oleic acid, and the amount of oleic acid used is 15g.

[0064] Preparation Example 8

[0065] The difference between this preparation example and preparation example 7 is that oleic acid is replaced with the same weight of linolenic acid.

[0066] Preparation Example 9

[0067] The difference between this preparation example and preparation example 8 is that the monomer does not include glycidyl acrylate.

[0068] Example

[0069] Examples 1-3

[0070] The following description uses Example 1 as an example.

[0071] Example 1

[0072] In this embodiment, the organosilane is a mixture of isooctyltriethoxysilane, cage-type silsesquioxane and KH-550 in a weight ratio of 3:1:3. The calcined activated diatomaceous earth is prepared according to the method of Preparation Example 1. The slag powder is the grinding product of S95 slag, and the average particle size of the slag powder is 1.2 μm. The redispersible latex powder is Wacker redispersible latex powder 5044N. The modified nanoparticles are prepared according to the method of Preparation Example 6.

[0073] This embodiment provides a protective coating for the surface of cement concrete components, including a primer, an intermediate coat, and a topcoat.

[0074] The primer comprises the following components by weight: 12 kg of organosilane, 1.2 kg of calcined activated diatomaceous earth, 0.5 kg of slag powder, 0.8 kg of redispersible latex powder, 2.5 kg of modified nanoparticles, 0.55 kg of warm wheel adhesive, and 80 kg of water.

[0075] The intermediate varnish consists of component A and component B. The molar ratio between the epoxy equivalent of component A and the active hydrogen equivalent of component B is 0.85:1. Component A is a waterborne epoxy resin, specifically composed of 45wt% bisphenol A type epoxy resin (E-51), 0.5wt% tetrabutylammonium bromide, 10wt% lactic acid, and 44.5wt% deionized water. Component B consists of a curing agent (Bayer MF20, CAS:35498) and a diluent in a weight ratio of 1:0.02. The diluent is butanediol diglycidyl ether.

[0076] The specific composition of the topcoat is as follows: 40wt% water-based paint base, 15wt% pigment, 15wt% filler, 10wt% additives, and 20wt% water. The water-based paint base is PT-008 water-based clear concrete paint, provided by Fenyangtang (Shanghai) Industrial Co., Ltd. The pigment is iron oxide ash, the filler is S95 slag powder, and the additives are composed of Efka 3570 leveling agent, Datian DT-605 defoamer, and water-based coating dispersant SN5027 in a weight ratio of 1:2.2:6.5.

[0077] This embodiment provides a method for preparing a protective coating for the surface of cement concrete structural members, including the following steps:

[0078] Organosilane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, warm wheel adhesive, and water are added to a reaction vessel and stirred for 30 minutes under constant temperature heating at 50°C to obtain a primer, which is set aside. Component A containing water-based epoxy resin and component B containing curing agent and diluent are mixed evenly, and water is added to adjust to a workable viscosity to obtain an intermediate coat, which is set aside. Water-based paint base, pigments, fillers, additives, and water are mixed evenly to obtain a topcoat, which is set aside.

[0079] This embodiment also provides a coating made of the above-mentioned protective coating for cement concrete components. The coating is applied to the surface of the concrete substrate and, from the inside out, includes a water-soluble organosilane spray material layer made of primer, a resin-based polymer film layer made of intermediate paint, and a mixed water-based paint material layer made of topcoat.

[0080] This embodiment also provides a method for applying a protective coating to the surface of cement concrete structural members, including the following steps:

[0081] (1) Clean the surface of the concrete structure, and then repair the damaged parts of the concrete structure surface with mortar. The amount of mortar is 5 kg per square meter, and the curing time is 7 days. The mortar includes the following components: 8 kg of P.O42.5 cement, 2 kg of rice husk ash, 4 kg of water, 30 kg of river sand, and 0.3 kg of calcium sulfate whiskers. The average particle size of the rice husk ash is 65 μm, the fineness modulus of the river sand is 2.7, and the average diameter of the calcium sulfate whiskers is 0.8 μm and the average length is 20 μm.

[0082] (2) Apply primer to the concrete structure surface at a dosage of 0.2 kg per square meter, and allow it to dry to form a water-soluble organosilane spray material layer.

[0083] (3) Apply intermediate paint to the concrete structure surface at a dosage of 0.1 kg per square meter, and let it dry to form a resin-based polymer film material layer.

[0084] (4) Apply topcoat to the concrete structure surface at a dosage of 0.05 kg per square meter, and let it dry to form a layer of water-based paint material.

[0085] As shown in Table 1, the main difference between Examples 1-3 is that the raw material ratios of the primer are different.

[0086] Table 1. Raw material ratio of primer

[0087] sample Example 1 Example 2 Example 3 organosilanes / kg 12 14 15 Calcinated activated diatomaceous earth / kg 1.2 1.25 1.3 Slag powder / kg 0.5 0.6 0.7 redispersible latex powder / kg 0.8 0.85 0.9 Modified nanoparticles / kg 2.5 2.6 2.7 Warm roller adhesive / kg 0.55 0.57 0.60 Water / kg 80 82 85

[0088] Examples 3-6

[0089] As shown in Table 2, the difference between Examples 3-6 lies in the different preparation methods of calcined activated diatomaceous earth.

[0090] Table 2 Examples of preparation of calcined activated diatomaceous earth

[0091] sample Preparation Example Example 3 Preparation Example 1 Example 4 Preparation Example 2 Example 5 Preparation Example 3 Example 6 Preparation Example 4

[0092] Examples 7-10

[0093] As shown in Table 3, the difference between Example 5 and Examples 7-10 is that the preparation examples of the modified nanoparticles are different.

[0094] Table 3 Examples of preparation of modified nanoparticles

[0095]

[0096]

[0097] Comparative Example

[0098] Comparative Example 1

[0099] In this comparative example, the surface protective agent for cement concrete components was applied to the concrete structure surface at a dosage of 0.35 kg per square meter.

[0100] In this comparative example, the diatomaceous earth slurry was prepared according to the following method:

[0101] A surface protective agent for cement concrete components is prepared using the following method:

[0102] Weigh diatomaceous earth, methyl methacrylate, redispersible latex powder (Wacker redispersible latex powder 5044N), titanate coupling agent (tetrabutyl titanate), KH-550, and cumene hydrogen peroxide according to the weight ratio of 20:40:10:3:1:0.1. Add titanate coupling agent and KH-550 to methyl methacrylate and stir evenly. Continue to add diatomaceous earth and redispersible latex powder and stir evenly. Add cumene hydrogen peroxide and initiate polymerization at 120°C. After reacting for 4 hours, a diatomaceous earth slurry is obtained.

[0103] (1) 1 kg of polyborosiloxane was put into a high-speed mixer and the temperature was adjusted to 175°C. After the polyborosiloxane was completely melted, 1 kg of calcined kaolin, 0.5 kg of clay and 0.3 kg of barite powder were evenly dispersed in the polyborosiloxane to obtain a blend. The blend was calcined at 550°C and pulverized to an average particle size of 2 μm. Then it was added to 1.7 kg of diatomaceous earth slurry and stirred evenly. 0.5 kg of magnesium chloride was added and stirred evenly to obtain the silane adsorbent.

[0104] (2) Mix 3 kg of isooctyltriethoxysilane, 1 kg of cage-type silsesquioxane, and 0.3 kg of silane adsorbent evenly for 2 h to obtain an intermediate;

[0105] (3) Add 3 kg of silane coupling agent KH-550 and 50 kg of water to the intermediate, mix evenly, and obtain the preform;

[0106] (4) Add 25 kg of 20 wt% hydrochloric acid inhibitor to the preform and react for 6 h; remove the hydrochloric acid solution by heating, and then add 8 kg of 20 wt% sodium hydroxide solution to obtain the protective agent.

[0107] Comparative Example 2

[0108] The difference between this comparative example and Example 1 is that the primer does not include calcined activated diatomaceous earth.

[0109] Comparative Example 3

[0110] The difference between this comparative example and Example 1 is that the primer does not include slag powder.

[0111] Comparative Example 4

[0112] The difference between this comparative example and Example 1 is that the primer does not include redispersible latex powder.

[0113] Comparative Example 5

[0114] The difference between this comparative example and Example 1 is that the primer does not include warming roller adhesive.

[0115] Comparative Example 6

[0116] The difference between this comparative example and Example 1 is that the primer does not include modified nanoparticles.

[0117] Comparative Example 7

[0118] The difference between this comparative example and Example 1 is that the primer is replaced with an intermediate coat.

[0119] Comparative Example 8

[0120] The difference between this comparative example and Example 1 is that, in the construction method of the protective coating on the surface of cement concrete components, the raw material components of the mortar do not include calcium sulfate whiskers.

[0121] Performance testing methods

[0122] C30 concrete cube specimens (150 mm side length, 90 days age) from the same batch were selected. Coatings were applied to the surface of the specimens according to the methods described in the examples and comparative examples. After coating formation, the concrete specimens were immersed in a 3.5 wt% sodium chloride solution. After 28 days, the specimens were crushed, and the chloride ion content in the debris was measured. Using the chloride ion content measured in Comparative Example 1 as a benchmark, the ratio between the chloride ion content measured in each example and comparative example and the chloride ion content measured in Comparative Example 1 was calculated. This ratio was recorded as the relative chloride content, and the results are shown in Table 4.

[0123] Table 4 Relative Chlorine Content

[0124] sample Relative chlorine content / % sample Relative chlorine content / % Example 1 73.8 Example 10 65.9 Example 2 72.5 Comparative Example 1 100.0 Example 3 72.1 Comparative Example 2 79.6 Example 4 70.5 Comparative Example 3 82.3 Example 5 68.4 Comparative Example 4 77.5 Example 6 69.7 Comparative Example 5 76.9 Example 7 67.6 Comparative Example 6 83.4 Example 8 66.4 Comparative Example 7 91.2 Example 9 63.8 Comparative Example 8 82.8

[0125] As can be seen from Examples 1-3 and Comparative Example 1, and in conjunction with Table 4, the relative chloride content measured in Examples 1-3 is relatively low. This is because this application specifies a primer with organosilane as the core component, an intermediate coat with waterborne epoxy resin as the core component, and a topcoat with waterborne paint base as the core component. Through the three-layer structure of primer, intermediate coat, and topcoat, the protective coating of this application can protect concrete from the inside out, significantly improving the durability of concrete, thereby achieving long-lasting protection of concrete through synergistic effects. Although the amount of protective agent used in Comparative Example 1 is comparable to that in Examples 1-3, its structure is relatively simple, and chloride ions are introduced during the preparation process, resulting in a large number of chloride ions penetrating into the interior of the concrete specimen, failing to fully exert its anti-corrosion performance, and thus failing to meet the construction needs of coastal engineering.

[0126] Combining Example 1 and Comparative Example 2 with Table 4, it can be seen that the relative chloride content measured in Example 1 is lower. This is because the primer in Comparative Example 2 lacks calcined activated diatomaceous earth, which cannot provide sufficient adhesion sites for organosilanes, thus affecting the protective performance of the primer. As a result, more chloride ions penetrate into the interior of the concrete specimen.

[0127] Combining Example 1 and Comparative Example 3 with Table 4, it can be seen that the relative chloride content measured in Example 1 is lower. This is because the primer in Comparative Example 3 lacks slag powder, which cannot provide sufficient adhesion sites for organosilanes, and the chloride ions cannot be cured by slag. Therefore, more chloride ions penetrate into the interior of the concrete specimen.

[0128] Combining Example 1 and Comparative Examples 4-6 with Table 4, it can be seen that the relative chloride content measured in Example 1 is lower. This is because Comparative Examples 4-6 cannot exert the synergistic effect of modified nanoparticles, warm wheel adhesive and redispersible latex powder, resulting in the coating formed by the primer not providing sufficient protection. Therefore, more chloride ions penetrate into the interior of the concrete specimen.

[0129] Combining Example 1 and Comparative Example 7 with Table 4, it can be seen that the relative chloride content measured in Example 1 is lower. This is because the coating of Comparative Example 7 lacks organosilane, which cannot achieve effective protection through the synergistic cooperation between the various film layers, resulting in more chloride ions penetrating into the interior of the concrete specimen.

[0130] Combining Example 1 and Comparative Example 8 with Table 4, it can be seen that the relative chloride content measured in Example 1 is lower. This is because calcium sulfate whiskers react chemically with calcium aluminate and calcium hydroxide in the cement paste to form ettringite and other substances that fill the pores and hinder the intrusion of chloride ions. Comparative Example 8, however, does not contain calcium sulfate whiskers, thus resulting in a greater intrusion of chloride ions into the concrete specimen.

[0131] As can be seen from Examples 3 and 4-6 and Table 4, the calcined activated diatomaceous earth prepared after calcination at 570-620℃ is more helpful in improving the protective effect of the coating.

[0132] As can be seen from Examples 5 and 7 and Table 4, the relative chlorine content measured in Example 7 is relatively low. This is because the polycarboxylic acid segments on the surface of the modified nanoparticles in Example 7 contain epoxy groups, which can react with the curing agent during the curing of the intermediate coat, thereby strengthening the bonding force between the primer and the intermediate coat and helping to fully protect against external erosion.

[0133] As can be seen from Examples 7 and 8 and Table 4, the relative chlorine content measured in Example 8 is lower. This is because unsaturated fatty acids can introduce long-chain alkyl groups into the polycarboxylic acid segments, which improves the compatibility between the polycarboxylic acid segments and organosilanes, helps to improve the adhesion of organosilanes on the concrete surface, and reduces the intrusion of chloride ions.

[0134] As can be seen from Examples 8 and 9 and Table 4, the relative chloride content measured in Example 8 is relatively low. This is because linolenic acid contains multiple unsaturated bonds. After each of these unsaturated bonds copolymerizes with the monomer, it can form multiple branches. The formation of the branch structure can improve the adsorption effect of polycarboxylic acid segments on the concrete surface, as well as calcined activated diatomaceous earth and slag powder, thereby further increasing the attachment sites of organosilanes. This helps to improve the adhesion effect of organosilanes on the concrete surface and reduces the intrusion of chloride ions.

[0135] As can be seen from Examples 9 and 10 and Table 4, when the polycarboxylic acid segments on the surface of the modified nanoparticles lack epoxy groups, even with chain extension by linolenic acid, it is still difficult to sufficiently reduce the intrusion of chloride ions.

[0136] The above embodiments are merely explanations of this application and are not intended to limit it. After reading this specification, those skilled in the art can make modifications to the embodiments of this application without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of this application.

Claims

1. A protective coating for the surface of cement concrete structural members, characterized in that, The coating comprises a primer, an intermediate coat, and a topcoat. The primer comprises the following components in parts by weight: 12-15 parts organosilane, 1.2-1.3 parts calcined activated diatomaceous earth, 0.5-0.7 parts slag powder, 0.8-0.9 parts redispersible latex powder, 2.5-2.7 parts modified nanoparticles, 0.55-0.60 parts warm wheel adhesive, and 80-85 parts water. The modified nanoparticles are nano-silica with polycarboxylic acid segments grafted onto their surface. The intermediate coat comprises water-based epoxy resin, a curing agent, and a diluent. The topcoat comprises water-based paint base, pigments, fillers, additives, and water. The organosilane is a mixture of isooctyltriethoxysilane, cage-type silsesquioxane, and KH-550 in a weight ratio of 3:1:

3.

2. The protective coating for cement concrete components according to claim 1, characterized in that, The calcined and activated diatomaceous earth is prepared according to the following method: (1) After grinding and sieving the raw diatomaceous earth, add it together with sodium hexametaphosphate into water. After ultrasonic treatment, dilute with water, let it stand and separate into layers, take the upper layer of slurry, let it stand and separate into layers again, remove the upper layer of suspension, take the bottom mud slurry for filtration and washing, and dry the filter cake to obtain refined diatomaceous earth. (2) The diatomaceous earth concentrate is calcined, cooled, and then washed with an alkaline solution, followed by an acidic solution, and finally washed with water and dried to obtain calcined activated diatomaceous earth.

3. The protective coating for cement concrete components according to claim 2, characterized in that, In the calcination operation, the calcination temperature is 570-620℃.

4. The protective coating for cement concrete structural members according to claim 1, characterized in that, The modified nanoparticles were prepared according to the following method: Nano-silica, anhydrous ethanol, water, vinylalkoxysilane, and hydrochloric acid are mixed and heated to obtain a modified silica dispersion. A monomer and an initiator are added to the modified silica dispersion under water bath heating conditions to carry out the reaction. After the reaction is completed, the mixture is naturally cooled, filtered, dried, and then ground to obtain modified nanoparticles. The monomer includes acrylic acid.

5. The protective coating for cement concrete components according to claim 4, characterized in that, In the method for preparing the modified nanoparticles, the monomers used also include glycidyl acrylate.

6. The protective coating for the surface of cement concrete structural members according to claim 4, characterized in that, In the method for preparing the modified nanoparticles, the monomers used also include unsaturated fatty acids.

7. The protective coating for cement concrete components according to claim 6, characterized in that, In the method for preparing the modified nanoparticles, the unsaturated fatty acid includes linolenic acid.

8. The method for preparing the protective coating for the surface of cement concrete structural members according to any one of claims 1-7, characterized in that, Includes the following steps: Organosilane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, warm wheel adhesive, and water are added to a reaction vessel and stirred under constant temperature heating to obtain a primer, which is set aside. Component A containing water-based epoxy resin and component B containing curing agent and diluent are mixed evenly, and water is added to adjust to a workable viscosity to obtain an intermediate coat, which is set aside. Water-based paint base, pigments, fillers, additives, and water are mixed evenly to obtain a topcoat, which is set aside.

9. A coating, characterized in that, The coating is made of the protective coating for the surface of cement concrete components as described in any one of claims 1-7, wherein the coating comprises, from the inside out, a water-soluble organosilane spray material layer made of primer, a resin-based polymer film layer made of intermediate paint, and a miscible water-based paint layer made of topcoat.

10. The method for applying a protective coating to the surface of cement concrete structural members according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Clean the surface of the concrete structure and then repair the damaged parts of the concrete structure surface with mortar; the raw material components of the mortar include rice husk ash and calcium sulfate whiskers. (2) Apply primer to the concrete structure surface and allow it to dry to form a water-soluble organosilane spray material layer; (3) Apply intermediate paint to the surface of the concrete structure and let it dry to form a resin-based polymer film material layer; (4) Apply topcoat to the concrete structure surface and let it dry to form a layer of water-based paint material.

Images