Cement concrete component surface protective paint, preparation method thereof, coating and construction method of coating

Abstract

The invention relates to the technical field of concrete protective materials, and particularly discloses a cement concrete component surface protective paint, a preparation method thereof, a coating and a construction method of the coating. The primer taking organosilane as a core component, the intermediate paint taking water-borne epoxy resin as a core component and the finish paint taking a water-borne paint base material as a core component are adopted. By means of a three-layer structure composed of the primer, the intermediate paint and the finish paint, the protective paint can protect concrete from inside to outside in an all-around mode, the durability of the concrete is remarkably improved, and therefore lasting protection on the concrete is fully achieved, the defect that concrete corrosion is easily intensified by inorganic ions such as chloride ions is overcome, and the service life of the concrete is prolonged. And the corrosion of the concrete in a coast engineering environment is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of concrete protective materials, and more specifically, to a surface protective coating for cement concrete mixed components, a preparation method thereof, a coating, and a coating construction method. Background Art

[0002] Cement-concrete components are multi-phase, porous structures. Often exposed to the elements, they are susceptible to external influences such as air, water, and de-icing salt, leading to deterioration of their internal structure and appearance. Cement-concrete components located near marine environments are also subject to additional damage from factors such as tidal wet-dry cycles, thermal stresses caused by diurnal temperature swings, and salt spray carried by sea breezes, significantly shortening their service life. To meet stringent construction requirements, surface protection is essential.

[0003] At present, coastal engineering concrete generally adopts dense concrete technology to prevent salt corrosion, and high-concentration organic solvent-based silane impregnation materials are also used for surface impregnation protection in necessary areas. In the related art, there is a surface protective agent for cement concrete components, which is prepared by the following preparation method: (1) Put polyborosiloxane into a high-speed mixer and adjust the temperature to 175°C. After the polyborosiloxane is completely melted, calcined kaolin, clay and heavy metal powder are evenly dispersed in the polyborosiloxane 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 to obtain a silane adsorbent; (2) Isooctyltriethoxysilane, cage-type silsesquioxane and silane adsorbent are uniformly mixed for 2 hours to obtain an intermediate; (3) Silane coupling agent KH-550 and water are added to the intermediate and uniformly mixed to obtain a preform; (4) Hydrochloric acid inhibitor is added to the preform and reacted for 6 hours; the hydrochloric acid solution is removed by heating and then sodium hydroxide is added to obtain a protective agent. The protective agent is sprayed or brushed on the surface of the cement concrete component or the damaged part to complete the protective treatment of the component.

[0004] Regarding the above-mentioned related technologies, the inventors believe that although the measures in the related technologies can achieve surface protection of concrete components, the protection approach of this method is relatively single and the actual protection effect is limited. Moreover, the chloride ions introduced by the components such as magnesium chloride and hydrochloric acid inhibitor used will also aggravate the corrosion of concrete, which is not conducive to improving the durability of concrete components. Summary of the Invention

[0005] The protection methods used in related technologies are relatively simple, with limited practical protection effects. Moreover, the chloride ions introduced during construction can exacerbate concrete corrosion, which is not conducive to improving the durability of concrete components. To address this shortcoming, the present application provides a surface protective coating for cement concrete components, a preparation method thereof, a coating, and an application method for the coating.

[0006] In the first aspect, the present application provides a surface protective coating for cement concrete mixed components, adopting the following technical solution: a surface protective coating for cement concrete mixed components, comprising a primer, an intermediate paint and a topcoat, the primer comprising 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 glue, and 80-85 parts of water; the modified nanoparticles are nano-silica with polycarboxylic acid chain segments grafted on the surface; the components of the intermediate paint include water-based epoxy resin, curing agent and diluent; the components of the topcoat include water-based paint base, pigment, filler, additives and water.

[0007] By adopting the above technical solution, the polycarboxylic acid chains on the surface of the modified nanoparticles in the silane adhesion agent can adsorb 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 attachment sites for the organosilane. The Wenlun glue significantly improves the adhesion of the primer and strengthens the bond between the primer and the concrete surface. The redispersible latex powder has excellent elasticity and strength properties, which can reduce shrinkage deformation caused by the primer film after formation. The synergistic effect of the modified nanoparticles, Wenlun glue, and redispersible latex powder enables the organosilane to fully adhere to the concrete surface and forms a strong protective film layer after the primer cures. This film layer does not introduce additional chloride ions to the concrete surface, and the slag powder in it also has the ability to solidify chloride ions, effectively limiting chloride ion penetration. On this basis, this application also uses an intermediate paint with a water-based epoxy resin as the core component and a topcoat with a water-based paint base as the core component. The water-based epoxy resin gives the intermediate paint good flexibility, which enables it to adapt to slight deformations on the concrete surface, helping to ensure the durability of the protective effect; the topcoat can provide the concrete surface with an aesthetically pleasing appearance, while improving resistance to natural factors such as ultraviolet rays and acid rain. The three-layer structure consisting of primer, intermediate paint, and topcoat can protect the concrete from the inside out in all directions, significantly improving the durability of the concrete, and fully realizing long-term protection of the concrete through synergistic effects. By using the surface protective coating for cement concrete components of the present application, the defect that inorganic ions such as chloride ions easily aggravate concrete corrosion can be overcome, effectively reducing the corrosion of concrete in coastal engineering environments. In addition, the utilization of slag in the present application realizes the rational disposal of waste, and the protective coatings of the present application all use water as a solvent, have no volatile organic compound emissions, and can fully meet environmental protection requirements.

[0008] Preferably, the calcined activated diatomite is prepared according to the following method: (1) grinding and sieving the diatomite raw soil and adding it to water together with sodium hexametaphosphate, ultrasonically treating it and diluting it with water, letting it stand for stratification and taking the upper slurry, letting it stand for stratification again and removing the upper suspension, taking the bottom mud, filtering and washing it, and drying the filter cake to obtain diatomite refined soil; (2) Calcining the diatomite, and after cooling, washing it with an alkaline solution, then washing it with an acid solution, and finally washing it with water and drying it to obtain calcined activated diatomite.

[0009] By adopting the above technical solution, the present application first sorted the raw diatomite and, by utilizing the differences in particle suspension and sedimentation velocity, removed impurities such as clay minerals, quartz, and stone chips from the raw diatomite, resulting in refined diatomite. After calcining the refined diatomite, the residual organic matter was removed. Alkaline and acid washing were then used to remove some of the oxide impurities, resulting in a calcined activated diatomite with a high specific surface area. This provides more attachment sites for organosilanes, helping to fully protect against external erosion.

[0010] Preferably, during the calcination operation, the calcination temperature is 570-620°C.

[0011] By adopting the above technical solution, the present application optimizes the calcination temperature of the calcined activated diatomite, which can effectively increase the specific surface area of ​​the calcined activated diatomite, thereby providing more attachment sites for organosilane, which helps to fully achieve protection against external erosion.

[0012] Preferably, the modified nanoparticles are prepared according to the following method: Nano-silica, anhydrous ethanol, water, vinyl alkoxysilane and hydrochloric acid are mixed and heated to obtain a modified silica dispersion. Monomers and initiators are added to the modified silica dispersion under water bath heating conditions to react. After the reaction is completed, the mixture is naturally cooled, the product is filtered and dried, and then ground to obtain modified nanoparticles. The monomer includes acrylic acid.

[0013] By adopting the above technical solution, the present application uses a silane coupling agent to modify nano-silica, grafts vinyl groups on the surface of the nano-silica, and then initiates copolymerization between the vinyl groups and the monomer under the action of an initiator, forming polycarboxylic acid segments on the surface of the nano-silica to obtain modified nanoparticles.

[0014] Preferably, in the method for preparing the modified nanoparticles, the monomer used further includes glycidyl acrylate.

[0015] By adopting the above technical solution, glycidyl acrylate can introduce epoxy groups into the polycarboxylic acid chain segment. These epoxy groups can react with the curing agent when the intermediate paint is cured, thereby strengthening the bonding force between the primer and the intermediate paint, and helping to fully achieve protection against external corrosion.

[0016] Preferably, in the method for preparing the modified nanoparticles, the monomer used further includes unsaturated fatty acids.

[0017] By adopting the above technical solution, unsaturated fatty acids can introduce long-chain alkyl groups into the polycarboxylic acid chain segments, thereby improving the compatibility between the polycarboxylic acid chain segments and the organosilane, and helping to improve the adhesion effect of the organosilane on the concrete surface.

[0018] Preferably, in the method for preparing the modified nanoparticles, the unsaturated fatty acid comprises linolenic acid.

[0019] By adopting the above technical solution, linolenic acid contains multiple unsaturated bonds, and the multiple unsaturated bonds can form multiple branches after copolymerization with monomers. The formation of the branched structure can improve the adsorption effect of the polycarboxylic acid chain segment on the concrete surface and calcined activated diatomaceous earth and slag powder, thereby further increasing the attachment sites of the organosilane, which helps to improve the adhesion effect of the organosilane on the concrete surface.

[0020] In a second aspect, the present application provides a method for preparing a surface protective coating for cement concrete mixed components, which adopts the following technical solution.

[0021] A method for preparing a surface protective coating for a cement concrete component comprises the following steps: Add organic silane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, Wenlun glue and water into a reaction container, stir and mix under constant temperature heating conditions to obtain a primer, which is set aside; mix component A containing water-based epoxy resin and component B containing curing agent and diluent evenly, add water to adjust to a workable viscosity, and obtain an intermediate paint, which is set aside; mix water-based paint base, pigment, filler, additive and water evenly to obtain a topcoat, which is set aside.

[0022] By adopting the above technical solution, the present application separately formulates a primer, an intermediate paint, and a topcoat, which are then combined to produce a protective coating for the surface of cement-concrete composite components. By using a ready-to-use formulation, the protective coating for the surface of cement-concrete composite components does not introduce additional chloride ions into the concrete surface, effectively reducing cracking caused by chloride ion corrosion and helping to fully achieve long-term protection for the concrete.

[0023] In a third aspect, the present application provides a coating that adopts the following technical solution.

[0024] A coating is made of any of the above-mentioned protective coatings for the surface of cement concrete components, and the coating comprises, from the inside to the outside, a water-soluble organic silane spray material layer made of a primer, a resin polymer coating material layer made of an intermediate paint, and a miscible water-based paint material layer made of a topcoat.

[0025] By adopting the above technical solution, the present application uses primer, intermediate paint and topcoat in sequence to form a water-soluble organosilane spray material layer, a resin polymer coating material layer and a miscible water-based paint material layer. The above three-layer structure can protect the concrete from the inside to the outside in all directions, significantly improves the durability of the concrete, and fully realizes the long-term protection of the concrete through synergistic effect.

[0026] In a fourth aspect, the present application provides a coating construction method, which adopts the following technical solution.

[0027] A method for applying protective coating on the surface of a cement concrete component comprises the following steps: (1) cleaning the surface of the concrete structure, and then repairing the damaged part of the surface of the concrete structure with mortar; the raw material components of the mortar include rice husk ash and calcium sulfate whiskers; (2) spraying a primer on the surface of the concrete structure and allowing it to dry to form a water-soluble organosilane spray material layer; (3) Applying an intermediate paint on the surface of the concrete structure and allowing it to dry to form a resin-based polymer coating material layer; (4) Apply topcoat to the surface of the concrete structure and let it dry to form a miscible water-based paint material layer.

[0028] By adopting the above technical solution, in areas where erosion is more serious, since the surface of concrete components that need to be post-treated for protection usually have already suffered a certain degree of damage, the present application first uses mortar for repair in the construction method, and limits the mortar to contain rice husk ash and calcium sulfate whiskers. Rice husk ash can effectively inhibit the carbonization of mortar and improve the mortar's resistance to sulfate erosion, while calcium sulfate whiskers can directly reinforce the mortar on the one hand. In addition to physical reinforcement, calcium sulfate whiskers also react chemically with calcium aluminate and calcium hydroxide in the cement paste to generate calcium aluminate and other substances that fill the pores, thereby indirectly increasing the strength. The synergistic effect of the two helps to avoid the phenomenon of protective failure caused by mortar peeling, thereby improving the protective effect of the coating formed by the protective coating on the concrete.

[0029] In summary, this application has the following beneficial effects: 1. This application utilizes a primer with an organosilane as its core ingredient, an intermediate coating with a waterborne epoxy resin as its core ingredient, and a topcoat with a waterborne paint base as its core ingredient. Through this three-layer structure, the protective coating of this application comprehensively protects concrete from the inside out, significantly improving its durability and achieving long-lasting protection through synergistic effects.

[0030] 2. The protective coating for cement-concrete composite components disclosed in this application can, to a certain extent, overcome the vulnerability of inorganic ions such as chloride ions to exacerbated concrete corrosion, thereby reducing concrete corrosion in coastal engineering environments. Furthermore, the utilization of slag in this application allows for the rational disposal of waste. Furthermore, the protective coating, which uses water as a solvent, emits no volatile organic compounds, fully meeting environmental protection requirements.

[0031] 3. This application introduces epoxy glue into the polycarboxylic acid segment of the modified nanoparticles. The epoxy group in the polycarboxylic acid segment can react with the curing agent when the intermediate paint is cured, thereby strengthening the bonding force between the primer and the intermediate paint, and helping to fully achieve protection against external erosion.

[0032] 4. In the construction method of this application, mortar containing rice husk ash and calcium sulfate whiskers is used to repair concrete components. The synergistic effect of rice husk ash and calcium sulfate whiskers helps to avoid protective failure caused by mortar peeling, thereby improving the protective effect of the coating formed by the protective coating on the concrete. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the Examples, Preparation Examples and Comparative Examples. The raw materials involved in the present application can all be obtained commercially.

[0034] Preparation example of calcined activated diatomite The following is an explanation using Preparation Example 1.

[0035] Preparation Example 1 In this preparation example, calcined activated diatomite was prepared according to the following method: (1) Grind the diatomite and pass it through an 80-mesh sieve, weigh 20 g, mix it with 0.1 g of sodium hexametaphosphate, and add them together into 60 g of water. Let it stand for 24 hours, and then ultrasonically treat it for 10 minutes. Then dilute it with water to a solid content of 10%. After standing for 5 minutes, take the upper slurry, let it stand for another 2 hours, remove the upper suspension, take the bottom mud, filter and wash it, and dry the filter cake to obtain diatomite fine soil; (2) The diatomite was calcined at a calcination temperature of 550°C for 5 hours. After cooling, it was alkaline washed with a 3wt% sodium hydroxide solution at a liquid-to-solid ratio of 3:1 at 45°C for 1 hour, and then acid washed with a 40wt% sulfuric acid solution at a liquid-to-solid ratio of 6:1 for 75 minutes. Finally, it was washed with water and dried to obtain calcined activated diatomite.

[0036] Preparation Example 2 This Preparation Example differs from Preparation Example 1 in that the calcination temperature is 570°C.

[0037] Preparation Example 3 This Preparation Example differs from Preparation Example 1 in that the calcination temperature is 600°C.

[0038] Preparation Example 4 This Preparation Example differs from Preparation Example 1 in that the calcination temperature is 620°C.

[0039] Preparation example of modified nanoparticles The following is an explanation using Preparation Example 5 as an example.

[0040] Preparation Example 5 In this preparation example, the modified nanoparticles were prepared according to the following method: 50 g of nano-silica, 840 g of anhydrous ethanol, 360 g of water, and 5 g of vinyltriethoxysilane were mixed, the pH was adjusted to 3.5 with 0.1 mol / L hydrochloric acid, and the mixture was reacted in a water bath at 60°C for 1 h to obtain a modified silica dispersion. 150 g of acrylic acid monomer and 1 g of ammonium persulfate initiator were added to the modified silica, and the mixture was reacted at 70°C for 4 h. After the reaction was completed, the mixture was naturally cooled, the product was filtered and dried, and then ground to obtain modified nanoparticles.

[0041] Preparation Example 6 The difference between this preparation example and preparation example 5 is that in the method for preparing modified nanoparticles, the monomer used further includes glycidyl acrylate, and the amount of glycidyl acrylate used is 10 g.

[0042] Preparation Example 7 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 15 g.

[0043] Preparation Example 8 This Preparation Example differs from Preparation Example 7 in that oleic acid is replaced by the same weight of linolenic acid.

[0044] Preparation Example 9 This Preparation Example is different from Preparation Example 8 in that the monomer does not include glycidyl acrylate. Example

[0045] Examples 1-3 The following description will be given using Example 1 as an example.

[0046] Example 1 In this example, the organosilane is prepared by mixing isooctyltriethoxysilane, cage 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 a ground 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.

[0047] This embodiment provides a surface protective coating for cement concrete components, including a primer, an intermediate paint, and a topcoat.

[0048] The primer includes the following components in parts 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 glue, and 80 kg of water.

[0049] The intermediate paint comprises component A and component B, wherein the molar ratio of the epoxy equivalent of component A to the active hydrogen equivalent of component B is 0.85:1; component A is a water-based epoxy resin, specifically composed of 45 wt% bisphenol A epoxy resin (E-51), 0.5 wt% tetrabutylammonium bromide, 10 wt% lactic acid, and 44.5 wt% deionized water; and component B comprises a curing agent (Bayer MF20, CAS: 35498) and a diluent in a weight ratio of 1:0.02, wherein the diluent is butanediol diglycidyl ether.

[0050] The specific composition of the topcoat is: 40wt% water-based paint base, 15wt% pigment, 15wt% filler, 10wt% additive, and 20wt% water; the water-based paint base is PT-008 water-based plain concrete paint, provided by Fenyangtang (Shanghai) Industrial Co., Ltd., the pigment is iron oxide gray, the filler is S95 slag powder, and the additives are Efka 3570 leveling agent, Datian DT-605 defoaming agent and water-based paint dispersant SN5027 according to the weight ratio of 1:2.2:6.5.

[0051] This embodiment provides a method for preparing a surface protective coating for a cement concrete component, comprising the following steps: Add organosilane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, Wenlun glue and water into a reaction container, stir and mix under constant temperature heating conditions of 50°C for 30 minutes to obtain a primer, which is set aside; mix component A containing water-based epoxy resin and component B containing a curing agent and a diluent evenly, add water to adjust to a workable viscosity, and obtain an intermediate paint, which is set aside; mix the water-based paint base, pigment, filler, additive and water evenly to obtain a topcoat, which is set aside.

[0052] This embodiment also provides a coating made of the above-mentioned cement concrete composite component surface protective coating, which is applied to the surface of the concrete substrate. The coating includes, from the inside to the outside, a water-soluble organic silane spray material layer made of a primer, a resin-based polymer coating material layer made of an intermediate paint, and a miscible water-based paint material layer made of a topcoat.

[0053] This embodiment also provides a method for applying a protective coating on the surface of a cement concrete component, comprising the following steps: (1) The surface of the concrete structure was cleaned and then the damaged part of the concrete structure surface was repaired with mortar. The mortar dosage was 5 kg per square meter and the curing time was 7 days. The mortar included 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 was 65 μm, and the fineness modulus of the river sand was 2.7. The average diameter of the calcium sulfate whiskers was 0.8 μm and the average length was 20 μm. (2) spraying primer on the surface of the concrete structure at a dosage of 0.2 kg per square meter, and forming a water-soluble organosilane spray material layer after standing and drying; (3) Applying an intermediate paint at a dosage of 0.1 kg per square meter on the surface of the concrete structure, and allowing it to dry to form a resin-based polymer coating material layer; (4) Apply topcoat to the surface of the concrete structure at a dosage of 0.05 kg per square meter, and let it dry to form a miscible water-based paint material layer.

[0054] As shown in Table 1, the main difference between Examples 1-3 is that the raw material ratios of the primers are different.

[0055] Table 1 Raw material ratio of primer sample Example 1 Example 2 Example 3 Organosilane / kg 12 14 15 Calcined 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 wheel rubber / kg 0.55 0.57 0.60 Water / kg 80 82 85 Examples 3-6 As shown in Table 2, the difference between Examples 3-6 is that the preparation examples of calcined activated diatomaceous earth are different.

[0056] Table 2 Preparation example of calcined activated diatomite sample Preparation Example Example 3 Preparation Example 1 Example 4 Preparation Example 2 Example 5 Preparation Example 3 Example 6 Preparation Example 4 Examples 7-10 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.

[0057] Table 3 Preparation examples of modified nanoparticles Comparative Example Comparative Example 1 In this comparative example, the cement concrete component surface protective agent was applied to the surface of the concrete structure at a dosage of 0.35 kg per square meter.

[0058] In this comparative example, diatomite slurry was prepared according to the following method: A cement concrete component surface protective agent is prepared by the following preparation method: Diatomaceous earth, methyl methacrylate, redispersible latex powder (Wacker redispersible latex powder 5044N), titanate coupling agent (tetrabutyl titanate), KH-550 and isopropylbenzene hydroperoxide were weighed in a weight ratio of 20:40:10:3:1:0.1. The titanate coupling agent and KH-550 were added to the methyl methacrylate and stirred evenly. Diatomaceous earth and redispersible latex powder were added and stirred evenly. Isopropylbenzene hydroperoxide was added and polymerization was initiated at 120°C. After reacting for 4 hours, a diatomaceous earth slurry was obtained.

[0059] (1) 1 kg of polyborosiloxane was put into a high-pressure 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 crushed to an average particle size of 2 μm. After that, 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 a silane adsorbent; (2) 3 kg of isooctyltriethoxysilane, 1 kg of cage-type silsesquioxane, and 0.3 kg of silane adsorbent were uniformly mixed for 2 h to obtain an intermediate; (3) adding 3 kg of silane coupling agent KH-550 and 50 kg of water to the intermediate and mixing them uniformly to obtain a preform; (4) Add 25 kg of 20 wt% hydrochloric acid inhibitor to the preform and react for 6 hours; heat to remove the hydrochloric acid solution, and then add 8 kg of 20 wt% sodium hydroxide solution to obtain a protective agent.

[0060] Comparative Example 2 This comparative example is different from Example 1 in that the primer does not include calcined activated diatomaceous earth.

[0061] Comparative Example 3 This comparative example is different from Example 1 in that the primer does not include slag powder.

[0062] Comparative Example 4 The difference between this comparative example and Example 1 is that the components of the primer do not include redispersible latex powder.

[0063] Comparative Example 5 The difference between this comparative example and Example 1 is that the components of the primer do not include warm wheel glue.

[0064] Comparative Example 6 This comparative example differs from Example 1 in that the components of the primer do not include modified nanoparticles.

[0065] Comparative Example 7 The difference between this comparative example and Example 1 is that the primer is replaced by an intermediate paint.

[0066] Comparative Example 8 The difference between this comparative example and Example 1 is that, in the construction method of the protective coating on the surface of the cement concrete mixed component, the raw material components of the mortar do not include calcium sulfate whiskers.

[0067] Performance testing methods C30 concrete cubes (150 mm side length, 90 days old) from the same batch were coated according to the methods described in the Examples and Comparative Examples. After the coating was formed, the concrete blocks were immersed in a 3.5 wt% sodium chloride solution. After 28 days, the blocks were crushed, and the chloride ion content of the debris was measured. Using the chloride ion content measured in Comparative Example 1 as a benchmark, the ratio of the chloride ion content measured in each Example and Comparative Example to the chloride ion content measured in Comparative Example 1 was calculated and recorded as the relative chloride content. The results are shown in Table 4.

[0068] Table 4 Relative chlorine content 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 Combining Examples 1-3 with Comparative Example 1 and Table 4, it can be seen that the relative chlorine content measured in Examples 1-3 is lower. This is because the present application specifies a primer with an organosilane as its core component, an intermediate with a waterborne epoxy resin as its core component, and a topcoat with a waterborne paint base as its core component. Through the three-layer structure of primer, intermediate, and topcoat, the protective coating of the present application can comprehensively protect concrete from the inside out, significantly improving its durability and thus achieving long-term protection for the concrete through synergistic effects. While the protective agent dosage 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 high level of chloride ion intrusion into the concrete specimens. This prevents the full utilization of its anti-corrosion properties and makes it difficult to meet the construction needs of coastal projects.

[0069] Combining Example 1 and Comparative Example 2 with Table 4, it can be seen that the relative chlorine 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 attachment sites for the organosilane, affecting the protective performance of the primer. As a result, more chloride ions penetrate into the interior of the concrete specimen.

[0070] Combining Example 1 and Comparative Example 3 with Table 4, it can be seen that the relative chlorine content measured in Example 1 is lower. This is because the primer in Comparative Example 3 lacks slag powder, which cannot provide sufficient attachment sites for the organosilane and cannot solidify the chloride ions through the slag. As a result, more chloride ions penetrate into the concrete specimen.

[0071] Combining Example 1 with Comparative Examples 4-6 and Table 4, it can be seen that the relative chlorine content measured in Example 1 is lower. This is because Comparative Examples 4-6 cannot exert the synergistic effect of the modified nanoparticles, the wet wheel glue, and the redispersible latex powder, resulting in the coating formed by the primer being unable to provide sufficient protection. As a result, more chloride ions penetrate into the interior of the concrete specimen.

[0072] Combining Example 1 and Comparative Example 7 with Table 4, it can be seen that the relative chlorine content measured in Example 1 is lower. This is because the coating of Comparative Example 7 lacks organosilane, and effective protection cannot be achieved through the coordinated cooperation between the various film layers, resulting in more chloride ions invading the interior of the concrete specimen.

[0073] Combining Example 1 with Comparative Example 8 and Table 4, it can be seen that Example 1 measured a lower relative chloride content. This is because the calcium sulfate whiskers chemically react with the calcium aluminate and calcium hydroxide in the cement paste to form ettringite, which fills the pores and blocks the intrusion of chloride ions. Comparative Example 8, on the other hand, does not contain calcium sulfate whiskers, resulting in a higher amount of chloride ions invading the concrete specimen.

[0074] Combining Example 3 with Examples 4-6 and Table 4, it can be seen that the calcined activated diatomaceous earth prepared after calcination at 570-620° C. is more helpful in improving the protective effect of the coating.

[0075] Combining Example 5, Example 7 and Table 4, it can be seen that the relative chlorine content measured in Example 7 is lower. This is because the polycarboxylic acid segment on the surface of the modified nanoparticles in Example 7 contains epoxy groups, which can react with the curing agent when the intermediate paint is cured, thereby strengthening the bonding force between the primer and the intermediate paint, and helping to fully achieve protection against external corrosion.

[0076] Combining Examples 7 and 8 with Table 4, it can be seen that the relative chlorine content measured in Example 8 is lower. This is because the unsaturated fatty acid can introduce long-chain alkyl groups into the polycarboxylic acid segments, improving the compatibility between the polycarboxylic acid segments and the organosilane, helping to improve the adhesion of the organosilane to the concrete surface and reducing the intrusion of chloride ions.

[0077] Combining Examples 8 and 9 with Table 4, it can be seen that the relative chlorine content measured in Example 8 is relatively low. This is because linolenic acid contains multiple unsaturated bonds, which can form multiple branches after copolymerization with monomers. The formation of the branched structure can improve the adsorption effect of the polycarboxylic acid segment on the concrete surface, calcined activated diatomaceous earth, and slag powder, thereby further increasing the attachment sites of the organosilane, helping to improve the adhesion of the organosilane to the concrete surface and reducing the intrusion of chloride ions.

[0078] From Example 9 and Example 10 and Table 4, it can be seen that when the polycarboxylic acid segments on the surface of the modified nanoparticles lack epoxy groups, even if the chains are extended by linolenic acid, it is still difficult to fully reduce the intrusion of chloride ions.

[0079] The above embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications to the embodiments of the present application as needed without any creative contribution. However, as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A surface protective coating for cement concrete components, characterized in that: The invention comprises a primer, an intermediate paint and a topcoat. 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 rubber, and 80-85 parts of water. The modified nanoparticles are nano-silica with polycarboxylic acid segments grafted on the surface. The intermediate paint comprises a water-based epoxy resin, a curing agent and a diluent. The topcoat comprises a water-based paint base, a pigment, a filler, an additive and water.

2. The surface protective coating for cement concrete components according to claim 1, characterized in that: The calcined activated diatomaceous earth is prepared according to the following method: (1) Grind the diatomite and sieve it, then add it into water together with sodium hexametaphosphate, treat it with ultrasound, dilute it with water, let it stand for stratification, take the upper slurry, let it stand for stratification again, remove the upper suspension, take the bottom mud, filter and wash it, and dry the filter cake to obtain diatomite fine soil; (2) Calcining the diatomite fine soil, and after cooling, first washing it with an alkaline solution, then washing it with an acid solution, and finally washing it with water and drying it to obtain calcined activated diatomite.

3. The surface protective coating for cement concrete components according to claim 2, characterized in that: During the calcination operation, the calcination temperature is 570-620°C.

4. The surface protective coating for cement concrete components according to claim 1, characterized in that: The modified nanoparticles are prepared as follows: Nano-silica, anhydrous ethanol, water, vinyl alkoxysilane and hydrochloric acid are mixed and heated to obtain a modified silica dispersion. Monomers and initiators are added to the modified silica dispersion under water bath heating conditions to react. After the reaction is completed, the mixture is naturally cooled, the product is filtered and dried, and then ground to obtain modified nanoparticles. The monomer includes acrylic acid.

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

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

7. The surface 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 a surface protective coating for cement concrete components according to any one of claims 1 to 7, characterized in that: The following steps are involved: Add organic silane, calcined activated diatomaceous earth, slag powder, redispersible latex powder, modified nanoparticles, Wenlun glue and water into a reaction container, stir and mix under constant temperature heating conditions to obtain a primer, which is set aside; mix component A containing water-based epoxy resin and component B containing curing agent and diluent evenly, add water to adjust to a workable viscosity, and obtain an intermediate paint, which is set aside; mix water-based paint base, pigment, filler, additive and water evenly to obtain a topcoat, which is set aside.

9. A coating, characterized in that The protective coating for the surface of a cement concrete component according to any one of claims 1 to 7 comprises, from the inside to the outside, a water-soluble organosilane spraying material layer made of a primer, a resin polymer coating material layer made of an intermediate paint, and a miscible water-based paint material layer made of a topcoat.

10. The construction method of the protective coating on the surface of cement concrete components according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Cleaning the surface of the concrete structure, and then using mortar to repair the damaged part of the surface of the concrete structure; the raw material components of the mortar include rice husk ash and calcium sulfate whiskers; (2) Spraying primer on the surface of the concrete structure and letting it dry to form a water-soluble organosilane spray material layer; (3) Apply intermediate paint on the surface of the concrete structure and let it dry to form a resin polymer coating material layer; (4) Apply topcoat to the surface of the concrete structure and let it dry to form a miscible water-based paint material layer.

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