Concrete composite coating suitable for power transmission and transformation station structure in salinized soil area and preparation method of concrete composite coating

Abstract

The invention belongs to the technical field of concrete material corrosion prevention, and discloses a concrete composite coating suitable for a transmission and transformation station structure in a saline soil area and a preparation method thereof.The concrete composite coating is prepared from coating primer and coating finish paint, and the coating primer is prepared from, by mass, 10-14 parts of sodium methylsilanolate, 2 parts of dispersing agent and 86-90 parts of water; the coating finish paint comprises 100 parts of Portland cement, 1 part of nano silicon dioxide, 3 parts of a microencapsulation material, 38 parts of water, 3 parts of a water reducing agent and 0.5-1.5 parts of a fluorine-containing organosilicon compound. According to the design of the composite coating, the compatibility and the synergistic effect of all the layers and the adaptability to the external environment are fully considered, erosion of salinized soil can be effectively resisted by combining materials with different characteristics, falling and stripping of a mortar layer on the surface of a concrete base can be prevented, and therefore stable operation, safety and reliability of an electric power system are guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete material corrosion prevention, and in particular relates to a concrete composite coating suitable for a transmission and substation structure in a saline soil area and a preparation method thereof. Background Art

[0002] In some areas, saline soil is widely distributed, which is characterized by low precipitation and high evaporation. The water in the soil evaporates easily, causing the salt in the soil to concentrate and accumulate on the surface or near the surface, forming salinization. In the power system, substations are key hubs, and their stability and safety are of vital importance. However, the saline soil environment poses a significant threat to the concrete structure in the substation. The soluble salts in the saline soil not only cause peeling and cracking on the surface of the concrete, but also penetrate into the interior of the concrete, destroying its original mechanical properties and durability, thereby weakening its function as a load-bearing and protective structure. In this environment, the safety and durability of buildings and structures face huge challenges. In order to ensure the stability of the structure, in addition to selecting materials with good resistance to saline soil erosion during the design stage, effective protective measures should be taken for the concrete structure of the built substation to prevent further damage. For example, significant concrete corrosion was observed in some substations in a certain city. At about 5 cm above the surface, the mortar layer on the concrete surface was prone to peeling, exposing the internal stones, resulting in a decrease in the actual strength of the concrete by about 5 MPa. In some areas, the corrosion problem is more serious, with concrete foundations generally experiencing peeling, aggregate exposure, and salt precipitation, which pose a major threat to the normal operation of power distribution facilities. Therefore, in saline soil areas, it is particularly important to strengthen the corrosion protection of concrete structures in existing substations.

[0003] At present, there are many coating materials and technologies on the market that are designed to improve the ability of concrete to resist saline soil erosion, mainly including three types: surface film-forming coatings, pore-sealing coatings, and hydrophobic impregnation coatings. However, in actual applications, due to the complex chemical composition in saline soil environments, existing coating materials often experience performance degradation under long-term exposure and cannot provide effective protection. In addition, the harsh environmental conditions in saline soil areas require that coating materials maintain good adhesion and integrity under extreme conditions, but current products are generally difficult to meet this requirement. Critical infrastructure such as transmission towers and substation equipment are extremely susceptible to corrosion in saline soil environments, and their surface mortar layers are prone to falling off and peeling off, resulting in a decrease in bearing capacity and a shortened service life, posing a great threat to the stable operation of the power system.

[0004] Chinese invention patent application CN117487416A discloses a cement-based concrete durable protective coating and its application, wherein the cement-based concrete durable protective coating is made of the following raw materials in parts by mass: 100 parts of liquid mixture and 150 parts of powder mixture; the liquid mixture includes 100 parts of emulsion, 1-3 parts of wetting and dispersing agent, 2-10 parts of thickener, 10-50 parts of composite inert filler, and 0.5-2 parts of defoaming agent; the powder mixture includes 60-100 parts of cement, 0-10 parts of fly ash, and 0-20 parts of quartz sand. However, as a wetting and dispersing agent, the sodium hexametaphosphate selected in the invention may decompose under certain conditions (such as high temperature and high humidity), thereby affecting the stability of the coating, and polycarboxylates or sodium polyacrylates are susceptible to ultraviolet rays, oxidation and other factors in outdoor environments, resulting in a decrease in coating performance.

[0005] Chinese invention patent application CN216195535U discloses a concrete protective coating structure, including a cement base, a cement-based permeable crystalline permeable layer, an acrylic air-permeable elastic layer, a basalt flake fluorosilicone anti-carbonization layer and an anti-stripping frame, wherein the cement-based permeable crystalline permeable layer covers the cement base, the two ends of the anti-stripping frame are respectively embedded in the cement base and the cement-based permeable crystalline permeable layer, and the acrylic air-permeable elastic layer and the basalt flake fluorosilicone anti-carbonization layer cover the cement-based permeable crystalline permeable layer in sequence. However, the acrylic air-permeable elastic layer has relatively weak weather resistance and UV resistance, and is prone to aging and cracking when exposed to sunlight for a long time.

[0006] Chinese invention patent application CN112143313A discloses a polymer concrete protective coating material, which is prepared by mixing an aqueous solution and a mixture; the aqueous solution includes 60-70 parts by weight of aqueous acrylic resin emulsion, 5-10 parts by weight of aqueous MMA resin emulsion, 5-10 parts by weight of aqueous polyurea, 2-3 parts by weight of alkoxysilane, 3-5 parts by weight of potassium silicate, and 2-3 parts by weight of silicate; the mixture includes 10-15 parts by weight of titanium dioxide, 3-5 parts by weight of silica powder, 5-9 parts by weight of diatomaceous earth, 0.3-0.5 parts by weight of defoamer, 0.3-0.5 parts by weight of dispersant, and 1-2 parts by weight of thickener. It can be used to maintain concrete structures and prevent the repaired concrete structures from being damaged again for a long time. However, the aqueous MMA resin emulsion is highly sensitive to humidity, which may cause blistering or peeling of the coating under high humidity conditions, and potassium silicate may increase the brittleness of the coating and reduce its impact resistance.

[0007] Chinese invention patent application CN218951293U discloses a coating anti-corrosion structure for concrete substrates, the coating anti-corrosion structure comprising a water-based polyvinylidene chloride closed primer coating, a water-based polyvinylidene chloride intermediate paint coating and a water-based polyvinylidene chloride topcoat coating arranged in sequence from the inside to the outside on the outer surface of the concrete substrate. Compared with the prior art, the coating anti-corrosion structure of the invention has excellent water resistance, salt water resistance, and resistance to chloride ion penetration, and the total VOC emission during the coating process is very low, providing an excellent performance environmentally friendly coating material for concrete substrate anti-corrosion. However, the wear resistance of water-based polyvinylidene chloride coatings is poor and they are easily subject to mechanical wear or scratches.

[0008] Chinese invention patent application CN105174900A discloses a method for preparing a concrete structure anti-sulfate corrosion coating material, comprising the following steps: Step 1: Take dead burnt magnesium oxide powder as an alkaline component, potassium dihydrogen phosphate as an acidic component, and add a composite retarder to prepare potassium magnesium phosphate cement; Step 2: Take the potassium magnesium phosphate cement, silica fume and limestone powder prepared in step 1, mix and prepare potassium magnesium phosphate cement-based material powder; then add water glass, polypropylene fiber and water to the prepared potassium magnesium phosphate cement-based material powder to prepare potassium magnesium phosphate cement-based material slurry, and the potassium magnesium phosphate cement-based material slurry is the concrete structure anti-sulfate corrosion coating material. However, polypropylene fiber has a low melting point and is not resistant to high temperatures, which may limit the application of the coating in high temperature environments.

[0009] At this stage, the coating may not be able to resist the influence of environmental factors (such as ultraviolet rays, temperature changes, etc.) for a long time, causing aging, powdering or peeling of the coating; it lacks self-repairing ability, and once cracks or damage occur, external intervention is required to repair it, otherwise it will affect the overall protective effect of the coating. Summary of the invention

[0010] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a concrete composite coating suitable for the structure of a substation in saline soil areas and a preparation method thereof. The design of the composite coating of the present invention fully considers the compatibility and synergy between the layers, as well as the adaptability to the external environment. By combining materials with different properties, it can effectively resist the erosion of saline soil and prevent the shedding and peeling of the mortar layer on the surface of the concrete base, thereby ensuring the stable operation and safe and reliable operation of the power system.

[0011] To achieve the above object, the present invention adopts the following technical solution: A concrete composite coating suitable for a transmission and substation structure in saline soil areas, wherein the raw materials include a coating primer and a coating topcoat, in parts by mass: The coating primer includes: 10-14 parts of sodium methylsiliconate, 2 parts of dispersant, and 86-90 parts of water; The coating topcoat includes: 100 parts of silicate cement, 1 part of nano silicon dioxide, 3 parts of microencapsulated materials, 38 parts of water, 3 parts of water reducing agent, and 0.5-1.5 parts of fluorine-containing organic silicon compounds.

[0012] Preferably, the dispersant is one of sodium dodecylbenzene sulfonate, sodium laurate and lauroyl diethanolamine.

[0013] Preferably, the silicate cement is ordinary silicate cement.

[0014] Preferably, the core material of the microencapsulation material is normal alkane paraffin, and the shell material is PMMA or polyurethane.

[0015] Preferably, the water reducing agent is a polycarboxylate water reducing agent.

[0016] Preferably, the fluorine-containing organic silicon compound is one of perfluorooctyltriethylsilane, perfluorodecyltrimethoxysilane and trifluoropropylmethyldimethoxysilane.

[0017] Preferably, the bonding strength between the concrete composite coating suitable for the transmission and substation structure in saline soil areas and the concrete substrate is 1.75-1.84 MPa.

[0018] Preferably, the concrete composite coating suitable for transmission and substation structures in saline soil areas has a compressive strength of 50-59 MPa, a mass change rate of 0.60%-0.64%, and a compressive corrosion resistance coefficient of 0.91-0.95 under dry-wet cycle conditions of 5wt% sodium sulfate solution.

[0019] The present invention also provides a method for preparing the concrete composite coating suitable for the structure of a transmission and substation in a saline soil area as described above, comprising: A composite coating primer is coated on the concrete surface, and then a composite coating topcoat is coated on the surface of the composite coating primer. After curing, the concrete composite coating suitable for the transmission and substation structure in saline soil areas is formed.

[0020] Preferably, the preparation method of the coating primer and the coating topcoat is as follows: Add sodium methylsiliconate and dispersant into water and stir evenly to obtain a coating primer; The silicate cement, nano silicon dioxide and microencapsulated materials are mixed to obtain a dry material mixture, and then water, a water reducing agent and a fluorine-containing organic silicon compound are added to the dry material mixture and mixed to obtain a coating topcoat.

[0021] The present invention has the following beneficial effects: The raw materials of the concrete composite coating suitable for the structure of the substation in the saline soil area include a coating primer and a coating topcoat, wherein the coating bottom layer formed by the coating primer can ensure the fusion of the concrete component and the bottom layer, and achieve uniform absorption and protection effect. The surface layer formed by the coating topcoat has a protective function to ensure the long-term safety and stability of the infrastructure. The present invention uses a penetrating primer in the bottom layer of the coating, and its key component is sodium methylsiliconate, which acts as a binder or reinforcing agent and provides excellent adhesion between the coating and the substrate. Since silicon alkoxide has good water resistance and weather resistance, it can effectively protect the substrate from moisture erosion and environmental factors. For the surface layer of the coating, the present invention proposes a composite formula comprising silicate cement slurry, nano-silicon dioxide, microencapsulated repair materials and fluorine-containing organosilicon compounds; the core of the design is to improve the overall performance of the coating through the synergistic effect between the components. First, silicate cement slurry, as the matrix of the coating, provides structural strength and provides a stable bearing platform for other components. The nano-silicon dioxide added on this basis, with its high specific surface area and chemical stability, enhances the hardness and wear resistance of the coating and improves the microstructure of the coating. Subsequently, the microencapsulated repair material is embedded in the enhanced matrix. When the coating is subjected to external stress and microcracks appear, the microcapsules can break and release the internal repair agent to fill the cracks and extend the service life of the coating. This self-healing mechanism complements the reinforcing effect of nano-silicon dioxide and jointly improves the durability of the coating. Finally, the introduction of fluorinated organosilicon compounds gives the coating surface hydrophobicity and anti-fouling properties, making it easy to clean, thereby further ensuring the stability of the coating under various environmental conditions. In summary, the present invention forms a coating system with high strength, self-healing ability and protective function by rationally selecting and combining the above materials, and the overall performance is better than the effect of a single material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the composite coating structure formed in an embodiment of the present invention.

[0023] In the figure, 1-component, 2-bottom layer, 3-surface layer. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described below in conjunction with specific embodiments. Each embodiment is an experimental example and provides real performance test data. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] The present invention is applicable to the concrete composite coating of the transmission and substation structure in saline soil areas, which is composed of a coating bottom layer and a coating surface layer. Figure 1As shown, the bottom layer ensures the integration of concrete components with it, achieving uniform absorption and protection effects. The protective function of the surface layer ensures the long-term safety and stability of the infrastructure.

[0026] Specifically, the present invention is applicable to the concrete composite coating material of the transmission and substation structure in saline soil areas, including a coating primer and a coating topcoat, in parts by mass, wherein: The coating primer includes: 10-14 parts of sodium methylsiliconate, 2 parts of dispersant, and 86-90 parts of water; The coating topcoat includes: 100 parts of silicate cement, 1 part of nano silicon dioxide, 3 parts of microencapsulated materials, 38 parts of water, 3 parts of water reducing agent, and 0.5-1.5 parts of fluorine-containing organic silicon compounds.

[0027] In the above scheme of the present invention, the microencapsulation material can adopt the following structure: the core material of the microencapsulation material adopts normal alkane paraffin, and the shell material adopts PMMA or polyurethane. The fluorine-containing organic silicon compound adopts one of perfluorooctyl triethyl silane, perfluorodecyl trimethoxy silane and trifluoropropyl methyl dimethoxy silane. The dispersant adopts one of sodium dodecyl benzene sulfonate, sodium laurate and lauroyl diethanolamine. The water reducer adopts polycarboxylic acid water reducer. The silicate cement adopts ordinary silicate cement.

[0028] The present invention, the method for preparing the concrete composite coating suitable for the structure of a transmission and substation in saline soil areas, comprises the following steps: 1) Preparation of coating primer, including: adding sodium methylsiliconate and dispersant into water according to a ratio, stirring evenly, to obtain coating primer; 2) Preparation of coating topcoat, including: mixing silicate cement, nano-silicon dioxide, and microencapsulated materials according to a ratio, and stirring evenly to obtain a dry material mixture. Then, adding water, a water reducing agent, and a fluorine-containing organic silicon compound to the dry material mixture according to a ratio, stirring, and obtaining a coating topcoat; 3) When using, first apply the coating primer on the surface of the concrete component, and then apply the composite coating topcoat on the surface of the coating primer. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0029] In the above scheme of the present invention, the inner primer (i.e., the coating primer) mainly includes sodium methylsiliconate, so the inner primer can form a stable chemical bond with the surface of the concrete substrate, provide a solid foundation, and effectively fill the concrete pores to enhance the waterproof and moisture-proof ability of the substrate. The surface layer contains nano-silicon dioxide, fluorine-containing organosilicon compounds and microencapsulated materials, wherein the nano-silicon dioxide significantly enhances the density and hardness of the coating, improves the impermeability and wear resistance, and the fluorine-containing organosilicon compounds give the coating surface excellent hydrophobicity and chemical stability, and the microencapsulated material as an intelligent repair agent can automatically release the repair agent when the coating is slightly damaged, fill the cracks, and extend the service life of the coating. In addition, the nano-silicon dioxide in the surface layer exists in the coating in a uniformly dispersed manner, forming a tiny barrier layer, which effectively prevents the penetration of harmful substances such as moisture and salt. The fluorine-containing organosilicon compound forms a protective film with low surface energy on the surface of the coating, which improves the hydrophobicity and anti-pollution properties of the coating. The microencapsulated material includes a repair agent and a shell material, and the shell material can break when the coating is damaged, and release the repair agent to fill the cracks. In summary, the present invention uses this double-layer design to enable the composite coating to effectively protect concrete and prevent erosion by saline soil.

[0030] Embodiment 1: This embodiment is suitable for the concrete composite coating of the substation structure in saline soil areas. The materials are prepared according to the following components, calculated by weight: 100 parts of ordinary Portland cement, 3 parts of polycarboxylic acid water reducer, 2 parts of sodium dodecylbenzene sulfonate, 0.5 parts of perfluorooctyl triethyl silane, 12 parts of sodium methyl siliconate, 1 part of nano-silica, 3 parts of microencapsulation material (shell material is polyurethane and core material is normal 18-alkane), and 126 parts of water.

[0031] This embodiment is applicable to the preparation method of the concrete composite coating of the transmission and substation structure in saline soil areas, and comprises the following steps: 1) Add 12 parts of sodium methylsiliconate and 2 parts of sodium dodecylbenzene sulfonate to 88 parts of water and stir for 30 seconds to achieve uniformity to obtain a coating primer.

[0032] 2) 100 parts of cement, 1 part of nano-silica and 3 parts of microencapsulated materials were mixed and stirred for 30 seconds to achieve uniformity to obtain a dry material mixture.

[0033] 3) Add 38 parts of water, 3 parts of water reducing agent and 0.5 parts of perfluorooctyltriethylsilane to the dry material mixture obtained in step 2) and stir for 120 seconds to obtain a coating topcoat.

[0034] 4) When using, first apply the composite coating primer on the concrete surface, and then apply the composite coating topcoat on the composite coating primer surface. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0035] Embodiment 2: This embodiment is suitable for the concrete composite coating of the substation structure in saline soil areas. The materials are prepared according to the following components, calculated by weight: 100 parts of ordinary Portland cement, 3 parts of polycarboxylic acid water reducer, 2 parts of sodium dodecylbenzene sulfonate, 1 part of perfluorooctyl triethyl silane, 12 parts of sodium methyl siliconate, 1 part of nano-silica, 3 parts of microencapsulation material (shell material is polyurethane and core material is normal 18-alkane), and 126 parts of water.

[0036] This embodiment is applicable to the preparation method of the concrete composite coating of the transmission and substation structure in saline soil areas, and comprises the following steps: 1) Add 12 parts of sodium methylsiliconate and 2 parts of sodium dodecylbenzene sulfonate to 88 parts of water and stir for 30 seconds to achieve uniformity to obtain a coating primer.

[0037] 2) 100 parts of cement, 1 part of nano-silica and 3 parts of microencapsulated materials were mixed and stirred for 30 seconds to achieve uniformity to obtain a dry material mixture.

[0038] 3) Add 38 parts of water, 3 parts of water reducing agent and 1 part of perfluorooctyltriethylsilane to the dry material mixture obtained in step 2) and stir for 120 seconds to obtain a coating topcoat.

[0039] 4) When using, first apply the composite coating primer on the concrete surface, and then apply the composite coating topcoat on the composite coating primer surface. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0040] Embodiment 3: This embodiment is suitable for the concrete composite coating of the substation structure in saline soil areas. The materials are prepared according to the following components, calculated by weight: 100 parts of ordinary Portland cement, 3 parts of polycarboxylic acid water reducer, 2 parts of sodium dodecylbenzene sulfonate, 1.5 parts of perfluorooctyl triethyl silane, 12 parts of sodium methyl siliconate, 1 part of nano-silica, 3 parts of microencapsulation material (shell material is polyurethane and core material is normal 18-alkane), and 126 parts of water.

[0041] This embodiment is applicable to the preparation method of the concrete composite coating of the transmission and substation structure in saline soil areas, and comprises the following steps: 1) Add 12 parts of sodium methylsiliconate and 2 parts of sodium dodecylbenzene sulfonate to 88 parts of water and stir for 30 seconds to achieve uniformity to obtain a coating primer.

[0042] 2) 100 parts of cement, 1 part of nano-silica and 3 parts of microencapsulated materials were mixed and stirred for 30 seconds to achieve uniformity to obtain a dry material mixture.

[0043] 3) Add 38 parts of water, 3 parts of water reducing agent and 1.5 parts of perfluorooctyltriethylsilane to the dry material mixture obtained in step 2) and stir for 120 seconds to obtain a coating topcoat.

[0044] 4) When using, first apply the composite coating primer on the concrete surface, and then apply the composite coating topcoat on the composite coating primer surface. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0045] Embodiment 4: This embodiment is suitable for the concrete composite coating of the substation structure in saline soil areas. The materials are prepared according to the following components, calculated by weight: 100 parts of ordinary Portland cement, 3 parts of polycarboxylic acid water reducer, 2 parts of sodium dodecylbenzene sulfonate, 1 part of perfluorooctyl triethyl silane, 10 parts of sodium methyl siliconate, 1 part of nano-silica, 3 parts of microencapsulation material (shell material is polyurethane and core material is normal 18-alkane), and 128 parts of water.

[0046] This embodiment is applicable to the preparation method of the concrete composite coating of the transmission and substation structure in saline soil areas, and comprises the following steps: 1) Add 10 parts of sodium methylsiliconate and 2 parts of sodium dodecylbenzene sulfonate to 90 parts of water and stir for 30 seconds to achieve uniformity to obtain a coating primer.

[0047] 2) 100 parts of cement, 1 part of nano-silica and 3 parts of microencapsulated materials were mixed and stirred for 30 seconds to achieve uniformity to obtain a dry material mixture.

[0048] 3) Add 38 parts of water, 3 parts of water reducing agent and 1 part of perfluorooctyltriethylsilane to the dry material mixture obtained in step 2) and stir for 120 seconds to obtain a coating topcoat.

[0049] 4) When using, first apply the composite coating primer on the concrete surface, and then apply the composite coating topcoat on the composite coating primer surface. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0050] Embodiment 5: This embodiment is suitable for the concrete composite coating of the substation structure in saline soil areas. The materials are prepared according to the following components, calculated by weight: 100 parts of ordinary Portland cement, 3 parts of polycarboxylic acid water reducer, 2 parts of sodium dodecylbenzene sulfonate, 1 part of perfluorooctyl triethyl silane, 14 parts of sodium methyl siliconate, 1 part of nano silicon dioxide, 3 parts of microencapsulation material (shell material is polyurethane and core material is normal 18-alkane), and 124 parts of water.

[0051] This embodiment is applicable to the preparation method of the concrete composite coating of the transmission and substation structure in saline soil areas, and comprises the following steps: 1) Add 14 parts of sodium methylsiliconate and 2 parts of sodium dodecylbenzene sulfonate to 86 parts of water and stir for 30 seconds to achieve uniformity to obtain a coating primer.

[0052] 2) 100 parts of cement, 1 part of nano-silica and 3 parts of microencapsulated materials were mixed and stirred for 30 seconds to achieve uniformity to obtain a dry material mixture.

[0053] 3) Add 38 parts of water, 3 parts of water reducing agent and 1 part of perfluorooctyltriethylsilane to the dry material mixture obtained in step 2) and stir for 120 seconds to obtain a coating topcoat.

[0054] 4) When using, first apply the composite coating primer on the concrete surface, and then apply the composite coating topcoat on the composite coating primer surface. The composite coating primer layer (the thickness of the primer should be controlled at 45~55μm) and the composite coating topcoat layer (the thickness of the topcoat should be controlled at 1~2mm) together form a concrete composite coating that resists saline soil erosion.

[0055] The present invention will use a pull-out test method to determine the bonding strength between the coating and the concrete substrate, and the specific steps are as follows: 1) Sample preparation: Select representative concrete specimens and ensure that the specimen surface is flat and clean. Then evenly apply the developed composite coating material on the specimen surface, and the coating thickness should meet the actual application requirements.

[0056] 2) Test disc installation: After the coating is completely cured, use a special adhesive to firmly stick the metal test disc to the coating surface, ensuring that there are no bubbles or gaps between the test disc and the coating.

[0057] 3) Loading and measurement: Connect the test plate to the pull-out test equipment and gradually increase the tensile force at a constant rate until the coating separates from the concrete substrate. Record the maximum tensile force value at separation.

[0058] 4) Data processing: Calculate the bonding strength between the coating and the substrate based on the maximum tensile force value and the area of ​​the test disc.

[0059] For the concrete coatings prepared in Examples 1 to 5, the specific bonding strength results are shown in Table 1: Table 1

[0060] According to the test results shown in Table 1, it can be seen that sodium methylsiliconate can generate a hydrophobic substance under the action of carbon dioxide and water in the air. This substance can penetrate into the base layer, effectively block the capillaries in the cement slurry, and form a hydrophobic film of a mesh polymer siloxane resin on the surface of the material. The formation of this film has a significant effect on enhancing the overall mechanical strength and bonding strength of the material.

[0061] In addition, fluorinated silicone compounds have chemical resistance and the surface treated with them can maintain good stability, thus helping to maintain high bonding strength for a long time.

[0062] The concrete coatings prepared in Examples 1 to 5 were coated on concrete for performance testing, and a concrete test block without any surface treatment and with the same curing method was used as blank sample 0. The compressive strength (MPa) data of different examples under the dry-wet cycle conditions of 5wt% sodium sulfate solution are shown in Table 2.

[0063] Table 2

[0064] According to the test results listed in Table 2, it can be seen that the concrete composite coating material of the present invention exhibits good performance in resisting saline soil erosion. Among them, the sodium methylsiliconate contained in the inner primer is an efficient waterproof and moisture-proof material. It can penetrate deeply into the concrete, react chemically with the concrete, and form a waterproof layer. This property enables the concrete to effectively block the erosion of moisture and salt, providing strong protection for the concrete and preventing damage from saline soil.

[0065] In the surface layer of the coating material, the addition of nano-silicon dioxide significantly improves the strength and durability of the cement slurry. Its nano-scale tiny size enables it to fill the tiny pores in the cement slurry, greatly enhancing the density and anti-penetration ability of the material. At the same time, the introduction of fully fluorinated organosilicon compounds strengthens the impermeability of concrete and effectively blocks the intrusion of moisture and other harmful substances. This not only helps to protect the internal structure of the concrete, but also delays the deterioration process of the concrete to a certain extent, indirectly maintaining the strength of the concrete. The mass change rate and compressive corrosion resistance coefficient of different embodiments after 150 dry-wet cycles in sulfate solution are shown in Table 3.

[0066] Table 3

[0067] According to the data analysis results in Table 3, it can be seen that the mass growth amplitude and rate of the uncoated specimens are more obvious than those of the coated specimens. This observation proves the important role of the coating in preventing the corrosive solution from penetrating into the capillary channels inside the concrete.

[0068] After 150 dry-wet cycles, the compressive corrosion resistance coefficient of the uncoated specimens dropped to the lowest point, reflecting that the concrete material suffered relatively serious damage and the corrosive solution caused significant damage to the specimens without coating protection. Under the same experimental conditions, the coated specimens showed a higher compressive corrosion resistance coefficient, which shows that the coating effectively slowed down the erosion rate of the corrosive solution on the concrete material, thereby improving the overall durability of the specimens.

[0069] The coating is corrosion-resistant mainly due to the sodium methylsiliconate used in its inner primer. This special material can form a solid chemical bond with the surface of the substrate, effectively blocking the penetration of corrosive media and providing a strong protective barrier for the substrate. In addition, the nano-silicon dioxide and fluorinated organosilicon compounds added to the surface layer of the coating significantly improve the density and impermeability of the coating, enhance the strength of the coating, and make it more resistant to corrosive substances such as sulfate solutions.

[0070] It can be seen from the above that the present invention has the following advantages: 1) The present invention adopts sodium methylsiliconate as the bottom layer, which is essentially an organic silicon compound. Sodium methylsiliconate is selected as the inner layer material due to its excellent adhesion, water resistance and chemical resistance. It can adhere tightly to the substrate to form a stable interface and provide a solid foundation for the outer layer.

[0071] 2) The present invention can improve the hardness and wear resistance of the entire coating by adding fluorinated organosilicon compounds and nano-silicon dioxide into the surface layer. The fluorinated organosilicon compounds have excellent hydrophobicity, oleophobicity and chemical resistance. In the coating, it can reduce the surface tension of the coating and make the coating have better hydrophobicity. At the same time, it can also improve the weather resistance and durability of the coating.

[0072] 3) Compared with the prior art, the anti-salinity soil erosion concrete composite coating material proposed in the present invention has the advantages of low cost, simple construction and strong durability. These advantages together ensure the stability and safety of concrete facilities in harsh environmental conditions such as saline soil erosion, and provide a strong guarantee for the long-term safe operation of infrastructure.

[0073] It can be seen from the above contents that the present invention fully considers the compatibility and synergy between the layers, which work together to protect the concrete structure.

[0074] First, the inner primer uses sodium methylsiliconate as the main ingredient, which can form a stable chemical bond with the surface of the concrete substrate, providing a solid foundation for the entire coating system. The permeability and reactivity of sodium methylsiliconate enable it to effectively fill the pores of the concrete and enhance the waterproof and moisture-proof ability of the substrate.

[0075] Next, nano-silica was introduced into the surface layer. Nano-silica, due to its tiny particle size and high specific surface area, can significantly enhance the density and hardness of the coating, thereby improving its impermeability and wear resistance. This layer is designed to further enhance the physical barrier effect of the coating and provide more comprehensive protection for the concrete structure. In addition, fluorinated organosilicon compounds and microencapsulated materials are added to the surface layer of the coating. Fluorinated organosilicon compounds give the coating surface excellent hydrophobicity and chemical stability, making it more resistant to harsh environments such as saline soil. The microencapsulated material, as an intelligent repair agent, can automatically release the repair agent when the coating is slightly damaged, fill the cracks, and extend the service life of the coating.

[0076] Through the combination of the above-mentioned layers of materials, the present invention achieves close combination and synergy between the layers of the composite coating. Therefore, the anti-salinity soil erosion concrete composite coating material proposed by the present invention has significant advantages in protecting concrete structures from saline soil erosion, and provides a strong guarantee for the long-term safe operation of infrastructure.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A concrete composite coating suitable for transmission and substation structures in saline soil areas, characterized in that: The raw materials include coating primer and coating topcoat, calculated by mass, of which: The coating primer includes: 10-14 parts of sodium methylsiliconate, 2 parts of dispersant, and 86-90 parts of water; The coating topcoat includes: 100 parts of silicate cement, 1 part of nano silicon dioxide, 3 parts of microencapsulated materials, 38 parts of water, 3 parts of water reducing agent, and 0.5-1.5 parts of fluorine-containing organic silicon compounds.

2. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The dispersant is one of sodium dodecylbenzene sulfonate, sodium laurate and lauroyl diethanolamine.

3. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The silicate cement adopts ordinary silicate cement.

4. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The core material of the microencapsulation material is normal alkane paraffin, and the shell material is PMMA or polyurethane.

5. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The water reducing agent is polycarboxylate water reducing agent.

6. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The fluorine-containing organic silicon compound is one of perfluorooctyltriethylsilane, perfluorodecyltrimethoxysilane and trifluoropropylmethyldimethoxysilane.

7. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The bonding strength between the concrete composite coating applicable to the transmission and substation structure in saline soil areas and the concrete substrate is 1.75-1.84 MPa.

8. The concrete composite coating suitable for transmission and substation structures in saline soil areas according to claim 1, characterized in that: The concrete composite coating suitable for the transmission and substation structure in saline soil areas has a compressive strength of 50-59 MPa under dry-wet cycle conditions of 5wt% sodium sulfate solution, a mass change rate of 0.60%-0.64%, and a compressive corrosion resistance coefficient of 0.91-0.

95.

9. The method for preparing the concrete composite coating suitable for the transmission and substation structure in saline soil areas according to any one of claims 1 to 8, characterized in that: include: A composite coating primer is coated on the concrete surface, and then a composite coating topcoat is coated on the surface of the composite coating primer. After curing, the concrete composite coating suitable for the transmission and substation structure in saline soil areas is formed.

10. The method for preparing a concrete composite coating suitable for a transmission and substation structure in saline soil areas according to claim 9, characterized in that: The preparation methods of the coating primer and coating topcoat are as follows: Add sodium methylsiliconate and dispersant into water and stir evenly to obtain a coating primer; The silicate cement, nano silicon dioxide and microencapsulated materials are mixed to obtain a dry material mixture, and then water, a water reducing agent and a fluorine-containing organic silicon compound are added to the dry material mixture and mixed to obtain a coating topcoat.

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