High-durability protective coating for high-water-head hydraulic concrete and preparation method of high-durability protective coating

Abstract

The invention relates to a high-durability protective coating for high-water-head hydraulic concrete and a preparation method of the high-durability protective coating. The coating comprises a component A and a component B, the component A is powder and is composed of 60%-65% of Portland cement, 20%-30% of slag powder, 5%-10% of titanium dioxide and 0.2%-5% of white carbon black; the component B is a liquid material and is prepared from 35%-40% of pure acrylic acid copolymer emulsion, 35%-50% of silicon carbide nanowire dispersion liquid, 0%-10% of a flocculating agent, 0.2%-5% of a defoaming agent, 0.05%-0.5% of a preservative, 3%-4% of a film-forming agent and 5%-15% of water. The component A and the component B are mixed and stirred uniformly according to the ratio of 1: 1 to obtain the paint. The consolidated material is environment-friendly, non-toxic, good in viscosity and toughness, breathable, impervious, wear-resistant, anti-scouring, anti-freezing and anti-carbonization; the one-time film forming thickness is gt; the high-water-head hydraulic concrete can be mechanically sprayed or manually scraped underwater or on a wet surface, construction is facilitated, the effect is easy to guarantee, durable protection such as abrasion resistance, scouring resistance, cavitation corrosion resistance and carbonization resistance of the high-water-head hydraulic concrete containing the suspended load and the bed load under harsh and complex environmental conditions can be realized, and the service life of the high-water-head hydraulic concrete structure is greatly prolonged. And a protection technical support is provided for high-quality green development of hydraulic concrete.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and relates to the technical field of surface protection of hydraulic concrete in a complex operating environment coupled with multiple factors such as freezing and thawing, impact abrasion, carbonization, etc., and specifically relates to a high-durability protective coating for high-head hydraulic concrete and a preparation method thereof. Background Art

[0002] High-head hydraulic concrete is prone to problems such as concrete surface powdering, cracks, spalling, and pitting under the influence of combined factors such as water erosion, natural carbonization, freeze-thaw cycles, dry-wet cycles, and penetration of corrosive media. These problems not only affect the appearance of concrete, but are also the main factor of internal structural deterioration, seriously affecting the safe operation and service life of buildings. Excellent surface protection materials are necessary measures to resist the deterioration of complex environmental projects.

[0003] At present, common concrete surface protective coatings are mainly based on polymer organic materials, such as polyurea, fluorocarbon, epoxy, silicone and modified asphalt. Although polymer organic coatings can greatly improve the water tightness and corrosion resistance of concrete, their density prevents water vapor from escaping from the hydraulic concrete matrix, which can easily cause peeling, bubbling, large-area hollowing and other damage in a short period of time; it is far different from the linear expansion coefficient of concrete, and it is easy to detach due to uncoordinated deformation; in any case, the life of modified polymer materials is its shortcoming. Therefore, protective coatings based on polymer organic materials cannot achieve durable protection of hydraulic concrete environments.

[0004] Inorganic materials can work on wet surfaces, have good air permeability, are resistant to aging, and have similar deformation properties to the concrete matrix. They are suitable for hydraulic concrete working environments, but they are brittle and have poor toughness. Using an emulsion that is compatible with inorganic materials to modify them can improve their performance. For example, the concrete surface protective coating disclosed in patent CN119119816A is a composite coating of inorganic materials and modified emulsions. The coating's crack resistance, temperature adaptability, and anti-fouling properties are improved by adding fibers, high-temperature resistant materials, and other materials; the hydraulic concrete surface protective agent for high-cold areas disclosed in patent CN110982315A is modified by adding a penetrating crystallizing agent to cement-based materials and a composite polymer emulsion to improve the flexibility and crack resistance of cement-based protective materials. The above inventions for modifying inorganic materials still cannot meet the protection requirements for the abrasion, scouring, and carbonization of hydraulic concrete projects by complex high-head water flows containing suspended sediment and bedload.

[0005] Therefore, in response to the above problems, it is urgent to develop a high-durability protective coating for high-head hydraulic concrete to provide protective technical support for the high-quality green development of hydraulic concrete. Summary of the invention

[0006] The purpose of the present invention is to provide a high-durability protective coating for high-head hydraulic concrete in response to the deficiencies in the prior art, which can solve the problem of insufficient toughness of inorganic material composite emulsion modified coatings, and significantly improve the abrasion resistance and scour resistance. It achieves the durable protection of inorganic material composite emulsion modified coatings for projects operating in harsh environments, and provides a green and low-carbon protective technology for the high-quality operation of newly built and existing high-head hydraulic concrete.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a high-durability protective coating for high-head hydraulic concrete, comprising component A and component B, wherein the mass ratio of component A to component B is 1:1; wherein, Component A includes by weight: Portland cement 60%~65%; Slag powder 20%~30%; Titanium dioxide 4%~10%; White carbon black 0.2%~5%; Component B includes by weight: Pure acrylic copolymer emulsion 35%~40%; Silicon carbide nanowire dispersion 35%~50%; Flocculant 0%~10%; Defoaming agent 0.2%~5%; Preservatives 0.05%~0.5%; Film former 3%~4%; Water 5%~15%.

[0008] As a preferred embodiment of the present invention, the silicate cement has a specific surface area of> 420m 2 / kg, white cement with strength grade of 52.5.

[0009] As a preferred embodiment of the present invention, the slag powder is S95 grade or above slag powder with a purity of >99%.

[0010] As a preferred embodiment of the present invention, the titanium dioxide is rutile type, TiO2%≥92%, and 45μm sieve residue≤0.07%.

[0011] As a preferred embodiment of the present invention, the white carbon black is a hydrophilic white carbon black, and the 45 μm sieve residue is ≤250 mg / kg.

[0012] As a preferred embodiment of the present invention, the solid content of the pure acrylic copolymer emulsion is 40% to 50%.

[0013] As a preferred embodiment of the present invention, the silicon carbide nanowire dispersion is prepared by adding silicon carbide nanowires with a diameter of 60 to 100 nm and a length of tens to hundreds of microns to a mixture of two or more dispersants including silane coupling agent, ethanol, polyacrylamide, polyethylene glycol, sodium phosphate and water, and subjecting to ultrasonic vibration for 30 minutes to obtain a uniformly dispersed silicon carbide nanowire dispersion with a solid content of 2%.

[0014] As a preferred embodiment of the present invention, the flocculant is one or a composite of several of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose, hydroxypropyl starch ether, polyacrylamide and chitosan.

[0015] As a preferred embodiment of the present invention, the defoaming agent is a composite of one or more non-ionic paraffin emulsion and unsaturated polyester resin emulsion.

[0016] As a preferred embodiment of the present invention, the preservative is one or a complex of Brobol (2-bromo-2-nitropropane-1, 3-propanediol), BIT (1, 2-benzisothiazolin-3-one), and Kesong (2-methyl-4-isothiazoline-3-one and 5-chloro-2-2methyl-4-isothiazoline-3-one).

[0017] As a preferred embodiment of the present invention, the film-forming agent is a vinyl-derived polymer selected from the group consisting of acrylate, acrylonitrile and acrylamide.

[0018] In addition, the present invention also provides a method for preparing a high-durability protective coating for high-head hydraulic concrete: According to the above weight ratio, the raw material components of component A are put into an automatic mixer and mixed evenly by physical and mechanical stirring to obtain component A; the raw material silicon carbide nanowire dispersion of component B is mixed evenly with water, flocculant, defoamer, preservative, and film-forming agent according to the above weight ratio, and then pure acrylic copolymer emulsion is added according to the above weight ratio, and a high-speed shear emulsifier is used to high-speed shear at a rate of 7000r / min for 10 minutes, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process to obtain component B. When used, component A and component B are mixed in a ratio of 1:1, and a stirring device with a speed of not less than 48r / min is used to stir evenly to obtain a high-head hydraulic concrete high-durability protective coating.

[0019] The technical principles of the present invention are as follows: The materials used have similar linear expansion coefficients, are corrosion-resistant, aging-resistant, environmentally friendly and non-toxic. By using titanium dioxide, white carbon black and silicon carbide nanowires to fill the pores of the matrix, a dense protective body is formed to enhance the mechanical strength, impermeability, corrosion resistance, wear resistance and impact resistance of the matrix; through the combined effects of pure acrylic emulsion, flocculant and silicon carbide nanowires in the three-dimensional network space of the matrix-interface optimization-hydration product improvement, the bending and shear strength, ductility and toughness, underwater interface bonding, high wear resistance and peeling resistance of the solidified material are enhanced, thereby obtaining a high-durability service protective material for high-head hydraulic concrete under harsh and complex environmental conditions.

[0020] The beneficial effects of the present invention are: (1) Good underwater wet adhesion: 28d bonding strength ≥2.5MPa.

[0021] (2) Early strength, high strength and high toughness: 7d compressive strength ≥30MPa, 28d compressive strength ≥40MPa, 28d flexural strength ≥12MPa, flexural strength increased by more than 30% compared with latex modified materials, ultimate tensile strain ≥2%.

[0022] (3) Abrasion and scour resistance: 28d abrasion resistance (underwater steel ball method) ≥10.0h•m 2 / kg, 28d abrasion resistance (ring method) ≥1.0h•m 2 / kg, the wear resistance and erosion resistance are improved by more than 50% compared with C50 concrete.

[0023] (4) Carbonization resistance: The carbonization depth is 0 after 7 days.

[0024] (5) Excellent antifreeze performance: After 200 freeze-thaw cycles, the coating remains intact.

[0025] The film thickness of the present invention is >500 μm at one time, and can be constructed by mechanical spraying or manual scraping underwater or on a wet surface. It is easy to construct and the effect is easy to ensure, and the service life of high-head hydraulic concrete structures can be greatly extended. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0027] Example 1 The high-durability protective coating for high-head hydraulic concrete of this embodiment is obtained by uniformly mixing component A of 52.5 white cement 650 parts, S95 grade mineral slag powder 250 parts, rutile titanium dioxide 80 parts, and hydrophilic white carbon black 20 parts; component B is obtained by uniformly mixing component B of pure acrylic copolymer emulsion 380 parts, silicon carbide nanowire dispersion 400 parts, polyacrylamide flocculant 20 parts, non-ionic paraffin emulsion defoamer 10 parts, Kaisong preservative 2 parts, acrylate film-forming agent 38 parts, and water 150 parts.

[0028] Example 2 The high-durability protective coating for high-head hydraulic concrete of this embodiment is obtained by uniformly mixing component A, which is calculated by weight as 600 parts of 52.5 white cement, 300 parts of S95 grade mineral slag powder, 80 parts of rutile titanium dioxide, and 20 parts of hydrophilic white carbon black; component B is calculated by weight as 400 parts of pure acrylic copolymer emulsion, 500 parts of silicon carbide nanowire dispersion, 10 parts of chitosan flocculant, 5 parts of polyester resin emulsion defoamer, 1 part of Kaisong preservative, 34 parts of acrylate film-forming agent, and 50 parts of water.

[0029] Example 3 The high-durability protective coating for high-head hydraulic concrete of this embodiment is obtained by uniformly mixing component A, which is calculated by weight as 650 parts of 52.5 white cement, 300 parts of S95 grade mineral slag powder, 40 parts of rutile titanium dioxide, and 10 parts of hydrophilic white carbon black; component B is calculated by weight as 350 parts of pure acrylic copolymer emulsion, 500 parts of silicon carbide nanowire dispersion, 5 parts of hydroxypropyl methylcellulose ether flocculant, 5 parts of polyester resin emulsion defoamer, 5 parts of BIT preservative, 35 parts of acrylamide film-forming agent, and 100 parts of water.

[0030] Example 4 The high-durability protective coating for high-head hydraulic concrete of this embodiment is obtained by uniformly mixing component A, which is calculated by weight as 600 parts of 52.5 white cement, 250 parts of S95 grade mineral slag powder, 100 parts of rutile titanium dioxide, and 50 parts of hydrophilic white carbon black; component B is calculated by weight as 400 parts of pure acrylic copolymer emulsion, 400 parts of silicon carbide nanowire dispersion, 5 parts of polyacrylamide flocculant, 8 parts of non-ionic paraffin emulsion defoamer, 2 parts of Kaisong preservative, 35 parts of acrylamide film-forming agent, and 150 parts of water.

[0031] Example 5 The high-durability protective coating for high-head hydraulic concrete of this embodiment is obtained by uniformly mixing component A, which is calculated by weight as 650 parts of 52.5 white cement, 250 parts of S95 grade mineral slag powder, 80 parts of rutile titanium dioxide, and 20 parts of hydrophilic white carbon black; component B is calculated by weight as 400 parts of pure acrylic copolymer emulsion, 350 parts of silicon carbide nanowire dispersion, 45 parts of hydroxyethyl methylcellulose flocculant, 10 parts of non-ionic paraffin emulsion defoamer, 5 parts of Bropol preservative, 40 parts of acrylamide film-forming agent, and 150 parts of water.

[0032] In the above embodiment, the raw material components of component A are put into an automatic mixer and mixed evenly by physical and mechanical stirring to obtain component A; the raw material silicon carbide nanowire dispersion of component B is mixed evenly with water, flocculant, defoamer, preservative, and film-forming agent in proportion, and then pure acrylic copolymer emulsion is added in proportion, and a high-speed shear emulsifier is used to high-speed shear at a rate of 7000r / min for 10 minutes, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to remove bubbles generated during the high-speed shearing process, thereby obtaining component B. When used, component A and component B are mixed in a ratio of 1:1, and a stirring device with a speed of not less than 48r / min is used to stir evenly to obtain a high-head hydraulic concrete high-durability protective coating.

[0033] Application Examples The following is the performance of the present invention: The high-durability protective coating for high-head hydraulic concrete is a two-component material. When used, the two components can be mixed evenly in proportion. The slurry properties prepared with the above mix ratio are shown in Table 1. The test method is carried out in accordance with the relevant provisions of standards such as JC / T2090 "Polymer Cement Waterproof Slurry", JG / T 335 "Film-forming Coating for Concrete Structure Protection", and SL 352-2020 "Hydraulic Concrete Test Procedure".

[0034] Table 1 Test results From the above test results, it can be seen that the high-durability protective coating for high-head hydraulic concrete provided by the present invention has good workability, mechanical properties, ductility and toughness, wet surface and underwater adhesion, abrasion resistance and scour resistance, carbonization resistance and frost resistance, and can meet the high-durability service protection requirements of high-head hydraulic concrete under harsh and complex environmental conditions.

[0035] Although the present invention lists some of the test results of the embodiments as disclosed above, they are not intended to limit the present invention. Anyone familiar with this art can make various changes or modifications without departing from the spirit and scope of the present invention, such as replacing pure acrylic copolymer emulsion with phenyl acrylic copolymer emulsion, etc. The effect after such adjustment is predictable, and such changes also fall within the scope defined by the protection scope of the claims of this application. Therefore, the protection scope of the present invention shall be based on the protection scope defined by the same or equivalent technical features of the claims of this application.

Claims

1. A high-durability protective coating for high-head hydraulic concrete, characterized in that: It includes component A and component B, and the mass ratio of component A to component B is 1:1; wherein, Component A includes by weight: Portland cement 60%~65%; Slag powder 20%~30%; Titanium dioxide 4%~10%; White carbon black 0.2%~5%; Component B includes by weight: Pure acrylic copolymer emulsion 35%~40%; Silicon carbide nanowire dispersion 35%~50%; Flocculant 0%~10%; Defoaming agent 0.2%~5%; Preservatives 0.05%~0.5%; Film former 3%~4%; Water 5%~15%.

2. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The silicate cement has a specific surface area of> 420m 2 / kg, white cement with strength grade of 52.

5.

3. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The slag powder is S95 grade or above slag powder with a purity of >99%.

4. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The titanium dioxide is rutile type, TiO2%≥92%, and 45μm sieve residue≤0.07%; The white carbon black is a hydrophilic white carbon black, and the 45 μm sieve residue is ≤250 mg / kg.

5. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The pure acrylic copolymer emulsion has a solid content of 40% to 50%.

6. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The silicon carbide nanowire dispersion is prepared by adding silicon carbide nanowires with a diameter of 60 to 100 nm and a length of tens to hundreds of microns into a mixture of two or more dispersants including silane coupling agent, ethanol, polyacrylamide, polyethylene glycol, sodium phosphate and water, and subjecting to ultrasonic vibration for 30 minutes to obtain a silicon carbide nanowire dispersion with a uniform dispersion and a solid content of 2%.

7. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The flocculant is one or a composite of hydroxypropyl methylcellulose ether, hydroxyethyl methylcellulose, hydroxypropyl starch ether, polyacrylamide, and chitosan; The defoaming agent is a composite of one or more nonionic paraffin emulsion and unsaturated polyester resin emulsion.

8. The high-durability protective coating for high-head hydraulic concrete according to claim 1, characterized in that: The preservative is one or a combination of Brobol (2-bromo-2-nitropropane-1, 3-propanediol), BIT (1, 2-benzisothiazolin-3-one), and Kesong (2-methyl-4-isothiazolin-3-one and 5-chloro-2-2-methyl-4-isothiazolin-3-one); The film former is a vinyl-derived polymer selected from the group consisting of acrylate, acrylonitrile and acrylamide.

9. A method for preparing a high-durability protective coating for high-head hydraulic concrete according to any one of claims 1 to 7, characterized in that: Preparation method of component A: according to the weight ratio, each raw material component of component A is put into an automatic mixer and mixed evenly by physical and mechanical stirring to obtain component A; Preparation method of component B: according to weight ratio, silicon carbide nanowire dispersion liquid of component B is uniformly mixed with water, flocculant, defoamer, preservative and film-forming agent, and then pure acrylic copolymer emulsion is added, and high-speed shearing is performed at a rate of 7000r / min for 10 minutes using a high-speed shear emulsifier, and then the sheared emulsion is ultrasonicated for 10 minutes using an ultrasonic disperser to obtain component B; Preparation method of protective coating: Mix component A and component B in a ratio of 1:1, and stir evenly using a stirring device at a speed of not less than 48 r / min to obtain a high-durability protective coating for high-head hydraulic concrete.

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