Concrete surface hole sealing agent, preparation method thereof and concrete

Abstract

The invention belongs to the technical field of novel chemical materials, and provides a concrete surface hole sealing agent, a preparation method thereof and concrete. The concrete surface hole sealing agent comprises the following components in parts by weight: 30-50 parts of waterborne epoxy resin, 5-15 parts of nano silicon dioxide, 8-12 parts of a microcapsule material, 3-8 parts of modified aerogel, 10-20 parts of a curing agent, 1-3 parts of a dispersing agent and 20-40 parts of water. The cured water-borne epoxy resin fills the surface and internal pores of the concrete to form a continuous sealing film; micropores formed by cement hydration are filled with nano silicon dioxide, and the nano silicon dioxide reacts with a cement hydration product to generate C-S-H gel to further densify a matrix structure; the modified aerogel blocks a heat conduction path, has hydrophobicity, and can avoid the increase of the heat conductivity coefficient caused by water absorption of pores. The microcapsule material can be gradually hydrolyzed and broken in a concrete alkaline environment, and silicic acid gel is released to fill new cracks, so that the durability of the concrete is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new chemical materials, in particular to a concrete surface pore sealing agent, a preparation method thereof and concrete. BACKGROUND

[0002] As the core substrate of new wall materials, the performance of concrete directly determines the energy saving, durability and safety level of buildings. New wall materials must meet the stringent requirements of low thermal conductivity, high impermeability and long durability. However, the pore structure of traditional concrete wall materials has inherent defects. The connected pores formed by cement hydration and the bubble pores introduced during construction result in a very high thermal conductivity, far exceeding the energy saving standard of new wall materials. In addition, this pore network provides a transmission channel for erosion media such as water and chloride ions, resulting in insufficient impermeability and durability of the material. Traditional walls usually have problems such as carbonation and steel corrosion after 5-10 years of service, and the related maintenance cost can account for more than 30% of the whole life cycle cost of the building. For the pore problem, existing technologies such as surface coating type pore sealing agents mainly rely on physical plugging of surface pores, but have the key defects of weak adhesion to the matrix and easy falling off during long-term service, and cannot completely solve the internal pore problem. In addition, existing technologies generally lack effective regulation ability of thermal conductivity, which has obvious short board in meeting the requirements of new wall materials. SUMMARY

[0003] The present application aims to overcome the problems of high thermal conductivity, poor impermeability and durability of concrete wall materials in the prior art, and provides a concrete surface pore sealing agent, a preparation method thereof and concrete.

[0004] In order to achieve the above-mentioned application purpose, the present application provides the following technical solutions: The present application provides a concrete surface pore sealing agent, which comprises the following components by weight: 30-50 parts of water-based epoxy resin, 5-15 parts of nano-silicon dioxide, 8-12 parts of microcapsule material, 3-8 parts of modified aerogel, 10-20 parts of curing agent, 1-3 parts of dispersing agent and 20-40 parts of water.

[0005] As a preferred, the water-based epoxy resin comprises bisphenol A type water-based epoxy resin; the epoxy equivalent weight of the bisphenol A type water-based epoxy resin is 450 g / eq-550 g / eq.

[0006] As a preferred, the particle size of the nano-silicon dioxide is 20 nm-50 nm, and the specific surface area is 200 m 2 / g-300 m 2 / g.

[0007] As a preferred, the microcapsule material comprises a core and a shell, the core is silica gel, and the shell is polylactic acid.

[0008] Preferably, the modified aerogel is a silica aerogel modified by a silane coupling agent.

[0009] Preferably, the curing agent comprises one or more of a polyetheramine, a cycloaliphatic amine, a modified aliphatic amine, and gamma-glycidoxypropyltrimethoxysilane.

[0010] Preferably, the dispersing agent comprises one or both of sodium polyacrylate and gamma-aminopropyltrimethoxysilane.

[0011] The present application also provides a method for preparing a concrete surface sealing agent, comprising the following steps: The components are mixed to obtain a concrete surface sealing agent.

[0012] The present application also provides the use of a concrete surface sealing agent in concrete.

[0013] The present application also provides a concrete, comprising the following components in parts by weight: Cement 90-110 parts, aggregate 150-200 parts, water 40-60 parts, and concrete surface sealing agent 3-8 parts.

[0014] The technical solution of the present application has the following advantages: The present application provides a concrete surface sealing agent, comprising the following components in parts by weight: water-based epoxy resin 30-50 parts, nano-silica 5-15 parts, microcapsule material 8-12 parts, modified aerogel 3-8 parts, curing agent 10-20 parts, dispersing agent 1-3 parts, and water 20-40 parts. The water-based epoxy resin and the nano-silica synergistically form an "organic-inorganic" interpenetrating network structure: the water-based epoxy resin fills the pores on the surface and inside the concrete after curing, forming a continuous sealing film; the nano-silica fills the micropores formed by cement hydration and reacts with the cement hydration products to form C-S-H gel, further densifying the matrix structure. The three-dimensional porous structure of the modified aerogel blocks the heat conduction path, effectively reducing the thermal conductivity. At the same time, the modified aerogel also has hydrophobicity, which can avoid the increase in thermal conductivity caused by water absorption in the pores, so that the material can balance the thermal insulation performance and impermeability. Finally, the microcapsule material will gradually hydrolyze and break down in the alkaline environment of the concrete, releasing silica gel to fill the newly formed cracks, achieving "dynamic repair during the hardening stage of the concrete", and further improving the durability of the concrete. DETAILED DESCRIPTION

[0015] The following examples are provided to better further understand the present application and are not limited to the best mode contemplated, do not constitute limitations on the scope of the application, and are not intended to convey any idea of the scope of the present application, any product that is the same or similar to the present application obtained by the inspiration of the present application or the combination of the present application with other prior art features falls within the scope of the present application.

[0016] The present application provides a concrete surface sealing agent, comprising the following components in parts by weight: The water-based epoxy resin is 30-50 parts, nano-silica is 5-15 parts, microcapsule material is 8-12 parts, modified aerogel is 3-8 parts, curing agent is 10-20 parts, dispersing agent is 1-3 parts and water is 20-40 parts.

[0017] In the present application, the water-based epoxy resin is 30-50 parts by weight, preferably 35-45 parts, further preferably 37-43 parts, and more preferably 40 parts.

[0018] In the present application, the nano-silica is 5-15 parts by weight, preferably 7-13 parts, further preferably 8-12 parts, and more preferably 10 parts.

[0019] In the present application, the microcapsule material is 8-12 parts by weight, preferably 8.5-11.5 parts, further preferably 9-11 parts, and more preferably 10 parts.

[0020] In the present application, the modified aerogel is 3-8 parts by weight, preferably 4-7 parts, further preferably 5-6 parts, and more preferably 5.5 parts.

[0021] In the present application, the curing agent is 10-20 parts by weight, preferably 12-18 parts, further preferably 14-16 parts, and more preferably 15 parts.

[0022] In the present application, the dispersing agent is 1-3 parts by weight, preferably 1.5-2.5 parts, further preferably 1.7-2.3 parts, and more preferably 2 parts.

[0023] In the present application, the water is 20-40 parts by weight, preferably 25-35 parts, further preferably 27-33 parts, and more preferably 30 parts.

[0024] In the present application, the water-based epoxy resin comprises a bisphenol A type water-based epoxy resin; the epoxy equivalent weight of the bisphenol A type water-based epoxy resin is preferably 450 g / eq-550 g / eq, further preferably 470 g / eq-530 g / eq, and more preferably 500 g / eq.

[0025] In this invention, the particle size of the nano-silica is preferably 20nm-50nm, more preferably 30nm-40nm, and even more preferably 35nm; the specific surface area is preferably 200m². 2 / g-300m 2 / g, further preferably 220m 2 / g-280m 2 / g, more preferably 250m 2 / g.

[0026] In this invention, the microcapsule material comprises a core and a shell, wherein the core is a silica gel and the shell is polylactic acid.

[0027] In this invention, the preparation method of the microcapsule material includes the following steps: (1) Mix tetraethyl orthosilicate and ethanol to obtain a first solution; mix the first solution with water to obtain a second solution; add ammonia dropwise to the second solution to carry out the reaction; after the reaction is completed, distill to obtain the precursor; (2) Mix polylactic acid and dichloromethane to obtain a third solution; mix polyvinyl alcohol and water to obtain a fourth solution; (3) Mix the precursor and the fourth solution evenly, then slowly add the third solution to emulsify and obtain an emulsion; distill the emulsion and cool it to room temperature to obtain a suspension; wash the suspension with water, filter and dry it in sequence to obtain the microcapsule material.

[0028] In this invention, the preferred mass ratio of tetraethyl orthosilicate, ethanol, and water in step (1) is (10-15):(5-10):(5-8), more preferably (11-14):(6-9):(6-7), and even more preferably 12.5:7.5:6.5; the preferred mass fraction of ammonia is 23%-27%, more preferably 24%-26%, and even more preferably 25%; the pH of the system adjusted by adding ammonia is preferably 8-9, more preferably 8.2-8.8, and even more preferably 8.5; the preferred reaction temperature is 20℃-30℃, more preferably 22℃-28℃, and even more preferably 25℃; the preferred reaction time is 2h-3h, more preferably 2.2h-2.8h, and even more preferably 2.5h.

[0029] In the present application, the molecular weight of the polylactic acid in step (2) is preferably 5000-10000, further preferably 6000-9000, and more preferably 7500; the polymerization degree of the polyvinyl alcohol is preferably 1700-1800, further preferably 1720-1780, and more preferably 1750; and the mass ratio of polylactic acid, dichloromethane, polyvinyl alcohol, and water is preferably (8-12):(15-20):(1-2):(50-60), further preferably (9-11):(16-19):(1.2-1.8):(52-58), and more preferably 10:17.5:1.5:55.

[0030] In the present application, the mass ratio of the polylactic acid in step (2) to the tetraethyl orthosilicate in step (1) is (8-12):(10-15), further preferably (9-11):(11-14), and more preferably 10:12.5.

[0031] In the present application, the rotation speed of the emulsification in step (3) is preferably 8000r / min-10000r / min, further preferably 8500r / min-9500r / min, and more preferably 9000r / min; and the time is preferably 20min-30min, further preferably 22min-28min, and more preferably 25min.

[0032] In the present application, the modified aerogel is a silica aerogel modified by a silane coupling agent.

[0033] In the present application, the silane coupling agent includes one or both of methacryloyloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane.

[0034] In the present application, the preparation method of the modified aerogel includes the following steps: The silica aerogel is placed in a silane coupling agent solution, and then subjected to reaction and filtration in sequence, the obtained filter cake is washed with ethanol, and finally dried to obtain the modified aerogel.

[0035] In the present application, the solvent of the silane coupling agent solution is preferably ethanol, the mass fraction of the silane coupling agent solution is preferably 5%-10%, further preferably 6%-9%, and more preferably 7.5%; and the mass ratio of the silane coupling agent in the silane coupling agent solution to the silica aerogel powder is preferably (2-5):100, further preferably (3-4):100, and more preferably 3.5:100.

[0036] In the present application, the reaction temperature is preferably 40℃-60℃, further preferably 45℃-55℃, and more preferably 50℃; and the reaction time is preferably 2h-4h, further preferably 2.5h-3.5h, and more preferably 3h.

[0037] In the present application, the curing agent comprises one or more of polyether amine, alicyclic amine, modified fatty amine, and gamma-glycidyl ether oxypropyl trimethoxysilane.

[0038] In the present application, the dispersant comprises one or both of sodium polyacrylate and gamma-aminopropyl trimethoxysilane.

[0039] The present application also provides a preparation method of the concrete surface pore sealing agent, comprising the following steps: Mixing the components to obtain the concrete surface pore sealing agent.

[0040] In the present application, the mixing process of the components comprises the following steps: (1) mixing the water-based epoxy resin, nano-silica, dispersant and water, and sequentially performing dispersion and ultrasonic treatment to obtain a first dispersion liquid; (2) adding the microcapsule material and modified aerogel to the first dispersion liquid, and performing dispersion to obtain a second dispersion liquid; (3) adding the curing agent to the second dispersion liquid, and performing stirring to obtain the concrete surface pore sealing agent.

[0041] In the present application, the rotation speed of the dispersion in step (1) is preferably 2000 r / min-3000 r / min, further preferably 2200 r / min-2800 r / min, and more preferably 2500 r / min; the time of the dispersion is preferably 30 min-60 min, further preferably 40 min-50 min, and more preferably 45 min; the power of the ultrasonic treatment is preferably 200 W-500 W, further preferably 300 W-400 W, and more preferably 350 W; and the time of the ultrasonic treatment is preferably 10 min-30 min, further preferably 15 min-25 min, and more preferably 20 min.

[0042] In the present application, the rotation speed of the dispersion in step (2) is preferably 500 r / min-800 r / min, further preferably 600 r / min-700 r / min, and more preferably 650 r / min; and the time of the dispersion is preferably 15 min-30 min, further preferably 20 min-25 min, and more preferably 22 min.

[0043] In the present application, the rotation speed of the stirring in step (3) is preferably 300 r / min-500 r / min, further preferably 350 r / min-450 r / min, and more preferably 400 r / min; and the time of the stirring is preferably 10 min-20 min, further preferably 12 min-18 min, and more preferably 15 min.

[0044] The application further provides application of the concrete surface sealing agent in concrete.

[0045] The application further provides a concrete comprising the following components in parts by weight: cement 90-110 parts, aggregate 150-200 parts, water 40-60 parts and concrete surface sealing agent 3-8 parts.

[0046] In the application, the cement is in parts by weight of 90-110, preferably 92-108, further preferably 95-105, and more preferably 100.

[0047] In the application, the aggregate is in parts by weight of 150-200, preferably 160-190, further preferably 170-180, and more preferably 175.

[0048] In the application, the water is in parts by weight of 40-60, preferably 45-55, further preferably 47-53, and more preferably 50.

[0049] In the application, the concrete surface sealing agent is in parts by weight of 3-8, preferably 4-7, further preferably 5-6, and more preferably 5.5.

[0050] In the application, the cement is preferably P・O 42.5 grade Portland cement; the aggregate preferably comprises natural sand and gravel, and the mass ratio of the natural sand and gravel is preferably 1: (2.5-3.5), further preferably 1: (2.7-3.3), and more preferably 1:3.

[0051] In the application, the preparation method of the concrete comprises the following steps: mixing the components, sequentially performing first stirring and second stirring, pouring into a mold after ending the stirring, and curing to obtain the concrete.

[0052] In the application, the rotation speed of the first stirring is preferably 200 r / min-300 r / min, further preferably 220 r / min-280 r / min, and more preferably 250 r / min; the time of the first stirring is preferably 2 min-3 min, further preferably 2.2 min-2.8 min, and more preferably 2.5 min; the rotation speed of the second stirring is preferably 600 r / min-800 r / min, further preferably 650 r / min-750 r / min, and more preferably 700 r / min; and the time of the second stirring is preferably 3 min-5 min, further preferably 3.5 min-4.5 min, and more preferably 4 min.

[0053] In the present application, the temperature of the curing is preferably 18-22°C, further preferably 19-21°C, more preferably 20°C; the relative humidity is preferably ≥90%, further preferably ≥92%, more preferably ≥93%; and the time is preferably 26-30 days, further preferably 27-29 days, more preferably 28 days.

[0054] When the specific experimental steps or conditions are not indicated in the examples, the operation or conditions can be carried out according to the conventional experimental steps described in the literature in the art. When the reagents or instruments are not indicated by the manufacturer, they are all conventional reagent products that can be obtained by purchase.

[0055] Example 1: The present example provides a concrete surface sealing agent, which comprises the following components in parts by weight: Bisphenol A type waterborne epoxy resin (epoxy equivalent weight is 500 g / eq) 40 parts, nano-silicon dioxide (particle size is 35 nm, specific surface area is 250 m 2 / g) 10 parts, microcapsule material (including silica gel core and polylactic acid shell) 10 parts, modified aerogel (γ-aminopropyl triethoxysilane modified silica aerogel) 5.5 parts, curing agent 15 parts (including polyether amine 10 parts, γ-glycidyl ether oxypropyl trimethoxysilane 5 parts), dispersant 2 parts (including sodium polyacrylate 1 part, γ-aminopropyl trimethoxysilane 1 part) and water 30 parts.

[0056] The preparation method of the microcapsule material comprises the following steps: The tetraethyl orthosilicate and ethanol are mixed, stirred at a temperature of 25 DEG C and a rotating speed of 400 r / min for 15 min to obtain a first solution; water is added into the first solution, and the stirring is continued at a temperature of 25 DEG C and a rotating speed of 400 r / min for 30 min to obtain a second solution; the mass ratio of the tetraethyl orthosilicate, ethanol and water is 12.5:7.5:6.5; then ammonia water with a mass fraction of 25% is added dropwise into the second solution to adjust the pH of the system to 8.5, the stirring speed is maintained at 400 r / min, and the reaction is carried out at 25 DEG C for 2.5 h; after the reaction is completed, ethanol is removed by distillation under reduced pressure at a temperature of 45 DEG C and a pressure of 4.5 kPa to obtain a precursor; polylactic acid (with a molecular weight of 7500) and dichloromethane are mixed, and ultrasonic treatment is carried out at a temperature of 30 DEG C and a power of 350 W for 20 min to obtain a third solution; polyvinyl alcohol (with a polymerization degree of 1750) and water are mixed, heated to 65 DEG C, stirred until completely dissolved, and then cooled to room temperature to obtain a fourth solution; the mass ratio of the polylactic acid, dichloromethane, polyvinyl alcohol and water is 10:17.5:1.5:55, and the mass ratio of the polylactic acid and tetraethyl orthosilicate is 10:12.5; the precursor obtained above and the fourth solution are mixed, the third solution is slowly added after uniform stirring, and emulsification is carried out by using a high-shear emulsifier (with a rotating speed of 9000 r / min) for 25 min to obtain an emulsion; the emulsion is transferred into a rotary evaporator, and dichloromethane is removed by distillation under reduced pressure at a temperature of 45 DEG C, a vacuum degree of 9 kPa and a rotating speed of 250 r / min for 5 h; after the distillation is completed, the system is cooled to room temperature to obtain a suspension; the suspension is washed with water (the rotating speed of water washing is 9000 r / min, the number of times of water washing is 4, and the time of each water washing is 10 min), and after the washing is completed, filtration is carried out, the filter cake is collected, and freeze-drying is carried out at -40 DEG C for 30 h to obtain a microcapsule material.

[0057] The preparation method of the modified aerogel comprises the following steps: The silica aerogel is placed into a γ-aminopropyl triethoxysilane solution (the solvent is ethanol, the mass fraction of γ-aminopropyl triethoxysilane in the γ-aminopropyl triethoxysilane solution is 7.5%, and the mass ratio of γ-aminopropyl triethoxysilane to silica aerogel powder is 3.5:100), and the reaction is carried out at 50 DEG C for 3 h; after the reaction is completed, the filter cake is obtained and washed with ethanol for 3 times; finally, the modified aerogel is obtained by drying at a temperature of 70 DEG C and a vacuum degree of 9 kPa for 5 h.

[0058] The preparation method of the concrete surface pore sealing agent also comprises the following steps: The aqueous epoxy resin, nano-silica, dispersant and water were mixed, dispersed at 2500 r / min for 45 min, and then ultrasonically treated at 350 W for 20 min to obtain a first dispersion liquid; the microcapsule material and modified aerogel were added to the first dispersion liquid, dispersed at 650 r / min for 22 min to obtain a second dispersion liquid; the curing agent was added to the second dispersion liquid, stirred at 400 r / min for 15 min to obtain the concrete surface sealing agent.

[0059] Examples 2-5 In Control Example 1, the weight fractions of the components in the concrete surface sealing agent were adjusted while other conditions remained unchanged. Specifically, the weight fractions of the components in the concrete surface sealing agent in Examples 1-5 are shown in Table 1.

[0060] Table 1 Weight fractions of the components in the concrete surface sealing agent in Examples 1-5 Case Aqueous epoxy resin Nanosilica Microcapsule material Modified aerogel Curing agent Dispersant Water Example 1 40 10 10 5.5 15 2 30 Example 2 35 7 8.5 4 12 1.5 25 Example 3 45 13 11.5 7 18 2.5 35 Example 4 37 8 9 5 14 1.7 27 Example 5 50 15 15 8 20 3 40 Comparative Example 1 In Control Example 1, the addition of the microcapsule material was omitted while other conditions remained unchanged.

[0061] Comparative Example 2 In Control Example 1, the addition of the modified aerogel was omitted while other conditions remained unchanged.

[0062] Comparative Example 3 In Control Example 1, the addition of the nano-silica was omitted while other conditions remained unchanged.

[0063] Experimental Example The concrete surface sealing agents prepared in Examples 1-5 and Comparative Examples 1-3 were applied to prepare concrete. Specifically, in Example 1, 100 parts of cement (P・O 42.5 grade Portland cement), 175 parts of aggregate (mass ratio of natural sand and gravel is 1:3), 50 parts of water, and 5.5 parts of the concrete surface sealing agent were mixed, stirred at 250 r / min for 2.5 min, and then stirred at 700 r / min for 4 min, and then poured and molded, and cured under the conditions of a temperature of 20°C and a relative humidity of 92.5% for 28 days to obtain concrete.

[0064] The properties of each concrete were tested, wherein the impermeability test was in accordance with GB / T 50082-2009, the thermal conductivity test was in accordance with GB / T 10294-2008, and the carbonation depth test was in accordance with GB / T 50082-2009; and finally the performance test results of Examples 1-5 and Comparative Examples 1-3 were obtained and recorded in Table 2.

[0065] Table 2 Performance test results of Examples 1-5 and Comparative Examples 1-3 Case Permeation resistance rating Thermal conductivity W / (m・K) Carbonization depth (56 days, mm) Example 1 P13 0.102 3.2 Example 2 P12 0.105 3.5 Example 3 P12 0.104 3.3 Example 4 P12 0.107 3.9 Example 5 P12 0.106 3.8 Comparative Example 1 P10 0.125 6.8 Comparative Example 2 P11 0.198 4.6 Comparative Example 3 P11 0.120 4.3 As can be seen from Table 2, the concrete surface sealing agent of the specific formulation of the present application applied to the concrete, the resulting concrete has excellent impermeability and durability, while also has good thermal insulation performance.

[0066] Obviously, the above embodiments are merely exemplary and are not intended to limit the embodiments. Based on the above description, one of ordinary skill in the art can make other different forms of changes or modifications. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or modifications derived therefrom are still within the protection scope of the present application.

Claims

1. A concrete surface sealing agent, characterized in that, The components include the following parts by weight: The mixture consists of 30-50 parts waterborne epoxy resin, 5-15 parts nano-silica, 8-12 parts microcapsule material, 3-8 parts modified aerogel, 10-20 parts curing agent, 1-3 parts dispersant, and 20-40 parts water.

2. The concrete surface sealing agent according to claim 1, characterized in that, The waterborne epoxy resin includes bisphenol A type waterborne epoxy resin; the epoxy equivalent of the bisphenol A type waterborne epoxy resin is 450g / eq-550g / eq.

3. The concrete surface sealing agent according to claim 1, characterized in that, The nano-silica has a particle size of 20nm-50nm and a specific surface area of ​​200m². 2 / g-300m 2 / g.

4. The concrete surface sealing agent according to claim 3, characterized in that, The microcapsule material includes a core and a shell, wherein the core is a silica gel and the shell is polylactic acid.

5. The concrete surface sealing agent according to claim 1, characterized in that, The modified aerogel is a silica aerogel modified with a silane coupling agent.

6. The concrete surface sealing agent according to claim 5, characterized in that, The curing agent includes one or more of polyetheramine, alicyclic amine, modified fatty amine, and γ-glycidoxypropyltrimethoxysilane.

7. The concrete surface sealing agent according to claim 6, characterized in that, The dispersant includes one or both of sodium polyacrylate and γ-aminopropyltrimethoxysilane.

8. A method for preparing the concrete surface sealing agent according to any one of claims 1-7, characterized in that, Includes the following steps: The components are mixed to obtain a concrete surface sealing agent.

9. The application of the concrete surface sealing agent according to any one of claims 1-7 in concrete.

10. A type of concrete, characterized in that, The components include the following parts by weight: The mixture comprises 90-110 parts cement, 150-200 parts aggregate, 40-60 parts water, and 3-8 parts of the concrete surface sealing agent as described in any one of claims 1-7.