Porous breathable anti-seepage protective material for outer wall of cooling tower and use method thereof

Abstract

The invention relates to a porous, breathable and anti-seepage protective material for the outer wall of a cooling tower, which comprises a component A and a component B, wherein the component A is a powder material and the component B is a liquid material. The component A contains: 25-35% of calcined kaolin powder, 0.5-5% of alumina powder, 5-10% of ultrafine mica powder, 5-10% of natural zeolite powder, 2-10% of nano silicon dioxide, 10-18% of basalt powder, and 15-25% of titanium dioxide; the component B contains: 68-80% of polyacrylate emulsion, 0.2-0.5% of polysiloxane, 1-3% of polyvinyl alcohol, 0.6-1.5% of sodium polyacrylate, and 16-30% of water. After the concrete base surface is solidified, the protective material of the invention can form a porous, breathable, anti-seepage and beautifying thin layer similar to the properties of pottery clay, thereby solving the technical problems of poor protective effect, poor anti-erosion and ultraviolet ability, short protective period, airtightness, easy bubbling and shedding of the existing protective materials for the outer wall of cooling towers.

Description

Technical Field

[0001] The invention relates to the technical field of concrete building maintenance, and in particular to a porous, breathable and anti-seepage protective material for the outer wall of a cooling tower and a use method thereof. Background Art

[0002] The cooling tower of a power plant is a large thin-shell structure. In order to make the hot water discharged from the power plant cooler reuseable after cooling in it to improve the water recycling rate, it is necessary to build a large circulating cooling water system, namely a cooling tower. The wall of the cooling tower is prefabricated with reinforced concrete. Due to the non-continuous micro cracks in reinforced concrete and the porous reinforced concrete structure, concrete is a building material composed of coarse aggregate, sand and cementing material, where solid, liquid and gas coexist, there will be a large number of pores and bubbles inside. These pores provide channels for the invasion of external substances. Water, carbon dioxide, sulfate and chloride ions in the air enter the concrete through the pores, react with the concrete to deteriorate, and significantly reduce the durability of the concrete.

[0003] In order to solve the above problems, it is necessary to roll protective materials on the surface of the cooling tower. At present, the outer wall of the traditional cooling tower is mostly made of organic coatings (solvent-based epoxy resin coatings, solvent-based polyurethane coatings, solvent-based acrylic, etc.). These organic coatings have the following problems: ① The expansion and contraction coefficient of the coating is too different from that of the concrete base surface, and it is very easy for the coating to crack and fall off due to heat. ② The expansion coefficient is different from that of the mineral matrix, and the paint surface is very easy to crack, especially under the influence of high temperature and ultraviolet rays, which will accelerate cracking and falling off. ③ Because the organic coating is film-forming and not breathable, it is easily affected by water vapor in the base surface to reduce adhesion, resulting in blistering and falling off. ④ Organic coatings have poor corrosion resistance and are easily damaged by alkaline erosion of the base, causing powdering and blistering. ⑤ The organic components in the aggregate provide a carbon source, which helps the growth of microorganisms and fungi, causing the base surface to be contaminated. ⑥ It cannot be cleaned with a high-pressure water gun (water pressure shock can easily cause the paint to crack, fall off and peel off). Once the surface is dirty, it can only be repainted; it is not flame retardant, and it is easy to produce organic volatile substances to pollute the water body, which is not environmentally friendly. ⑦ Before painting, you must first use putty to do leveling steps. The flatness of the base surface is required to be high. An uneven base surface will cause the film-forming paint to form several holes and fall off easily.

[0004] In summary, most of the existing protective materials for the outer wall of cooling towers have unsatisfactory protective effects, short protective cycles, and complex processes. Some even contain organic toxic materials, which seep into the water during long-term contact with water, causing water pollution. Although some protective materials have good anti-seepage effects and can effectively isolate harmful factors such as water vapor, sulfates, and chloride ions from entering the concrete, thus protecting the structure, these protective materials cannot provide good air permeability, which results in the inability to smoothly drain out the gas and liquid that already exist in the pores and micro-cracks inside the concrete structure, making the protective material layer susceptible to the influence of water vapor inside the concrete base surface, reducing adhesion, and causing bubbling, shedding, and other problems. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a porous, breathable, and anti-seepage protective material for the outer wall of a cooling tower, which draws on the formula characteristics of ceramics, pottery, clay, etc., and optimizes the composition and content by adding components. A porous, breathable, and anti-seepage thin layer with properties similar to clay can be formed on the thin-walled concrete structure of the cooling tower, thereby solving the technical problems of existing protective materials for the outer wall of cooling towers, such as poor protective effect, poor anti-corrosion and UV capabilities, short protection period, airtightness, and easy bubbling and shedding.

[0007] (II) Technical solution

[0008] The technical solution of the present invention is as follows:

[0009] In a first aspect, the present invention provides a porous, breathable and anti-seepage protective material for the outer wall of a cooling tower, which comprises a component A and a component B, wherein the component A is a powder and the component B is a liquid;

[0010] Measured by mass percentage, component A contains: calcined kaolin powder 25-35%, alumina powder 0.5-5%, ultrafine mica powder 5-10%, natural zeolite powder 5-10%, nano silicon dioxide 2-10%, basalt powder 10-18%, titanium dioxide 15-25%;

[0011] Calculated by mass percentage, component B contains: 68-80% of polyacrylate emulsion, 0.2-0.5% of polysiloxane, 1-3% of polyvinyl alcohol, 0.6-1.5% of sodium polyacrylate, and 16-30% of water.

[0012] According to a preferred embodiment of the present invention, the particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99%, and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5%, and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; and the particle size of titanium dioxide is 0.2-0.26μm.

[0013] The particle size that meets the above requirements can ensure the density and fineness of the coating; after mixing component A and component B, a slurry with better uniformity and workability is obtained, which is not easy to bleed and stratify. The slurry has a suitable consistency and brush / roller coating construction property. The coating has good fineness and cohesive strength, is not easy to crack and peel, has good adhesion and impermeability, and increases the protective effect of the coating and extends the protection period. On the contrary, if the particle size is too large, the coating slurry is prone to bleeding and stratification, the coating construction property is poor, and the density and fineness of the coating cannot be guaranteed. The impermeability and chloride ion resistance are poor; and if the particle size is too small, on the one hand, the pre-treatment energy consumption will double, including the doubling of the grinding energy consumption and cost, and on the other hand, it will also cause the coating slurry to have too high a consistency, which is not easy to apply, and the coating is too dense and lacks air permeability; in addition, if the powder particle size is too small, the coating will be thin after one application, and it often needs to be applied multiple times, which increases the complexity of construction, and the powder particle size is too fine, the wear resistance and corrosion resistance of the coating will deteriorate, and the protection period will be shortened.

[0014] The present invention does not use fiber reinforcement materials. Although fiber reinforcement materials can enhance the crack resistance of the coating, fiber reinforcement materials are prone to form small defects and flaws due to their special morphology during the construction process, and the density and fineness of the coating cannot be guaranteed, resulting in poor impermeability and chloride ion resistance of the coating. The present invention is mainly a protective material for the surface of a concrete base surface, which forms a very thin protective layer after brushing, and is not easy to crack, so there is no need to add fiber material for reinforcement.

[0015] According to a preferred embodiment of the present invention, in component A, calcined kaolin powder is 26-30%, alumina powder is 3-5%, ultrafine mica powder is 7-10%, natural zeolite powder is 5-6%, nano silicon dioxide is 10%, basalt powder is 18%, and titanium dioxide is 25%;

[0016] In component B, polyacrylate emulsion accounts for 70-75%, polysiloxane accounts for 0.3-0.4%, polyvinyl alcohol accounts for 2%, sodium polyacrylate accounts for 0.8-1%, and water accounts for the balance.

[0017] The functions of the above components in the porous breathable anti-seepage protective material of the present invention are described as follows:

[0018] In component A:

[0019] Calcined kaolin powder: It provides whiteness, plasticity, adhesion, electrical insulation, good acid solubility resistance, alkali corrosion resistance and fire resistance, and also plays a role in filling the skeleton and reducing costs. However, the calcined kaolin powder should be controlled between 25-35%. If too much is added, it is difficult to apply, the coating appearance is not smooth, and the anti-seepage property is poor.

[0020] Alumina powder: High-purity alumina powder can be added directly without agglomeration and has good adhesion. It can be easily combined with other functional micropowders to significantly improve the wear and corrosion resistance of the product without affecting other properties of the coating. It improves the high thermal stability of the material, and can maintain the integrity of the coating even in a high temperature environment. It can also effectively block ultraviolet radiation on the beauty coating and extend the life of the coating. However, the addition amount should be controlled between 0.5-5%. Too much addition will affect the appearance and mechanical properties of the coating; too little addition will not have a significant effect.

[0021] Ultrafine mica powder: Ultrafine mica powder can be used as a functional filler to improve its mechanical strength, toughness, anti-aging and corrosion resistance. The material has extremely high electrical insulation, acid and alkali corrosion resistance, elasticity, toughness and sliding, heat resistance and sound insulation, and a small thermal expansion coefficient. However, the mica surface is smooth and has poor adhesion. The content should not be greater than 10% by mass. Too much will affect the antifreeze and anti-seepage properties; if the addition amount is too low, the mechanical strength of the coating will be insufficient.

[0022] Natural zeolite powder: Zeolite has properties such as adsorption, ion exchange, catalysis, acid and heat resistance, and is a natural molecular sieve structure mineral. Its molecular sieve properties can be used to filter water molecules in the air, and it has deodorizing properties. It can also play a role in dispersion, filling, and enhancing hardness, increasing product stability and tensile and compressive strength. It is a good active mixed material; and most importantly, natural zeolite powder can play a breathable role in the coating (it has a maze effect, providing a slow penetration path for internal water vapor instead of direct breathability, but can prevent external water, sulfate, chloride ions and other corrosive media from penetrating inward, achieving breathable and anti-seepage effects), which is conducive to the evacuation of harmful water vapor that already exists in the pores and gaps inside the concrete building base, improving the adhesion of the coating and preventing bubbling and shedding. However, natural zeolite powder is a porous material. Adding too much will affect the antifreeze and anti-seepage properties, and should be controlled at 5-10%. Natural zeolite powder is a lightweight material that does not easily increase the specific gravity of the coating and can remain firmly in the coating. Its strong adsorption properties can adsorb and intercept harmful factors in the external environment when they penetrate into the concrete base.

[0023] Nano-silicon dioxide: It plays a role in reinforcing, thickening, preventing aggregation and precipitation for the molded body of the material after mixing, and can also improve the wear resistance, anti-sagging and anti-caking effects of the material. Too much addition can easily lead to excessive hardness and cause stress cracking, so it should be controlled at 2-10%.

[0024] Basalt powder: Improves the material's resistance to chloride ion penetration, and enhances the material's weather resistance and corrosion resistance and applicability in harsh environments. Basalt powder forms a layered tile-like structure in the coating to delay the penetration of corrosive media such as water and air. Its unique chemical composition makes it more resistant to chloride ion corrosion. Adding basalt powder can delay the penetration of corrosive media and protect the substrate, thereby greatly improving the coating's salt spray resistance. Basalt powder is composed of dozens of metal oxides, such as silicon oxide, aluminum oxide, and iron oxide. Its unique chemical composition makes it more resistant to chloride ion corrosion than other fillers. However, basalt contains a small amount of radioactive elements and some heavy metal elements, such as lead, mercury, and chromium. It should not be added too much and should be controlled at 10-18%.

[0025] Titanium dioxide: The addition of titanium dioxide can make the material colorful, with high hiding power, strong tinting power, low dosage, and a wide variety. It can protect the stability of the medium, enhance the mechanical strength and adhesion of the paint film, prevent cracks, reflect ultraviolet rays, prevent ultraviolet rays and water from penetrating, and extend the life of the coating. In particular, it can improve the anti-aging ability of the organic components in component B. However, adding too much titanium dioxide will also lead to agglomeration or flocculation. Adding too much will not achieve the desired effect; adding too little will result in poor coating hiding power and ultraviolet reflection, and will not achieve the desired effect. It should be controlled at 15-25%.

[0026] Component B:

[0027] Polyacrylate emulsion: obtained by copolymerizing methacrylic acid and methyl methacrylate in a ratio of 50:50, and using alkylbenzene polyether sodium sulfonate emulsifier and additives to make an emulsion with water as the medium. Polyacrylate emulsion can increase the flexibility, adhesion, impermeability and corrosion resistance of the coating. The solid content of industrial polyacrylate emulsion is (45±2)%. The polyacrylate emulsion used in this application is a commercially available product.

[0028] Polysiloxane defoamer: It can quickly eliminate water-phase foam and has a long-term anti-foaming effect. It can quickly break the foam when brushing or rolling without causing surface defects.

[0029] Polyvinyl alcohol: As a thickener for water-based coatings, a very small amount added can significantly improve the coating's cohesive strength, adhesion, and water resistance, improve the coating's surface fineness, and provide excellent durability. The coating is not likely to fall off even after polishing.

[0030] Sodium polyacrylate: Mainly used as a dispersant to increase and improve the dispersion of materials, improve the roller coating performance of the coating, and increase the uniformity of the coating quality.

[0031] Water: Adjust viscosity and construction performance such as roller coating and spraying.

[0032] In a second aspect, the present invention provides a method for using a porous air-permeable anti-seepage protective material for an outer wall of a cooling tower, comprising:

[0033] S1. Base surface treatment: clean the concrete surface of the outer wall of the cooling tower, and then spray inorganic silicate penetrating crystallization material for maintenance;

[0034] S2. Mix component A and component B in a mass ratio of 1:0.9-1.1, stir evenly, and apply by brushing;

[0035] S3, 6-7 days of maintenance.

[0036] Preferably, in step S1, the cleaning includes: using a power tool to thoroughly remove loose mortar, sharp corners, debris, microorganisms, algae and attachments on the concrete surface of the outer wall of the cooling tower.

[0037] Preferably, in step S1, the inorganic silicate infiltration crystallization material is purchased from the market or is a nano-modified silicate aqueous solution infiltration crystallization material independently developed and produced by Beijing Yishengyuan Environmental Protection Engineering Co., Ltd.

[0038] Preferably, in step S1, the curing time of spraying the inorganic silicate infiltration crystallization material is 2-4 hours. In an environment with high temperature or high wind speed, the curing time is only 2 hours.

[0039] Preferably, in step S2, the number of times of brushing is 2 or more, and the amount of each brushing is 350-450g / ㎡. Brushing 2 or more times can obtain a protective coating of a predetermined thickness and is less likely to cause missed brushing.

[0040] The step of using inorganic silicate penetrating crystallization material for maintenance is very critical. When the inorganic silicate penetrating crystallization material is sprayed on the cleaned concrete surface, the active silicate ions contained in it can quickly and effectively react with calcium hydroxide, calcium aluminide, and calcium silicate in the concrete structure layer to form inert crystals embedded in the capillary pores of the concrete, sealing fine cracks, thereby greatly enhancing the density and compressive strength of the concrete surface. More importantly, after the inorganic silicate penetrating crystallization material treats the concrete surface, it will provide a large number of active groups on the surface of the outer wall of the cooling tower, so as to combine with the porous breathable anti-seepage protective material applied in step S2 through chemical bonds such as hydrogen bonds, thereby improving the adhesion firmness of the porous breathable anti-seepage protective material on the outer wall of the cooling tower and extending the protective life.

[0041] Compared with the situation of using organic film-forming agents or dispersed emulsions to directly apply the paint film to the concrete base surface, the present invention uses hydrogen bonds formed by a large number of active groups to increase the bonding strength of the coating. Under the same use environment, the protective life of the protective coating can be extended by 2-3 times.

[0042] When using inorganic silicate permeable crystallization materials to maintain the plain surface of concrete, a silica gel film is first produced in the pores and capillary pores of the concrete. When the water in the silica gel film evaporates, it solidifies into a crystalline substance. These solidified crystalline substances are embedded in the capillaries and fine gaps of the concrete (width ≤ 0.3mm), achieving the effect of sealing the concrete, improving the density and enhancing the compressive / impact strength of the plain surface of the concrete. At the same time, the inorganic silicate permeable crystallization material does not affect the air permeability of the concrete. In the dry state of concrete, the crystalline substance is dormant, and a small amount of water vapor diffused outward from the inside of the concrete can still be drained out. When encountering water, the crystals in the capillaries and fine gaps expand again, and the crystals fill the capillaries of the concrete to block the penetration of water. That is, the crystalline substance cycles between the mode of water evaporation → solidification and crystallization → expansion and waterproof penetration when encountering water, and the concrete is permanently sealed for waterproofing and air permeability.

[0043] (III) Beneficial effects

[0044] The porous, breathable and anti-seepage protective material for the outer wall of the cooling tower of the present invention comprises a powder component A and a liquid component B. After the components A and B are mixed and stirred evenly to prepare a slurry, they are roller-coated on the outer wall of the cooling tower, and after short-term maintenance, a layer of breathable, anti-seepage and beautifying thin layer can be formed. The material of the present invention can guide water vapor, enhance water resistance, and UV resistance to the concrete of the outer wall of the cooling tower. At the same time, the material does not decompose when heated, and can meet the construction requirements of the cooling tower of the power plant without stopping. In addition, the protective coating does not contain organic solvents, which can solve the problems of volatilization of harmful components and environmental pollution.

[0045] When the porous, breathable and anti-seepage protective material for the outer wall of a cooling tower of the present invention is used in construction, the cleaned concrete base surface can be first sprayed with an inorganic silicate penetrating crystalline material for maintenance, and then the protective material can be roller-coated. This can not only enhance the density and compressive strength of the concrete surface, extend the service life of the thin-walled concrete structure of the cooling tower, and ensure the drainage of internal water vapor, but also greatly improve the adhesion firmness of the protective material and extend the protection period of the protective coating. DETAILED DESCRIPTION

[0046] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods.

[0047] Example 1

[0048] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0049] Component A: 26% calcined kaolin powder, 5% alumina powder, 10% ultrafine mica powder, 6% natural zeolite powder, 10% nano silicon dioxide, 18% basalt powder, and 25% titanium dioxide.

[0050] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0051] Component B: polyacrylate emulsion 75%, polysiloxane 0.3%, polyvinyl alcohol 2%, polyacrylic acid sodium salt 0.8%, water 21.9%.

[0052] Example 2

[0053] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0054] Component A: 30% calcined kaolin powder, 5% alumina powder, 7% ultrafine mica powder, 5% natural zeolite powder, 10% nano silicon dioxide, 18% basalt powder, and 25% titanium dioxide.

[0055] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0056] Component B: polyacrylate emulsion 70%, polysiloxane 0.4%, polyvinyl alcohol 2%, polyacrylic acid sodium salt 1.0%, water 26.6%.

[0057] Example 3

[0058] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0059] Component A: 25% calcined kaolin powder, 4% alumina powder, 10% ultrafine mica powder, 10% natural zeolite powder, 10% nano silicon dioxide, 18% basalt powder, and 23% titanium dioxide.

[0060] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0061] Component B: polyacrylate emulsion 76%, polysiloxane 0.4%, polyvinyl alcohol 2%, polyacrylic acid sodium salt 1.0%, water 20.6%.

[0062] Example 4

[0063] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0064] Component A: 35% calcined kaolin powder, 3% alumina powder, 8% ultrafine mica powder, 8% natural zeolite powder, 7% nano silicon dioxide, 15% basalt powder, and 24% titanium dioxide.

[0065] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0066] Component B: 80% polyacrylate emulsion, 0.4% polysiloxane, 2.6% polyvinyl alcohol, 1.0% sodium polyacrylate, and 16% water.

[0067] Example 5

[0068] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0069] Component A: 32% calcined kaolin powder, 4% alumina powder, 9% ultrafine mica powder, 9% natural zeolite powder, 7% nano silicon dioxide, 15% basalt powder, and 24% titanium dioxide.

[0070] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0071] Component B: polyacrylate emulsion 68%, polysiloxane 0.4%, polyvinyl alcohol 3%, polyacrylic acid sodium salt 1.0%, water 27.6%.

[0072] Example 6

[0073] The porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of this embodiment is composed as follows:

[0074] Component A: 29% calcined kaolin powder, 4% alumina powder, 10% ultrafine mica powder, 9% natural zeolite powder, 8% nano silicon dioxide, 15% basalt powder, and 25% titanium dioxide.

[0075] The particle size of calcined kaolin powder is <2μm; the purity of alumina powder is 99.99% and the particle size is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the purity of nano-silicon dioxide is 99.5% and the particle size is 20-40nm; the particle size of basalt powder is 10-45μm; the particle size of titanium dioxide is 0.2-0.26μm.

[0076] Component B: polyacrylate emulsion 68%, polysiloxane 0.5%, polyvinyl alcohol 3%, polyacrylic acid sodium salt 1.5%, water 27%.

[0077] The A component and the B component of the porous air-permeable anti-seepage protective material for the outer wall of the cooling tower of Examples 1-6 were mixed and stirred in a mass ratio of 1:1, and then roller-coated on the concrete sample bricks, brushed back and forth twice, and the amount of each brushing was 400g / ㎡, and then dry-cured for 7 days to obtain the concrete sample bricks with protective coating. The brushing includes dry base surface brushing and wet base surface brushing. The dry base surface is to keep the surface of the concrete sample brick dry. The wet base surface brushing is to put the concrete sample brick into water in advance and soak it for 12 hours, then take it out and wipe off the floating water with a cloth.

[0078] The performance tests were conducted on the six porous breathable anti-seepage protective coatings of Examples 1-6. The test indicators and testing standards are shown in Table 1, and the test results are shown in Table 2.

[0079] Table 1:

[0080]

[0081]

[0082] Table 2:

[0083]

[0084] In order to study the effect of the addition amount of some ingredients on the performance of the protective material, the experiment also increased and decreased the content of some ingredients in component A, and formed the following comparative experiment.

[0085] Comparative Example 1

[0086] In this comparative example, the amount of alumina powder added to component A is reduced to 0.3% on the basis of Example 1, and the part less than 100% is filled with calcined kaolin powder. The other components remain unchanged, and component B is the same as Example 1. Component A and component B are mixed in a mass ratio of 1:1, stirred evenly, and roller-coated on the concrete sample bricks, brushed back and forth 2 times, each brushing amount is 400g / ㎡, and then dry-cured for 7 days to obtain concrete sample bricks with protective coating.

[0087] Compared with the porous air-permeable anti-seepage protective material coating of Example 1, it is shown that the wear resistance of the protective coating in Example 1 is deteriorated, and the wear loss (500g / 100r) is 1.37g. In addition, the moisture and heat resistance and salt spray resistance cannot meet the requirement of "no significant change in 3000h", and the alkali resistance cannot meet the requirement of "no significant change in 30d". It can be seen that alumina powder helps to increase the wear resistance, high temperature resistance and corrosion resistance of the coating, and it is not conducive to extending the life of the coating when alumina is not added or the amount of alumina added is too low.

[0088] Comparative Example 2

[0089] In this comparative example, based on Example 1, the addition amount of ultrafine mica powder in component A is increased to 15%, the titanium dioxide is reduced to 20%, the other components remain unchanged, and component B is the same as Example 1.

[0090] Compared with the porous breathable anti-seepage protective material coating of Example 1, the wear resistance, moisture and heat resistance, salt spray resistance and alkali resistance of the protective material coating of Comparative Example 2 are enhanced, but the dry base surface bonding strength and wet base surface bonding strength are reduced to 0.6Mpa and 0.66Mpa respectively, and the anti-seepage is less than 0.5Mpa. It can be seen that ultrafine mica powder helps to improve the mechanical strength, corrosion resistance and other properties of the protective material, but when the addition amount is too high, it will lead to reduced adhesion strength and poor anti-seepage.

[0091] Comparative Example 3

[0092] This comparative example is based on Example 1, except that the natural zeolite powder in component A is reduced to 2%, and the calcined kaolin powder is increased to 30%. Other components remain unchanged, and component B is the same as Example 1.

[0093] Compared with the porous breathable anti-seepage protective material coating of Example 1, the air permeability of the protective material coating in Comparative Example 3 is significantly reduced, and the tested air permeability is reduced to 59, which is a significant decrease in air permeability. The chloride ion permeability of the protective coating reaches 11.7×10 -3 mg / (cm 2.d), the permeation exceeds the index requirement. In addition, the wear resistance of the protective coating also decreases. It can be seen that a higher content of natural zeolite powder helps to improve the air permeability and chloride ion permeability of the protective material, can adsorb and intercept chloride ions, and is also beneficial to improve the wear resistance of the coating. When the amount of natural zeolite powder added is too little or omitted, the protective performance of the protective coating will be significantly weakened.

[0094] Comparative Example 4

[0095] This comparative example is based on Example 1, except that the basalt powder in component A is reduced to 6%, the calcined kaolin powder is increased to 35%, and the natural zeolite powder is adjusted to 9%; other components remain unchanged, and component B is the same as Example 1.

[0096] Compared with the porous breathable impermeability protective material coating of Example 1, it is shown that the impermeability, salt spray resistance, alkali resistance and chloride ion permeability resistance of the protective material coating of Comparative Example 4 are reduced, wherein the impermeability is reduced to 0.5Mpa, the salt spray resistance cannot meet the requirement of "no significant change for 3000h", and the alkali resistance cannot meet the requirement of "no significant change for 30d". The chloride ion permeability resistance is 8.1×10 -3 mg / (cm 2 .d), the penetration volume exceeds the index requirements.

[0097] It can be seen that a higher content of basalt powder helps to improve the corrosion resistance, impermeability and chloride ion permeability of the protective material. When the amount of basalt powder added is insufficient or omitted, the protective performance of the protective coating will be significantly weakened.

[0098] Comparative Example 5

[0099] In this comparative example, component B is adjusted on the basis of Example 1, and polyvinyl alcohol in component B is replaced with CMC. Other components remain unchanged, and component A is the same as Example 1.

[0100] Compared with the porous breathable anti-seepage protective material coating of Example 1, it is shown that the bonding strength of the protective material coating of Example 5 on the dry base surface and the wet base surface is significantly reduced, and the bonding strength is less than 0.6Mpa. In addition, although the impermeability is still >0.5Mpa, it has dropped to 0.7Mpa, which is far less than the impermeability of the protective coating of Example 1. In the moisture and heat resistance experimental test, the performance of the protective material coating of Example 5 is also reduced compared with the aforementioned embodiments. The coating was polished, and powder shedding was obvious during the polishing process. This shows that when other thickeners are used to replace polyvinyl alcohol, it is not conducive to improving the cohesive strength between the powder materials inside the coating material, and it is easy to shed powder when the coating needs to be polished and trimmed.

[0101] Example 7

[0102] This embodiment is an optimized method for using the porous air-permeable anti-seepage protective material for the outer wall of the cooling tower, specifically including:

[0103] (1) Surface treatment: concrete sample bricks that have been placed in the natural environment for more than 2 years are treated to simulate the working environment of the outer wall of the cooling tower exposed to the sun and rain. The treatment includes: using power tools to thoroughly remove the loose mortar, sharp corners, debris, and other pollutants and other attachments on the surface of the concrete sample bricks, and then spraying inorganic silicate penetrating crystallization material for curing for 3 hours. The inorganic silicate penetrating crystallization material is a commercially available product. For usage, please refer to the product instructions or conventional operations. The spraying amount of inorganic silicate penetrating crystallization material is 250-280mL per square meter.

[0104] The treated concrete sample bricks include dry base surface painting and wet base surface painting. The dry base surface is to keep the surface of the concrete sample bricks dry, and the wet base surface painting is to soak them in water for 12 hours and then take them out and wipe off the floating water.

[0105] (2) Component A and component B in Example 1 were mixed in a mass ratio of 1:1, stirred evenly, and then roller-coated for 2 times with a brushing amount of 400 g / m2 each time, followed by 7 days of dry curing.

[0106] The protective coating in this embodiment was tested. The test method is as mentioned above, and the test results are shown in Table 3.

[0107] Table 3:

[0108]

[0109] In summary, if before applying the porous breathable anti-seepage protective material of the cooling tower outer wall of the present invention, the inorganic silicate permeable crystal material is first sprayed for maintenance before construction, the bonding strength, impermeability and chloride ion permeability of the porous breathable anti-seepage protective coating on the outer wall of the cooling tower can be further improved, and the protective coating still has good air permeability, which is conducive to the drainage of harmful water vapor in the tiny pores and fine cracks inside the concrete, and prevents the peeling of the protective coating caused by water vapor. In addition, it also has a certain improvement effect on the wear resistance of the protective coating.

[0110] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A porous, breathable and anti-seepage protective material for the outer wall of a cooling tower, characterized in that: It includes component A and component B, component A is powder material, and component B is liquid material; Measured by mass percentage, component A contains: calcined kaolin powder 25-35%, alumina powder 0.5-5%, ultrafine mica powder 5-10%, natural zeolite powder 5-10%, nano silicon dioxide 2-10%, basalt powder 10-18%, titanium dioxide 15-25%; Measured by mass percentage, component B contains: polyacrylate emulsion 68-80%, polysiloxane 0.2-0.5%, polyvinyl alcohol 1-3%, sodium polyacrylate 0.6-1.5%, water 16-30%; Among them, the particle size of calcined kaolin powder is <2μm; the particle size of alumina powder is 20-30μm; the particle size of ultrafine mica powder is 1.5-19μm; the particle size of natural zeolite powder is 3-6nm; the particle size of nano-silicon dioxide is 20-40nm; the particle size of basalt powder is 10-45μm; and the particle size of titanium dioxide is 0.2-0.26μm.

2. A porous air-permeable anti-seepage protective material for the outer wall of a cooling tower according to claim 1, characterized in that: The purity of alumina powder is 99.99%; the purity of nano-silicon dioxide is 99.5%.

3. A porous air-permeable anti-seepage protective material for the outer wall of a cooling tower according to claim 1, characterized in that: In component A, calcined kaolin powder is 26-30%, alumina powder is 3-5%, ultrafine mica powder is 7-10%, natural zeolite powder is 5-6%, nano silicon dioxide is 10%, basalt powder is 18%, and titanium dioxide is 25%; In component B, polyacrylate emulsion accounts for 70-75%, polysiloxane accounts for 0.3-0.4%, polyvinyl alcohol accounts for 2%, sodium polyacrylate accounts for 0.8-1%, and water accounts for the balance.

4. A method for using the porous air-permeable anti-seepage protective material for the outer wall of a cooling tower according to any one of claims 1 to 3, characterized in that: include: S1. Base surface treatment: clean the concrete surface of the outer wall of the cooling tower, and then spray inorganic silicate penetrating crystallization material for maintenance; S2. Mix component A and component B in a mass ratio of 1:0.9-1.1, stir evenly, and apply by brushing; S3, 6-7 days of maintenance.

5. The method of use according to claim 4, characterized in that: In S1, a power tool is used to completely remove the attachments on the concrete surface of the outer wall of the cooling tower, wherein the attachments include loose mortar, sharp corners, debris and microorganisms and algae.

6. The method of use according to claim 5, characterized in that: In S1, the inorganic silicate infiltration crystallization material is purchased from the market or is a nano-modified silicate aqueous solution infiltration crystallization material independently developed and produced by Beijing Yishengyuan Environmental Protection Engineering Co., Ltd.

7. The method of use according to claim 5, characterized in that: In S2, the number of times of application is 2 or more, and the amount of application each time is 350-450g / ㎡.

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