Fly ash-based super-hydrophobic material suitable for foam concrete and preparation method thereof

Abstract

The invention discloses a fly ash-based super-hydrophobic material suitable for foam concrete, a preparation method of the fly ash-based super-hydrophobic material, and a preparation method of waterproof foam concrete. The fly ash-based super-hydrophobic material comprises the following components in percentage by mass: 1-10% of superfine fly ash; 1-2.5% of stearic acid; 1-2.5% of hydrogen-containing silicone oil; 1%-2% of a bonding accelerant, namely a silane coupling agent KH550; the volume concentration of the industrial ethanol is 95%. The super-hydrophobic material is sprayed on the surface of the foam concrete and permeates into the interior, so that the waterproof performance of the foam concrete is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, in particular to a fly ash-based super-hydrophobic material suitable for foam concrete, a preparation method thereof, and a preparation method of waterproof foam concrete. Background Art

[0002] As an inorganic porous material, foam concrete has the characteristics of thermal insulation and non-flammability. However, foam concrete is extremely easy to absorb water and has a high water absorption rate. After absorbing water, the thermal conductivity coefficient increases greatly, and its mechanical properties and anti-freeze properties will be affected. Therefore, it greatly limits the application of foam concrete in the field of building energy conservation.

[0003] Although the method of traditional internal admixture waterproofing agent has certain energy waterproof effect, it is impossible to realize isolation of moisture from entering foam concrete inside the surface. Therefore how to prepare a kind of super hydrophobic material applicable to foam concrete is a technical problem urgently to be solved in this area. In addition, when foam concrete is used as building materials, first, building materials are exposed to the natural environment for a long time, are subjected to ultraviolet radiation, and the multiple factors such as temperature and humidity alternation affect, and secondly, the foam concrete surface is subject to the friction of particles such as sand grains, or is subject to mechanical scratching. Once again, when super hydrophobic material is used in a large number of applications in foam concrete waterproofing, the convenience of operation is needed in construction technology. Therefore, the super hydrophobic material performance of preparation is in urgent need of taking into account structural adaptability, environmental tolerance and economic feasibility, but existing super hydrophobic material preparation technology, seldom considers foam concrete as building materials to the requirement of performances such as use environment, hydrophobic material anti-wear performance, weather resistance. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and provide a fly ash-based super-hydrophobic material suitable for foam concrete and a preparation method thereof, as well as a preparation method of waterproof foam concrete. The super-hydrophobic material is sprayed on the surface of the foam concrete and penetrates into the interior, thereby improving the waterproof performance of the foam concrete.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] According to one aspect of the present invention, there is provided a fly ash-based super-hydrophobic material suitable for foam concrete, comprising, by mass percentage:

[0007] Ultrafine fly ash 1-10%;

[0008] Stearic acid 1-2.5%;

[0009] Hydrogen silicone oil 1-2.5%;

[0010] Adhesion promoter - silane coupling agent KH5501~2%;

[0011] The balance is industrial ethanol with a volume concentration of 95%;

[0012] According to another aspect of the present invention, there is also provided a method for preparing the fly ash-based super-hydrophobic material suitable for foam concrete, comprising the following steps:

[0013] Step 1, adopts 200 ℃ to dry the moisture and some impurities in ultrafine fly ash, specifically, first ultrafine fly ash is placed in an open glass container, which is conducive to the dispersion of moisture and impurities during drying, and then the open glass container is placed in a constant temperature blast drying oven at 200 ℃, and a drying process of not less than 30 minutes is carried out. Free water and some weakly bound water can be effectively removed by high temperature drying. In addition, the low-boiling volatile organic compounds (such as benzene, toluene, etc.) remaining in the fly ash can also be removed. By 200 ℃ high temperature drying, the purity of fly ash is improved, the moisture content in fly ash decreases, and its fluidity and stability can be improved. The surface of fly ash particles is more fully exposed, and the contact area with the reacting material increases, and the activity is improved. After the fly ash is dried, it is sealed and stored to avoid being affected by moisture in the air again.

[0014] Step 2: first, solid-state stearic acid and liquid hydrogen-containing silicone oil are placed in a sealable glass container, then industrial ethanol with a volume concentration of 95% is added, and a magnetic stirrer is placed in. After the sealing, the glass container is placed on a magnetic stirrer at a constant temperature of 40° C. to heat and dissolve the solid-state stearic acid. The magnetic stirrer is kept stirring throughout the entire process, and the stirring time is ensured to be not less than 5 minutes. By heating for dissolution and sufficient stirring, it is ensured that stearic acid and hydrogen-containing silicone oil can be fully dissolved and mixed with industrial ethanol.

[0015] Step 3: Add the dried and sealed ultrafine fly ash to the mixed liquid obtained in step 2, and stir the mixture thoroughly by magnetic stirring for at least 5 minutes to obtain a mixed liquid.

[0016] Step 4: Ultrasonicate the mixture using an ultrasonic disperser at a power of 100-500W for 15 minutes. The specific procedure is as follows: Place the glass container containing the ultrafine fly ash mixture on a magnetic stirrer maintained at a constant temperature of 40°C. Insert the ultrasonic disperser's vibrating rod partially into the mixture. Seal the top of the glass container, insert the ultrasonic vibrating rod through the opening, and seal the perimeter of the opening. Maintain magnetic stirring throughout the ultrasonication process to ensure uniform dispersion of the fly ash particles in the mixture and prevent them from settling and accumulating at the bottom. The ultrasonic power and duration are controlled by the ultrasonic disperser's controller.

[0017] Step 5: After ultrasonication, add the adhesion promoter, silane coupling agent KH550, and stir evenly with magnetic force for at least 10 minutes to obtain a fly ash-based superhydrophobic material suitable for foam concrete.

[0018] Optionally, in steps 2 to 5, the container is sealed during the dissolving and stirring process.

[0019] Optionally, the ultrasonic power is 200W.

[0020] Optionally, during the ultrasonication process, the preparation container is placed in a constant temperature environment at 20°C.

[0021] Optionally, the method further includes storing the fly ash-based superhydrophobic material suitable for foam concrete in a sealed container to prevent ethanol from volatilizing.

[0022] According to another aspect of the present invention, a method for preparing waterproof foamed concrete is also provided. The fly ash-based super-hydrophobic material suitable for foamed concrete is prepared as described above, sprayed on the surface of the foamed concrete, and placed in a natural environment to evaporate the remaining industrial ethanol to obtain the waterproof foamed concrete.

[0023] Optionally, when spraying the fly ash-based super-hydrophobic material suitable for foam concrete, the material is sprayed multiple times according to a set amount, and the spraying pressure is 0.4 MPa.

[0024] The present invention provides a fly ash-based super-hydrophobic material suitable for foam concrete, a preparation method thereof, and a preparation method of waterproof foam concrete. The materials and processes have multiple synergistic effects, thereby effectively improving the hydrophobicity of foam concrete. Specifically:

[0025] When selecting low surface energy modification materials, considering that building waterproof materials must consider both waterproof performance and durability, stearic acid has a lower surface energy and can effectively improve the hydrophobicity of objects. Hydrogenated silicone oil, as an organic siloxane compound, has the dual advantages of hydrophobicity and durability. Therefore, stearic acid and hydrogenated silicone oil are used in combination as low surface energy modification materials.

[0026] The fly ash used is ultrafine fly ash, with a particle size distribution range of 0.662 to 34.3 μm and a volume average particle size of 0.9169 μm. The volume average particle size of ultrafine fly ash particles is only about 10 μm. After being modified with a low-surface-energy substance, the fly ash particles can tightly bind and deposit on the surface of foamed concrete and penetrate into its interior through the pores. Ultrafine fly ash has both active groups and a micron-sized particle size. The small particle size facilitates the formation of a micro- and nano-scale rough structure on the super-hydrophobic surface.

[0027] The hydrophobic mechanism is to replace the polar hydrophilic silanol groups in fly ash with non-polar alkyl groups. Ultrasound is used to promote the reaction between the hydrophobic materials stearic acid and hydrogenated silicone oil and fly ash, thereby enhancing the hydrophobic properties of the super-hydrophobic material. The molecular structure of stearic acid is carbon-carbon, and a stearic acid molecule is connected to multiple alkyl groups (-CH2, -CH3). The alkyl groups have low surface energy, and the molecular end is connected to a carboxyl group (-COOH). These groups can react with the silicon and aluminum hydroxyl groups (-Si-OH, -Al-OH) on the surface of ultrafine fly ash and connect through covalent bonds. The reaction results in the surface of the fly ash particles carrying methylene (-CH2) and methyl (-CH3), with the methylene (-CH2) group having lower surface energy being the main group. The molecular structure of hydrogenated silicone oil is silicon-oxygen bonds (-Si-O) as the main chain, carbon-silicon bonds as side chains, and each silicon atom is connected to a methyl group (-CH3). The silicon atoms in the siloxane backbone have low electronegativity, making the groups or atoms attached to them easily break, resulting in more active silicon-hydrogen bonds (-Si-H) on the side chains. Under the action of ultrasound, the silicon-hydrogen bonds (-Si-H) first break and undergo hydrolysis. The resulting silanols undergo a dehydration reaction with the hydroxyl groups (-OH) on the surface of the fly ash particles, forming silicon-oxygen covalent bonds. This grafts the hydrogenated silicone oil, which contains a large number of hydrophobic groups, onto the fly ash particle surfaces. The surface of the modified fly ash particles is covered with a network of siloxanes, with numerous methyl groups (-CH3) located outside the silicon-oxygen bonds (-Si-O). This structural distribution forms a directional hydrophobic coating on the surface of the fly ash particles, achieving hydrophobic modification of the fly ash. Simultaneously, the alkyl groups reduce the number of hydroxyl groups (-OH) in the fly ash through substitution reactions. The reduction in the number of hydrophilic groups and the increase in the number of hydrophobic groups are the key factors in the transformation of foamed concrete from hydrophilic to superhydrophobic.

[0028] The prepared superhydrophobic material is an organic material, while foamed concrete is an inorganic material. The addition of a bonding promoter, silane coupling agent KH550, enhances the bonding quality of the superhydrophobic material to the foamed concrete surface, significantly improving the compatibility and adhesion between the two. The addition of the bonding promoter enhances the affinity between the two interfaces and the overall performance of the composite material.

[0029] Using 95% industrial ethanol as a solvent, and utilizing the highly volatile properties of 95% industrial ethanol, after the prepared super-hydrophobic solution is sprayed on the surface of foamed concrete, the excess industrial ethanol will evaporate naturally after drying, and will not remain in the super-hydrophobic material or remain on the surface of the foamed concrete, therefore, it will not affect the performance of the super-hydrophobic material. The film thickness and porosity of the super-hydrophobic coating can also be flexibly regulated by adjusting the ethanol concentration (30% to 99.5%). When low-concentration ethanol (60% to 70%) is suitable for the inner layer penetration of the gradient hydrophobic structure, high-concentration ethanol (≥95%) is suitable for dense surface coating. In addition, the selection of industrial ethanol as a super-hydrophobic material solvent has the following advantages: First, industrial ethanol (purity ≥95%) has good solubility for two organic materials, stearic acid and hydrogen-containing silicone oil, which can achieve uniform dispersion of super-hydrophobic components. Its moderately polar hydroxyl structure can both destroy intermolecular hydrogen bonds and form a stable composite system with hydrophobic groups. Secondly, ethanol's low surface tension (22mN / m) and strong penetrating power can promote the penetration of solvents into porous substrates such as foam concrete, thereby enhancing the bonding strength between superhydrophobic materials and substrates. Thirdly, process adaptability and volatility are controllable. The boiling point of ethanol (78.3°C) is moderate, which can not only control the volatilization rate by adjusting the ambient temperature (such as accelerating curing by heating), but also avoid coating defects (such as pinholes and cracks) caused by rapid volatilization. Fourthly, it is economical and safe. The raw materials for industrial ethanol are widely available (starch fermentation and ethylene hydration), and the cost of large-scale production is only 1 / 3-1 / 2 of other organic solvents (such as acetone and DMF). It is low-cost and easy to obtain. Fifthly, the reaction activity is significant. The hydroxyl groups of ethanol can undergo esterification or condensation reactions with hydrophobic modifiers (such as siloxanes), thereby enhancing the chemical bonding strength between the coating and the substrate and improving durability.

[0030] The specific effects of ultrasound in the preparation of superhydrophobic materials include:

[0031] 1. Particle Dispersion and Structure Construction. Agglomerate Dispersion: Ultrasonic cavitation generates instantaneous high pressure (>1000 atm) and micro-jets to effectively break up ultrafine fly ash agglomerates, forming a stable, dispersed suspension of micro- and nano-particles, which provides a uniform particle distribution foundation for the surface roughness structure. Particle Size Refinement: Ultrasonic energy further reduces the size of fly ash particles (down to the nanometer scale) through shear and shock wave effects, enhancing the formation of a multi-level roughness structure and improving hydrophobicity.

[0032] 2. Promote surface modification reactions and accelerate molecular migration: The high-frequency vibration of ultrasound (usually 20-100kHz) accelerates the diffusion rate of stearic acid and hydrogenated silicone oil molecules in the ethanol solvent, allowing them to quickly adsorb to the fly ash surface and shorten the modification reaction time. The high-frequency vibration of ultrasound accelerates the migration of stearic acid and hydrogenated silicone oil molecules to the fly ash surface, while also promoting the formation of intermolecular chemical bonds through mechanical shear force, enhancing the bonding strength between the low-surface-energy modifier and the substrate.

[0033] 3. Improve coating performance. Enhanced bonding strength: Ultrasonic mechanical vibrations align modifier molecules on the fly ash surface, forming a dense and stable low-surface-energy layer. The contact angle can be increased to over 150°, significantly enhancing hydrophobic durability. Reduced defect generation: Ultrasonic-assisted uniform dispersion improves the coating's mechanical stability and scratch resistance.

[0034] The present invention also utilizes a 0.4 MPa high-pressure, multi-round spraying technique. The next spraying round is repeated after the surface has slightly dried, increasing the penetration depth and ensuring the hydrophobic material has penetrated deeply into the foamed concrete. Furthermore, the coating preparation process has been optimized, employing uniform atomization spraying. During the solvent evaporation forming stage, high-pressure spraying atomizes the modified fly ash-ethanol mixture into micron-sized droplets (controllable particle size of 10-50 μm). This ensures a uniform coating thickness (uniformity >95%), avoids the splashing and accumulation of droplets associated with traditional spraying, and reduces bubbles and cracks within the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The changes of the surface contact angle of foam concrete, (a) is the surface contact angle corresponding to different concentrations of hydrophobic materials, (b) is the surface contact angle test results;

[0036] Figure 2 This is a graph showing the change of contact angle and rolling angle of foam concrete surface with the amount of ultrafine fly ash used;

[0037] Figure 3 The diagram of the hydrophobic performance change of foam concrete, (a) is without waterproofing treatment, (b) is 1.5% concentration hydrophobic material spraying (PMHS), (c) is 2.5% concentration hydrophobic material spraying (SA), (d) is prepared super hydrophobic material spraying (hydrogen silicone oil and stearic acid mass concentration 2.5%, fly ash mass ratio 4%);

[0038] Figure 4 The graph of the penetration depth of super-hydrophobic materials at the same spraying pressure shows that (a) shows the penetration depth of five pressure spraying conditions, (b) shows the penetration depth of 0.4 MPa pressure spraying, and (c) shows the penetration depth of 0.5 MPa pressure spraying.

[0039] Figure 5 (a) is the durability test of super hydrophobic materials, (b) is the high temperature resistance test

[0040] Figure 6 This is the anti-wear test diagram of super hydrophobic foam concrete;

[0041] Figure 7 Schematic diagram of ultrasonic treatment. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0043] This embodiment provides a fly ash-based super hydrophobic material suitable for foam concrete. The chemical formula of the raw material stearic acid used is C 18 H 36 O2, produced by Guangzhou Xilong Chemical Co., Ltd.; the main component of hydrogen-containing silicone oil is polymethylhydrogensiloxane, produced by Shandong Hengyu New Materials Co., Ltd. Other materials include commercially available industrial ethanol with a volume concentration of 95%, fly ash produced by Xuzhou China Resources Power Co., Ltd., and the adhesion promoter - silane coupling agent KH550. Silane coupling agent KH550 is produced by Jiangsu Chenguang Coupling Agent Co., Ltd., and its main component is 3-aminopropyltriethoxysilane. Silane coupling agent KH550 can not only enhance the bonding strength at the interface between organic and inorganic materials, but also improve the mechanical properties and anti-aging properties of the product. The preparation method includes the following steps:

[0044] Step 1, adopts 200 ℃ to dry the moisture and some impurities in ultrafine fly ash, specifically, first ultrafine fly ash is placed in an open glass container, which is conducive to the dispersion of moisture and impurities during drying, and then the open glass container is placed in a constant temperature blast drying oven at 200 ℃ for a drying process of not less than 30 minutes. Free water and some weakly bound water can be effectively removed by high temperature drying. In addition, the low-boiling volatile organic compounds (such as benzene, toluene, etc.) remaining in the fly ash can also be removed. By 200 ℃ high temperature drying, the purity of the fly ash is improved, the moisture content in the fly ash decreases, and its fluidity and stability can be improved. The surface of the fly ash particles is more fully exposed, the contact area with the reacting material is increased, and the activity is improved. After the fly ash is dried, it is sealed and stored to avoid being affected by moisture in the air again.

[0045] Step 2: first, solid-state stearic acid and liquid hydrogen-containing silicone oil are placed in a sealable glass container, then industrial ethanol with a volume concentration of 95% is added, and a magnetic stirrer is placed in. After the sealing, the glass container is placed on a magnetic stirrer at a constant temperature of 40° C. to heat and dissolve the solid-state stearic acid. The magnetic stirrer is kept stirring throughout the entire process, and the stirring time is ensured to be not less than 5 minutes. By heating for dissolution and sufficient stirring, it is ensured that stearic acid and hydrogen-containing silicone oil can be fully dissolved and mixed with industrial ethanol.

[0046] Step 3: adding the dried and sealed ultrafine fly ash to the mixed liquid obtained in step 2, and stirring the mixture thoroughly with magnetic stirring for at least 5 minutes to obtain a mixed solution;

[0047] Step 4: Use an ultrasonic disperser to perform ultrasonic treatment on the mixed solution, with an ultrasonic power of 100 to 500 W, preferably 200 W, for 15 minutes.

[0048] As an example, combining Figure 7 The ultrasonic disperser includes an ultrasonic vibrating rod 1, an ultrasonic vibrating rod 1 connected to a controller 2, and the end of the ultrasonic vibrating rod 1 is inserted through the top opening of the sealing cover of the glass container 3 and kept sealed. The specific operation process is as follows: Place the glass container containing the mixed liquid of ultrafine fly ash on a constant temperature 40°C magnetic stirrer 4, and place the magnetic stirrer 5 into the mixed liquid of the glass container 3. Insert the ultrasonic vibrating rod 1 of the ultrasonic disperser into a part of the mixed liquid, seal the top of the glass container 3, insert the ultrasonic vibrating rod 1 through the opening, and seal the area around the hole. Maintain magnetic stirring during the ultrasonic treatment process to ensure that the fly ash particles are evenly dispersed in the mixed liquid to avoid settling and gathering at the bottom. The ultrasonic power and duration are achieved through the operation of the controller of the ultrasonic disperser.

[0049] Step 5: After ultrasonication, add the adhesion promoter, silane coupling agent KH550, and stir evenly with magnetic force for at least 10 minutes to obtain a fly ash-based superhydrophobic material suitable for foam concrete.

[0050] In the following examples, it is described how the present invention obtains the optimal ratio of super-hydrophobic materials through comparative experiments. It should be understood that the types of raw materials used are the same as above.

[0051] Example 1

[0052] Without adding ultrafine fly ash, stearic acid and hydrogenated silicone oil were used as hydrophobic materials, with a mass concentration of 1-2.5%, as well as hydrogenated silicone oil stock solution. Since stearic acid is solid at room temperature, the stock solution cannot be used. The concentration and number of the hydrophobic materials are shown in the following table:

[0053] Table 1 Mass concentration of two hydrophobic materials and sample numbers

[0054]

[0055] Without adding ultrafine fly ash and at different mass concentrations, both hydrophobic materials did not meet the superhydrophobic performance requirements. The relevant test results are as follows: Figure 1 shown.

[0056] Example 2: Stearic acid and hydrogenated silicone oil were added at 2.5% by weight, and ultrafine fly ash was added at 1% to 10% of the mass of the hydrophobic material solution, with an interval of 1%, and the balance was 95% industrial ethanol. A control group without ultrafine fly ash was also prepared. After spraying the prepared hydrophobic material, the contact angle and rolling angle of the foam concrete surface were tested. Each group of samples was tested at 5 different locations, and the average value was taken as the result (see Figure 2-3 ).

[0057] Without the addition of ultrafine fly ash, the stearic acid and hydrogenated silicone oil composite hydrophobic material formed a relatively smooth waterproof layer on the foam concrete surface, with a contact angle of only 111.18° and a rolling angle of 17.47°. This demonstrates that the lack of micro-nano roughness on the foam concrete surface makes it difficult to achieve superhydrophobic properties. Increasing the ultrafine fly ash content from 1% to 4% increased the contact angle of the hydrophobic material from 128.64° to 156.65°, while the rolling angle decreased from 12.88° to 4.85°, achieving superhydrophobicity on the foam concrete surface. Further increasing the ultrafine fly ash content to 10%, the contact angle of the hydrophobic material initially decreased and then increased, remaining roughly between 149° and 150° in the 7% to 10% range, while the rolling angle remained roughly around 9.5°. At 4% ultrafine fly ash, the contact angle reached its maximum and the rolling angle minimized, representing the optimal addition level. This ratio was used in all subsequent superhydrophobic material tests.

[0058] Example 3

[0059] The penetration depth of super-hydrophobic materials in foam concrete has a significant impact on its service life and wear resistance. The colorimetric method was used to study the effect of spraying pressure on the penetration depth. The greater the penetration depth, the better the waterproof performance of the hydrophobic material. The spraying amount of super-hydrophobic materials on the foam concrete surface was the same, both 600mL / m 2 , using different spraying pressures, the spraying pressure is 0.1 ~ 0.5MPa, the interval is 0.1MPa, the super hydrophobic material preparation: stearic acid and hydrogen silicone oil are added according to the mass ratio of 2.5%, ultrafine fly ash is added 4%, and the balance is 95% industrial ethanol. The relevant results are shown in the following table:

[0060] Table 2 Relationship between spraying pressure and penetration depth

[0061]

[0062] Combine Figure 4 The analysis revealed that the penetration depth of the super-hydrophobic material in foam concrete initially increased with the spraying pressure and then remained essentially constant. At a spraying pressure of 0.4 MPa, the penetration depth reached a maximum of 23.26 mm, approximately 1.51 times the initial value.

[0063] Example 4

[0064] The durability of superhydrophobic materials significantly impacts their waterproof lifespan. Foamed concrete is affected by a variety of environmental factors. Under natural conditions, it is primarily affected by solar radiation and temperature fluctuations. Therefore, superhydrophobic materials must possess excellent UV and high-temperature resistance. Furthermore, during construction, foamed concrete surfaces may be subject to wear, scratches, and other external damage. Therefore, superhydrophobic materials must possess excellent wear resistance, which is also crucial for maintaining long-term waterproofing.

[0065] Preparation of superhydrophobic material: stearic acid and hydrogenated silicone oil were added at a mass ratio of 2.5%, and ultrafine fly ash was added at 4%. The effects of adding different proportions of adhesion promoter - silane coupling agent KH550 on anti-ultraviolet, high temperature resistance and wear resistance were compared. The adhesion promoter - silane coupling agent KH550 was added at a ratio of 1-2%, with an interval of 1%, and the balance was 95% industrial ethanol. A control group without addition was prepared.

[0066] The preparation method comprises the following steps: 1, drying and removing moisture and some impurities in ultrafine fly ash at 200° C.; 2, placing stearic acid and hydrogen-containing silicone oil in industrial ethanol with a volume concentration of 95% at a constant temperature of 40° C., dissolving the mixture, and stirring the mixture thoroughly to obtain a uniform system; 3, adding the dried ultrafine fly ash to the uniform system, stirring the mixture thoroughly by magnetic stirring to obtain a mixed solution; 4, ultrasonically treating the mixed solution by using an ultrasonic disperser, with an ultrasonic power of 200 W and a duration of 15 minutes; and 5, adding an adhesion promoter, silane coupling agent KH550, after the ultrasonic treatment, and stirring the mixture thoroughly by magnetic stirring to obtain a fly ash-based super-hydrophobic material suitable for foam concrete.

[0067] Table 3 Silane coupling agent KH550 addition mass ratio

[0068]

[0069] Prepare foam concrete samples for testing, each group is tested at 600mL / m 2 Spray the super hydrophobic material with a spraying pressure of 0.4 MPa, and place the prepared sample in an ultraviolet accelerated aging tester. Figure 5 As shown in (a), the ultraviolet radiation intensity is 40W / m 2 , conduct a continuous 120h UV irradiation test, and test the contact angle and rolling angle of the super-hydrophobic material before the test. The contact angle and rolling angle of the super-hydrophobic material are measured every 10h during the test. The specimens used in the high temperature resistance test and the test time interval of the data are the same as those in the UV resistance test. Figure 5As shown in (b), the electric blast drying oven is set to a constant temperature of 80°C and maintained at high temperature for 120 hours. The durability of the superhydrophobic material is determined by analyzing the changes in contact angle and rolling angle.

[0070] Table 4 Durability test results of superhydrophobic materials prepared by adding different mass ratios of silane coupling agent KH550

[0071]

[0072]

[0073] Analysis of the UV resistance test results for superhydrophobic materials revealed that the addition of the silane coupling agent KH550 improved the material's performance. After 120 hours of UV irradiation, the contact and rolling angles on the surface of the superhydrophobic foam concrete remained stable, remaining above 150° and below 10°. Only slight fluctuations in the contact and rolling angles at certain test points were observed, attributed to differences in contact angle test locations. This demonstrates the material's excellent UV resistance, with optimal performance achieved when adding 1% of the agent.

[0074] When the silane coupling agent KH550 was added at a 1% concentration, the superhydrophobic foam concrete, after being exposed to an 80°C high temperature for 120 hours, achieved a final surface contact angle and rolling angle of 156.71° and 5.32°, respectively. During the high-temperature test, the contact and rolling angles of the superhydrophobic material exhibited small fluctuations, rather than a gradual decrease with exposure. At the 80th hour, the contact angle reached a minimum of 154.97°, while the rolling angle reached a maximum of 5.35° at the 40th hour. This indicates that the material's superhydrophobic properties are generally stable, demonstrating its excellent high-temperature resistance.

[0075] Example 5: During the construction process, foamed concrete may be damaged by external factors such as wear and tear. Therefore, super-hydrophobic materials must have good wear resistance. Good wear resistance is also important for maintaining its waterproof performance.

[0076] The test sample is also based on 600mL / m 2 The super-hydrophobic material of Example 4 is sprayed in an amount such as Figure 6 As shown in the figure, a cubic specimen with a side length of 70.7 mm is placed on the surface of 500-grit sandpaper. The sandpaper is fixed to the flat test table with 3M strong double-sided tape. A 500g weight is placed on the specimen. The specimen is gently pushed forward and the distance moved is measured with a ruler. The contact angle and rolling angle of the worn surface are measured every 1m of movement. The cumulative wear distance is 15m, and the test data is recorded.

[0077] Table 5 Wear resistance of superhydrophobic materials under different KH550 addition conditions

[0078]

[0079] As can be seen in the table above, the addition of the silane coupling agent KH550 improves the wear resistance of the superhydrophobic material. Again, optimal performance is achieved at a 1% addition. As the wear distance increases, the contact angle of the superhydrophobic material decreases overall, while the rolling angle increases. Within the first 11 meters, both the contact and rolling angles show significant changes, with the contact angle decreasing by approximately 3.2% and the rolling angle increasing by approximately 2.59°. Within the final 5 meters of the wear test, the contact angle exhibits a fluctuating downward trend, while the rolling angle fluctuates more. The results show that even after 15 meters of wear, the material surface still exhibits superhydrophobic properties, demonstrating the excellent wear resistance of the developed superhydrophobic material.

[0080] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A fly ash-based super-hydrophobic material suitable for foam concrete, characterized in that: Content by mass percentage includes: Ultrafine fly ash 1-10%; Stearic acid 1-2.5%; Hydrogen silicone oil 1-2.5%; Adhesion promoter - silane coupling agent KH550 1-2%; Industrial ethanol.

2. The fly ash-based super-hydrophobic material suitable for foam concrete according to claim 1, wherein The volume concentration of the industrial ethanol is 95%.

3. A method for preparing a fly ash-based super-hydrophobic material suitable for foam concrete according to claim 1, characterized in that: The steps include: Step 1: drying and removing moisture and some impurities in the ultrafine fly ash at 200° C., specifically, using a constant temperature blast drying oven to dry the ultrafine fly ash at 200° C. for no less than 30 minutes. The high-temperature drying effectively removes free water and some weakly bound water, reduces the moisture content to improve its fluidity and stability, and after drying the moisture, the surface of the fly ash particles is more fully exposed, the contact area with the reacting material is increased, the activity is improved, and the unburned organic carbon impurities and low-boiling point volatile organic compounds remaining in the fly ash are removed; Step 2: Stearic acid and hydrogenated silicone oil are placed in industrial ethanol with a volume concentration of 95%, and the mixture is heated and dissolved in a constant temperature magnetic stirrer at 40° C. and stirred thoroughly for at least 5 minutes. After the mixture is dissolved and stirred thoroughly, a uniform colloidal dispersion system is obtained. Step 3, adding the dried ultrafine fly ash to the uniform system, stirring the mixture by magnetic stirring to obtain a mixed solution, and stirring for no less than 5 minutes; Step 4: ultrasonically treat the mixed solution using an ultrasonic disperser with an ultrasonic power of 100 to 500 W for 15 minutes. Magnetic stirring is maintained during the ultrasonic treatment to ensure that the fly ash particles are evenly dispersed in the mixed solution and to prevent them from settling and gathering at the bottom. Step 5: After ultrasonication, add the adhesion promoter, silane coupling agent KH550, and stir evenly with magnetic force for at least 10 minutes to obtain a fly ash-based superhydrophobic material suitable for foam concrete.

4. The preparation method according to claim 3, characterized in that In step 2, the container is sealed during the dissolving and stirring process.

5. The preparation method according to claim 3, characterized in that The ultrasonic power is 200W.

6. The preparation method according to claim 3, characterized in that During the sonication process, the preparation container was placed in a constant temperature environment at 20°C.

7. The preparation method according to claim 3, characterized in that The method further includes storing the fly ash-based super-hydrophobic material suitable for foam concrete in a sealed container to prevent ethanol from volatilizing.

8. A method for preparing waterproof foam concrete, characterized in that: The fly ash-based super-hydrophobic material suitable for foam concrete is prepared by the method according to claim 3, sprayed on the surface of the foam concrete, and placed in a natural environment to volatilize the remaining industrial ethanol.

9. The method for preparing waterproof foamed concrete according to claim 8, characterized in that: When spraying the fly ash-based super-hydrophobic material suitable for foam concrete, spray it multiple times according to the set amount, and the last spraying should be carried out after the previous spraying is slightly dry. The spraying pressure is 0.4 MPa.

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