A method for protecting concrete by integrating internal and external coordination

Abstract

A method for internal and external coordinated integrated protection of concrete, relating to a method for protecting concrete. The present invention is to solve the technical problem that the current concrete materials are facing erosion and destruction from various complex environments, which leads to the gradual deterioration of their performance and even causes structural failure. The present invention provides a method for internal and external coordinated integrated protection of concrete, which is achieved through two innovative aspects: one is to utilize the combination of reinforcement and cement to significantly improve the density and strength of concrete through a special surface treatment process; the second is to adopt super-hydrophobic anti-corrosion coating technology to sequentially construct microscopic and nanoscopic double rough structures on the concrete surface to form an efficient super-hydrophobic layer. The method of the present invention effectively resists the erosion of the external environment, solves the problems of concrete carbonization, sulfate corrosion and steel corrosion, and provides a high-performance, long-life concrete material solution for the field of civil engineering.

Description

Technical Field

[0001] The present invention relates to a method for protecting concrete. Background Art

[0002] In civil engineering, cement concrete is a widely used building material. Its durability and long-term stability are directly related to the safety and lifespan of engineering structures. However, in practical applications, cement concrete often faces erosion and damage from various complex environments, leading to gradual degradation of its performance and even structural failure. This corrosion phenomenon is not limited to specific marine environments but is also widespread in industrially polluted areas, around chemical plants, and in areas with extreme climate change.

[0003] The root cause of corrosion primarily stems from the interaction between external environmental factors and the physical and chemical changes within concrete. For example, harmful gases such as carbon dioxide and sulfides in the air, as well as dissolved salts in water, can penetrate into concrete and react with cement hydration products, leading to problems such as carbonation and sulfate attack. Furthermore, extreme temperature cycles and alternating wet and dry conditions can accelerate the expansion of microcracks in concrete, reducing its density and strength. More seriously, when steel bars embedded in concrete are attacked by humid environments or harmful ions, electrochemical corrosion reactions occur, generating rust products that expand in volume, further squeezing and destroying the surrounding concrete cover, creating a vicious cycle. This process not only weakens the structure's bearing capacity but can also lead to sudden failure, posing a threat to life and property.

[0004] Therefore, the development of highly effective anti-corrosion cement concrete materials and their associated protective technologies has become a critical and pressing issue in the current civil engineering field. Improving the density of cement concrete or applying surface coatings can effectively enhance concrete's impermeability, chemical resistance, and durability, thereby extending the service life of engineering structures and ensuring their safe and stable operation. Summary of the Invention

[0005] The present invention aims to solve the technical problem that concrete materials are currently exposed to erosion and damage from various complex environments, which leads to gradual deterioration of their performance and even structural failure, and to provide a method for integrated internal and external synergistic protection of concrete.

[0006] The method for the internal and external coordinated integrated protective concrete of the present invention is carried out according to the following steps:

[0007] 1. Internal protection: Provide a method of using reinforcement to improve the density of cement concrete. The specific process is as follows:

[0008] 1. Surface treatment of a reinforcement, wherein the reinforcement comprises one or a mixture of organic fibers, inorganic fibers, whiskers and carbon nanotubes;

[0009] 2. Prepare cement gel, dissolve the reinforcement treated in step 1 into a solvent, then add it to the cement gel for mixing, then pour it into a mold for forming, then solidify, remove the mold, and cure indoors to obtain a cement concrete specimen;

[0010] 2. External protection: Using super-hydrophobic anti-corrosion coating technology, a double rough structure of microscopic and nanoscopic structures is sequentially constructed on the concrete surface to form a highly effective anti-corrosion layer. The specific process is as follows:

[0011] 1. Microstructure construction

[0012] ①, using a solvent to dissolve the resin and curing agent, heating in a water bath and magnetic stirring to obtain a mixed solution; the mass of the resin and curing agent is (9-12):1;

[0013] ② Then immerse the surface of the cement concrete specimen to be protected after curing in step 1 in the mixed solution for 2 to 3 seconds, and then take it out; repeat this step twice, that is, immerse it three times in total, to obtain a bonding layer on the surface of the cement concrete specimen to be protected;

[0014] ③ The particles are evenly dispersed on the surface of the bonding layer of the cement concrete specimen through a sieve to obtain a composite material with a microscopic rough structure, and then solidified;

[0015] 2. Construction of nanostructure

[0016] ① Use solvent to dissolve resin, curing agent, hydrophobic modifier and nanoparticles, heat in a water bath and stir magnetically to form a uniform superhydrophobic suspension;

[0017] The mass ratio of the resin to the curing agent is (9-12):1; the mass ratio of the curing agent to the hydrophobic modifier is 1:1;

[0018] ② Immerse the surface of the cement concrete to be protected after curing in step 1 in the superhydrophobic suspension for 2s to 3s, then take it out and cure it for 1h to 1.5h;

[0019] ③. Repeat step ② once;

[0020] ④. Immerse the surface of the cement concrete to be protected after being cured in step ③ in the superhydrophobic suspension for 2s to 3s, take it out and cure it for 3h to 3.5h to obtain a concrete structure with integrated internal and external protection.

[0021] The present invention provides a method for internal and external collaborative integrated protection of concrete, aiming to significantly improve the durability and service life of concrete. The invention is achieved through two innovative aspects: first, by combining reinforcement with cement, the density and strength of concrete are significantly improved by a special surface treatment process; second, by using super-hydrophobic anti-corrosion coating technology, a microscopic and nanoscopic double rough structure is sequentially constructed on the concrete surface to form an efficient super-hydrophobic layer. The method of the present invention effectively resists the erosion of the external environment, solves the problems such as concrete carbonization, sulfate corrosion and steel corrosion, and provides a high-performance, long-life concrete material solution for the field of civil engineering. The concrete structure prepared by the present invention is significantly improved in corrosion resistance compared to traditional cement-based materials, and simultaneously exhibits enhanced self-cleaning, anti-icing, anti-seepage, high and low temperature cycle resistance, ultraviolet aging resistance and other properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a comparison chart of the contact angle measurement results of Experiment 5;

[0023] Figure 2 This is the data graph of the contact angle of the coating at different friction times in test six;

[0024] Figure 3 This is a photo of the coating surface of Sample No. 1 in Test 7 before the tape peeling test in Test 3;

[0025] Figure 4 This is a photo of the coating surface of Sample No. 1 in Test 7 after the tape was peeled off compared to Test 3;

[0026] Figure 5 This is a photo of the coating surface of Sample No. 2 in Test 3 before the tape peeling test in Test 7;

[0027] Figure 6 This is a photo of the coating surface of Sample No. 2 in Test 3 after the tape was peeled off in Test 7;

[0028] Figure 7 This is a photograph of the coating surface of sample No. 1 before the tape peeling test when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in Test 1 of Test 7;

[0029] Figure 8 This is a photograph of the coating surface of sample No. 1 after tape peeling when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in test 1 of test 7;

[0030] Figure 9 This is a photograph of the coating surface of sample No. 2 before the tape peeling test when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in Test 1 of Test 7;

[0031] Figure 10This is a photograph of the coating surface of sample No. 2 after tape peeling when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in Test 1 of Test 7;

[0032] Figure 11 The scratch images in Experiment 8 are compared with those in Experiment 3;

[0033] Figure 12 This is the scratch image of the experiment 1 in experiment 8 with a mass ratio of nanoparticles to anhydrous ethanol of 1:10;

[0034] Figure 13 This is a diagram of the macroscopic morphology changes of cement-based specimens with different treatments before and after immersion in Experiment 9. DETAILED DESCRIPTION

[0035] Specific embodiment 1: This embodiment is a method for protecting concrete by internal and external coordinated integration, which is specifically carried out in the following steps:

[0036] 1. Internal protection: Provide a method of using reinforcement to improve the density of cement concrete. The specific process is as follows:

[0037] 1. Performing surface treatment on a reinforcement, wherein the reinforcement comprises one or a mixture of organic fibers, inorganic fibers, whiskers and carbon nanotubes;

[0038] 2. Prepare cement gel, dissolve the reinforcement treated in step 1 into a solvent, then add it to the cement gel for mixing, then pour it into a mold for forming, then solidify, remove the mold, and cure indoors to obtain a cement concrete specimen;

[0039] 2. External protection: Using super-hydrophobic anti-corrosion coating technology, a double rough structure of microscopic and nanoscopic structures is sequentially constructed on the concrete surface to form a highly effective anti-corrosion layer. The specific process is as follows:

[0040] 1. Microstructure construction

[0041] ①, using a solvent to dissolve the resin and curing agent, heating in a water bath and magnetic stirring to obtain a mixed solution; the mass of the resin and curing agent is (9-12):1;

[0042] ② Then immerse the surface of the cement concrete specimen to be protected after curing in step 1 in the mixed solution for 2 to 3 seconds, and then take it out; repeat this step twice, that is, immerse it three times in total, to obtain a bonding layer on the surface of the cement concrete specimen to be protected;

[0043] ③ The particles are evenly dispersed on the surface of the bonding layer of the cement concrete specimen through a sieve to obtain a composite material with a microscopic rough structure, and then solidified;

[0044] 2. Construction of nanostructure

[0045] ① Use solvent to dissolve resin, curing agent, hydrophobic modifier and nanoparticles, heat in a water bath and stir magnetically to form a uniform superhydrophobic suspension;

[0046] The mass ratio of the resin to the curing agent is (9-12):1; the mass ratio of the curing agent to the hydrophobic modifier is 1:1;

[0047] ② Immerse the surface of the cement concrete to be protected after curing in step 1 in the superhydrophobic suspension for 2s to 3s, then take it out and cure it for 1h to 1.5h;

[0048] ③. Repeat step ② once;

[0049] ④. Immerse the surface of the cement concrete to be protected after being cured in step ③ in the superhydrophobic suspension for 2s to 3s, take it out and cure it for 3h to 3.5h to obtain a concrete structure with integrated internal and external protection.

[0050] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the organic fiber in step 1 includes polyester fiber, polypropylene fiber, nylon fiber and natural fiber. Other aspects are the same as specific embodiment 1.

[0051] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the inorganic fibers described in step 1 include glass fibers, carbon fibers, basalt fibers, and metal fibers. Other aspects are the same as specific embodiment 1 or 2.

[0052] Specific embodiment 4: This embodiment differs from specific embodiment 3 in that: when the reinforcement described in step 1 is carbon fiber, the surface treatment method of the reinforcement is:

[0053] (1) Desizing of carbon fiber surface

[0054] Place the beaker containing carbon fiber and anhydrous ethanol in an ultrasonic cleaner and turn on the ultrasonic treatment mode for 60 minutes to achieve effective desizing treatment on the carbon fiber surface;

[0055] The carbon fibers were taken out and ultrasonically treated in deionized water for 30 min to completely remove the residual anhydrous ethanol on the surface of the carbon fibers.

[0056] The container containing the carbon fiber is placed in an oven and the temperature is set at 60-80°C for drying until the carbon fiber reaches a constant weight to obtain the desizing carbon fiber;

[0057] (2) Carbon fiber heat treatment

[0058] The desizing carbon fibers are spread in a container, placed in a muffle furnace, and the temperature of the muffle furnace is set to 100° C. to 500° C. to heat treat the carbon fibers for 10 to 30 minutes to complete the surface treatment of the carbon fibers.

[0059] Specific embodiment 5: This embodiment differs from specific embodiment 1 in that the cement in the cement gel in step 1 includes silicate cement, sulfoaluminate cement, phosphate cement, high alumina cement or slag cement. Other aspects are the same as specific embodiment 4.

[0060] Specific embodiment 6: This embodiment differs from specific embodiment 5 in that the indoor curing time in step 1 is 28 days and the temperature is 18° C. to 22° C. The rest is the same as specific embodiment 5.

[0061] Specific embodiment 7: This embodiment differs from specific embodiment 6 in that the curing agents used in the construction of the microstructure and nanostructure in step 2 are all amines, anhydrides, phenolic forms, isocyanates, or water-based curing agents. Other aspects are the same as specific embodiment 6.

[0062] Specific embodiment 8: This embodiment differs from specific embodiment 7 in that the particles in step 2 are quartz sand particles, silicate minerals, silicon powder, or silica beads; and the curing in step 2 (1) is performed at 45°C for 5 hours or at room temperature. Other aspects are the same as specific embodiment 7.

[0063] Specific embodiment 9: This embodiment differs from specific embodiment 8 in that the hydrophobic modifier in step 2 is polydimethylsiloxane, a fluorosilane hydrophobic modifier, an organosilicon hydrophobic modifier, or an acrylate hydrophobic modifier. Other aspects are the same as specific embodiment 8.

[0064] Specific embodiment 10: This embodiment differs from specific embodiment 9 in that the nanoparticles in step 2 are nano-SiO2, nano-TiO2, nano-Al2O3, carbon nanotubes, graphene nanosheets or nanoclay. Other aspects are the same as specific embodiment 9.

[0065] The present invention is verified by the following test:

[0066] Test 1: This test is a method of internal and external coordinated integrated protection of concrete, which is carried out in the following steps:

[0067] 1. Internal protection: Provide a method of using reinforcement to improve the density of cement concrete. The specific process is as follows:

[0068] 1. Surface treatment of carbon fiber:

[0069] (1) Desizing of carbon fiber surface

[0070] A layer of carbon fiber was placed on the bottom of a dried beaker to ensure uniform fiber distribution; anhydrous ethanol was added to the beaker to ensure that the liquid surface completely covered the carbon fiber; the beaker containing the carbon fiber and anhydrous ethanol was placed in an ultrasonic cleaner and ultrasonic treatment mode was turned on for 60 minutes to effectively desizing the carbon fiber surface; the carbon fiber was 6mm chopped carbon fiber;

[0071] Use tweezers to remove the ultrasonically treated carbon fiber from the anhydrous ethanol and transfer it to another beaker filled with deionized water to ensure that the carbon fiber is completely immersed. Ultrasonic treatment is then performed again for 30 minutes to completely remove the residual anhydrous ethanol on the surface of the carbon fiber.

[0072] The carbon fibers that have undergone secondary ultrasonic treatment are taken out of the deionized water and gently spread out in a clean stainless steel container to avoid overlapping. The stainless steel container containing the carbon fibers is placed in an oven and dried at 80°C until the carbon fibers reach a constant weight, thereby obtaining desizing-treated carbon fibers.

[0073] (2) Carbon fiber heat treatment

[0074] The desizing carbon fiber is evenly and flatly spread in a stainless steel container, the stainless steel container is placed in a muffle furnace, and the temperature of the muffle furnace is set to 300 ° C. The carbon fiber is heat treated for 15 minutes to complete the surface treatment of the carbon fiber;

[0075] 2. Add carboxymethyl cellulose to water to completely dissolve it. The mass ratio of carboxymethyl cellulose to water is 1:400 to obtain a solvent. In this process, carboxymethyl cellulose is used as a dispersant to promote the uniform dispersion of carbon fibers in the subsequent mixing step.

[0076] The carbon fibers heat-treated in step 1 were dissolved in the solvent at a ratio of carbon fibers to water of 0.01:1 to obtain a carbon fiber dispersion solution. To ensure that the carbon fibers were evenly dispersed in the solution, an electric stirrer was used for stirring at a speed of 600 rpm.

[0077] The cementitious components of magnesium phosphate cement (cementitious components include dead-burned magnesium oxide, potassium dihydrogen phosphate and sodium borate decahydrate) are mixed, and the mass ratio of dead-burned magnesium oxide, potassium dihydrogen phosphate and borax is 4:1:0.32; the mixed cementitious components are placed in a stirring pot, and the stirring equipment is started, and mechanical dry mixing is performed at 62r / min for 5 minutes. This step is intended to pre-mix the cementitious material to a state close to being completely uniform by mechanical force; after the cementitious material is uniformly stirred, the carbon fiber dispersion solution is uniformly poured into the stirring pot and stirred for 90 seconds to form a uniform mixture. The mass ratio of the sum of the mass of burnt magnesium oxide, potassium dihydrogen phosphate, and borax to the mass of water is 1:0.14; the mixture is quickly and evenly poured into a mold and molded (vibrated). During this process, it is necessary to ensure that the material fills every corner of the mold to avoid bubbles or voids. After the molding process is completed, it is allowed to stand for 15 minutes. After the material is initially solidified, the mold is removed. Care must be taken during demolding to avoid damaging the specimen. After demolding, the specimen is placed indoors for natural curing for 28 days at a curing temperature of 20°C to obtain a cement concrete specimen (size 160 mm × 40 mm × 20 mm).

[0078] 2. External protection: Using super-hydrophobic anti-corrosion coating technology, a double rough structure of microscopic and nanoscopic structures is sequentially constructed on the concrete surface to form a highly effective anti-corrosion layer. The specific process is as follows:

[0079] 1. Microstructure construction

[0080] ① Dissolve epoxy resin and curing agent DETA in anhydrous ethanol, heat in a water bath with magnetic stirring for 5 minutes (500 rpm, 30°C) to obtain a mixed solution; the mass ratio of the epoxy resin to the curing agent is 10:1, and the mass ratio of the epoxy resin to anhydrous ethanol is 1:2;

[0081] ② Then, immerse the surface to be protected (a non-exposed surface of 160 mm × 40 mm) of the cement concrete specimen cured in step 1 in the mixed solution for 2 seconds and then remove it; repeat this step twice, i.e., immerse it a total of 3 times, to obtain a bonding layer on the surface to be protected of the cement concrete specimen;

[0082] ③, quartz sand particles of 40-60 mesh were evenly dispersed on the surface of the bonding layer of the cement concrete specimen through a 60-mesh sieve to obtain a composite material with a microscopic rough structure, and then cured at 45°C for 5 hours;

[0083] 2. Construction of nanostructure

[0084] ① Dissolve epoxy resin, curing agent DETA, polydimethylsiloxane (Part A mass: Part B mass = 10:1) and nanoparticles in anhydrous ethanol, and heat in a water bath with magnetic stirring for 30 minutes (300 rpm, 30°C) to form a uniform superhydrophobic suspension; the nanoparticles are nano-SiO2;

[0085] The mass ratio of the epoxy resin to the curing agent DETA was 10:1; the mass ratio of the epoxy resin to anhydrous ethanol was 1:10; the mass ratio of the curing agent DETA to polydimethylsiloxane was 1:1; the mass ratios of the nanoparticles to anhydrous ethanol were (3, 5, 8, 10, and 12):100, respectively, and these five ratios were used for comparison.

[0086] ② Immerse the surface of the cement concrete to be protected after curing in step 1 in the superhydrophobic suspension for 2 seconds, remove it and cure it for 1 hour at a curing temperature of 45°C;

[0087] ③. Repeat step ② once;

[0088] ④. Immerse the surface of the cement concrete to be protected after curing in step ③ in the superhydrophobic suspension for 2 seconds, take it out and cure it for 3 hours at a curing temperature of 45°C to obtain a concrete structure with integrated internal and external protection.

[0089] Comparative test 1: The difference from test 1 is that in step ③ of nanostructure construction, the process of step ② is repeated 0 times, and then cured for 4 hours in step ④. The rest is the same as test 1, that is, two cycles.

[0090] Comparative Experiment 2: The difference from Experiment 1 is that in step ② of the nanostructure construction, the curing is performed for 5 hours, and steps ③ and ④ are omitted, which constitutes one cycle. Other aspects are the same as Experiment 1.

[0091] Experiment 2: This experiment differs from Experiment 1 in that the nanoparticles described in step 2 are nano-TiO2. Other aspects are the same as Experiment 1.

[0092] Experiment 3: This experiment differs from Experiment 1 in that the nanoparticles used are nano-Al2O3. Other aspects are the same as Experiment 1.

[0093] Comparative experiment three: The difference from experiment three is that in step ③ of nanostructure construction, the process of step ② is repeated 0 times, and then cured for 4 hours in step ④. The rest is the same as experiment three, that is, two cycles.

[0094] Experiment 4: This experiment differs from Experiment 1 in that the nanoparticles used are carbon nanotubes. All other aspects are the same as Experiment 1.

[0095] Experiment 5: The contact angle of the super-hydrophobic coating prepared in Experiment 1, Experiment 2, Experiment 3, Experiment 4, Comparative Experiment 1 and Comparative Experiment 2 was measured using a wetting angle meter. The volume of the water droplet used in the test was controlled to be 0.8μL~1μL. The contact angle measurement value was the average of the data measured at two different positions on the super-hydrophobic surface. The contact angle was calculated and analyzed by the software provided by the contact angle meter. The results are as follows: Figure 1 , nanomaterial concentration represents the mass fraction of nanoparticles in anhydrous ethanol. By comparing the contact angle data of super-hydrophobic coating materials prepared with the same nanomaterial type and the same number of treatments, it was found that: for nano-SiO2, the contact angle showed an upward trend as the concentration increased. When the concentration was greater than 10%, the contact angle decreased, that is, 10% was the optimal concentration of nano-SiO2. Among them, there were three groups of parameters that met the super-hydrophobic condition (contact angle greater than 150 °): SiO2-8% - three cycles, SiO2-10% - one cycle, and SiO2-10% - three cycles. Similarly, the optimal concentration of nano-TiO2 was also 10%. However, under the premise of keeping the experimental conditions consistent, it was observed that the contact angle data of TiO2 were always lower than the corresponding values ​​of SiO2 and Al2O3 nanomaterials. For nano-Al2O3, its contact angle data always showed an upward trend.

[0096] Test 6: Prepare 800# sandpaper and place it with the rough surface facing down on the coating surface of the specimen. Place a 200g standard weight on the sandpaper and pull the sandpaper horizontally on the specimen at a constant speed by hand. The position of the sandpaper where the weight is located completely rubs the coating surface as one friction cycle. Measure the change in contact angle of the super-hydrophobic coating after different friction cycles, and use the contact angle as an evaluation index to evaluate the friction and wear resistance of the super-hydrophobic coating. The change in the contact angle of the coating under different friction times is shown in Figure 2 ▲ represents the mass ratio of nanoparticles to anhydrous ethanol in Experiment 1, which was 1:10; ◆ represents Comparative Experiment 3. As can be seen from the figure, under the same test conditions, the contact angle of the coating with the parameters of 12%-Al2O3-cycled twice remained consistently higher than that of the coating with the parameters of 10%-SiO2-cycled three times, indicating that the 12%-Al2O3-cycled twice coating has superior hydrophobic properties. Furthermore, the contact angle of the 12%-Al2O3-cycled twice coating fluctuated more narrowly, reaching a maximum of 153.5° and a minimum of 146.5°, a difference of only 7°. In contrast, the contact angle of the 10%-SiO2-cycled three times coating varied more widely, ranging from a high of 151.5° to a low of 140.5°, a difference of 11°. This comparison demonstrates that the 12%-Al2O3-cycled twice coating exhibits superior stability during friction and wear.

[0097] Test 7: To enhance the reliability of the data and reduce the test error, two specimens were selected as parallel samples for each coating ratio for testing. After the coating was completely cured, 64 square grids of 2mm×2mm were evenly scratched on the surface of the specimen using a grid knife device. The debris from the scratches was then removed with a brush. Finally, 3M tape was evenly adhered to the small squares. After waiting for 2 minutes, the tape was quickly removed from the coating surface. The adhesion of the super-hydrophobic coating was evaluated by the integrity of the paint film in the grid. The test results are shown in Table 1 and Figure 3-10 As shown, Figure 3 For comparison, the coating surface photo of sample No. 1 in test 3 before the tape peeling test is shown. Figure 4 For comparison, the coating surface photo of sample No. 1 in test 3 after the tape was peeled off is shown. Figure 5 For comparison, the coating surface photo of sample No. 2 in test 3 before the tape peeling test is shown. Figure 6 For comparison, the coating surface photo of sample No. 2 in test 3 after the tape was peeled off is shown. Figure 7 This is a photo of the coating surface of sample No. 1 before the tape peeling test when the mass ratio of nanoparticles to anhydrous ethanol is 1:10 in experiment 1. Figure 8 This is a photo of the coating surface of sample No. 1 after the tape was peeled off when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in test 1. Figure 9 This is a photo of the coating surface of sample No. 2 before the tape peeling test when the mass ratio of nanoparticles to anhydrous ethanol was 1:10 in experiment 1. Figure 10 This is a photograph of the coating surface of sample No. 2 after tape stripping, using a nanoparticle-to-anhydrous ethanol mass ratio of 1:10 in Test 1. Both coatings demonstrate strong substrate adhesion. This is due to the epoxy resin in the bottom adhesive layer, a thermosetting resin. Its highly cross-linked three-dimensional network structure imparts excellent bonding properties, resulting in excellent mechanical robustness against tape stripping.

[0098] Table 1 Tape peeling test results

[0099]

[0100] Test 8: Starting from the hardest pencil, scratch the coatings of Test 1 and Comparative Test 3 in order until the selected pencil does not scratch the coating, and record it as the hardness of the coating, see Table 2 below. Figure 11 and Figure 12 , Figure 11 For comparison with the scratch image of experiment 3, Figure 12This is an image of a scratch in Experiment 1, where the mass ratio of nanoparticles to anhydrous ethanol was 1:10. As can be seen, the coating with the 10% SiO2 coating cycled three times exhibits significantly higher hardness than the 12% Al2O3 coating cycled twice, reaching a hardness rating of 6H. This is likely due to the high hardness of SiO2, its uniform distribution and good bonding within the coating, combined with the three-cycle preparation process, which together contribute to the significant improvement in coating hardness.

[0101] Table 2 Comparison of hardness of coating samples with different parameters

[0102]

[0103] Experiment 9: The cement test block obtained in comparative experiment 3 and the one not coated with super-hydrophobic coating (the product after internal protection in step 1 of experiment 1) were placed in a 3.5% NaCl solution. Table 3 below shows the change in contact angle after 30 days of immersion. Figure 13 The figure shows the macroscopic morphology changes of cement-based specimens with different treatments before and after immersion. It was found that there was no obvious change in the surface morphology.

[0104] Table 3 Variation of coating contact angle with immersion time (unit: °)

[0105]

[0106] Test 10: Freeze-thaw cycle test: The sample was placed in a freeze-thaw cycle test chamber to test the change in the contact angle of the coating and the change in the bonding strength between the coating and the substrate to evaluate the coating's ability to resist freeze-thaw, see Tables 4 and 5 below.

[0107] Table 4 Changes in coating contact angle with freeze-thaw cycle number (unit: °)

[0108]

[0109] Table 5 Changes in the bonding strength between the coating and the substrate with the number of freeze-thaw cycles

[0110]

[0111] Comparing the data in the table, the contact angle change after 50 freeze-thaw cycles for the 12%-Al2O3-treated coating in Experiment 3 was less pronounced than for the 10%-SiO2-treated coating in Experiment 1, which had undergone three freeze-thaw cycles. However, it's worth noting that the former exhibited a more pronounced decrease in adhesion, indicating that while freeze-thaw resistance may have some advantages over contact angle stability, the coating-substrate bond strength suffers a greater impact.

Claims

1. A method for protecting concrete by integrating internal and external coordination, characterized in that The method of internal and external coordinated integrated protective concrete is carried out in the following steps:

1. Internal protection: Provide a method of using reinforcement to improve the density of cement concrete. The specific process is as follows: (1) Surface treatment of the reinforcement, wherein the reinforcement is carbon fiber, is performed by: ①Desizing of carbon fiber surface Place the beaker containing carbon fiber and anhydrous ethanol in an ultrasonic cleaner and turn on the ultrasonic treatment mode for 60 minutes to achieve effective desizing treatment on the carbon fiber surface; The carbon fibers were taken out and ultrasonically treated in deionized water for 30 min to completely remove the residual anhydrous ethanol on the surface of the carbon fibers. The container containing the carbon fiber is placed in an oven and the temperature is set at 60-80°C for drying until the carbon fiber reaches a constant weight to obtain the desizing carbon fiber; ② Carbon fiber heat treatment The desizing carbon fiber is spread in a container, placed in a muffle furnace, and the temperature of the muffle furnace is set to 100°C to 500°C to heat treat the carbon fiber for 10 to 30 minutes to complete the surface treatment of the carbon fiber; (2) preparing cement gel, dissolving the reinforcement treated in step (1) into a solvent, then adding the mixture to the cement gel for mixing, then pouring the mixture into a mold for forming, then curing, demolding, and curing indoors to obtain a cement concrete specimen; The solvent is prepared by adding carboxymethyl cellulose into water and completely dissolving the carboxymethyl cellulose in a mass ratio of 1:400 to obtain the solvent; 2. External protection: Using super-hydrophobic anti-corrosion coating technology, a double rough structure of microscopic and nanoscopic structures is sequentially constructed on the concrete surface to form a highly effective anti-corrosion layer. The specific process is as follows: (1) Microstructure ① Dissolve the resin and curing agent in anhydrous ethanol, heat in a water bath and stir magnetically to obtain a mixed solution; the mass ratio of the resin to the curing agent is (9-12):1; ② Then immerse the surface of the cement concrete specimen to be protected after curing in step 1 in the mixed solution for 2 to 3 seconds, and then take it out; repeat this step twice, that is, immerse it three times in total, to obtain a bonding layer on the surface of the cement concrete specimen to be protected; ③ The particles are evenly dispersed on the surface of the bonding layer of the cement concrete specimen through a sieve to obtain a composite material with a microscopic rough structure, and then solidified; (2) Construction of nanostructure ① Use anhydrous ethanol to dissolve the resin, curing agent, hydrophobic modifier and nanoparticles, heat in a water bath and stir magnetically to form a uniform super-hydrophobic suspension; The mass ratio of the resin to the curing agent is (9-12):1; the mass ratio of the curing agent to the hydrophobic modifier is 1:1; ② Immerse the surface of the cement concrete specimen to be protected after being cured in step 2 (1) in the superhydrophobic suspension for 2s to 3s, take it out and cure it for 1h to 1.5h; ③. Repeat step ② once; ④. Immerse the surface of the cement concrete specimen to be protected after being cured in step ③ in the superhydrophobic suspension for 2s~3s, take it out and cure it for 3h~3.5h to obtain a concrete structure with integrated internal and external protection.

2. The method for protecting concrete by integrating internal and external coordination according to claim 1 is characterized in that The cement in the cement gel in step 1 includes silicate cement, sulphoaluminate cement, phosphate cement, high alumina cement or slag cement.

3. The method for protecting concrete by integrated internal and external coordination according to claim 1 is characterized in that The indoor curing time described in step 1 is 28 days, and the temperature is 18℃~22℃.

4. The method for protecting concrete by integrating internal and external coordination according to claim 1 is characterized in that The curing agent used in the construction of the microstructure and nanostructure in step 2 is an amine, anhydride, phenolic, isocyanate or water-based curing agent.

5. The method for protecting concrete by integrated internal and external coordination according to claim 1 is characterized in that The particles described in step 2 are quartz sand particles, silicate minerals, silicon powder or silicon dioxide microbeads; and the curing in step 2 (1) is curing at 45° C. for 5 h or curing at room temperature.

6. The method for protecting concrete by integrated internal and external coordination according to claim 1 is characterized in that The hydrophobic modifier described in step 2 is polydimethylsiloxane, a fluorosilane hydrophobic modifier, an organosilicon hydrophobic modifier or an acrylate hydrophobic modifier.

7. The method for protecting concrete by integrating internal and external coordination according to claim 1 is characterized in that The nanoparticles described in step 2 are nano-SiO2, nano-TiO2, nano-Al2O3, carbon nanotubes, graphene nanosheets or nano-clay.

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