A high-efficiency concrete crack-resistant and waterproofing agent and its preparation method

Abstract

This invention relates to the field of concrete waterproofing agents, specifically to a high-efficiency concrete crack-resistant waterproofing agent and its preparation method. It comprises the following raw materials in parts by weight: calcium sulfoaluminate expansion agent; lightly calcined magnesium oxide; heavily calcined magnesium oxide; nano-sized silica; metakaolin; polypropylene fiber; basalt fiber; styrene-acrylic emulsion; silane emulsion; silica fume; hydroxypropyl methylcellulose; and polycarboxylate superplasticizer compatibilizer. This invention's high-efficiency concrete crack-resistant waterproofing agent achieves dual waterproofing through the synergistic sealing of multi-level pores from nano- to macro-level by nano-silica, metakaolin, and styrene-acrylic emulsion, resulting in both physical filling and chemical film formation. Polypropylene and basalt fiber are ultrasonically dispersed to optimize interface bonding, forming a three-dimensional crack-resistant network. Furthermore, precise proportioning, graded mixing, and directional granulation ensure component uniformity and functional stability, while also being compatible with industrial production fluctuations, guaranteeing reliability for large-scale applications. This overcomes the problems of traditional waterproofing agents' single function and insufficient durability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete waterproofing agent, in particular to a high-efficiency concrete anti-cracking waterproofing agent and a preparation method thereof. BACKGROUND

[0002] The concrete waterproofing agent is a functional material for improving the impermeability and anti-cracking of concrete. By reducing porosity, compensating shrinkage stress, or forming a waterproof barrier, it prevents the penetration of water and harmful media, thereby prolonging the durability of the structure. The core function is to improve the internal compactness and anti-deformation ability of concrete, making it suitable for high-humidity or easily-cracking environments such as underground engineering and hydraulic structures.

[0003] However, conventional waterproofing agents typically rely on single functional components, such as calcium aluminate expanders, organic silicon hydrophobic agents, or short-cut fibers. Calcium aluminate expanders are easily affected by environmental humidity, leading to shrinkage rebound in the later stage. Organic silicon agents can only seal surface pores and cannot improve the internal micro-nano pore structure of concrete, resulting in poor long-term waterproofing performance. Short-cut fibers have poor dispersibility, tend to clump, and have weak adhesion to the matrix, limiting their anti-cracking effect. Additionally, the synergy between traditional components is poor, and they easily compete with water-reducing agents and other additives, leading to deterioration of concrete workability and making it difficult to meet complex engineering requirements.

[0004] To address the aforementioned technical problems, the present application provides a high-efficiency concrete anti-cracking waterproofing agent and a preparation method thereof. SUMMARY

[0005] The present application aims to provide a high-efficiency concrete anti-cracking waterproofing agent and a preparation method thereof to solve the problems mentioned in the background.

[0006] To achieve the above-mentioned objectives, the present application provides the following technical solutions:

[0007] A high-efficiency concrete anti-cracking waterproofing agent, consisting of the following raw materials by weight: calcium sulphoaluminate expander: 80-120 parts; light-burned magnesium oxide: 30-50 parts; heavy-burned magnesium oxide: 20-40 parts; nano-sized silicon dioxide: 10-20 parts; metakaolin: 50-80 parts; polypropylene fiber: 3-8 parts; basalt fiber: 2-5 parts; benzene propylene emulsion: 40-60 parts; silane emulsion: 10-20 parts; silica ash: 30-60 parts; hydroxypropyl methylcellulose: 2-5 parts; polycarboxylic acid water-reducing agent compatibilizer: 5-10 parts.

[0008] Preferably, the calcium sulphoaluminate expander is prepared by mixing bauxite and gypsum at a mass ratio of 3:1, calcining in a rotary kiln at 1350-1450°C for 2-3 hours, and then rapidly cooling and grinding to a specific surface area of ≥400 square meters per kilogram. The purity of calcium sulphoaluminate in the product is ≥92%.

[0009] Preferably, the light-burned magnesium oxide is obtained by crushing magnesite to a particle size of 5-10 mm, calcining in a shaft kiln at 800-900 DEG C for 1.5-2 hours, and screening after grinding to obtain light-burned magnesium oxide powder with an active magnesium oxide content of ≥85%.

[0010] Preferably, the heavy-burned magnesium oxide is obtained by pressing the light-burned magnesium oxide into pellets, sintering in a tunnel kiln at 1500-1600 DEG C for 4-6 hours, and crushing to 50-100 microns after slow cooling with a loss on ignition of ≤3%.

[0011] Preferably, the nano-sized silicon dioxide is obtained by gas phase deposition of silane gas and oxygen in a high temperature reaction furnace at 1200-1500 DEG C to generate silicon dioxide particles with a particle size of 10-30 nm, and collecting by cyclone separation with a purity of ≥99%.

[0012] Preferably, the styrene-acrylic emulsion is obtained by mixing styrene, butyl acrylate and emulsifier in water, adding ammonium persulfate initiator, and emulsion polymerizing in a reaction kettle at 70-80 DEG C for 6-8 hours with a solid content of 48-52%.

[0013] Preferably, the silane emulsion is obtained by mixing methyltrimethoxysilane and deionized water at a ratio of 1:5, adding acetic acid to adjust the pH to 4-5, and hydrolyzing into siloxane emulsion by stirring at 50-60 DEG C for 3-4 hours.

[0014] Preferably, the polycarboxylic acid water reducer compatible agent is obtained by esterification of polyethylene glycol monomethyl ether and phosphorus pentoxide at 80-90 DEG C for 5-6 hours to generate a phosphate ester compound, and then adding ethylene oxide to polymerize, with a final product having a solid content of ≥40% and a pH of 7-8.

[0015] Based on the above high-efficiency concrete anti-cracking waterproof agent formula, the application also proposes a preparation method of high-efficiency concrete anti-cracking waterproof agent, comprising the following steps:

[0016] S1. According to the formula, the raw materials are weighed: calcium sulfoaluminate expansive agent 80-120 parts, light-burned magnesium oxide 30-50 parts, heavy-burned magnesium oxide 20-40 parts, nano-sized silicon dioxide 10-20 parts, metakaolin 50-80 parts, silica fume 30-60 parts, hydroxypropyl methylcellulose 2-5 parts, polycarboxylic acid water reducer compatible agent 5-10 parts, polypropylene fiber 3-8 parts and basalt fiber 2-5 parts are cut to lengths of 6-12 mm and 12-18 mm respectively using a fiber cutting machine, and short fibers and impurities are removed by a vibrating screen, and the styrene-acrylic emulsion 40-60 parts and the silane emulsion 10-20 parts are pre-mixed in a constant temperature stirring tank, with the temperature controlled at 25-30 DEG C to avoid emulsion layering;

[0017] S2. Put calcium sulphoaluminate expansive agent, light-burned magnesium oxide, heavy-burned magnesium oxide, metakaolin, silica fume, nano-silica into a double-shaft forced mixer, mix at a low speed of 30 rpm for 5 min to make the expansive agent and mineral fillers preliminarily uniform, add hydroxypropyl methylcellulose and polycarboxylic acid water reducer compatibilizer, increase the speed to 50 rpm and continue to stir for 10 min, break the cellulose ether agglomerates by mechanical shear force, grade the mixed dry materials by an air classifier to remove coarse particles with a particle size > 50 μm, and ensure the powder fluidity;

[0018] S3. Put the pretreated polypropylene fibers and basalt fibers into a three-dimensional motion mixer in batches, mix with the dry materials obtained in step S2, run at a speed of 20 rpm for 15 min to make the fibers uniformly dispersed in the powder, start an ultrasonic disperser, and intermittently treat the mixed materials by ultrasonic waves for 5 min each time with an interval of 2 min, further strip the powder adsorbed on the fiber surface by cavitation effect, and improve the interfacial bonding force;

[0019] S4. Slowly put the fiber-dry material mixture obtained in step S3 into a high-speed shearing emulsifier, inject the premixed styrene-acrylic emulsion and silane emulsion at the same time, stir at an initial speed of 1000 rpm for 3 min to form a slurry, gradually increase the speed to 3000 rpm, and continue to shear for 5-9 min to make the emulsion fully wrap the powder particles and penetrate into the fiber surface, pump the slurry into a fluidized bed granulator, control the inlet air temperature to be 60-70℃, and spray dry to form spherical particles with a particle size of 0.5-2.0 mm and a water content of ≤1.5%;

[0020] S5. Transfer the granulated semi-finished product to a constant-temperature curing bin, and stand still in an environment with a temperature of 40-50℃ for 24-48 hours to make the emulsion film completely solidified and release internal stress, remove coarse particles > 5.0 mm and fine powder < 0.5 mm adhered during the curing process by using a vibrating sieve separator, retain homogeneous particles with a size of 0.5-2.0 mm, detect foreign matters by a metal detector, and ensure that the metal impurity content in the product is ≤0.01%;

[0021] S6. Pack the finished particles into moisture-proof composite film bags at 25 kg / bag, seal the bags by using an automatic weighing packaging machine, store in a cool and dry warehouse with a humidity of ≤40%, and randomly sample and detect the performance.

[0022] Preferably, the performance detection of step S6 includes verifying the particle distribution by a laser particle size analyzer, testing the limited expansion rate, and finally adding the agent according to the C30 concrete ratio, forming a test piece, and measuring the impermeable pressure and crack width.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] The high-efficiency concrete anti-cracking waterproofing agent realizes physical filling and chemical film forming dual waterproofing by nano-silicon dioxide, metakaolin and benzene propylene emulsion synergistic plugging of multi-level pores from nano to macro; polypropylene and basalt fiber form a three-dimensional anti-cracking network through ultrasonic dispersion optimization of interface combination; the application also ensures component uniformity and functional stability through precise proportioning, hierarchical mixing and directional granulation, and is compatible with industrial production fluctuations, thereby guaranteeing large-scale application reliability and breaking through the problems of single function and insufficient durability of traditional waterproofing agents. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0026] I. Materials

[0027] The material components of the high-efficiency concrete anti-cracking waterproofing agent are all commercially available unless otherwise specified.

[0028] The application provides a high-efficiency concrete anti-cracking waterproofing agent, which is composed of the following raw materials in parts by weight: calcium sulfoaluminate expansive agent: 80-120 parts; light-burned magnesium oxide: 30-50 parts; heavy-burned magnesium oxide: 20-40 parts; nano-silicon dioxide: 10-20 parts; metakaolin: 50-80 parts; polypropylene fiber: 3-8 parts; basalt fiber: 2-5 parts; benzene propylene emulsion: 40-60 parts; silane emulsion: 10-20 parts; silica ash: 30-60 parts; hydroxypropyl methyl cellulose: 2-5 parts; and polycarboxylic acid water reducing agent compatibilizer: 5-10 parts.

[0029] It should be further noted that the calcium sulfoaluminate expansive agent is obtained by mixing bauxite and gypsum at a mass ratio of 3:1, calcining in a rotary kiln at 1350-1450 DEG C for 2-3 hours, and then rapidly cooling and grinding to a specific surface area of greater than or equal to 400 square meters per kilogram, and the purity of calcium sulfoaluminate in the product is greater than or equal to 92%.

[0030] It should be further noted that the light-burned magnesium oxide is obtained by crushing magnesite to a particle size of 5-10 mm, calcining in a vertical kiln at 800-900 DEG C for 1.5-2 hours, and then screening the ground light-burned magnesium oxide powder to obtain light-burned magnesium oxide powder with an active magnesium oxide content of greater than or equal to 85%.

[0031] It should be further noted that the heavy-burned magnesium oxide is obtained by pressing the light-burned magnesium oxide into pellets, sintering in a tunnel kiln at 1500-1600 DEG C for 4-6 hours, and then slowly cooling and crushing to 50-100 microns, with a loss on ignition of less than or equal to 3%.

[0032] It should be noted that the nano-silica is obtained by gas phase deposition of silane gas and oxygen at 1200-1500℃ in a high-temperature reaction furnace to generate silica particles with a particle size of 10-30 nanometers, and the purity is ≥99% after cyclone separation.

[0033] It should be noted that the styrene-acrylic emulsion is obtained by mixing styrene, butyl acrylate and emulsifier in water, adding ammonium persulfate initiator, and emulsion polymerization in a reaction kettle at 70-80℃ for 6-8 hours, and the solid content is 48-52%.

[0034] It should be noted that the silane emulsion is obtained by mixing methyltrimethoxysilane and deionized water in a ratio of 1:5, adding acetic acid to adjust the pH to 4-5, and stirring at 50-60℃ for 3-4 hours to hydrolyze into siloxane emulsion.

[0035] It should be noted that the polycarboxylic acid water reducing agent compatible agent is obtained by esterification of polyethylene glycol monomethyl ether and phosphorus pentoxide at 80-90℃ for 5-6 hours to generate phosphate ester compounds, and then addition polymerization with ethylene oxide, and the final product has a solid content ≥40%, and a pH value of 7-8.

[0036] II. Process:

[0037] Based on the above high-efficiency concrete anti-cracking waterproof agent formula, the application also provides a preparation method of the high-efficiency concrete anti-cracking waterproof agent, comprising the following steps:

[0038] S1. According to the formula proportion, weigh each raw material: calcium sulfoaluminate expansive agent 80-120 parts, light burned magnesium oxide 30-50 parts, heavy burned magnesium oxide 20-40 parts, nano-silica 10-20 parts, metakaolin 50-80 parts, silica fume 30-60 parts, hydroxypropyl methylcellulose 2-5 parts, polycarboxylic acid water reducing agent compatible agent 5-10 parts, and accurately to ±0.5% error range, cut polypropylene fiber 3-8 parts and basalt fiber 2-5 parts to length 6-12mm and 12-18mm respectively with a fiber cutting machine, and remove short fibers and impurities through a vibrating screen, and pre-mix styrene-acrylic emulsion 40-60 parts and silane emulsion 10-20 parts in a constant temperature stirring tank, and control the temperature at 25-30℃ to avoid emulsion stratification;

[0039] S2. Put calcium sulphoaluminate expansive agent, light-burned magnesium oxide, heavy-burned magnesium oxide, metakaolin, silica fume, nano-silica into a double-shaft forced mixer, mix at a low speed of 30 rpm for 5 min to make the expansive agent and mineral fillers preliminarily uniform, add hydroxypropyl methylcellulose and polycarboxylic acid water reducer compatibilizer, increase the speed to 50 rpm and continue to stir for 10 min to break the cellulose ether agglomerates by mechanical shear force, grade the mixed dry materials by an air classifier to remove coarse particles with a particle size > 50 μm, and ensure the powder fluidity;

[0040] S3. Put the pretreated polypropylene fibers and basalt fibers into a three-dimensional motion mixer in batches, mix with the dry materials obtained in step S2 at a speed of 20 rpm for 15 min to make the fibers uniformly dispersed in the powder, start an ultrasonic disperser to intermittently treat the mixed materials for 5 min each time with an interval of 2 min to further strip the powder adsorbed on the fiber surface by cavitation effect and improve the interfacial bonding force;

[0041] S4. Slowly put the fiber-dry material mixture obtained in step S3 into a high-speed shearing emulsifier, inject the premixed benzene and propylene emulsion and silane emulsion at the same time, stir at an initial speed of 1000 rpm for 3 min to form a slurry, gradually increase the speed to 3000 rpm, and continue to shear for 5-9 min to make the emulsion fully wrap the powder particles and penetrate into the fiber surface, pump the slurry into a fluidized bed granulator, control the inlet air temperature to 60-70℃, and spray dry to form spherical particles with a particle size of 0.5-2.0 mm and a water content of ≤1.5%;

[0042] S5. Transfer the granulated semi-finished product to a constant-temperature curing bin, and stand still at 40-50℃ for 24-48 hours to make the emulsion film completely solidify and release internal stress, remove the coarse particles > 5.0 mm and fine powder < 0.5 mm adhered during the curing process by a vibrating sieve separator, retain the homogeneous particles of 0.5-2.0 mm, detect foreign matters by a metal detector to ensure that the metal impurity content in the product is ≤0.01%;

[0043] In this embodiment, a preparation method of a high-efficiency concrete anti-cracking waterproof agent is disclosed, which specifically comprises the following steps:

[0044] S1. Raw material pretreatment: accurately weigh all materials with an error of ±0.5%, cut the polypropylene fibers to 6-12 mm and the basalt fibers to 12-18 mm, and remove impurities by a vibrating sieve; premix 50 parts of benzene and propylene emulsion with 15 parts of silane emulsion at a constant temperature of 25-30℃;

[0045] S2. Dry mixing: calcium sulphoaluminate expansive agent 100 parts, light burned magnesium oxide 40 parts, heavy burned magnesium oxide 30 parts, metakaolin 65 parts, silica fume 45 parts, nano-silica 15 parts into double shaft mixer: 30 rpm, 5 minutes; add hydroxypropyl methylcellulose 3 parts and polycarboxylic acid water reducer compatibilizer 7 parts, increase to 50 rpm and stir for 10 minutes; airflow classification to remove >50 pm coarse particles;

[0046] S3. Fiber dispersion: mixing of fibers and dry materials in a three-dimensional mixer: 20 rpm, 15 minutes; ultrasonic treatment: 28 kHz, 200 W, 5 minutes of ultrasonic treatment / 2 minutes of interval, for a total of 3 times;

[0047] S4. Emulsion blending and granulation: mixing of the mixture and emulsion in a high-speed shearing emulsifier: 1000→3000 rpm, 12 minutes of shearing; fluidized bed granulation: inlet air temperature 65°C, granules 0.5-2.0 mm, moisture content ≤1.5%;

[0048] S5. Curing and sieving: curing bin 40°C for 36 hours of standing; vibration sieving to remove >5.0 mm and <0.5 mm particles.

[0049] Example 2, in this example, the calcium sulphoaluminate expansive agent is reduced to 80 parts, and other material components and process parameters are the same as in Example 1;

[0050] Example 3, in this example, the calcium sulphoaluminate expansive agent is increased to 120 parts, and other material components and process parameters are the same as in Example 1;

[0051] Example 4, in this example, the nano-silica is reduced to 10 parts, and the metakaolin is reduced to 50 parts, and other material components and process parameters are the same as in Example 1;

[0052] Example 5, in this example, the light burned magnesium oxide is increased to 50 parts, and the polypropylene fiber is increased to 8 parts, and other material components and process parameters are the same as in Example 1.

[0053] Record the material parts parameters in each example, see Table 1:

[0054] Table 1 Material parts parameters in examples

[0055] Material name Example 1 Example 2 Example 3 Example 4 Example 5 Calcium sulphoaluminate expansive agent 100 80 120 100 100 Light-burned magnesium oxide 40 40 40 30 50 Heavy-burned magnesium oxide 30 30 30 30 30 Nanoscale silica 15 15 15 10 20 Metakaolin 65 65 65 50 80 Polypropylene fibres 5 5 5 3 8 Basalt fibres 3 3 3 2 5 Styrene-acrylic emulsion 50 50 50 40 60 Silane emulsion 15 15 15 10 20 Silica fume 45 45 45 30 60 Hydroxypropyl methylcellulose 3 3 3 2 5 Polycarboxylate superplasticizer compatibilizer 7 7 7 5 10

[0056] Comparative Example 1, in this example, the calcium sulphoaluminate expansive agent is over-dosed to 130 parts, exceeding the upper limit of the formula range (80-120 parts), and other materials and process parameters are the same as in Example 1;

[0057] Comparative Example 2, in this example, light burned magnesium oxide is reduced to 20 parts, which is lower than the lower limit of the formula range (30-50 parts), and other materials and process parameters are the same as in Example 1;

[0058] Comparative Example 3, in this example, heavy burned magnesium oxide is reduced to 10 parts, which is lower than the lower limit of the formula range (20-40 parts), and other materials and process parameters are the same as in Example 1;

[0059] Comparative Example 4, in this example, nano-sized silicon dioxide is reduced to 5 parts, and styrene-acrylic emulsion is reduced to 30 parts, both of which are lower than the lower limit of the range, and other materials and process parameters are the same as in Example 1;

[0060] Comparative Example 5, in this example, polypropylene fiber is over-dosed to 10 parts, and basalt fiber is over-dosed to 7 parts, both of which exceed the upper limit of the range, and other materials and process parameters are the same as in Example 1.

[0061] Record the mass parts of materials in each comparative example, see Table 2:

[0062] Table 2: Mass parts of materials in comparative examples

[0063]

[0064]

[0065] III. Performance testing:

[0066] Prepare the waterproofing agent according to the preparation process in the examples and comparative examples, and verify the particle distribution (D50=1.2-1.5mm) of the sample by laser particle size analyzer, and test the limited expansion rate (7 days in water≥0.025%, 21 days in air≤-0.010%) according to GB / T 23439-2017.

[0067] Finally, according to the C30 concrete ratio, add 8-10% of the agent, and measure the 28-day impermeable pressure of the molded test piece to be≥1.2MPa, and the crack width to be≤0.1mm;

[0068] Record the performance parameters of the waterproofing agent samples prepared in the examples, see Table 3:

[0069] Table 3: Performance data table of examples

[0070] Test index Example 1 Example 2 Example 3 Example 4 Example 5 Expansion in water for 7 days (%) 0.030 0.025 0.035 0.022 0.028 Shrinkage in air for 21 days (%) -0.008 -0.010 -0.005 -0.012 -0.009 Permeability pressure (MPa) 1.40 1.25 1.38 1.18 1.32 Crack width (mm) 0.06 0.08 0.05 0.12 0.07

[0071] Record the performance parameters of the waterproofing agent samples prepared in the comparative examples, see Table 4:

[0072] Table 4: Performance data table of comparative examples

[0073]

[0074]

[0075] IV. Analysis Conclusion:

[0076] From the data in Tables 1-4, it can be seen that:

[0077] Examples 1-5 have stable expansion rates (0.022-0.035%) and shrinkage rates ≤-0.012% by using calcium sulphoaluminate (80-120 parts) in combination with magnesium oxide (light-burnt 30-50 parts + heavy-burnt 20-40 parts). In contrast, the comparative examples have excessive expansion (0.042%) or increased shrinkage (-0.028%) due to the components being out of range (130 parts of calcium sulphoaluminate in Comparative Example 1). In the examples, nano-silica (10-20 parts) + styrene-acrylic emulsion (40-60 parts) block multi-scale pores, and the anti-permeation pressure is ≥1.18 MPa. In Comparative Example 4, the anti-permeation pressure is only 0.85 MPa due to insufficient pore filling (5 parts of nano-silica). In the examples, polypropylene fibers (3-8 parts) and basalt fibers (2-5 parts) are uniformly dispersed, and the crack width is ≤0.12 mm. In Comparative Example 5, the crack width is 0.20 mm due to fiber clumping (10 parts of polypropylene fibers). In summary, the formulation parts range in the examples of the present application is within a reasonable range.

[0078] In addition, in Example 1 of the present application, calcium sulphoaluminate (100 parts) and magnesium oxide (light-burnt 40 parts + heavy-burnt 30 parts) form a stepped expansion, matching the shrinkage time domain, while nano-silica (15 parts), metakaolin (65 parts), and styrene-acrylic emulsion (50 parts) cover nano-macro pores, achieving full-scale pore blocking. In addition, through the synergistic effect of polypropylene fibers (5 parts) and basalt fibers (3 parts), the crack width is only 0.06 mm. Finally, all component ratios are balanced, avoiding the influence of process fluctuations, and the performance stability is optimal. Therefore, Example 1 of the present application is the best embodiment.

[0079] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0080] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. A high-performance concrete anti-cracking waterproofing agent, characterized in that, It is composed of the following weight parts of raw materials: calcium sulphoaluminate expanding agent: 80-120 parts; light burned magnesia: 30-50 parts; dead burned magnesia: 20-40 parts; nanoscale silicon dioxide: 10-20 parts; metakaolin: 50-80 parts; polypropylene fiber: 3-8 parts; basalt fiber: 2-5 parts; styrene-acrylic emulsion: 40-60 parts; silane emulsion: 10-20 parts; silica fume: 30-60 parts; hydroxypropyl methyl cellulose: 2-5 parts; polycarboxylic acid water reducing agent compatibilizer: 5-10 parts; The preparation method of the high-efficiency concrete anti-cracking waterproof agent comprises the following steps: S1. According to the formula proportion, the raw materials are weighed: calcium sulphoaluminate expanding agent 80-120 parts, light burned magnesia 30-50 parts, dead burned magnesia 20-40 parts, nanoscale silicon dioxide 10-20 parts, metakaolin 50-80 parts, silica fume 30-60 parts, hydroxypropyl methyl cellulose 2-5 parts, and polycarboxylic acid water reducing agent compatibilizer 5-10 parts. The polypropylene fiber 3-8 parts and the basalt fiber 2-5 parts are cut to lengths of 6-12 mm and 12-18 mm respectively by a fiber cutting machine, and short fibers and impurities are removed by a vibrating screen. The styrene-acrylic emulsion 40-60 parts and the silane emulsion 10-20 parts are pre-mixed in a constant temperature stirring tank, and the temperature is controlled at 25-30 DEG C to avoid emulsion stratification; S2. The calcium sulphoaluminate expanding agent, light burned magnesia, dead burned magnesia, metakaolin, silica fume, and nanoscale silicon dioxide are put into a double-shaft forced mixer, and mixed at a low speed of 30 rpm for 5 min to make the expanding agent and mineral fillers preliminarily uniform. The hydroxypropyl methyl cellulose and the polycarboxylic acid water reducing agent compatibilizer are added, and the stirring speed is increased to 50 rpm for continuous stirring for 10 min. The mechanical shear force is used to break the cellulose ether agglomerates. The mixed dry materials are classified by an air flow classifier to remove coarse particles with a particle size greater than 50 microns to ensure the powder fluidity; S3. The pretreated polypropylene fiber and basalt fiber are added to a three-dimensional motion mixer in batches, mixed with the dry materials obtained in step S2 at a speed of 20 rpm for 15 min to make the fibers uniformly dispersed in the powder. An ultrasonic disperser is started to intermittently treat the mixed materials for 5 min each time with an interval of 2 min. The cavitation effect is used to further strip the powder adsorbed on the surface of the fibers to improve the interfacial bonding force; S4. The fiber-dry material mixture obtained in step S3 is slowly added to a high-speed shearing emulsifier, and the pre-mixed styrene-acrylic emulsion and silane emulsion are injected at the same time. The stirring speed is initially 1000 rpm for 3 min to form a slurry. The stirring speed is gradually increased to 3000 rpm for continuous shearing for 5-9 min to make the emulsion fully wrap the powder particles and penetrate into the surface of the fibers. The slurry is pumped into a fluidized bed granulator, the inlet air temperature is controlled at 60-70 DEG C, and the spray drying is performed to form spherical particles with a particle size of 0.5-2.0 mm and a water content of ≤1.5%. S5. The granulated semi-finished product is transferred to a constant temperature curing bin, and is left to stand for 24-48 hours at an environment of 40-50℃, so that the emulsion film is completely cured and internal stress is released. A vibrating screen is used to remove coarse particles of >5.0 mm and fine powder of <0.5 mm adhered during the curing process, and homogeneous particles of 0.5-2.0 mm are retained. A metal detector is used to detect foreign matter, so that the content of metal impurities in the product is ≤0.01%; S6. The finished product particles are packed into moisture-proof composite film bags at 25 kg per bag, and the bags are sealed by an automatic weighing packaging machine. The product is stored in a cool and dry warehouse with a humidity of ≤40%, and is randomly sampled for performance testing.

2. The high-efficiency concrete anti-cracking waterproofing agent according to claim 1, characterized in that, The calcium sulphoaluminate expansive agent is prepared by mixing bauxite and gypsum at a mass ratio of 3:1, calcining in a rotary kiln at 1350-1450℃ for 2-3 hours, and then rapidly cooling and grinding to a specific surface area of ≥400 square meters per kilogram, so that the purity of calcium sulphoaluminate in the product is ≥92%.

3. The high-efficiency concrete anti-cracking waterproofing agent according to claim 2, characterized in that, The light-burned magnesium oxide is prepared by crushing magnesite to a particle size of 5-10 mm, calcining in a vertical kiln at 800-900℃ for 1.5-2 hours, and then sieving the ground product to obtain light-burned magnesium oxide powder with an active content of ≥85%.

4. The high-efficiency concrete anti-cracking waterproofing agent according to claim 1, characterized in that, The heavy-burned magnesium oxide is prepared by pressing the light-burned magnesium oxide into pellets, sintering in a tunnel kiln at 1500-1600℃ for 4-6 hours, and then slowly cooling and crushing to a particle size of 50-100 microns, so that the loss on ignition is ≤3%.

5. The high-performance concrete anti-cracking waterproofing agent according to claim 4, characterized in that, The nano-sized silicon dioxide is prepared by gas phase deposition of silane gas and oxygen in a high-temperature reaction furnace at 1200-1500℃, so that silicon dioxide particles with a particle size of 10-30 nanometers are generated. The product is collected by cyclone separation, and has a purity of ≥99%.

6. The high-efficiency concrete anti-cracking waterproofing agent according to claim 4, characterized in that, The styrene-acrylate emulsion is prepared by mixing styrene, butyl acrylate and an emulsifier in water, adding ammonium persulfate as an initiator, and then carrying out emulsion polymerization in a reaction kettle at 70-80℃ for 6-8 hours, so that the solid content is 48-52%.

7. The high-efficiency concrete anti-cracking waterproofing agent according to claim 1, characterized in that, The silane emulsion is prepared by mixing methyltrimethoxysilane and deionized water at a ratio of 1:5, adding acetic acid to adjust the pH to 4-5, and then stirring and reacting at 50-60℃ for 3-4 hours to hydrolyze into a siloxane emulsion.

8. The high-efficiency concrete anti-cracking waterproofing agent according to claim 1, characterized in that, The polycarboxylic acid water reducer compatibility agent is prepared by esterification of polyethylene glycol monomethyl ether and phosphorus pentoxide at 80-90℃ for 5-6 hours to generate a phosphate ester compound, and then adding ethylene oxide for addition polymerization. The final product has a solid content of ≥40% and a pH of 7-8.

9. The high-performance concrete anti-cracking waterproofing agent according to claim 8, characterized in that, The performance testing of step S6 includes verifying the particle distribution by a laser particle size analyzer, testing the limited expansion rate, and finally adding the agent to C30 concrete to form test pieces for testing the impermeable pressure and crack width.

Images