High-strength anticorrosive formwork material and preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to a high-strength corrosion-resistant formwork material and a preparation method thereof, which is composed of the following raw materials: composite cementitious material, aggregate, water-based epoxy resin, modified basalt fiber, permeable crystalline active material, composite retarder, early strength agent, water reducing agent and water; the modified twisted basalt fiber is used to replace traditional steel fiber and polypropylene fiber, so that the defects that the steel fiber is prone to rust in a strong corrosion environment and causes the matrix to expand and crack are fundamentally avoided, meanwhile, the problem that the interface bonding between the polypropylene fiber and the cement matrix is weak and prone to slippage and falling is overcome; the application builds an organic-inorganic interpenetrating network and a multiple physical-chemical corrosion prevention mechanism, solves the problems that the traditional formwork material is slow in strength development, poor in anti-dispersion, easy to be eroded by ions and unable to self-repair microcracks in a strong corrosion environment, and realizes the synergistic improvement of the high-strength, corrosion resistance, anti-dispersion and self-repair functions.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a high-strength anti-corrosion molding material and its preparation method. Background Technology

[0002] Castable mortar is a general term for concrete materials that are poured and formed using formwork in engineering construction. In special projects such as marine engineering (e.g., cross-sea bridges, port terminals), saline-alkali land areas (e.g., western salt lakes, saline-alkali land infrastructure), municipal sewage and waste treatment facilities (e.g., waste storage pits, sewage pipelines), and underwater repair, concrete structures are exposed to high concentrations of chloride ions (Cl-) for extended periods. - ), sulfate ions (SO4) 2- In corrosive media environments, these ions penetrate into the concrete through capillaries and microcracks. On the one hand, they cause steel reinforcement to corrode and expand; on the other hand, they react chemically with cement hydration products (such as generating expansive products like ettringite and gypsum), leading to concrete cracking and spalling, ultimately causing the structure to lose its load-bearing capacity, resulting in huge economic losses and safety hazards.

[0003] In existing technologies, methods to improve the corrosion resistance of concrete can be mainly divided into three categories: First, using special cement or adding a large amount of mineral admixtures (such as silica fume, fly ash, and slag) to improve density and corrosion resistance by improving pore structure. However, its early strength development is slow, especially in low-temperature or underwater environments. Second, surface coating protection, such as coating with epoxy, polyurethane, or other organic coatings or penetrating crystalline waterproofing materials. However, the bonding strength between the coating and the concrete substrate is limited, and it is easily damaged and peeled off under the scouring of flowing water or impact of hard objects. Third, adding rust inhibitors, such as calcium nitrite, to form a passivation film on the surface of steel bars. However, this cannot fundamentally prevent the intrusion of corrosive media, and its long-term effect is limited.

[0004] Sulfoaluminate cement has the advantages of rapid hardening, early strength, micro-expansion, and good impermeability, making it suitable for underwater or rapid construction projects. However, its setting time is too fast (initial setting is usually less than 20 minutes), which cannot meet the construction requirements of long-distance transportation and complex structure casting, and its later strength growth potential is not as good as that of ordinary Portland cement. To solve the setting time problem, retarders are often added, but traditional organic retarders (such as citric acid and tartaric acid) are prone to decomposition or destruction of complex structures under the alkaline environment of cement hydration and the heat generated by mechanical stirring, resulting in uncontrollable retarding effect and deviations from the design expectations in the initial fluidity and workable time of the cast-in-place material.

[0005] Furthermore, microcracks inevitably develop in concrete structures during service, and these microcracks are the main channels for corrosive media to penetrate. Traditional anti-corrosion technologies are mostly "passive barriers" and lack the ability to "actively repair" microcracks.

[0006] Therefore, developing a high-performance castable material that combines controllable setting time, good anti-dispersion properties, excellent anti-corrosion performance, and self-healing crack capability is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-strength anti-corrosion molding material and its preparation method, so as to solve the problems of slow strength development, poor anti-dispersion properties, easy ion erosion, and inability to self-repair microcracks of existing molding materials in strong corrosive environments.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A high-strength anti-corrosion molding material is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 200-300 parts aggregate, 4-8 parts water-based epoxy resin, 3-6 parts modified basalt fiber, 2-5 parts penetrating crystallizing active material, 0.1-0.4 parts composite retarder, 0.05-0.2 parts early strength agent, 0.5-1.5 parts water-reducing agent, and 28-38 parts water; The modified basalt fiber is obtained by acid etching and surface modification of stranded basalt fiber with silane coupling agent, and has a diameter of 10-15μm and a length of 10-15mm.

[0009] As a further technical solution, the composite cementitious material is made by mixing sulfoaluminate cement and ordinary silicate cement at a mass ratio of 1:0.6-1.5.

[0010] As a further technical solution, the permeating crystallizing active material is a cement-based permeating crystallizing waterproof material that generates insoluble crystals upon contact with water to fill pores and microcracks.

[0011] As a further technical solution, the composite retarder is composed of an organic retarder and an inorganic retarder in a mass ratio of 1:0.5-2; the organic retarder is selected from one or more of citric acid, tartaric acid, and sodium gluconate; the inorganic retarder is selected from one or more of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, and borax.

[0012] As a further technical solution, the preparation steps of the modified basalt fiber include: S1. The stranded basalt fiber is placed in a 5-10% hydrochloric acid solution and soaked at 50-70℃ for 30-60 minutes. After filtration, washing with water until neutral and drying, etched fiber is obtained. S2. Etched fibers and a 0.5% (by mass) silane coupling agent solution are mixed at a solid-liquid ratio of 1:10-15, stirred at 50-70°C for 30-60 minutes, filtered and dried to obtain the final product; the silane coupling agent is one or more of KH-550, KH-560, and KH-570.

[0013] As a further technical solution, the waterborne epoxy resin is a two-component waterborne epoxy resin system, including an epoxy resin emulsion and a matching curing agent, with a mass ratio of 1:1-1.5.

[0014] As a further technical solution, the early strength agent is lithium sulfate, and the water-reducing agent is a polycarboxylate-based high-performance water-reducing agent with a water reduction rate of ≥30%.

[0015] As a further technical solution, the aggregate is continuously graded manufactured sand or river sand with a fineness modulus of 2.3-3.0 and a mud content of ≤1.0%.

[0016] The penetrating crystallizing active material conforms to the GB18445-2012 standard "Cement-based penetrating crystallizing waterproof materials".

[0017] As a further technical solution, the mass ratio of sulfoaluminate cement to ordinary silicate cement in the composite cementitious material is 1:0.8-1.2.

[0018] The preparation method of high-strength anti-corrosion molding compound includes the following steps: (1) Dry mixing: According to the proportion, put the composite cementitious material, aggregate, modified basalt fiber and penetrating crystallization active material into the mixer and dry mix at 20-40 rpm for 2-4 minutes to obtain the dry mixture; (2) Wet mixing: Mix water, waterborne epoxy resin, composite retarder, early strength agent and water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 50-80 rpm for 3-5 minutes to obtain the finished product.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention uses modified stranded basalt fiber to replace traditional steel fiber and polypropylene fiber, which fundamentally avoids the defects of steel fiber being prone to corrosion in strong corrosive environments, leading to matrix expansion and cracking. At the same time, it overcomes the problems of weak interfacial bonding and easy slippage and detachment of polypropylene fiber with cement matrix. Stranded basalt fiber has a three-dimensional helical structure, which can form a stable spatial network skeleton in the slurry. After acid etching, micron-level pits are formed on the fiber surface, which greatly increases the specific surface area. Then, through silane coupling agent grafting modification, amino and epoxy active functional groups are introduced into the fiber surface, which can chemically bond with cement hydration products, significantly improving the interfacial bonding strength. At the same time, a hydrophobic interface is formed on the modified fiber surface, which effectively blocks the penetration path of water and corrosive ions along the interface, ultimately improving the flexural strength, crack resistance and underwater anti-dispersion properties of the castable material.

[0020] (2) This invention introduces a penetrating crystallizing active material to construct an active crack repair system. Upon contact with water, the active chemical substances within this material rapidly dissolve and react with calcium hydroxide, a cement hydration product, continuously generating needle-like insoluble calcium carbonate and ettringite crystals. These crystals grow and accumulate along capillaries and microcracks, gradually filling and sealing the pore channels, achieving self-healing of microcracks. This repair process is continuous; even if new microcracks appear later, contact with water can still trigger a repair reaction, upgrading from the "passive barrier" of traditional anti-corrosion materials to an "active repair" mode, effectively preventing corrosive media such as chloride ions and sulfate ions from penetrating the matrix.

[0021] (3) This invention employs an organic-inorganic composite retarding system to precisely control the hydration process of sulfoaluminate cement. The organic retarder (citric acid, tartaric acid, sodium gluconate) slows down the initial hydration rate by complexing calcium ions on the surface of cement particles, providing a basic retarding effect; the inorganic retarder (sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, borax) forms a stable physical adsorption film on the surface of cement particles, isolating water contact and buffering the interference of external factors such as high temperature and mechanical stirring on the retarding effect; the two are synergistically compounded to avoid the disadvantages of single organic retarder being easily decomposed at high temperature and having large effect fluctuations, or single inorganic retarder being too strong and affecting the later strength, so as to achieve controllable setting time, ensure that the castable material has sufficient construction time, and has stable initial fluidity and workability.

[0022] (4) This invention constructs a multi-layered physical-chemical composite anti-corrosion barrier through the synergistic effect of composite cementitious materials, waterborne epoxy resin, modified basalt fiber, and penetrating crystallizing active materials. In the composite cementitious materials, sulfoaluminate cement provides early-stage rapid hardening, early strength, and micro-expansion properties, while ordinary silicate cement ensures continuous strength growth in the later stages. The hydration products of both materials mutually fill each other, forming a dense cement stone matrix. After curing, the waterborne epoxy resin forms a flexible three-dimensional cross-linked membrane, sealing capillaries and cutting off ion diffusion channels. The modified basalt fiber constructs a rigid reinforcing network, inhibiting crack initiation and propagation. The penetrating crystallizing active materials provide self-healing capabilities for cracks. The synergistic superposition of these multiple mechanisms results in a 28-day compressive strength ≥75MPa, an impermeability grade ≥P14, an electrical flux ≤600C, and an underwater anti-dispersion turbidity ≤70NTU, demonstrating excellent overall performance and suitability for highly corrosive and complex working conditions such as marine environments, saline-alkali environments, and wastewater environments.

[0023] Instruction manual illustrations Figure 1 This is a schematic diagram showing the initial setting time statistics of the examples and comparative examples. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The core concept of this invention lies in constructing a three-in-one technical system that combines "rigidity and flexibility in physical enhancement, chemical densification, and multi-target coagulation regulation." Specifically: First, stranded basalt fibers are used and their surface modified by acid etching and silane coupling agents. Basalt fibers are inorganic mineral fibers with advantages such as acid and alkali resistance, high elastic modulus, and good compatibility with cementitious matrices. Their stranded morphology (three-dimensional helical shape) gives them superior mechanical anchoring force to the matrix compared to straight fibers. Acid or alkali etching creates micron-sized pits on the fiber surface, increasing the specific surface area. Then, silane coupling agents are grafted onto the fiber surface, introducing active functional groups such as amino and epoxy groups, which can form chemical bonds with cement hydration products. The modified fibers have a hydrophobic interface, effectively preventing moisture and harmful ions from penetrating along the fiber-matrix interface, while significantly improving the bond strength between the fiber and the cement matrix. This forms a three-dimensional network structure in the slurry, supporting aggregates and inhibiting the propagation of microcracks.

[0026] Second, a penetrating crystalline active material is introduced. This material uses silicate cement, quartz sand, and various active chemicals as its base material. When microcracks form in the concrete and moisture seeps in, the active chemicals react with calcium hydroxide in the cement hydration products to form insoluble needle-like crystals (mainly calcium carbonate and ettringite), which block capillary channels and microcracks. This process can continue, achieving automatic repair of cracks and thus preventing further intrusion of corrosive media. Compared with microcapsule-type self-healing systems, the penetrating crystalline material is lower in cost, has better compatibility with the cement matrix, and is easier to apply.

[0027] Third, an organic-inorganic composite retarding system is adopted. Organic retarder (citric acid, tartaric acid, sodium gluconate) inhibits initial cement hydration by complexing calcium ions, providing the main retarding effect; inorganic retarder (sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, borax) forms a physical barrier layer on the surface of cement particles, stabilizing the interface and buffering the impact of environmental changes on the retarding effect. The combined use of these two retarder systems allows for more precise and stable control of the setting time of sulfoaluminate cement, avoiding state deviations caused by high-temperature stirring.

[0028] Fourth, waterborne epoxy resin and the composite cementitious system synergistically form an "organic-inorganic" interpenetrating network. After curing, the waterborne epoxy resin forms a water-insoluble three-dimensional cross-linked film on the surface and in the pores of cement hydration products, sealing capillaries and cutting off Cl-. -SO4 2- Plasma diffusion channels are formed. Simultaneously, sulfoaluminate cement in the composite cementitious material provides early strength and micro-expansion, while ordinary silicate cement ensures continuous strength growth in later stages. The hydration products of both materials interpenetrate, forming a dense structure. The flexible network of epoxy resin interweaves with the rigid skeleton of cement stone, improving impermeability while compensating for the negative impact of epoxy on rigid strength.

[0029] Based on the above concept, the present invention provides the following technical solution: This invention provides a high-strength anti-corrosion molding material, comprising composite cementitious material, aggregate, waterborne epoxy resin, modified basalt fiber, penetrating crystallizing active material, composite retarder, early strength agent, water-reducing agent and water.

[0030] In this invention, the composite cementitious material is composed of sulfoaluminate cement and ordinary silicate cement.

[0031] In this invention, the aggregate is continuously graded manufactured sand or river sand with a fineness modulus of 2.3-3.0 and a mud content of ≤1.0%.

[0032] In this invention, the waterborne epoxy resin is a two-component waterborne epoxy resin system, comprising an epoxy resin emulsion and a matching curing agent, with a mass ratio of 1:1-1.5.

[0033] In this invention, the modified basalt fiber is obtained by acid etching and surface modification of stranded basalt fiber with silane coupling agent, with a diameter of 10-15μm and a length of 10-15mm.

[0034] In this invention, the penetrating crystallizing active material is a cement-based penetrating crystallizing waterproof material that generates insoluble crystals upon contact with water to fill pores and microcracks.

[0035] In this invention, the composite retarder is composed of citric acid and sodium hexametaphosphate.

[0036] In this invention, the early strength agent is lithium sulfate.

[0037] In this invention, the water-reducing agent is a polycarboxylate-based high-performance water-reducing agent with a water reduction rate of ≥30%.

[0038] This invention also provides a method for preparing the above-mentioned high-strength anti-corrosion molding material, comprising the following steps: (1) Dry mixing: According to the proportion, put the composite cementitious material, aggregate, modified basalt fiber and penetrating crystallization active material into the mixer and dry mix at 20-40 rpm for 2-4 minutes to obtain the dry mixture; (2) Wet mixing: Mix water, waterborne epoxy resin, composite retarder, early strength agent and water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 50-80 rpm for 3-5 minutes to obtain the finished product.

[0039] To further illustrate the present invention, the following embodiments will be described in detail.

[0040] Raw material source: Sulfoaluminate cement (SC): P·W 42.5 grade, Tangshan Arctic Bear Cement; Ordinary Portland cement (C): P·O 42.5 grade, Huaxin Cement; Aggregate: River sand, fineness modulus 2.6, mud content 0.8%; Waterborne epoxy resin: H123A (resin) / H123B (curing agent), two components, mass ratio 1:1.3; Stranded basalt fiber: 12μm in diameter, 12mm in length, with a stranding angle of approximately 30°; Silane coupling agent: KH-550 (γ-aminopropyltriethoxysilane); Permeation crystallization active material: VELOSIT CA112 (Crystal, Germany); Water-reducing agent: Polycarboxylate high-performance water-reducing agent, powder, water reduction rate 35%; Citric acid and tartaric acid: analytical grade; Sodium hexametaphosphate, sodium tripolyphosphate: industrial grade; Lithium sulfate: Industrial grade, Li2SO4 content ≥98.5%.

[0041] Preparation of modified basalt fibers: S1. Immerse the stranded basalt fiber in an 8% hydrochloric acid solution, treat at 60°C for 45 minutes, filter, wash with water until neutral, and dry to obtain etched fiber. S2. The etched fiber is mixed with a 0.5% KH-550 solution at a solid-liquid ratio of 1:12, stirred at 60°C for 45 minutes, filtered and dried to obtain modified basalt fiber.

[0042] Example 1: A high-strength anti-corrosion molding material is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 250 parts aggregate, 6 parts water-based epoxy resin, 4 parts modified basalt fiber, 3 parts penetrating crystallizing active material, 0.08 parts citric acid, 0.08 parts sodium hexametaphosphate, 0.10 parts lithium sulfate, 1.0 part water-reducing agent, and 32 parts water; the composite cementitious material is composed of 50 parts sulfoaluminate cement and 50 parts ordinary silicate cement.

[0043] The preparation method of the high-strength anti-corrosion molding material in this embodiment includes the following steps: (1) Dry mixing: According to the proportion, put 50kg sulfoaluminate cement, 50kg ordinary silicate cement, 250kg aggregate, 4kg modified basalt fiber and 3kg penetrating crystallization active material into the mixer and dry mix at 30rpm for 2min to obtain dry mixture. (2) Wet mixing: Mix 32kg water, 6kg waterborne epoxy resin, 0.08kg citric acid, 0.08kg sodium hexametaphosphate, 0.10kg lithium sulfate and 1.0kg water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 60 rpm for 4 minutes to obtain the finished product.

[0044] Example 2: A high-strength anti-corrosion molding material is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 250 parts aggregate, 5 parts water-based epoxy resin, 5 parts modified basalt fiber, 4 parts penetrating crystallizing active material, 0.06 parts citric acid, 0.10 parts sodium hexametaphosphate, 0.08 parts lithium sulfate, 1.0 part water-reducing agent, and 34 parts water; the composite cementitious material is composed of 60 parts sulfoaluminate cement and 4 parts ordinary silicate cement.

[0045] The preparation method of the high-strength anti-corrosion molding material in this embodiment includes the following steps: (1) Dry mixing: According to the proportion, put 60kg of sulfoaluminate cement, 40kg of ordinary silicate cement, 250kg of aggregate, 5kg of modified basalt fiber and 4kg of penetrating crystallizing active material into the mixer and dry mix at 30rpm for 2min to obtain dry mixture. (2) Wet mixing: Mix 34kg water, 5kg waterborne epoxy resin, 0.06kg citric acid, 0.10kg sodium hexametaphosphate, 0.08kg lithium sulfate and 1.0kg water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 60 rpm for 4 minutes to obtain the finished product.

[0046] Example 3: A high-strength anti-corrosion molding material is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 250 parts aggregate, 7 parts water-based epoxy resin, 3 parts modified basalt fiber, 2 parts penetrating crystallizing active material, 0.10 parts citric acid, 0.06 parts sodium hexametaphosphate, 0.12 parts lithium sulfate, 1.0 part water-reducing agent, and 30 parts water; the composite cementitious material is composed of 40 parts sulfoaluminate cement and 60 parts ordinary silicate cement.

[0047] The preparation method of the high-strength anti-corrosion molding material in this embodiment includes the following steps: (1) Dry mixing: Add 40kg of sulfoaluminate cement, 60kg of ordinary silicate cement, 250kg of aggregate, 3kg of modified basalt fiber and 2kg of penetrating crystallization active material into the mixer according to the proportion, and dry mix at 30rpm for 2min to obtain dry mixture. (2) Wet mixing: Mix 30kg water, 7kg waterborne epoxy resin, 0.10kg citric acid, 0.06kg sodium hexametaphosphate, 0.12kg lithium sulfate and 1.0kg water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 60 rpm for 4 minutes to obtain the finished product.

[0048] Comparative Example 1: A casting material is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 250 parts aggregate, 6 parts water-based epoxy resin, 3 parts ordinary steel fiber, 1 part polypropylene fiber, 0.08 parts citric acid, 0.10 parts lithium sulfate, 1.0 part water-reducing agent, and 32 parts water; the composite cementitious material is composed of 50 parts sulfoaluminate cement and 50 parts ordinary silicate cement.

[0049] The preparation method of this comparative model casting material includes the following steps: (1) Dry mixing: According to the proportion, put 50kg sulfoaluminate cement, 50kg ordinary silicate cement, 250kg aggregate, 3kg ordinary steel fiber and 1kg polypropylene fiber into the mixer and dry mix at 30rpm for 2min to obtain dry mixture. (2) Wet mixing: Mix 32kg water, 6kg waterborne epoxy resin, 0.08kg citric acid, 0.10kg lithium sulfate and 1.0kg water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 60 rpm for 4 minutes to obtain the finished product.

[0050] Comparative Example 2: A casting material is composed of the following raw materials in parts by weight: 100 parts of composite cementitious material, 250 parts of aggregate, 6 parts of water-based epoxy resin, 0.08 parts of sodium hexametaphosphate, 0.10 parts of lithium sulfate, 1.0 part of water-reducing agent, and 32 parts of water; the composite cementitious material is composed of 50 parts of sulfoaluminate cement and 50 parts of ordinary silicate cement.

[0051] The preparation method of this comparative model casting material includes the following steps: (1) Dry mixing: According to the proportion, put 50kg of sulfoaluminate cement, 50kg of ordinary silicate cement and 250kg of aggregate into the mixer and dry mix at 30rpm for 2min to obtain dry mixture. (2) Wet mixing: Mix 32kg water, 6kg waterborne epoxy resin, 0.08kg sodium hexametaphosphate, 0.10kg lithium sulfate and 1.0kg water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 60 rpm for 4 minutes to obtain the finished product.

[0052] Performance testing: Test method: Setting time: tested according to GB / T1346-2011 standard; compressive strength and flexural strength: tested according to GB / T17671-2021 standard; impermeability grade: tested according to the stepwise pressurization method in GB / T50082-2009 standard; electrical flux: tested for 56 days according to ASTM C1202-19 standard; underwater anti-dispersion: tested for turbidity with reference to DL / T5117-2000 standard; sulfate erosion resistance coefficient: tested after 15 cycles of dry and wet cycling with 5% Na2SO4 solution according to GB / T50082-2009 standard.

[0053] Test results: Table 1. Performance test results of the examples and comparative examples. As shown in Table 1, the high-strength anti-corrosion molding materials obtained in Examples 1, 2, and 3 have an initial setting time of 62-78 min and a final setting time of 105-128 min, with controllable setting time; a 28-day compressive strength ≥75.6 MPa and a 28-day flexural strength ≥11.9 MPa, exhibiting excellent mechanical properties; a 28-day impermeability grade ≥P14; a 56-day electrical flux ≤590C; an underwater anti-dispersion turbidity ≤68 NTU; and a 28-day sulfate erosion resistance coefficient ≥0.95, demonstrating outstanding anti-corrosion and anti-dispersion performance.

[0054] Comparative Example 1 did not add modified basalt fiber and penetrating crystallization active material, but used a combination of ordinary steel fiber and polypropylene fiber. Ordinary steel fiber is prone to corrosion in corrosive environments and cannot form a stable three-dimensional reinforcing network. It also lacks the crack self-healing function of penetrating crystallization active material, resulting in a permeability grade of only P12, an electrical flux of 650C at 56 days, and an underwater anti-dispersion turbidity of 85 NTU. Its overall performance is significantly lower than that of the examples.

[0055] Comparative Example 2 did not use an organic-inorganic composite retarder system, but only added the inorganic retarder sodium hexametaphosphate. The single inorganic retarder had an excessively strong inhibitory effect on cement hydration, which significantly reduced the strength development rate of the castable material. As a result, the 28-day compressive strength was only 67.3 MPa, the 28-day flexural strength was only 10.2 MPa, the impermeability grade was only P10, the 56-day electrical flux was as high as 850C, and the sulfate attack resistance coefficient was only 0.91. The performance was far inferior to that of the other examples, which proves that the organic-inorganic composite retarder system plays a key role in improving the overall performance of the castable material.

[0056] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A high-strength, corrosion-resistant molding compound, characterized in that, It is composed of the following raw materials in parts by weight: 100 parts composite cementitious material, 200-300 parts aggregate, 4-8 parts water-based epoxy resin, 3-6 parts modified basalt fiber, 2-5 parts penetrating crystallizing active material, 0.1-0.4 parts composite retarder, 0.05-0.2 parts early strength agent, 0.5-1.5 parts water-reducing agent, and 28-38 parts water; The modified basalt fiber is obtained by acid etching and surface modification of stranded basalt fiber with silane coupling agent, and has a diameter of 10-15μm and a length of 10-15mm.

2. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The composite cementitious material is made by mixing sulfoaluminate cement and ordinary silicate cement at a mass ratio of 1:0.6-1.

5.

3. The high-strength anti-corrosion molding material according to claim 1, characterized in that, The penetrating crystallizing active material is a cement-based penetrating crystallizing waterproof material that generates insoluble crystals upon contact with water to fill pores and microcracks.

4. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The composite retarder is composed of an organic retarder and an inorganic retarder in a mass ratio of 1:0.5-2; the organic retarder is selected from one or more of citric acid, tartaric acid, and sodium gluconate; the inorganic retarder is selected from one or more of sodium hexametaphosphate, sodium tripolyphosphate, sodium pyrophosphate, and borax.

5. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The preparation steps of the modified basalt fiber include: S1. Place the stranded basalt fiber in a 5-10% hydrochloric acid solution, soak at 50-70℃ for 30-60 minutes, filter, wash with water until neutral and dry to obtain etched fiber; S2. Etched fibers and a 0.5% (by mass) silane coupling agent solution are mixed at a solid-liquid ratio of 1:10-15, stirred at 50-70°C for 30-60 minutes, filtered and dried to obtain the final product; the silane coupling agent is one or more of KH-550, KH-560, and KH-570.

6. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The waterborne epoxy resin is a two-component waterborne epoxy resin system, comprising an epoxy resin emulsion and a matching curing agent, with a mass ratio of 1:1-1.

5.

7. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The early strength agent is lithium sulfate, and the water-reducing agent is a polycarboxylate-based high-performance water-reducing agent with a water reduction rate of ≥30%.

8. The high-strength anti-corrosion molding compound according to claim 1, characterized in that, The aggregate is continuously graded manufactured sand or river sand with a fineness modulus of 2.3-3.0 and a mud content of ≤1.0%.

9. The high-strength anti-corrosion molding material according to claim 1, characterized in that, The mass ratio of sulfoaluminate cement to ordinary silicate cement in the composite cementitious material is 1:0.8-1.

2.

10. A method for preparing the high-strength anti-corrosion molding compound according to any one of claims 1-9, characterized in that, Includes the following steps: (1) Dry mixing: According to the proportion, put the composite cementitious material, aggregate, modified basalt fiber and penetrating crystallization active material into the mixer and dry mix at 20-40 rpm for 2-4 minutes to obtain the dry mixture; (2) Wet mixing: Mix water, waterborne epoxy resin, composite retarder, early strength agent and water-reducing agent evenly to obtain a liquid mixture; (3) Mixing: Add the liquid mixture to the dry mixture and stir at 50-80 rpm for 3-5 minutes to obtain the finished product.

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