Chemical corrosion resistant ferroaluminate cement concrete and preparation method thereof

Abstract

The present invention relates to the technical field of building materials, and discloses a chemical corrosion resistant ferroaluminate cement concrete and a preparation method thereof. The molecular structure of sodium alginate is rich in carboxyl groups, which can react with Ca in blast furnace slag. 2+ 、Al 3+ Coordination cross-linking is generated to form a hydrogel with a three-dimensional structure, which forms a dense "double network" structure with the original covalent network, making it difficult for external ions to diffuse and enhancing the corrosion resistance of the concrete; the silicone fluoroepoxy modified acrylic emulsion can form a waterproof layer on the surface of the concrete, preventing the entry of erosion factors in a physical barrier manner, further improving the corrosion resistance of the concrete; the mutual penetration and interpenetration of the organic hydrogel and inorganic filler also increase the cross-linking density of the entire mixed network. Through the "internal mixing" and "external coating" processes, the mechanical strength and anti-permeability of the concrete material are further improved, which is low-cost, environmentally friendly and easy to industrialize.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a chemical corrosion resistant ferroaluminate cement concrete and a preparation method thereof. Background Art

[0002] Concrete is the most widely used and largest-volume civil engineering material today. However, concrete is porous and heterogeneous, and is a typical brittle material with defects such as poor toughness and large drying shrinkage. Compared with its compressive strength, concrete is more easily "broken"; currently, concrete buildings and components often suffer from surface corrosion due to various external forces during use. If this situation is not handled in time, the scope of corrosion will continue to expand; in certain oceans, saline-alkali lands, groundwater or surface deicing salt spraying environments, concrete structures are often corroded and damaged by surrounding harmful ions, and have poor resistance to chemical corrosion; at the same time, due to the existence of pores inside the concrete, it is possible for water to penetrate, which in turn causes damage to the concrete interior, resulting in a reduction in the strength of the concrete structure, thereby affecting the life and use of the concrete. Therefore, the development of a concrete that is resistant to chemical corrosion has become a hot topic of research.

[0003] Ferroaluminate cement is a calcined cement clinker composed primarily of anhydrous calcium sulfoaluminate, dicalcium silicate, and calcium aluminoferrite, made from raw materials such as iron, bauxite, and silicates. This is then ground into a suitable amount of limestone and gypsum. It exhibits excellent durability and is a very environmentally friendly building material. However, ferroaluminate cement concrete exhibits a high risk of thermal cracking due to its rapid hydration and concentrated heat release. Furthermore, while ferroaluminate cement concrete can achieve a certain level of corrosion resistance, specific application environments, such as saline-alkali environments in western China, the ocean, or sewage treatment plant effluent pools, place higher demands on waterproof and anti-corrosion materials. Existing concrete often fails to meet these requirements, requiring it to withstand the erosion of high-salt and high-alkaline environments for extended periods while maintaining stable performance.

[0004] The currently commonly used ferroaluminate cement has average bonding strength with old concrete components, and the interface is prone to cracking and leakage. External moisture and harmful corrosive media will enter the interior of the concrete through the cracks, inducing various corrosion damages, which seriously limits its scope of use. The present invention prepares blast furnace slag cementitious material and organic silicon fluorine epoxy modified acrylic emulsion, adopts a combination of "internal mixing" and "external coating" to prepare ferroaluminate cement concrete with excellent chemical corrosion resistance, thereby significantly improving the mechanical properties and durability of the concrete. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a chemical corrosion resistant ferroaluminate cement concrete and a preparation method thereof, which significantly improves the corrosion resistance and waterproof and crack resistance of the ferroaluminate cement concrete.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A chemical corrosion-resistant ferroaluminate cement concrete comprises the following components in parts by weight: 320-360 parts of ferroaluminate cement, 150-170 parts of tap water, 1050-1150 parts of coarse aggregate, 700-750 parts of fine aggregate, 70-90 parts of fly ash, 3-8 parts of polycarboxylate high-efficiency water reducer, 2-4 parts of early strength agent, 1-5 parts of blast furnace slag cementitious material, 3-15 parts of organosilicon fluoride epoxy modified acrylic emulsion and 10-15 parts of expansion agent.

[0008] The preparation method of blast furnace slag cementitious material is as follows: 8-12 mol / L sodium hydroxide solution is added to commercially available liquid water glass with a modulus of 3.3, the mixture is stirred evenly, and an alkali activator with a modulus of 1.6 is prepared and allowed to stand for use; sodium alginate and particle-sized blast furnace slag in a mass ratio of 1:(360-450) are weighed, added to the alkali activator, and stirred at room temperature for 5-10 minutes to obtain the blast furnace slag cementitious material.

[0009] Preferably, the particle size of the granular blast furnace slag is 0.03-0.05 mm, and its chemical composition includes: 35.4% CaO, 33.2% SiO2, 12.5% ​​Al2O3, 9.0% MgO, 2.4% TiO2, 1.5% Fe2O3 and other substances.

[0010] Preferably, the early strength agent is any one of triethanolamine, water glass or sodium aluminate; and the expansion agent is calcium sulfoaluminate expansion agent.

[0011] Preferably, the coarse aggregate is crushed stone with a particle size of 5-25 mm, and the fine aggregate is quartz sand with a particle size of 0.6-0.9 mm.

[0012] Preferably, the preparation method of the organosilicon-fluorinated epoxy-modified acrylic emulsion is:

[0013] Step (1): Under a nitrogen atmosphere, bis(dimethyl(vinyl)silyl)amine and ethanol are added to a reaction flask, stirred evenly, and then perfluorooctyl bromide and sodium hydride are added. The mixture is stirred for reaction. After the reaction is completed, vacuum distillation is performed and column chromatography is performed to purify the monomer. The preparation reaction formula is as follows:

[0014]

[0015] Step (2), under a nitrogen atmosphere, add isopropyl alcohol, 1 / 3 of the total mass of methacrylic acid, butyl acrylate, epoxy resin E-44 and alkenyl organosilicon fluorine monomer to a reaction flask, and after complete dissolution, add 1 / 3 of the mass of azobisisobutyronitrile, heat to 75-90°C and react for 20-40 minutes, add the remaining 2 / 3 of the mass of methacrylic acid, butyl acrylate, epoxy resin E-44 and alkenyl organosilicon fluorine monomer and azobisisobutyronitrile dropwise, continue to react for 2-4 hours, cool to 45-55°C, add triethylamine for neutralization, add deionized water for dispersion under high-speed stirring, and obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0016] Preferably, in step (1), the mass ratio of bis(dimethyl(vinyl)silyl)amine, ethanol, perfluorooctyl bromide, and sodium hydride is 1:(15-30):(2.2-3):(0.15-0.25).

[0017] Preferably, the reaction temperature in step (1) is 60-80° C., and the reaction time is 24-48 h.

[0018] Preferably, in step (2), the mass ratio of isopropyl alcohol, methacrylic acid, butyl acrylate, epoxy resin E-44, alkenyl organosilicone fluorine monomer, and azobisisobutyronitrile is 100:(9-15):(25-40):(5-10):(3-15):(0.6-1.2).

[0019] Preferably, the preparation method is: pouring ferroaluminate cement, coarse aggregate, fine aggregate, fly ash, and blast furnace slag cementitious material into a concrete mixer and dry mixing for 50-80 seconds. After mixing evenly, adding tap water and early strength agent, mixing and stirring for 1-2 minutes, then adding polycarboxylate water reducer, organosilicon fluorine epoxy modified acrylic emulsion and expansion agent, stirring for 2-3 minutes, mixing evenly, pouring into a standard mold, vibrating and compacting, and naturally curing after forming to obtain chemical corrosion resistant ferroaluminate cement concrete.

[0020] Preferably, the temperature of natural curing is 20-30°C and the humidity is 90-95%.

[0021] By adopting the above technical solution, the beneficial effects of the present invention are:

[0022] The present invention first reacts bis(dimethyl(vinyl)silyl)amine and perfluorooctyl bromide under the action of sodium hydride to obtain an alkenyl organosilicon fluorine monomer, which is then polymerized with methacrylic acid, epoxy resin, etc. to obtain an organosilicon fluorine epoxy modified acrylic emulsion. Then, sodium alginate is used to crosslink and modify alkalized blast furnace slag to obtain a blast furnace slag cementitious material. Finally, ferroaluminate cement, blast furnace slag cementitious material, organosilicon fluorine epoxy modified acrylic emulsion, etc. are uniformly mixed to obtain chemical corrosion resistant ferroaluminate cement concrete.

[0023] Under the action of alkaline activators, the internal Si-O and Al-O covalent bonds of blast furnace slag in blast furnace slag cementitious materials are broken, releasing silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons, which are further condensed and reconstructed in alkaline solution to form a three-dimensional covalent network structure connected by Si-O-Al or Si-O-Si covalent bonds; at the same time, the molecular structure of sodium alginate is rich in carboxyl groups, which can react with Ca in blast furnace slag. 2+ 、Al 3+ Coordination cross-linking is generated to form a hydrogel with a three-dimensional structure. Therefore, the original covalent network and the newly formed coordination cross-linking network play a synergistic role, making the cross-linking network more uniform and enhancing the stability of the gelling molecular structure, thereby forming a dense "double network" structure, making it difficult for external ions to diffuse, and enhancing the corrosion resistance of the concrete; on the other hand, the silicone fluoroepoxy modified acrylic emulsion contains fluorine-containing groups with good hydrophobic properties and silicone with chemical solvent resistance, which can form a waterproof layer on the concrete surface, preventing the entry of erosion factors in a physical barrier manner, and further improving the corrosion resistance of the concrete.

[0024] Silicone fluoroepoxy modified acrylic emulsion can form a hydrophobic protective layer on the surface of concrete to prevent the expansion of surface cracks; blast furnace slag cementitious material can increase the anti-seepage performance, thereby preventing the entry of external liquids and the formation of microcracks in the material, making the internal structure of the concrete stable. The mutual penetration and interpenetration of the organic hydrogel and inorganic filler network also increase the cross-linking density of the entire mixed network. Through the combination of "internal mixing" and "external coating" processes, the material strength, deformation resistance and anti-seepage performance are improved. It can be used in the reinforcement of concrete structures with high requirements on strength and anti-seepage and the repair of water leakage. The raw materials utilize waste fly ash, blast furnace slag, etc., which are low-cost, environmentally friendly and easy to industrialize. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Unless otherwise specified, “parts” in the present invention refer to “parts by weight”.

[0027] The particle size of the granular blast furnace slag is 0.03-0.05 mm, and its chemical composition includes: 35.4% CaO, 33.2% SiO2, 12.5% ​​Al2O3, 9.0% MgO, 2.4% TiO2, 1.5% Fe2O3 and other substances.

[0028] Bis(dimethyl(vinyl)silyl)amine, CAS number 7691-02-3.

[0029] Perfluorooctyl bromide, CAS number is 423-55-2.

[0030] Example 1

[0031] (1) Under nitrogen atmosphere, 30 parts of bis(dimethyl(vinyl)silyl)amine and 750 parts of ethanol were added to a reaction flask, and after stirring evenly, 72 parts of perfluorooctyl bromide and 11.4 parts of sodium hydride were added. The reaction was carried out at 70°C for 32 hours, and the mixture was distilled under reduced pressure and purified by column chromatography using a mobile phase of ethyl acetate and petroleum ether in a ratio of 1:3 to obtain an alkenyl organosilicone fluorine monomer.

[0032] (2) Under nitrogen atmosphere, 100 parts of isopropanol, 4 parts of methacrylic acid, 9 parts of butyl acrylate, 2 parts of epoxy resin E-44 and 1 part of alkenyl organosilicon fluorine monomer were added to the reaction flask. After they were completely dissolved, 0.3 parts of azobisisobutyronitrile were added. The temperature was raised to 85°C and the reaction was carried out for 30 minutes. 8 parts of methacrylic acid, 18 parts of butyl acrylate, 4 parts of epoxy resin E-44 and 2 parts of alkenyl organosilicon fluorine monomer and 0.6 parts of azobisisobutyronitrile were added dropwise. The reaction was continued for 3 hours. The temperature was lowered to 50°C, triethylamine was added for neutralization, and deionized water was added for dispersion under high-speed stirring to obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0033] (3) Add 10 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mix and stir evenly, and prepare an alkaline activator with a modulus of 1.6, which is then allowed to stand for use; weigh 15 parts of sodium alginate and 5700 parts of particle-sized blast furnace slag, add them to the alkaline activator, and stir at room temperature for 8 minutes to obtain a blast furnace slag cementitious material.

[0034] (4) 350 parts of ferroaluminate cement, 1100 parts of crushed stone with a particle size of 20 mm, 720 parts of quartz sand with a particle size of 0.8 mm, 70 parts of fly ash, and 1 part of blast furnace slag cementitious material were poured into a concrete mixer and dry mixed for 75 seconds. After mixing evenly, 170 parts of tap water and 3 parts of triethanolamine were added and mixed for 1 minute. Then, 3 parts of polycarboxylic acid water reducer, 3 parts of organosilicon fluoroepoxy modified acrylic emulsion and 15 parts of calcium sulfoaluminate expansion agent were added and stirred for 3 minutes. After mixing evenly, the mixture was poured into a standard mold, vibrated and compacted, and naturally cured after molding. The temperature of natural curing was 25°C and the humidity was 90%, thereby obtaining chemical corrosion resistant ferroaluminate cement concrete.

[0035] Example 2

[0036] (1) Under nitrogen atmosphere, 60 parts of bis(dimethyl(vinyl)silyl)amine and 900 parts of ethanol were added to a reaction flask, stirred evenly, and then 132 parts of perfluorooctyl bromide and 9 parts of sodium hydride were added. The reaction was carried out at 80°C for 24 hours, and the mixture was distilled under reduced pressure and purified by column chromatography using a mobile phase of ethyl acetate and petroleum ether in a ratio of 1:3 to obtain an alkenyl organosilicone fluorine monomer.

[0037] (2) Under nitrogen atmosphere, 100 parts of isopropanol, 3 parts of methacrylic acid, 9 parts of butyl acrylate, 2.5 parts of epoxy resin E-44 and 2 parts of alkenyl organosilicon fluorine monomer were added to the reaction flask. After they were completely dissolved, 0.2 parts of azobisisobutyronitrile were added. The temperature was raised to 90°C and the reaction was carried out for 35 minutes. 6 parts of methacrylic acid, 18 parts of butyl acrylate, 5 parts of epoxy resin E-44 and 4 parts of alkenyl organosilicon fluorine monomer and 0.4 parts of azobisisobutyronitrile were added dropwise. The reaction was continued for 2 hours. The temperature was lowered to 55°C, triethylamine was added for neutralization, and deionized water was added for dispersion under high-speed stirring to obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0038] (3) Add 8 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mix and stir evenly, and prepare an alkaline activator with a modulus of 1.6, which is then allowed to stand for use; weigh 10 parts of sodium alginate and 3600 parts of particle-sized blast furnace slag, add them to the alkaline activator, and stir at room temperature for 5 minutes to obtain a blast furnace slag cementitious material.

[0039] (4) 320 parts of ferroaluminate cement, 1050 parts of crushed stone with a particle size of 10 mm, 700 parts of quartz sand with a particle size of 0.6 mm, 80 parts of fly ash, and 3 parts of blast furnace slag cementitious material were poured into a concrete mixer and dry mixed for 50 seconds. After mixing evenly, 165 parts of tap water and 2 parts of water glass were added and mixed for 1.5 minutes. Then, 4.5 parts of polycarboxylic acid water reducer, 6 parts of organosilicon fluoroepoxy modified acrylic emulsion and 10 parts of calcium sulfoaluminate expansion agent were added and stirred for 2.5 minutes. After mixing evenly, the mixture was poured into a standard mold, vibrated and compacted, and naturally cured after molding. The natural curing temperature was 30°C and the humidity was 95%, thereby obtaining chemical corrosion resistant ferroaluminate cement concrete.

[0040] Example 3

[0041] (1) Under nitrogen atmosphere, 20 parts of bis(dimethyl(vinyl)silyl)amine and 600 parts of ethanol were added to a reaction flask, stirred evenly, and then 60 parts of perfluorooctyl bromide and 5 parts of sodium hydride were added. The reaction was carried out at 60°C for 48 hours, and the mixture was distilled under reduced pressure and purified by column chromatography with a mobile phase of ethyl acetate and petroleum ether in a ratio of 1:3 to obtain an alkenyl organosilicone fluorine monomer.

[0042] (2) Under nitrogen atmosphere, 100 parts of isopropanol, 5 parts of methacrylic acid, 13 parts of butyl acrylate, 3 parts of epoxy resin E-44 and 3 parts of alkenyl organosilicon fluorine monomer were added to the reaction flask. After they were completely dissolved, 0.4 parts of azobisisobutyronitrile were added. The temperature was raised to 75°C and the reaction was carried out for 40 minutes. 10 parts of methacrylic acid, 26 parts of butyl acrylate, 6 parts of epoxy resin E-44 and 6 parts of alkenyl organosilicon fluorine monomer and 0.8 parts of azobisisobutyronitrile were added dropwise. The reaction was continued for 4 hours. The temperature was lowered to 45°C, triethylamine was added for neutralization, and deionized water was added for dispersion under high-speed stirring to obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0043] (3) Add 12 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mix and stir evenly, and prepare an alkaline activator with a modulus of 1.6, which is then allowed to stand for use; weigh 8 parts of sodium alginate and 3150 parts of particle-sized blast furnace slag, add them to the alkaline activator, and stir at room temperature for 10 minutes to obtain a blast furnace slag cementitious material.

[0044] (4) 360 parts of ferroaluminate cement, 1150 parts of crushed stone with a particle size of 5 mm, 750 parts of quartz sand with a particle size of 0.9 mm, 85 parts of fly ash, and 3 parts of blast furnace slag cementitious material were poured into a concrete mixer and dry mixed for 80 seconds. After mixing evenly, 160 parts of tap water and 4 parts of sodium aluminate were added and mixed for 2 minutes. Then, 5.5 parts of polycarboxylic acid water reducer, 9 parts of organosilicon fluoroepoxy modified acrylic emulsion and 12 parts of calcium sulfoaluminate expansion agent were added and stirred for 2 minutes. After mixing evenly, the mixture was poured into a standard mold, vibrated and compacted, and naturally cured after molding. The temperature of natural curing was 20°C and the humidity was 90%, thereby obtaining chemical corrosion resistant ferroaluminate cement concrete.

[0045] Example 4

[0046] (1) Under nitrogen atmosphere, 15 parts of bis(dimethyl(vinyl)silyl)amine and 390 parts of ethanol were added to a reaction flask, stirred evenly, and then 42 parts of perfluorooctyl bromide and 3.3 parts of sodium hydride were added. The reaction was carried out at 75°C for 35 hours, and the mixture was distilled under reduced pressure and purified by column chromatography using a mobile phase of ethyl acetate and petroleum ether in a ratio of 1:3 to obtain an alkenyl organosilicone fluorine monomer.

[0047] (2) Under nitrogen atmosphere, 100 parts of isopropanol, 3.5 parts of methacrylic acid, 10 parts of butyl acrylate, 2 parts of epoxy resin E-44 and 4 parts of alkenyl organosilicon fluorine monomer were added to the reaction flask. After they were completely dissolved, 0.3 parts of azobisisobutyronitrile were added. The temperature was raised to 90°C and the reaction was carried out for 35 minutes. 7 parts of methacrylic acid, 20 parts of butyl acrylate, 4 parts of epoxy resin E-44 and 8 parts of alkenyl organosilicon fluorine monomer and 0.6 parts of azobisisobutyronitrile were added dropwise. The reaction was continued for 3 hours. The temperature was lowered to 50°C, triethylamine was added for neutralization, and deionized water was added for dispersion under high-speed stirring to obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0048] (3) Add 11 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mix and stir evenly, and prepare an alkaline activator with a modulus of 1.6, which is then allowed to stand for use; weigh 5 parts of sodium alginate and 2100 parts of particle-sized blast furnace slag, add them to the alkaline activator, and stir at room temperature for 90 minutes to obtain a blast furnace slag cementitious material.

[0049] (4) 340 parts of ferroaluminate cement, 1120 parts of crushed stone with a particle size of 25 mm, 730 parts of quartz sand with a particle size of 0.8 mm, 70 parts of fly ash, and 5 parts of blast furnace slag cementitious material were poured into a concrete mixer and dry mixed for 80 seconds. After mixing evenly, 155 parts of tap water and 3.5 parts of triethanolamine were added and mixed and stirred for 1.5 minutes. Then, 7 parts of polycarboxylic acid water reducer, 15 parts of organosilicon fluoroepoxy modified acrylic emulsion and 14 parts of calcium sulfoaluminate expansion agent were added and stirred for 2 minutes. After mixing evenly, the mixture was poured into a standard mold, vibrated and compacted, and naturally cured after molding. The temperature of natural curing was 25°C and the humidity was 95%, thereby obtaining chemical corrosion resistant ferroaluminate cement concrete.

[0050] Example 5

[0051] (1) Under nitrogen atmosphere, 10 parts of bis(dimethyl(vinyl)silyl)amine and 250 parts of ethanol were added to a reaction flask, stirred evenly, and then 26 parts of perfluorooctyl bromide and 2.2 parts of sodium hydride were added. The reaction was carried out at 75°C for 24 hours, and the mixture was distilled under reduced pressure and purified by column chromatography using a mobile phase of ethyl acetate and petroleum ether in a ratio of 1:3 to obtain an alkenyl organosilicone fluorine monomer.

[0052] (2) Under nitrogen atmosphere, 100 parts of isopropanol, 5 parts of methacrylic acid, 13 parts of butyl acrylate, 3 parts of epoxy resin E-44 and 5 parts of alkenyl organosilicon fluorine monomer were added to the reaction flask. After they were completely dissolved, 0.4 parts of azobisisobutyronitrile were added. The temperature was raised to 85°C and the reaction was carried out for 35 minutes. 10 parts of methacrylic acid, 27 parts of butyl acrylate, 6 parts of epoxy resin E-44 and 10 parts of alkenyl organosilicon fluorine monomer and 0.8 parts of azobisisobutyronitrile were added dropwise. The reaction was continued for 4 hours. The temperature was lowered to 50°C, triethylamine was added for neutralization, and deionized water was added for dispersion under high-speed stirring to obtain an organosilicon fluorine epoxy modified acrylic emulsion.

[0053] (3) Add 12 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mix and stir evenly, and prepare an alkaline activator with a modulus of 1.6, which is then allowed to stand for use; weigh 2 parts of sodium alginate and 790 parts of particle-sized blast furnace slag, add them to the alkaline activator, and stir at room temperature for 6 minutes to obtain a blast furnace slag cementitious material.

[0054] (4) 350 parts of ferroaluminate cement, 1150 parts of crushed stone with a particle size of 20 mm, 750 parts of quartz sand with a particle size of 0.8 mm, 90 parts of fly ash, and 5 parts of blast furnace slag cementitious material were poured into a concrete mixer and dry mixed for 75 seconds. After mixing evenly, 150 parts of tap water and 4 parts of water glass were added and mixed for 10 minutes. Then, 8 parts of polycarboxylic acid water reducer, 15 parts of organosilicon fluoroepoxy modified acrylic emulsion and 1.5 parts of calcium sulfoaluminate expansion agent were added and stirred for 15 minutes. After mixing evenly, the mixture was poured into a standard mold, vibrated and compacted, and naturally cured after molding. The temperature of natural curing was 25°C and the humidity was 95%, thereby obtaining chemical corrosion resistant ferroaluminate cement concrete.

[0055] Comparative Example 1

[0056] 350 parts of ferroaluminate cement, 1100 parts of crushed stone with a particle size of 20 mm, 720 parts of quartz sand with a particle size of 0.8 mm, 70 parts of fly ash, and 1 part of blast furnace slag are poured into a concrete mixer and dry mixed for 75 seconds. After mixing evenly, 170 parts of tap water and 3 parts of triethanolamine are added and mixed and stirred for 1 minute. Subsequently, 3 parts of polycarboxylate water reducer, 3 parts of organosilicon fluoroepoxy modified acrylic emulsion and 15 parts of calcium sulfoaluminate expansion agent are added and stirred for 3 minutes. After mixing evenly, the mixture is poured into a standard mold, vibrated to compact, and naturally cured after molding. The natural curing temperature is 25°C and the humidity is 90% to obtain ferroaluminate cement concrete.

[0057] Comparative Example 2

[0058] 350 parts of ferroaluminate cement, 1100 parts of crushed stone with a particle size of 20 mm, 720 parts of quartz sand with a particle size of 0.8 mm, 70 parts of fly ash, and 1 part of blast furnace slag are poured into a concrete mixer and dry mixed for 75 seconds. After mixing evenly, 170 parts of tap water and 3 parts of triethanolamine are added and mixed and stirred for 1 minute. Then, 3 parts of polycarboxylate water reducer and 15 parts of calcium sulfoaluminate expansion agent are added and stirred for 3 minutes. After mixing evenly, the mixture is poured into a standard mold, vibrated and compacted, and naturally cured after molding. The natural curing temperature is 25°C and the humidity is 90% to obtain ferroaluminate cement concrete.

[0059] Comparative Example 3

[0060] 350 parts of ferroaluminate cement, 1100 parts of crushed stone with a particle size of 20 mm, 720 parts of quartz sand with a particle size of 0.8 mm, and 70 parts of fly ash are poured into a concrete mixer and dry mixed for 75 seconds. After mixing evenly, 170 parts of tap water and 3 parts of triethanolamine are added and mixed and stirred for 1 minute. Then, 3 parts of polycarboxylate water reducer and 15 parts of calcium sulfoaluminate expansion agent are added and stirred for 3 minutes. After mixing evenly, the mixture is poured into a standard mold, vibrated and compacted, and naturally cured after molding. The natural curing temperature is 25°C and the humidity is 90% to obtain ferroaluminate cement concrete.

[0061] Concrete expansion rate test: Concrete with a curing age of 28 days was prepared into a sample with a size of 100 mm × 100 mm × 515 mm. The sample was placed in a magnesium sulfate solution with a sulfate concentration of 6.22 parts / L to test the expansion rate of the concrete in the sulfate solution.

[0062] Determination of chloride ion diffusion coefficient: The concrete with curing age of 28 days was prepared into The sample was placed in a 4 mol / L sodium chloride solution, and then the sample was vacuum treated for water retention. The chloride ion diffusion coefficient of concrete was tested using the chloride ion diffusion coefficient determination method.

[0063] Table 1 Corrosion resistance test

[0064]

[0065]

[0066] The expansion rate of concrete against sulfate erosion is directly related to the durability and stability of concrete. When concrete is exposed to an environment containing sulfate, sulfate ions will penetrate into the concrete and react chemically with certain components in the concrete, causing the concrete performance to gradually deteriorate. Therefore, the smaller the expansion rate, the better. In concrete, the smaller the chloride ion diffusion coefficient, the slower the diffusion rate of chloride ions in the concrete, which means that the concrete has a stronger ability to resist chloride ion erosion, thereby better protecting internal structures such as steel bars from corrosion and extending the service life of the concrete structure.

[0067] The test results in the table above show that as the content of blast furnace slag cementitious material and organosilicon fluoroepoxy modified acrylic emulsion in concrete increases, the corrosion resistance of ferroaluminate cement concrete gradually increases. The expansion rate of Example 5 in sulfate solution is only 0.015%, and the chloride ion diffusion coefficient is 1.32×10 -12 m 2 / s, has good chemical corrosion resistance; this is because, on the one hand, the blast furnace slag in the blast furnace slag cementitious material breaks the internal Si-O and Al-O covalent bonds under the action of the alkaline activator, releasing silicon oxygen tetrahedron and aluminum oxygen tetrahedron, which are further condensed and reconstructed in the alkaline solution to form a three-dimensional covalent network structure connected by Si-O-Al or Si-O-Si covalent bonds; at the same time, the molecular structure of sodium alginate is rich in carboxyl groups, which can react with the Ca in the blast furnace slag to form a three-dimensional covalent network structure; 2+ 、Al 3+Coordination cross-linking is generated to form a hydrogel with a three-dimensional structure. Therefore, the original covalent network and the newly formed coordination cross-linking network play a synergistic role, making the cross-linking network more uniform and enhancing the stability of the gelling molecular structure, thereby forming a dense "double network" structure, making it difficult for external ions to diffuse, and enhancing the corrosion resistance of the concrete; on the other hand, the silicone fluoroepoxy modified acrylic emulsion contains fluorine-containing groups with good hydrophobic properties and silicone with chemical solvent resistance, which can form a waterproof layer on the concrete surface, preventing the entry of erosion factors in a physical barrier manner, and further improving the corrosion resistance of the concrete.

[0068] The blast furnace slag in Comparative Example 1 was not modified with sodium alginate and could only be used as a mineral admixture to fill the voids in the concrete without forming a cross-linked network structure; in Comparative Example 2, no silicone fluoroepoxy modified acrylic emulsion was added and the concrete surface could not be effectively filled; in Comparative Example 3, no blast furnace slag cementitious material and silicone fluoroepoxy modified acrylic emulsion were contained and the chemical corrosion resistance was the worst.

[0069] Compressive strength: The test was conducted with reference to GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete", with a curing age of 28 days, a sample size of 150mm×150mm×150mm, and a given loading rate of 0.8MPa / s for the concrete compression testing machine.

[0070] Water penetration resistance test: Referring to GB / T 50082-2009 "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete", the water penetration height method was used to test the water penetration resistance of concrete. Concrete with a curing age of 28 days was made into a truncated cone with an upper inner diameter of 175mm, a lower inner diameter of 185mm, and a height of 250mm. The cone was placed in a concrete permeameter for water penetration resistance test.

[0071] Table 2 Concrete performance test

[0072] Compressive strength (MPa) Water seepage height (cm) Example 1 65.3 12.5 Example 2 73.5 10.8 Example 3 80.2 8.3 Example 4 82.3 7.5 Example 5 84.1 7.4 Comparative Example 1 53.8 13.9 Comparative Example 2 45.0 16.1 Comparative Example 3 32.4 18.0

[0073] Silicone fluoroepoxy modified acrylic emulsion can form a hydrophobic protective layer on the surface of concrete to prevent the expansion of surface cracks; blast furnace slag cementitious materials can increase the anti-seepage performance, thereby preventing the entry of external liquids and the formation of microcracks in the material, making the internal structure of the concrete stable. The mutual penetration and interpenetration of the organic hydrogel and inorganic filler network also increase the cross-linking density of the entire mixed network. Through the "internal mixing" and "external coating" processes, the material strength, deformation resistance and anti-seepage performance are improved. It can be used in marine, saline-alkali and military emergency repair and construction fields in extreme environments with high requirements for strength and corrosion resistance. The raw materials used are waste fly ash, blast furnace slag, etc., which are low-cost, environmentally friendly and easy to industrialize.

[0074] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. The methods used in the present application, unless otherwise specified, are conventional methods.

Claims

1. A chemical corrosion resistant ferroaluminate cement concrete, characterized in that: The ferroaluminate cement concrete comprises the following components in parts by weight: 320-360 parts of ferroaluminate cement, 150-170 parts of tap water, 1050-1150 parts of coarse aggregate, 700-750 parts of fine aggregate, 70-90 parts of fly ash, 3-8 parts of polycarboxylate high-efficiency water reducer, 2-4 parts of early strength agent, 1-5 parts of blast furnace slag cementitious material, 3-15 parts of organosilicon fluoride epoxy modified acrylic emulsion and 10-15 parts of expansion agent; The preparation method of the blast furnace slag cementitious material comprises: adding 8-12 mol / L sodium hydroxide solution to commercially available liquid water glass with a modulus of 3.3, mixing and stirring uniformly, preparing an alkaline activator with a modulus of 1.6, and setting it aside for use; weighing sodium alginate and granulated blast furnace slag in a mass ratio of 1:(360-450), adding the mixture to the alkaline activator, and stirring at room temperature for 5-10 minutes to obtain the blast furnace slag cementitious material; The preparation method of the organosilicon-fluorine epoxy modified acrylic emulsion is: Step (1), under a nitrogen atmosphere, add bis(dimethyl(vinyl)silyl)amine and ethanol to a reaction flask, stir evenly, add perfluorooctyl bromide and sodium hydride, stir to react, and after the reaction is completed, distill under reduced pressure and purify by column chromatography to obtain an alkenyl organosilicone fluorine monomer; Step (2), under a nitrogen atmosphere, add isopropyl alcohol, 1 / 3 of the total mass of methacrylic acid, butyl acrylate, epoxy resin E-44 and alkenyl organosilicon fluorine monomer to a reaction flask, after complete dissolution, add 1 / 3 of the mass of azobisisobutyronitrile, heat to 75-90°C and react for 20-40 minutes, add the remaining 2 / 3 of the mass of methacrylic acid, butyl acrylate, epoxy resin E-44 and alkenyl organosilicon fluorine monomer and azobisisobutyronitrile dropwise, continue to react for 2-4 hours, cool to 45-55°C, add triethylamine for neutralization, add deionized water for dispersion under high-speed stirring, and obtain an organosilicon fluorine epoxy modified acrylic emulsion; In step (1), the mass ratio of bis(dimethyl(vinyl)silyl)amine, ethanol, perfluorooctyl bromide, and sodium hydride is 1:(15-30):(2.2-3):(0.15-0.25); In step (2), the mass ratio of isopropyl alcohol, methacrylic acid, butyl acrylate, epoxy resin E-44, alkenyl organosilicone fluorine monomer, and azobisisobutyronitrile is 100:(9-15):(25-40):(5-10):(3-15):(0.6-1.2).

2. The chemical corrosion resistant ferroaluminate cement concrete according to claim 1, characterized in that: The particle size of the granulated blast furnace slag is 0.03-0.05 mm, and its chemical composition and weight percentage are: 35.4% CaO, 33.2% SiO2, 12.5% ​​Al2O3, 9.0% MgO, 2.4% TiO2, 1.5% Fe2O3 and other substances.

3. The chemical corrosion resistant ferroaluminate cement concrete according to claim 1, characterized in that: The early strength agent is any one of triethanolamine, water glass or sodium aluminate; and the expansion agent is calcium sulfoaluminate expansion agent.

4. The chemical corrosion resistant ferroaluminate cement concrete according to claim 1, characterized in that: The coarse aggregate is crushed stone with a particle size of 5-25 mm, and the fine aggregate is quartz sand with a particle size of 0.6-0.9 mm.

5. The chemical corrosion resistant ferroaluminate cement concrete according to claim 1, characterized in that: In the step (1), the reaction temperature is 60-80° C. and the reaction time is 24-48 h.

6. A method for preparing chemical corrosion resistant ferroaluminate cement concrete according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: pouring ferroaluminate cement, coarse aggregate, fine aggregate, fly ash and blast furnace slag cementitious material into a concrete mixer and dry-mixing for 50-80 seconds; after mixing evenly, adding tap water and an early strength agent, mixing and stirring for 1-2 minutes; then adding a polycarboxylate water reducer, an organosilicon fluorine epoxy modified acrylic emulsion and an expansion agent, stirring for 2-3 minutes; mixing evenly, pouring into a standard mold, vibrating and compacting, and naturally curing after forming to obtain chemical corrosion resistant ferroaluminate cement concrete.

7. The method for preparing chemical corrosion resistant ferroaluminate cement concrete according to claim 6, characterized in that: The temperature of the natural curing is 20-30° C., and the humidity is 90-95%.

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