Low-carbon environment-friendly seawater corrosion-resistant mortar and preparation method thereof

Abstract

The invention relates to the technical field of building engineering materials, in particular to low-carbon environment-friendly seawater corrosion resistant mortar and a preparation method thereof. The low-carbon environment-friendly seawater corrosion resistant mortar is prepared from the following preparation raw materials in parts by mass: 320 to 360 parts of aluminoferrite cement, 100 to 120 parts of a modified coal gangue cementing material, 250 to 280 parts of coarse aggregate, 250 to 280 parts of fine aggregate, 8 to 12 parts of organic silicon graphene modified acrylic emulsion, 5 to 8 parts of an efficient water reducing agent, 1 to 2 parts of a retarder and 100 to 130 parts of water. The low-carbon environment-friendly seawater corrosion-resistant mortar disclosed by the invention has remarkable advantages in the aspects of improving the corrosion resistance, compressive strength, impermeability and waterproof and anti-cracking properties of concrete, has environment-friendly and economic benefits, and is a material with a wide application prospect.

Description

Technical Field

[0001] The present application relates to the technical field of building engineering materials, and in particular to a low-carbon, environmentally friendly, seawater corrosion-resistant mortar and a preparation method thereof. Background Art

[0002] As the main material for the construction of marine facilities, marine concrete is subject to corrosion from the marine environment in two main ways: on the one hand, physical damage, as mud, ice, etc. in the seawater are washed away by waves on the concrete structure; on the other hand, concrete structures in the tidal splash zone are subjected to the alternating dry and wet effects of the tides for a long time, resulting in salt crystallization and precipitation, which damages the concrete structure; and on the other hand, freeze-thaw damage to concrete structures caused by seawater in winter.

[0003] On the other hand, chemical erosion caused by cracks in concrete structures. Cl, as a strong anode activator, will destroy the passivation film on the surface of the steel bars in the concrete, forming a galvanic cell and causing steel bar corrosion. Long-term immersion in seawater will also cause the relatively soluble component Ca(OH) in cement hydration products to 2 The dissolution of the above-mentioned corrosion causes often occurs simultaneously and promotes each other, which puts forward more stringent requirements on the corrosion resistance of marine concrete structures. The adhesion between the commonly used ferroaluminate cement and old concrete components is generally average, and the interface is prone to cracking and leakage. External moisture and harmful corrosive media will enter the concrete through the cracks, inducing various corrosion damages, which seriously limits its scope of use. Therefore, how to improve the corrosion resistance and waterproof and crack resistance of marine mortar is of great significance to improving the service life of marine infrastructure. Summary of the invention

[0004] In response to the shortcomings of current technology, the present application provides a low-carbon, environmentally friendly, seawater corrosion-resistant mortar and a preparation method thereof. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar preparation method of the present application has the advantages of simple preparation, low cost, long service life, and green environmental protection. At the same time, the low-carbon, environmentally friendly, seawater corrosion-resistant engineering concrete made using the mortar has excellent corrosion resistance, compressive strength, impermeability, and waterproof and crack resistance.

[0005] In the first aspect, the present application provides a low-carbon, environmentally friendly, seawater corrosion-resistant mortar, which adopts the following technical solution: A low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following raw materials, measured by weight: 320-360 parts of ferroaluminate cement, 100-120 parts of modified coal gangue cementitious material, 250-280 parts of coarse aggregate, 250-280 parts of fine aggregate, 8-12 parts of organosilicon graphene modified acrylic emulsion, 5-8 parts of high-efficiency water reducing agent, 1-2 parts of retarder and 100-130 parts of water.

[0006] By adopting the above technical scheme, ferroaluminate cement: as the main cementitious material, it provides the basic strength and structural support of concrete. Modified coal gangue cementitious material: through the synergistic effect with ferroaluminate cement, it enhances the impermeability and corrosion resistance of concrete. At the same time, the mineral components in the coal gangue cementitious material help to improve the density and stability of concrete. Coarse aggregate and fine aggregate: as the main structural materials of concrete, they provide the skeleton and compressive strength of concrete. At the same time, the particle size and shape of aggregate have an important influence on the workability and durability of concrete. Organic silicon graphene modified acrylic emulsion: forms a waterproof layer on the surface of concrete to prevent erosion factors from entering the interior of concrete. At the same time, the thermal conductivity of graphene helps to reduce the temperature difference between the inside and outside of concrete and reduce temperature stress. High-efficiency water reducer: reduces water consumption while maintaining or improving the workability of concrete, and improves the strength and durability of concrete. Retarder: delays the speed of cement hydration reaction, reduces the temperature stress problem caused by the early heat release concentration, and avoids the generation of temperature cracks. At the same time, the retarder also helps to improve the workability of concrete. Water: As a component of concrete mixture, it reacts with cement, aggregate and other materials to generate hydration products, forming the strength and structure of concrete. These components work together in the preparation process of concrete through reasonable proportions and process control. Ferroaluminate cement and modified coal gangue cementitious materials provide basic strength and stability; aggregates provide the necessary compressive strength and structural support; organosilicon graphene modified acrylic emulsion and retarder improve the corrosion resistance, impermeability and waterproof crack resistance of concrete through physical and chemical modification. High-efficiency water reducer optimizes the workability and strength of concrete. The synergistic effect of these components makes the final prepared concrete have excellent performance and meets the requirements of low-carbon, environmentally friendly and seawater corrosion resistance.

[0007] Preferably, the method for preparing the modified coal gangue cementitious material comprises the following steps: S21, according to the mass fractions, put 40 parts of calcium hydroxide, 40 parts of ammonium sulfate and 6 parts of graphene nanosheets into a ball mill for ball milling at a ball milling speed of 30-40 r / min and a ball milling time of 15-18 min to obtain a mixture A; S22, according to the mass parts, put 2 parts of sodium alginate and 280-300 parts of coal gangue into a ball mill for ball milling, the ball milling speed is 30-40r / min, the ball milling time is 15-18min, and a mixture B is obtained; S23, putting mixture A and mixture B into a ball mill for ball milling, the ball milling speed is 30-40r / min, and the ball milling time is 20-25min, so as to obtain a modified coal gangue cementitious material.

[0008] By adopting the above technical scheme, the prepared modified gangue cementitious material forms a gel network with a three-dimensional structure through interaction with sodium alginate. This structure can enhance the stability of the gelling molecular structure, form a dense "double network" structure, make it difficult for external ions to diffuse, and thus improve the corrosion resistance of concrete. The modified gangue cementitious material can increase the impermeability of concrete, prevent the entry of external liquids and the formation of microcracks in the material. This helps to maintain the stability of the internal structure of concrete and prevent the invasion of corrosive substances. Through the mutual penetration and interpenetration of the organic hydrogel and inorganic filler network, the modified gangue cementitious material increases the crosslinking density of the entire mixed network. This structure not only improves the compressive strength of concrete, but also enhances its impermeability and waterproof and crack resistance. The modified gangue cementitious material works together with other raw materials such as organosilicon graphene modified acrylic emulsion to improve the overall performance of concrete through physical barriers and chemical modifications. For example, organosilicon graphene modified acrylic emulsion can form a hydrophobic protective layer on the surface of concrete to prevent the expansion of surface cracks. At the same time, the excellent thermal conductivity of graphene helps to reduce the temperature difference between the inside and outside of concrete, reduce temperature stress, and avoid the generation of temperature cracks. In summary, the modified coal gangue cementitious material plays a key role in the preparation of low-carbon, environmentally friendly, seawater corrosion-resistant mortar, which not only improves the corrosion resistance and impermeability of concrete, but also enhances its mechanical strength and waterproof and crack resistance. At the same time, the preparation method of this material also reflects its cost-effectiveness and environmental protection characteristics, providing feasibility for industrial production.

[0009] Preferably, the coal gangue has a particle size of 1-5 mm accounting for 70-80% by mass, and a particle size of 0.5-1 mm accounting for 20-30% by mass.

[0010] Preferably, the method for preparing the organosilicon graphene modified acrylic emulsion comprises the following steps: S41. According to the mass fractions, under a nitrogen atmosphere, add dimethylsilylamine and ethanol to a reaction flask, stir evenly, add perfluorooctyl bromide and sodium hydride, stir, heat to 80-85° C., react for 16-24 hours, distill under reduced pressure, and purify by column chromatography to obtain an alkenyl organosilicone fluorine monomer; S42. In a nitrogen atmosphere, add isopropanol, methacrylic acid, butyl acrylate, epoxy resin E-51, modified graphene dispersion and alkenyl silicone fluorine monomer into a reaction flask according to their mass fractions. After they are completely dissolved, add azobisisobutyronitrile, raise the temperature to 85-90°C and react for 4-5h. Lower the temperature to 45-55°C, add triethylamine to neutralize, add deionized water to disperse under high-speed stirring to obtain silicone graphene modified acrylic emulsion.

[0011] By adopting the above technical scheme, the graphene in the organosilicon graphene modified acrylic emulsion is evenly dispersed inside the concrete, has good thermal conductivity, can significantly improve the thermal conductivity of concrete, thereby reducing the temperature difference between the inside and outside of the concrete. At the same time, the retarder plays a role in delaying the heat release time of cement hydration, alleviating the problem of early heat release concentration of ferroaluminate cement marine engineering concrete, and avoiding the situation of temperature cracks caused by excessive temperature stress. These factors work together to improve the corrosion resistance of concrete. The organosilicon graphene modified acrylic emulsion can form a hydrophobic protective layer on the surface of concrete to prevent the expansion of surface cracks. At the same time, the modified coal gangue cementitious material can increase the impermeability, prevent the entry of external liquids and the formation of material microcracks. These characteristics jointly improve the impermeability and waterproof crack resistance of concrete. Graphene is evenly dispersed inside the concrete, which can improve the mechanical strength of concrete. At the same time, the mutual penetration and interpenetration of the organic hydrogel and inorganic filler network increase the crosslinking density of the entire mixed network, further improving the mechanical properties of concrete. The preparation method of the emulsion is simple, low-cost and environmentally friendly, and easy to industrialize. At the same time, due to its good corrosion resistance and impermeability, it can reduce the cost of later maintenance and has high economic value. In summary, organic silicon graphene modified acrylic emulsion plays a key role in low-carbon environmentally friendly seawater corrosion resistant mortar, which not only improves the corrosion resistance and impermeability of concrete, but also enhances its mechanical properties, and has environmental protection and economic benefits.

[0012] Preferably, in step S41, the mass ratio of the bisdimethylsilylamine, ethanol, perfluorooctyl bromide and sodium hydride is 1:(30-35):(2.6-3):(0.2-0.25).

[0013] Preferably, in step S42, the mass ratio of isopropanol, methacrylic acid, butyl acrylate, epoxy resin E-51, modified graphene dispersion, alkenyl organosilicon fluorine monomer, azobisisobutyronitrile, triethylamine and deionized water is 100:14:35:(8-10):(15-18):(6-9):(0.8-1.2):(2-3):80.

[0014] Preferably, the method for preparing the modified graphene dispersion comprises the following steps: S71, heating 20 parts of 15% sodium hydroxide aqueous solution to 90-100° C. by mass, then adding 15 parts of chlorinated polyvinyl chloride resin and reacting for 3-5 hours to remove an appropriate amount of hydrogen chloride from the chlorinated polyvinyl chloride resin for standby use; S72. Dissolve 15 parts of dechlorinated chlorinated polyvinyl chloride resin in 850 parts of cyclopentanone solution according to their mass fractions. Add 4 parts of benzoyl peroxide and 12 parts of maleic anhydride and stir for 3-4 hours under heating condition of 60-80°C. Then slowly add 100 parts of graphene oxide and stir ultrasonically for 3-4 hours to obtain a modified graphene dispersion.

[0015] By adopting the above technical scheme, a small amount of chlorinated polyvinyl chloride is grafted with maleic anhydride, and then ultrasonically stirred and reacted with graphene oxide. Graphene oxide and maleic anhydride form a graphene oxide / maleic anhydride composite due to hydrogen bonding to obtain a modified graphene dispersion. The dispersion can fully achieve good blending with acrylic emulsion. Graphene oxide is introduced into the acrylic resin emulsion by chemical modification. Graphene is uniformly dispersed in the concrete. Graphene has excellent thermal conductivity, which can greatly improve the thermal conductivity of concrete and reduce the temperature difference between the inside and outside of concrete. At the same time, the retarder delays the heat release time of cement hydration, thereby alleviating the problem of early heat release concentration of ferroaluminate cement marine concrete, avoiding the occurrence of temperature cracks caused by excessive temperature stress, and improving the mechanical properties, impermeability and corrosion resistance of concrete.

[0016] Preferably, the high-efficiency water reducer is composed of a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a mass ratio of 3:2.

[0017] By adopting the above technical scheme, the high-efficiency water reducer can significantly reduce the amount of mixing water for concrete without affecting the workability of concrete. This means that the amount of cement can be reduced while maintaining the same workability, thereby reducing costs. By reducing the amount of mixing water, the cement particles in the concrete can be more tightly combined, thereby improving the strength of the concrete. At the same time, the reduced amount of water also helps to improve the compactness of the concrete and further enhance its strength. Reducing the amount of mixing water helps to reduce the capillary porosity inside the concrete, thereby improving the durability of the concrete, including impermeability, freeze-thaw resistance and chemical corrosion resistance. High-efficiency water reducers can reduce the drying shrinkage and cracking of concrete, which is very important for improving the overall quality and durability of concrete. The mass ratio of polycarboxylate high-efficiency water reducer and aliphatic high-efficiency water reducer is 3:2. This ratio can give full play to the synergistic effect of the two water reducers. Polycarboxylate high-efficiency water reducers usually have strong dispersibility and high water reduction efficiency, while aliphatic high-efficiency water reducers have good water retention and fluidity improvement. The combination of the two can ensure good workability and stability of concrete while maintaining high water reduction efficiency, thereby improving overall performance.

[0018] Preferably, the fine aggregate is quartz sand with a particle size of 0.5-0.9 mm; the coarse aggregate includes small stones with a continuous gradation of 5-16 mm and large stones with a continuous gradation of 16-25 mm; and the retarder is one of sucrose and glucose.

[0019] In the second aspect, the present application provides a method for preparing a low-carbon, environmentally friendly, seawater corrosion-resistant mortar, which adopts the following technical solution: According to the mass proportions, first pour the ferroaluminate cement, coarse aggregate, fine aggregate and modified coal gangue cementitious material into a concrete mixer and dry mix for 50-80 seconds. After mixing evenly, add tap water and mix and stir for 1-2 minutes. Then add high-efficiency water reducing agent, silicone graphene modified acrylic emulsion and retarder and stir for 2-3 minutes to obtain a low-carbon, environmentally friendly and seawater corrosion-resistant mortar.

[0020] In summary, the beneficial technical effects of this application are: 1. Improved corrosion resistance: Sodium alginate and Ca in coal gangue 2+ 、Al 3+ The hydrogel with three-dimensional structure and the silicone graphene-modified acrylic emulsion form a waterproof layer on the concrete surface, which effectively improves the corrosion resistance of the concrete.

[0021] 2. Enhanced compressive strength and impermeability: The mutual penetration and interpenetration of organic hydrogel and inorganic filler increase the cross-linking density of the mixed network. At the same time, the excellent thermal conductivity of graphene helps to reduce the temperature difference between the inside and outside of the concrete, thereby improving the compressive strength and impermeability of the concrete.

[0022] 3. Environmental protection and economic benefits: The materials used are low-cost, the preparation method is simple and easy to industrialize. At the same time, the mortar has the characteristics of green environmental protection and meets the needs of sustainable development.

[0023] 4. Enhanced crack resistance: Organic silicon graphene modified acrylic emulsion can form a hydrophobic protective layer on the concrete surface to prevent the expansion of surface cracks. Modified coal gangue cementitious materials can increase the anti-permeability performance, prevent the entry of external liquids and the formation of micro-cracks in the material.

[0024] 5. Alleviate the problem of early heat release concentration: The use of retarder delays the heat release time of cement hydration, alleviates the problem of early heat release concentration of ferroaluminate cement marine concrete, and avoids the situation of temperature cracks caused by excessive temperature stress. At the same time, graphene is evenly dispersed in the concrete, improving the mechanical properties, impermeability and corrosion resistance of the concrete.

[0025] 6. Improved construction convenience: The use of retarder effectively solves the problem of ferroaluminate cement coagulation and hardening blocks, making construction more convenient. DETAILED DESCRIPTION

[0026] The implementation solutions of the present application will be described in detail below in conjunction with embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present application and should not be construed as limiting the scope of the present application. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0027] In the following examples, preparation examples, and preparation comparative examples, 1 part represents 1 kg.

[0028] The main chemical components of the coal gangue in the preparation examples and examples are shown in Table 1 below: Table 1 Main chemical components of coal gangue The particle size of the coal gangue is 75% by mass fraction in the range of 1 - 5 mm and 25% by mass fraction in the range of 0.5 - 1 mm.

[0029] Preparation Example 1 Preparation of modified coal gangue cementitious material The preparation method of the modified coal gangue cementitious material includes the following steps: S21. According to the mass parts, put 40 parts of calcium hydroxide, 40 parts of ammonium sulfate, and 6 parts of graphene nanosheets into a ball mill for ball milling. The ball milling speed is 35 r / min, and the ball milling time is 17 min to obtain mixture A; S22. According to the mass parts, put 2 parts of sodium alginate and 290 parts of coal gangue into a ball mill for ball milling. The ball milling speed is 35 r / min, and the ball milling time is 17 min to obtain mixture B; S23. Put mixture A and mixture B into a ball mill for ball milling. The ball milling speed is 35 r / min, and the ball milling time is 23 min to obtain the modified coal gangue cementitious material.

[0030] Preparation Example 2 Preparation of modified graphene dispersion The preparation method of the modified graphene dispersion includes the following steps: S71. According to the mass parts, heat 20 parts of 15% mass concentration sodium hydroxide aqueous solution to 95 °C, then add 15 parts of chlorinated polyvinyl chloride resin and react for 4 hours to make the chlorinated polyvinyl chloride resin remove an appropriate amount of hydrogen chloride for use; S72. According to the mass parts, dissolve 15 parts of dechlorinated chlorinated polyvinyl chloride resin in 850 parts of cyclopentanone solution. Under the condition of heating at 70 °C, add 4 parts of benzoyl peroxide and 12 parts of maleic anhydride and stir for 3.4 hours, then slowly add 100 parts of graphene oxide and stir ultrasonically for 3 h to obtain the modified graphene dispersion.

[0031] Preparation Example 3 Preparation of silicone graphene modified acrylic emulsion The preparation method of organosilicon graphene modified acrylic emulsion comprises the following steps: S41. According to the mass fractions, under a nitrogen atmosphere, add 1 part of bisdimethylsilylamine and 34 parts of ethanol to a reaction flask, stir evenly, then add 2.8 parts of perfluorooctyl bromide and 0.22 parts of sodium hydride, stir, raise the temperature to 83°C, react for 19 hours, distill under reduced pressure, and purify by column chromatography to obtain an alkenyl organosilicone fluorine monomer; S42. According to the mass proportions, under a nitrogen atmosphere, add 100 parts of isopropanol, 14 parts of methacrylic acid, 35 parts of butyl acrylate, 9 parts of epoxy resin E-51, 17 parts of modified graphene dispersion and 8 parts of alkenyl organosilicon fluorine monomer to the reaction flask. After they are completely dissolved, add 1 part of azobisisobutyronitrile, heat to 87°C and react for 4.5h, cool to 50°C, and add 2.3 parts of The mixture was neutralized with triethylamine, and 80 parts of deionized water were added under high-speed stirring to disperse the mixture, thereby obtaining an organosilicon graphene-modified acrylic emulsion.

[0032] Example 1 A low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following raw materials by weight: 320 parts of ferroaluminate cement, 100 parts of modified coal gangue cementitious material, 250 parts of coarse aggregate, 250 parts of fine aggregate, 8 parts of organosilicon graphene modified acrylic emulsion, 5 parts of high-efficiency water reducer, 1 part of sucrose, and 100 parts of water, wherein the high-efficiency water reducer comprises a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a weight ratio of 3:2, the fine aggregate is quartz sand with a particle size of 0.5-0.9 mm; the coarse aggregate comprises small stones with a continuous gradation of 5-16 mm and large stones with a continuous gradation of 16-25 mm; The preparation method of the above-mentioned low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following steps: first, according to the mass fractions, pour ferroaluminate cement, coarse aggregate, fine aggregate, and modified coal gangue cementitious material into a concrete mixer and dry mix for 50 seconds. After mixing evenly, add tap water and mix and stir for 1 minute. Then, add a high-efficiency water reducing agent, silicone graphene modified acrylic emulsion and sucrose, and stir for 2 minutes to obtain a low-carbon, environmentally friendly, seawater corrosion-resistant mortar.

[0033] Example 2 A low-carbon, environmentally friendly, seawater corrosion-resistant mortar, comprising the following raw materials by weight: 360 parts of ferroaluminate cement, 120 parts of modified coal gangue cementitious material, 280 parts of coarse aggregate, 280 parts of fine aggregate, 12 parts of organosilicon graphene modified acrylic emulsion, 8 parts of high-efficiency water reducer, 2 parts of glucose, and 130 parts of water, wherein the high-efficiency water reducer is composed of a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a weight ratio of 3:2, the fine aggregate is quartz sand with a particle size of 0.5-0.9 mm; the coarse aggregate includes small stones with a continuous gradation of 5-16 mm and large stones with a continuous gradation of 16-25 mm; The preparation method of the above-mentioned low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following steps: first, according to the mass fractions, pour ferroaluminate cement, coarse aggregate, fine aggregate, and modified coal gangue cementitious material into a concrete mixer and dry mix for 80 seconds. After mixing evenly, add tap water and mix and stir for 2 minutes. Then, add high-efficiency water reducing agent, silicone graphene modified acrylic emulsion and glucose, and stir for 3 minutes to obtain low-carbon, environmentally friendly, seawater corrosion-resistant mortar.

[0034] Example 3 A low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following raw materials by weight: 340 parts of ferroaluminate cement, 110 parts of modified coal gangue cementitious material, 270 parts of coarse aggregate, 260 parts of fine aggregate, 10 parts of organic silicon graphene modified acrylic emulsion, 7 parts of high-efficiency water reducer, 1.2 parts of sucrose, and 110 parts of water, wherein the high-efficiency water reducer is composed of a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a weight ratio of 3:2, the fine aggregate is quartz sand with a particle size of 0.5-0.9 mm; the coarse aggregate comprises small stones with a continuous gradation of 5-16 mm and large stones with a continuous gradation of 16-25 mm; The preparation method of the above-mentioned low-carbon, environmentally friendly, seawater corrosion-resistant mortar comprises the following steps: first, according to the mass fractions, pour ferroaluminate cement, coarse aggregate, fine aggregate, and modified coal gangue cementitious material into a concrete mixer and dry mix for 70 seconds. After mixing evenly, add tap water and mix and stir for 1.5 minutes. Then, add high-efficiency water reducing agent, silicone graphene modified acrylic emulsion and sucrose, and stir for 2.3 minutes to obtain a low-carbon, environmentally friendly, seawater corrosion-resistant mortar.

[0035] Comparative Example 1 The same as Example 3, except that 450 parts of ferroaluminate cement and 0 parts of modified coal gangue cementitious material are used.

[0036] Comparative Example 2 The same as Example 3, except that 350 parts of ferroaluminate cement and 0 part of organosilicon graphene modified acrylic emulsion are used.

[0037] Comparative Example 3 The same as Example 3, except that 460 parts of ferroaluminate cement, 0 parts of modified coal gangue cementitious material, and 0 parts of organosilicon graphene modified acrylic emulsion are used.

[0038] Comparative Example 4 The same as Example 3, except that the high-efficiency water reducer is an aliphatic high-efficiency water reducer.

[0039] Comparative Example 5 The same as Example 3, except that the high-efficiency water reducer is a polycarboxylate high-efficiency water reducer.

[0040] Performance Testing The low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in Examples 1 to 3 and Comparative Examples 1 to 5 was poured into a standard mold, vibrated to compact, and naturally cured after molding. The natural curing temperature was 25°C and the humidity was 90%. The following tests were performed, and the test results are shown in Table 2.

[0041] 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, and placed in a magnesium sulfate solution with a sulfate concentration of 6.22 g / L to test the expansion rate of the concrete in the sulfate solution.

[0042] Determination of chloride ion diffusion coefficient: Concrete with a curing age of 28 days was prepared into a sample with a size of 100mm×100mm×515mm, and placed in a sodium chloride solution with a concentration of 4mol / L. The sample was then subjected to vacuum water retention treatment, and the chloride ion diffusion coefficient of concrete was tested using the chloride ion diffusion coefficient determination method.

[0043] Compressive strength: The test was carried out with reference to GB / T50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete", the curing age was 28 days, the sample size was 150mm×150mm×150mm, and the concrete pressure testing machine had a given loading rate of 0.8MPa / s.

[0044] 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 is used to test the water penetration resistance of concrete. The concrete with a curing age of 28 days is made into a truncated cone with an upper inner diameter of 175mm, a lower inner diameter of 185mm, and a height of 250mm, and placed in a concrete permeameter for water penetration resistance test.

[0045] Drying shrinkage: For concrete with a curing age of 28 days, the test is carried out in accordance with T0574-2020 Cement Concrete Shrinkage Test Method (Contact Method) in JTG3420-2020 "Test Procedures for Cement and Cement Concrete for Highway Engineering".

[0046] Table 2 Performance test Analyzing the data in Table 2, we can see that: 1) The low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in Examples 1 to 3 is used to make low-carbon, environmentally friendly, seawater corrosion-resistant engineering concrete, which has excellent corrosion resistance, compressive strength, impermeability, and waterproof and crack resistance.

[0047] 2) The performance comparison analysis of the low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in combination with Example 3 and Comparative Example 1 shows that the modified coal gangue cementitious material prepared in this application forms a gel network with a three-dimensional structure through interaction with sodium alginate. This structure can enhance the stability of the gelling molecular structure, form a dense "double network" structure, and make it difficult for external ions to diffuse, thereby improving the corrosion resistance of concrete. The modified coal gangue cementitious material can increase the impermeability of concrete, prevent the entry of external liquids and the formation of microcracks in the material. This helps to maintain the stability of the internal structure of concrete and prevent the invasion of corrosive substances. The modified coal gangue cementitious material works together with other raw materials such as organosilicon graphene modified acrylic emulsion to improve the overall performance of concrete through physical barriers and chemical modifications. For example, organosilicon graphene modified acrylic emulsion can form a hydrophobic protective layer on the surface of concrete to prevent the expansion of surface cracks. At the same time, the excellent thermal conductivity of graphene helps to reduce the temperature difference between the inside and outside of concrete, reduce temperature stress, and avoid the generation of temperature cracks. In summary, modified coal gangue cementitious materials play a key role in the preparation of low-carbon, environmentally friendly, seawater corrosion-resistant mortar. It not only improves the corrosion resistance and impermeability of concrete, but also enhances its mechanical strength and waterproof and crack resistance.

[0048] 3) The performance comparison analysis of the low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in combination with Example 3 and Comparative Example 2 shows that the graphene in the organosilicon graphene modified acrylic emulsion prepared in the present application is evenly dispersed inside the concrete, has good thermal conductivity, and can significantly improve the thermal conductivity of the concrete, thereby reducing the temperature difference between the inside and outside of the concrete. The organosilicon graphene modified acrylic emulsion can form a hydrophobic protective layer on the surface of the concrete to prevent the expansion of surface cracks. At the same time, the modified coal gangue cementitious material can increase the impermeability, prevent the entry of external liquids and the formation of material microcracks. These characteristics jointly improve the impermeability and waterproof crack resistance of the concrete. Graphene is evenly dispersed inside the concrete, which can improve the mechanical strength of the concrete. At the same time, the mutual penetration and interpenetration of the organic hydrogel and inorganic filler network increase the cross-linking density of the entire mixed network, further improving the mechanical properties of the concrete. In summary, silicone graphene modified acrylic emulsion plays a key role in low-carbon, environmentally friendly, seawater corrosion-resistant mortar. It not only improves the corrosion resistance and impermeability of concrete, but also enhances its mechanical properties, while having environmental protection and economic benefits.

[0049] 4) The performance comparison analysis of the low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in combination with Example 3 and Comparative Example 3 shows that the performance of the product is significantly reduced without adding the modified coal gangue cementitious material and the organosilicon graphene modified acrylic emulsion prepared in this application. 5) The performance comparison analysis of the low-carbon, environmentally friendly, seawater corrosion-resistant mortar prepared in combination with Example 3 and Comparative Example 3 shows that the high-efficiency water reducer is composed of a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a mass fraction ratio of 3:2, and the high-efficiency water reducer can significantly reduce the amount of concrete mixing water without affecting the workability of the concrete. This means that the amount of cement can be reduced while maintaining the same workability, thereby reducing costs. By reducing the amount of mixing water, the cement particles in the concrete can be more closely combined, thereby improving the strength of the concrete. At the same time, the reduced amount of water also helps to improve the compactness of the concrete and further enhance its strength. Reducing the amount of mixing water helps to reduce the capillary porosity inside the concrete, thereby improving the durability of the concrete, including impermeability, freeze-thaw resistance and chemical corrosion resistance. High-efficiency water reducers can reduce the drying shrinkage and cracking of concrete, which is very important for improving the overall quality and durability of concrete. The synergistic effect of polycarboxylate high-efficiency water reducers and aliphatic high-efficiency water reducers can ensure good workability and stability of concrete while maintaining high water reduction efficiency, thereby improving overall performance.

[0050] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. A low-carbon, environmentally friendly, seawater corrosion-resistant mortar, characterized in that: The preparation raw materials include the following by weight: 320-360 parts of ferroaluminate cement, 100-120 parts of modified coal gangue cementitious material, 250-280 parts of coarse aggregate, 250-280 parts of fine aggregate, 8-12 parts of organosilicon graphene modified acrylic emulsion, 5-8 parts of high-efficiency water reducing agent, 1-2 parts of retarder and 100-130 parts of water.

2. According to claim 1, a low-carbon, environmentally friendly, seawater corrosion-resistant mortar is characterized in that: The preparation method of the modified coal gangue cementitious material comprises the following steps: S21, according to the mass fractions, put 40 parts of calcium hydroxide, 40 parts of ammonium sulfate and 6 parts of graphene nanosheets into a ball mill for ball milling at a ball milling speed of 30-40 r / min and a ball milling time of 15-18 min to obtain a mixture A; S22, according to the mass parts, put 2 parts of sodium alginate and 280-300 parts of coal gangue into a ball mill for ball milling, the ball milling speed is 30-40r / min, the ball milling time is 15-18min, and a mixture B is obtained; S23, putting mixture A and mixture B into a ball mill for ball milling, the ball milling speed is 30-40r / min, and the ball milling time is 20-25min, so as to obtain a modified coal gangue cementitious material.

3. According to claim 2, a low-carbon, environmentally friendly, seawater corrosion-resistant mortar is characterized in that: The coal gangue has a particle size of 1-5 mm, which accounts for 70-80% by mass, and a particle size of 0.5-1 mm, which accounts for 20-30% by mass.

4. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 1, characterized in that: The preparation method of the organosilicon graphene modified acrylic emulsion comprises the following steps: S41. According to the mass fractions, under a nitrogen atmosphere, add dimethylsilylamine and ethanol to a reaction flask, stir evenly, add perfluorooctyl bromide and sodium hydride, stir, heat to 80-85° C., react for 16-24 hours, distill under reduced pressure, and purify by column chromatography to obtain an alkenyl organosilicone fluorine monomer; S42. In a nitrogen atmosphere, add isopropanol, methacrylic acid, butyl acrylate, epoxy resin E-51, modified graphene dispersion and alkenyl silicone fluorine monomer into a reaction flask according to their mass fractions. After they are completely dissolved, add azobisisobutyronitrile, raise the temperature to 85-90°C and react for 4-5h. Lower the temperature to 45-55°C, add triethylamine to neutralize, add deionized water to disperse under high-speed stirring to obtain silicone graphene modified acrylic emulsion.

5. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 4, characterized in that: In step S41, the mass ratio of the bisdimethylsilylamine, ethanol, perfluorooctyl bromide and sodium hydride is 1:(30-35):(2.6-3):(0.2-0.25).

6. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 4, characterized in that: In step S42, the mass ratio of isopropanol, methacrylic acid, butyl acrylate, epoxy resin E-51, modified graphene dispersion, alkenyl organosilicon fluorine monomer, azobisisobutyronitrile, triethylamine and deionized water is 100:14:35:(8-10):(15-18):(6-9):(0.8-1.2):(2-3):

80.

7. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 4, characterized in that: The preparation method of the modified graphene dispersion comprises the following steps: S71. Heat 20 parts of 15% sodium hydroxide aqueous solution to 90-100° C. by mass, then add 15 parts of chlorinated polyvinyl chloride resin and react for 3-5 hours to remove an appropriate amount of hydrogen chloride from the chlorinated polyvinyl chloride resin for standby use; S72. Dissolve 15 parts of dechlorinated chlorinated polyvinyl chloride resin in 850 parts of cyclopentanone solution according to their mass fractions. Add 4 parts of benzoyl peroxide and 12 parts of maleic anhydride and stir for 3-4 hours under heating condition of 60-80°C. Then slowly add 100 parts of graphene oxide and stir ultrasonically for 3-4 hours to obtain a modified graphene dispersion.

8. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 1, characterized in that: The high-efficiency water reducer is composed of a polycarboxylate high-efficiency water reducer and an aliphatic high-efficiency water reducer in a mass ratio of 3:

2.

9. The low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to claim 1, characterized in that: The fine aggregate is quartz sand with a particle size of 0.5-0.9 mm; the coarse aggregate includes small stones with a continuous gradation of 5-16 mm and large stones with a continuous gradation of 16-25 mm; the retarder is one of sucrose and glucose.

10. A method for preparing a low-carbon, environmentally friendly, seawater corrosion-resistant mortar according to any one of claims 1 to 9, characterized in that: The following steps are involved: According to the mass proportions, first pour the ferroaluminate cement, coarse aggregate, fine aggregate and modified coal gangue cementitious material into a concrete mixer and dry mix for 50-80 seconds. After mixing evenly, add tap water and mix and stir for 1-2 minutes. Then add high-efficiency water reducing agent, silicone graphene modified acrylic emulsion and retarder and stir for 2-3 minutes to obtain a low-carbon, environmentally friendly and seawater corrosion-resistant mortar.

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