Green high-durability marine concrete and preparation method thereof

Abstract

The application discloses green high-durability marine concrete and a preparation method thereof. The concrete is prepared from the following components in proportion by mass: cement 310-330 parts, slag powder 110-130 parts, mixed water 183-187 parts, coarse aggregate 1050-1080 parts, fine aggregate 810-830 parts, modified fiber 14.3-14.4 parts, green corrosion inhibitor 10-12 parts, water reducing agent 4-6 parts, defoaming agent 0.16-0.24 parts and hydrophobic composite material 34-36 parts. The application effectively improves the crack resistance, mechanical properties and durability of the concrete, and can significantly prolong the service life of the marine concrete structure.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and in particular to a green, high-durability marine concrete and its preparation method. Background Technology

[0002] Concrete is inherently a hydrophilic and porous material. The gel pores in the cement paste, the microcracks in the concrete matrix, and the interconnected pores in the interfacial transition zones all serve as channels for the transport of harmful media. For concrete structures located in coastal areas or deep in the ocean, harmful substances such as chlorides and sulfates, carried by water, can penetrate into the concrete matrix through these transport channels. Under the combined effects of the external environment and loads, this leads to the deterioration of concrete performance, rusting and expansion of the reinforcing steel, and ultimately, continuous cracking of the concrete, severely compromising the safety and durability of the structure and causing significant economic losses. Therefore, preparing high-durability marine concrete is a crucial measure to improve the durability of concrete structures.

[0003] Currently, many scholars have conducted research on the preparation of marine concrete, but the preparation technology still needs further improvement. For example, invention patent: "An anti-erosion marine concrete and its preparation method" (CN116375422B), uses nine solid materials—fly ash, slag powder, limestone powder, silica fume, recycled micro powder, steel slag, nickel slag, silicate cement, and lightweight aggregate—to prepare the concrete matrix, greatly increasing the number of concrete preparation steps. Although this increases the crack resistance of fiber-reinforced concrete, the waterproof performance of the marine concrete is not improved, and the prepared marine concrete is highly susceptible to damage from seawater erosion. Invention patent: "An anti-erosion marine concrete and its preparation method" (CN111320431B), using... Paraffin wax has poor adhesion to concrete, which makes the concrete more vulnerable to micro-cracks. Most anti-seepage agents are inorganic, which is not conducive to environmental protection and goes against the sustainable development concept of green concrete. The bonding performance between polypropylene fibers and the matrix has not been improved, and the crack resistance of fibers to concrete needs to be further improved. The invention patent: high-strength low-heat hydration marine concrete (CN111620618B) only reduces the heat of hydration of concrete, but does not optimize the crack resistance, hydrophobicity and corrosion resistance of marine concrete, and the service life of marine concrete structures is difficult to guarantee. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the prior art by providing a green, high-durability marine concrete and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a green and high-durability marine concrete, which is composed of the following components by mass fraction: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts green corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material.

[0006] Specifically, the cement is ferric silicate cement.

[0007] Specifically, the slag powder is S95 or S105 grade slag powder.

[0008] Specifically, the coarse aggregate is graded crushed stone with a particle size distribution range of 5-25mm; the fine aggregate is river sand with a particle size not exceeding 4.75mm.

[0009] Specifically, the defoamer is tributyl phosphate.

[0010] Specifically, the water-reducing agent is a naphthalene-based water-reducing agent.

[0011] Specifically, the modified fiber is obtained by modifying polyethylene fiber, wherein the length of the polyethylene fiber does not exceed 12 mm. The specific preparation method includes the following steps:

[0012] P1. Immerse polyethylene fibers in anhydrous ethanol solution and subject the solution to ultrasonic treatment for 30-35 minutes.

[0013] P2. Remove the polyethylene fiber from the anhydrous ethanol solution and repeatedly wash the polyethylene fiber with deionized water to remove any residue on the surface of the polyethylene fiber.

[0014] P3. Place the cleaned polyethylene fibers in a forced-air drying oven and dry them at 50℃ for 4-4.5 hours.

[0015] P4. Place 20g of polyethylene fiber into 1L of 5% polyvinylpyrrolidone solution and sonicate the solution for 30-35 minutes. After sonication, soak the fiber for another 30-35 minutes.

[0016] P5. Remove the polyethylene fiber from the solution in P4, rinse the polyethylene fiber repeatedly with anhydrous ethanol and deionized water, and dry it at 50°C for 4-4.5 hours.

[0017] P6. The polyethylene fiber from P5 is placed in a nano-silica solution with a concentration of 5 g / L, and the solution is subjected to ultrasonic treatment for 3 hours to obtain the modified fiber.

[0018] Specifically, the preparation method of the green corrosion inhibitor includes the following steps:

[0019] M1. Soak palm leaves in a water tank for 30 minutes, then rinse them with deionized water. Grind the cleaned leaves into powder using a grinder, and dry the powder in a drying oven at 105°C for 24 hours.

[0020] M2. Mix the dried powder with a 30% sodium hydroxide solution at a solid-liquid ratio of 1:8 to obtain mixture A.

[0021] M3. Continue stirring the mixture A and heat the mixture A at 170°C for 3 hours;

[0022] M4. Filter the mixture A and wash the filter material of the mixture A with distilled water;

[0023] M5. Add sulfuric acid with a mass fraction of 20% to the filtered mixture of A after washing until the pH of the mixture of A and sulfuric acid reaches 2, then stop adding sulfuric acid to obtain mixture B.

[0024] M6. Centrifuge the B mixture for 10 min at 3500 rpm to obtain the reacted solid. Place the solid in an oven at 50°C and dry for 24 h.

[0025] M7. The dried solid was repeatedly rinsed and filtered with a solution of pH 2 to remove residual hemicellulose. The resulting lignin was then dried in a 50°C oven for 24 hours to obtain a green corrosion inhibitor.

[0026] Specifically, the preparation method of hydrophobic composite materials includes the following steps:

[0027] N1. Mix 34.8g of water, 24.7g of coal slag and 1.39g of sodium hydroxide in a beaker and stir at 400r / min for 4.5h to obtain mixture C;

[0028] N2, add 0.36g polymethylhydrosiloxane, 0.31g dimethylhydroxy silicone oil, 0.25g isobutyltriethoxysilane and 1.26g silica sol to the C mixture, stir at 400r / min for 3h, and place the beaker in a 100℃ oven to dry for 24h;

[0029] N3. Crush the dried solid and sieve it through a 250-mesh sieve to obtain a hydrophobic composite material.

[0030] A method for preparing green, high-durability marine concrete includes the following steps:

[0031] S1. Weigh the following components by weight: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts green corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material.

[0032] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0033] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0034] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0035] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0036] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0037] The beneficial effects of this invention are:

[0038] 1. The marine concrete prepared by this invention uses modified fibers, which significantly improves the adhesion between polyethylene fibers and the concrete matrix interface, thereby enhancing the crack resistance and mechanical properties of the marine concrete.

[0039] 2. The marine concrete prepared by this invention uses a green corrosion inhibitor. This green corrosion inhibitor not only consumes agricultural waste, but is also easier to degrade than traditional inorganic nitrite corrosion inhibitors. It is low in cost and does not harm the human body, thus achieving green preparation and sustainability of marine concrete to a certain extent.

[0040] 3. The hydrophobic composite material for marine concrete prepared by this invention uses solid waste materials, providing a new path for the resource utilization of solid waste. At the same time, it has good three-dimensional superhydrophobicity, which makes the marine concrete have excellent waterproof performance and can effectively improve the durability of marine concrete.

[0041] 4. This invention increases the crack resistance of marine concrete by modifying fibers, delays the corrosion and expansion of steel bars by using green corrosion inhibitors, and increases the durability of the concrete matrix by using composite hydrophobic materials. This forms a three-in-one technology of interface reinforcement, steel bar corrosion protection and matrix waterproofing, which can significantly improve the service life of marine concrete structures.

[0042] 5. This invention uses high-iron phase silicate cement, which can effectively reduce the heat of hydration of concrete and prevent early cracking of concrete, making marine concrete applicable to large-volume concrete structure engineering. Detailed Implementation

[0043] The present invention will be further described below with reference to embodiments:

[0044] A green, high-durability marine concrete, by mass fraction, is composed of the following components: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts green corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material.

[0045] The cement is high-ferro-phase silicate cement with a strength grade of 42.5, which can effectively reduce the heat of hydration of concrete and prevent early cracking, making marine concrete applicable to large-volume concrete structure projects; the slag powder is S95 or S105 grade slag powder with an apparent density of 2860 kg / m³. 3 The specific surface area is 453 m² / kg; the coarse aggregate is graded crushed stone with a particle size distribution range of 5-25 mm; the fine aggregate is river sand with a particle size not exceeding 4.75 mm; the defoamer is tributyl phosphate defoamer, a colorless and transparent liquid; the water-reducing agent is naphthalene-based water-reducing agent, a brownish-red viscous liquid with a solid content of 40% and an apparent density of 1220 kg / m³. 3 .

[0046] The mineral composition of cement is shown in Table 1:

[0047] Table 1 Cement mineral composition

[0048] <![CDATA[C4AF]]> <![CDATA[C3S]]> <![CDATA[C2S]]> <![CDATA[C3A]]> 18.8 49.2 27.5 0.4

[0049] The chemical composition of slag powder and coal slag is shown in Table 2:

[0050] Table 2 Chemical composition of slag powder and coal slag powder

[0051] Element <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> MgO CaO <![CDATA[Na2O]]> <![CDATA[SO3]]> Others Slag powder 32.9 14.6 0.3 5.3 41.3 0.5 3.2 1.9 cinder 51.3 21.7 8.8 1.4 2.4 - - 14.4

[0052] The modified fiber is obtained by modifying polyethylene fiber. The polyethylene fiber has a length of no more than 12 mm, a diameter of 24 μm, a tensile strength of 3000 MPa, and an elastic modulus of 80 GPa. The specific preparation method includes the following steps:

[0053] P1. Immerse polyethylene fibers in anhydrous ethanol solution and subject the solution to ultrasonic treatment for 30-35 minutes.

[0054] P2. Remove the polyethylene fiber from the anhydrous ethanol solution and repeatedly wash the polyethylene fiber with deionized water to remove any residue on the surface of the polyethylene fiber.

[0055] P3. Place the cleaned polyethylene fibers in a forced-air drying oven and dry them at 50℃ for 4-4.5 hours.

[0056] P4. Place 20g of polyethylene fiber into 1L of 5% polyvinylpyrrolidone solution and sonicate the solution for 30-35 minutes. After sonication, soak the fiber for another 30-35 minutes. The solute in the polyvinylpyrrolidone solution is polyvinylpyrrolidone, the solvent is ethanol, and polyvinylpyrrolidone is a white powder.

[0057] P5. Remove the polyethylene fiber from the solution in P4, rinse the polyethylene fiber repeatedly with anhydrous ethanol and deionized water, and dry it at 50°C for 4-4.5 hours.

[0058] P6. The polyethylene fibers from P5 are placed in a 5 g / L nano-silica solution, and the solution is subjected to ultrasonic treatment for 3 hours to obtain modified fibers; wherein the solute in the nano-silica solution is nano-silica, and the solvent is ethanol; the particle size range of the nano-silica is 9-41 nm, and the specific surface area is not less than 370 m². 2 / g, here the specific surface area can be selected as 380m² 2 / g.

[0059] Polyvinylpyrrolidone can effectively enhance the interfacial adhesion between fibers and the concrete matrix, and improve the ductility of concrete; furthermore, nano-silica can make the fiber surface rougher, enhance the friction between the fiber and the matrix, and make the concrete have better crack resistance.

[0060] The preparation method of green corrosion inhibitor includes the following steps:

[0061] M1. Soak palm leaves in a water tank for 30 minutes, then rinse them with deionized water. Grind the cleaned leaves into powder using a grinder, and dry the powder in a drying oven at 105°C for 24 hours.

[0062] M2. Mix the dried powder with a 30% sodium hydroxide solution at a solid-liquid ratio of 1:8 to obtain mixture A.

[0063] M3. Continue stirring the mixture A and heat the mixture A at 170°C for 3 hours;

[0064] M4. Filter the mixture A and wash the filter material of the mixture A with distilled water;

[0065] M5. Add sulfuric acid with a mass fraction of 20% to the filtered mixture of A after washing until the pH of the mixture of A and sulfuric acid reaches 2, then stop adding sulfuric acid to obtain mixture B.

[0066] M6. Centrifuge the B mixture for 10 min at 3500 rpm to obtain the reacted solid. Place the solid in an oven at 50°C and dry for 24 h.

[0067] M7. The dried solid was repeatedly rinsed and filtered with a solution of pH 2 to remove residual hemicellulose. The resulting lignin was then dried in a 50°C oven for 24 hours to obtain a green corrosion inhibitor.

[0068] This green corrosion inhibitor, by adhering to the surface of reinforcing steel, can delay the anodic reaction, thereby effectively reducing the rate of corrosion. This green corrosion inhibitor not only consumes agricultural waste but is also more easily degraded than traditional inorganic nitrite corrosion inhibitors, is low in cost, and poses no harm to human health, thus contributing to the green preparation and sustainability of marine concrete to a certain extent.

[0069] The preparation method of hydrophobic composite materials includes the following steps:

[0070] N1. Mix 34.8g of water, 24.7g of coal slag and 1.39g of sodium hydroxide in a beaker and stir at 400r / min for 4.5h to obtain mixture C;

[0071] N2, add 0.36g polymethylhydrosiloxane, 0.31g dimethylhydroxy silicone oil, 0.25g isobutyltriethoxysilane and 1.26g silica sol to the C mixture, stir at 400r / min for 3h, and place the beaker in a 100℃ oven to dry for 24h;

[0072] N3. Crush the dried solid and sieve it through a 250-mesh sieve to obtain a hydrophobic composite material.

[0073] Hydrophobic composite materials utilize solid waste materials, providing a new path for the resource utilization of solid waste. At the same time, they have good three-dimensional superhydrophobicity, which gives marine concrete excellent waterproof performance and can effectively improve the durability of marine concrete.

[0074] A method for preparing green, high-durability marine concrete includes the following steps:

[0075] S1. Weigh the following components by weight: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts green corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material.

[0076] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0077] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0078] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0079] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0080] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0081] This invention increases the crack resistance of marine concrete by adding modified fibers, delays the corrosion and expansion of steel bars by using green corrosion inhibitors, and increases the durability of the concrete matrix by using composite hydrophobic materials. This forms a three-in-one technology of interface reinforcement, steel bar corrosion protection, and matrix waterproofing, which can significantly improve the service life of marine concrete structures.

[0082] Example 1

[0083] A green and high-durability marine concrete is composed of the following components by mass fraction: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0084] A method for preparing green, high-durability marine concrete includes the following steps:

[0085] S1. Weigh the following components by weight: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0086] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0087] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0088] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0089] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0090] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0091] Example 2

[0092] A green and high-durability marine concrete, by mass fraction, is composed of the following components: 330 parts cement, 110 parts slag powder, 187 parts mixing water, 1080 parts coarse aggregate, 810 parts fine aggregate, 14.4 parts modified fiber, 12 parts green corrosion inhibitor, 6 parts water-reducing agent, 0.24 parts defoamer, and 36 parts hydrophobic composite material.

[0093] A method for preparing green, high-durability marine concrete includes the following steps:

[0094] S1. Weigh the following components by weight: 330 parts cement, 110 parts slag powder, 187 parts mixing water, 1080 parts coarse aggregate, 810 parts fine aggregate, 14.4 parts modified fiber, 12 parts green corrosion inhibitor, 6 parts water-reducing agent, 0.24 parts defoamer, and 36 parts hydrophobic composite material.

[0095] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0096] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0097] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0098] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0099] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0100] Example 3

[0101] A green and high-durability marine concrete, by mass fraction, is composed of the following components: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 11 parts green corrosion inhibitor, 5 parts water-reducing agent, 0.2 parts defoamer, and 35 parts hydrophobic composite material.

[0102] A method for preparing green, high-durability marine concrete includes the following steps:

[0103] S1. Weigh the following components by weight: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 11 parts green corrosion inhibitor, 5 parts water-reducing agent, 0.2 parts defoamer, and 35 parts hydrophobic composite material.

[0104] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0105] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0106] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0107] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0108] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0109] Comparative Example 1

[0110] Compared to Example 1, no modification was performed on the fibers in Comparative Example 1.

[0111] A green and high-durability marine concrete is composed of the following components by mass fraction: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0112] A method for preparing green, high-durability marine concrete includes the following steps:

[0113] S1. Weigh the following components by weight: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0114] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0115] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0116] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0117] S5. Slowly and evenly add the fiber to the E mixture and stir until the fiber is fully dispersed. Stirring time is 5-7 minutes.

[0118] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0119] Comparative Example 2

[0120] Compared to Example 1, no green corrosion inhibitor was added in Comparative Example 2.

[0121] A green and high-durability marine concrete, by mass fraction, is composed of the following components: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0122] A method for preparing green, high-durability marine concrete includes the following steps:

[0123] S1. Weigh the following components by weight: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 4 parts water-reducing agent, 0.16 parts defoamer, and 34 parts hydrophobic composite material.

[0124] S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes.

[0125] S3. Add the water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is denoted as mixture D.

[0126] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0127] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0128] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0129] Comparative Example 3

[0130] Compared to Example 1, no hydrophobic composite material was added in Comparative Example 3.

[0131] A green and high-durability marine concrete is composed of the following components by mass fraction: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, and 0.16 parts defoamer.

[0132] A method for preparing green, high-durability marine concrete includes the following steps:

[0133] S1. Weigh the following components by weight: 310 parts cement, 130 parts slag powder, 183 parts mixing water, 1050 parts coarse aggregate, 830 parts fine aggregate, 14.3 parts modified fiber, 10 parts green corrosion inhibitor, 4 parts water-reducing agent, and 0.16 parts defoamer.

[0134] S2. Add cement, slag powder, coarse aggregate, and fine aggregate to the mixer and mix evenly for 3-4 minutes.

[0135] S3. Add the green corrosion inhibitor, water-reducing agent and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D.

[0136] S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture.

[0137] S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes.

[0138] S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

[0139] Table 3 shows the amounts of raw materials used in Examples 1-3 and Comparative Examples 1-3.

[0140] Table 3 shows the amount of raw materials used in Examples 1-3 and Comparative Examples 1-3.

[0141]

[0142]

[0143] Note: The fibers in Comparative Example 1 were not modified.

[0144] According to standards GB / T 2419-2005 and GB / T 50081-2019, the 28-day compressive strength and 28-day flexural strength of the marine concrete in Examples 1-3 and Comparative Examples 1-3 were tested respectively. The resistivity of the marine concrete in Examples 1-3 and Comparative Examples 1-3 after 56 days of corrosion was tested to evaluate the durability of the concrete structure. The water absorption rate of the marine concrete in Examples 1-3 and Comparative Examples 1-3 after immersion in water for 1 day was tested. The corrosion resistance coefficient of the marine concrete in Examples 1-3 and Comparative Examples 1-3 was tested under three factors: scouring, wet-dry cycles, and chloride ion attack. The corrosion resistance coefficient was defined as the ratio of the compressive strength of the concrete after corrosion to that before corrosion. Table 4 shows the performance of the marine concrete in Examples 1-3 and Comparative Examples 1-3.

[0145] Table 4. Performance of marine concrete in Examples 1-3 and Comparative Examples 1-3

[0146]

[0147] By comparing the performance results of Examples 1-3 and Comparative Examples 1-3 in Table 4, it can be found that the marine concrete in Examples 1-3 has better mechanical properties, higher resistivity, lower water absorption, and higher corrosion resistance coefficient, indicating that the marine concrete has better durability.

[0148] Compared with Example 1, since the fibers in Comparative Example 1 were not modified, the compressive strength and flexural strength of the marine concrete in Comparative Example 1 were both lower than those in Example 1. This indicates that modifying the fibers can enhance the bonding performance between the fibers and the concrete matrix, thereby enhancing the mechanical properties of the concrete. At the same time, it can be found that the corrosion resistance coefficient of the marine concrete in Comparative Example 1 is reduced. This is because the modified fibers can slow down the damage rate of the concrete.

[0149] As can be seen from Example 1 and Comparative Example 2, the addition of green corrosion inhibitor has little effect on the compressive strength, flexural strength and 1-day water absorption rate of concrete. The addition of green corrosion inhibitor can significantly enhance the resistivity and corrosion resistance coefficient of concrete, giving marine concrete better durability and steel reinforcement corrosion resistance.

[0150] As can be seen from Example 1 and Comparative Example 3, hydrophobic composite materials can slightly increase the compressive strength and flexural strength of concrete, with little impact on mechanical properties. However, the addition of hydrophobic composite materials can increase the resistivity and corrosion resistance coefficient of concrete, effectively reduce the water absorption coefficient of concrete, and significantly improve the durability of concrete.

[0151] The marine concrete provided by this invention increases the crack resistance of marine concrete by modifying fibers, delays the corrosion and expansion of steel bars by using green corrosion inhibitors, and increases the durability of the concrete matrix by using composite hydrophobic materials. This forms a three-in-one technology of interface reinforcement, steel bar corrosion protection and matrix waterproofing, which can significantly improve the service life of marine concrete structures and give them good mechanical properties and durability.

Claims

1. A high-durability marine concrete, characterized in that, The mixture is composed of the following components by mass fraction: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material. The modified fiber is obtained by modifying polyethylene fiber, wherein the length of the polyethylene fiber does not exceed 12 mm. The specific preparation method includes the following steps: P1. Immerse polyethylene fibers in anhydrous ethanol solution and subject the solution to ultrasonic treatment for 30-35 minutes. P2. Remove the polyethylene fiber from the anhydrous ethanol solution and repeatedly wash the polyethylene fiber with deionized water to remove any residue on the surface of the polyethylene fiber. P3. Place the cleaned polyethylene fibers in a forced-air drying oven and dry them at 50℃ for 4-4.5 hours. P4. Place 20g of polyethylene fiber into 1L of 5% polyvinylpyrrolidone solution and sonicate the solution for 30-35 minutes. After sonication, soak the fiber for another 30-35 minutes. P5. Remove the polyethylene fiber from the solution in P4, rinse the polyethylene fiber repeatedly with anhydrous ethanol and deionized water, and dry it at 50°C for 4-4.5 hours. P6. The polyethylene fiber in P5 is placed in a nano silica solution with a concentration of 5 g / L, and the solution is subjected to ultrasonic treatment for 3 hours to obtain the modified fiber. The preparation method of hydrophobic composite materials includes the following steps: N1. Mix 34.8g of water, 24.7g of coal slag and 1.39g of sodium hydroxide in a beaker and stir at 400r / min for 4.5h to obtain mixture C; N2, add 0.36g polymethylhydrosiloxane, 0.31g dimethylhydroxy silicone oil, 0.25g isobutyltriethoxysilane and 1.26g silica sol to the C mixture, stir at 400r / min for 3h, and place the beaker in a 100℃ oven to dry for 24h; N3. Crush the dried solid and sieve it through a 250-mesh sieve to obtain a hydrophobic composite material.

2. The high-durability marine concrete according to claim 1, characterized in that, The cement is ferric silicate cement.

3. The high-durability marine concrete according to claim 1, characterized in that, The slag powder is S95 or S105 grade slag powder.

4. The high-durability marine concrete according to claim 1, characterized in that, The coarse aggregate is graded crushed stone with a particle size distribution range of 5-25mm; the fine aggregate is river sand with a particle size not exceeding 4.75mm.

5. The high-durability marine concrete according to claim 1, characterized in that, The defoamer is tributyl phosphate.

6. The high-durability marine concrete according to claim 1, characterized in that, The water-reducing agent is a naphthalene-based water-reducing agent.

7. The high-durability marine concrete according to claim 1, characterized in that, The preparation method of the corrosion inhibitor includes the following steps: M1. Soak palm leaves in a water tank for 30 minutes, then rinse them with deionized water. Grind the cleaned leaves into powder using a grinder, and dry the powder in a drying oven at 105°C for 24 hours. M2. Mix the dried powder with a 30% sodium hydroxide solution at a solid-liquid ratio of 1:8 to obtain mixture A. M3. Continue stirring the mixture A and heat the mixture A at 170°C for 3 hours; M4. Filter the mixture A and wash the filter material of the mixture A with distilled water; M5. Add sulfuric acid with a mass fraction of 20% to the filtered mixture of A after washing until the pH of the mixture of A and sulfuric acid reaches 2, then stop adding sulfuric acid to obtain mixture B. M6. Centrifuge the B mixture for 10 min at 3500 rpm to obtain the reacted solid. Place the solid in an oven at 50°C and dry for 24 h. M7. The dried solid was repeatedly rinsed and filtered with a solution of pH 2 to remove residual hemicellulose. The resulting lignin was then dried in an oven at 50°C for 24 hours to obtain the corrosion inhibitor.

8. A method for preparing high-durability marine concrete as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Weigh the following components by weight: 310-330 parts cement, 110-130 parts slag powder, 183-187 parts mixing water, 1050-1080 parts coarse aggregate, 810-830 parts fine aggregate, 14.3-14.4 parts modified fiber, 10-12 parts corrosion inhibitor, 4-6 parts water-reducing agent, 0.16-0.24 parts defoamer, and 34-36 parts hydrophobic composite material. S2. Add cement, slag powder, coarse aggregate, fine aggregate, and hydrophobic composite material to the mixer and mix evenly for 3-4 minutes. S3. Add corrosion inhibitor, water reducer and defoamer to the mixing water and stir evenly for 1-2 minutes. The resulting mixture is called mixture D. S4. Add the D mixture evenly to the mixture in S2 and stir evenly for 3-4 minutes. The resulting mixture is the E mixture. S5. Slowly and evenly add the modified fiber to the E mixture and stir until the fiber is fully dispersed. The stirring time is 5-7 minutes. S6. Pour the fresh concrete obtained in S5 into a mold for curing. Curing is carried out for 24 hours at a temperature of 22±2℃ and a humidity of 99%. After demolding, it is cured to a fixed age to obtain cured marine concrete.

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