Low-carbon high-corrosion-resistance cement-based marine concrete and preparation method thereof

Abstract

The invention provides low-carbon high-corrosion-resistance cement-based marine concrete. Comprising 150-300 parts by weight of ordinary Portland cement, 50-120 parts by weight of fly ash, 50-120 parts by weight of mineral powder, 10-80 parts by weight of metakaolin, 30-80 parts by weight of a micro-expanding agent, 750-950 parts by weight of limestone macadam with the particle size of 10-20 mm, 100-200 parts by weight of limestone macadam with the particle size of 5-10 mm, 650-800 parts by weight of river sand with the particle size of 1-5 mm, 5-15 parts by weight of a polycarboxylate superplasticizer and 100-200 parts by weight of underground water. The invention further provides a related preparation method, the low-carbon high-corrosion-resistance cement-based marine concrete can reduce carbon emission and the cracking risk of the concrete, has excellent durability, impermeability and corrosion resistance, and prolongs the service life of the concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and more specifically, to the technical field of concrete materials, particularly a low-carbon and highly corrosion-resistant cement-based marine concrete and a preparation method thereof. Background Art

[0002] Building materials are various materials used in construction projects. There are many types of building materials, which can be roughly divided into: (1) inorganic materials, including metallic materials (including ferrous metallic materials and non-ferrous metallic materials) and non-metallic materials (such as natural stones, fired clay products, cement, concrete, and silicate products, etc.); (2) organic materials, including plant materials, synthetic polymer materials (including plastics, coatings, adhesives), and bituminous materials; (3) composite materials, including asphalt concrete, polymer concrete, etc., which are generally composed of inorganic non-metallic materials and organic materials.

[0003] Concrete is made by mixing cementitious materials, water, aggregates, and admixtures, and has good plasticity and load-bearing capacity, and is inexpensive with simple and convenient construction technology. It is the most widely used material in the world. However, due to various durability reasons, the macroscopic properties of concrete gradually deteriorate, and among them, the durability problems of coastal concrete structures have received extensive attention. Existing coastal concrete usually includes cement, coarse aggregates, fine aggregates, water reducers, and water, and improves the corrosion resistance by adding some concrete corrosion-resistant admixtures, or improves the pozzolanic activity of the admixtures by adding some mineral activators. Among the many factors causing the durability damage of coastal concrete structures, the corrosion problem caused by chloride ion erosion is the most serious. At the same time, the cementitious materials in concrete often have a great impact on the physical and chemical properties of concrete.

[0004] Therefore, it is desired to provide a coastal concrete that can reduce carbon emissions, reduce the risk of concrete cracking, has excellent durability, impermeability, and corrosion resistance, and improves the service life of concrete. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages in the prior art, an object of the present invention is to provide a low-carbon and highly corrosion-resistant cement-based marine concrete that can reduce carbon emissions, reduce the risk of concrete cracking, has excellent durability, impermeability, and corrosion resistance, improves the service life of concrete, and is suitable for large-scale popularization and application.

[0006] Another object of the present invention is to provide a preparation method of a low-carbon and highly corrosion-resistant cement-based marine concrete, which is simple to operate, and the low-carbon and highly corrosion-resistant cement-based marine concrete prepared therefrom can reduce carbon emissions, reduce the risk of concrete cracking, has excellent durability, impermeability, and corrosion resistance, improves the service life of concrete, and is suitable for large-scale popularization and application.

[0007] To achieve the above object, in the first aspect of the present invention, a low-carbon and highly corrosion-resistant cement-based marine concrete is provided, which is characterized by comprising the following raw materials in parts by weight:

[0008]

[0009] Preferably, the ordinary Portland cement is 180 parts by weight to 280 parts by weight, the fly ash is 60 parts by weight to 100 parts by weight, the slag powder is 60 parts by weight to 100 parts by weight, the metakaolin is 15 parts by weight to 50 parts by weight, the micro-expansion agent is 40 parts by weight to 60 parts by weight, the limestone gravel with a particle size of 10 mm to 20 mm is 800 parts by weight to 900 parts by weight, the limestone gravel with a particle size of 5 mm to 10 mm is 130 parts by weight to 180 parts by weight, the river sand with a particle size of 1 mm to 5 mm is 700 parts by weight to 780 parts by weight, the polycarboxylate water reducer is 6 parts by weight to 12 parts by weight, and the water is 120 parts by weight to 180 parts by weight.

[0010] Preferably, the ordinary Portland cement is 42.5-grade ordinary Portland cement.

[0011] Preferably, the fly ash is class I fly ash, the residue on a 45μm square-hole sieve of the class I fly ash is not more than 10% by weight, the water demand ratio of the class I fly ash is not more than 95%, and the specific surface area of the class I fly ash is greater than 400m 2 / kg.

[0012] Preferably, the slag powder is S95-grade granulated blast furnace slag powder, the specific surface area of the S95-grade granulated blast furnace slag powder is greater than 400m 2 / kg, and the 28d strength ratio of the S95-grade granulated blast furnace slag powder is 99.5%.

[0013] Preferably, the micro-expansion agent is a calcium-magnesium double-expansion-source high-performance expansion and crack-resistant agent.

[0014] Preferably, the 3d compressive strength of the low-carbon and highly corrosion-resistant cement-based marine concrete is greater than 30 MPa but not greater than 35 MPa, the 28d compressive strength of the low-carbon and highly corrosion-resistant cement-based marine concrete is greater than 50 MPa, and the 60d compressive strength of the low-carbon and highly corrosion-resistant cement-based marine concrete is greater than 60 MPa.

[0015] In the second aspect of the present invention, a preparation method of the above low-carbon and highly corrosion-resistant cement-based marine concrete is provided, which is characterized by comprising the following steps:

[0016] (1) Stir the limestone gravel with a particle size of 10 mm to 20 mm, the limestone gravel with a particle size of 5 mm to 10 mm, the river sand with a particle size of 1 mm to 5 mm, the fly ash, the mineral powder, the metakaolin, the micro-expansion agent and the ordinary Portland cement evenly.

[0017] (2) Add the water and the polycarboxylate water reducer, and stir evenly after standing to form a mixture.

[0018] Preferably, in the step (1), the stirring is carried out by a mixer for 120 s.

[0019] Preferably, in the step (2), the standing time is 120 s to 180 s.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention includes: 150 to 300 parts by weight of ordinary Portland cement, 50 to 120 parts by weight of fly ash, 50 to 120 parts by weight of mineral powder, 10 to 80 parts by weight of metakaolin, 30 to 80 parts by weight of micro-expansion agent, 750 to 950 parts by weight of limestone gravel with a particle size of 10 mm to 20 mm, 100 to 200 parts by weight of limestone gravel with a particle size of 5 mm to 10 mm, 650 to 800 parts by weight of river sand with a particle size of 1 mm to 5 mm, 5 to 15 parts by weight of polycarboxylate water reducer and 100 to 200 parts by weight of water. Therefore, it can reduce carbon emissions, reduce the risk of concrete cracking, has excellent durability, impermeability and corrosion resistance, improves the service life of concrete, and is suitable for large-scale popularization and application.

[0022] 2. The preparation method of the low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention includes: (1) Stir the limestone gravel with a particle size of 10 mm to 20 mm, the limestone gravel with a particle size of 5 mm to 10 mm, the river sand with a particle size of 1 mm to 5 mm, the fly ash, the mineral powder, the metakaolin, the micro-expansion agent and the ordinary Portland cement evenly; (2) Add the water and the polycarboxylate water reducer, and stir evenly after standing to form a mixture. Therefore, its operation is simple, and the low-carbon and high-corrosion-resistant cement-based marine concrete prepared by it can reduce carbon emissions, reduce the risk of concrete cracking, has excellent durability, impermeability and corrosion resistance, improves the service life of concrete, and is suitable for large-scale popularization and application.

[0023] These and other objects, features and advantages of the present invention are fully embodied by the following detailed description and claims, and can be realized by the means, devices and their combinations specifically pointed out in the appended claims. Detailed Embodiments

[0024] In order to reduce the traditional cement consumption, reduce carbon emissions, reduce the risk of concrete cracking, improve the durability, impermeability and corrosion resistance of concrete, the inventor has proposed a low-carbon and highly corrosion-resistant cement-based marine concrete and its preparation method through in-depth and extensive research.

[0025] First of all, the present invention provides a low-carbon and highly corrosion-resistant cement-based marine concrete, comprising the following raw materials in parts by weight:

[0026]

[0027] The parts by weight of the ordinary Portland cement, the fly ash, the slag powder, the metakaolin, the micro-expansion agent, the limestone gravel with a particle size of 10 mm to 20 mm, the limestone gravel with a particle size of 5 mm to 10 mm, the river sand with a particle size of 1 mm to 5 mm, the polycarboxylate water reducer, and the water can be determined as needed. Preferably, the ordinary Portland cement is 180 to 280 parts by weight, the fly ash is 60 to 100 parts by weight, the slag powder is 60 to 100 parts by weight, the metakaolin is 15 to 50 parts by weight, the micro-expansion agent is 40 to 60 parts by weight, the limestone gravel with a particle size of 10 mm to 20 mm is 800 to 900 parts by weight, the limestone gravel with a particle size of 5 mm to 10 mm is 130 to 180 parts by weight, the river sand with a particle size of 1 mm to 5 mm is 700 to 780 parts by weight, the polycarboxylate water reducer is 6 to 12 parts by weight, and the water is 120 to 180 parts by weight.

[0028] The ordinary Portland cement can be any suitable grade of ordinary Portland cement. Preferably, the ordinary Portland cement is 42.5-grade ordinary Portland cement, which has good compatibility with the polycarboxylate water reducer.

[0029] The fly ash can be any suitable fly ash. Preferably, the fly ash is grade-I fly ash. The residue on a 45μm square-hole sieve of the grade-I fly ash is not more than 10% by weight, the water demand ratio of the grade-I fly ash is not more than 95%, and the specific surface area of the grade-I fly ash is greater than 400m 2 / kg.

[0030] The slag powder can be any suitable slag powder. Preferably, the slag powder is S95-grade granulated blast furnace slag powder. The specific surface area of the S95-grade granulated blast furnace slag powder is greater than 400m 2 / kg, and the 28d strength ratio of the S95-grade granulated blast furnace slag powder is 99.5%.

[0031] The micro-expansive agent can be any suitable micro-expansive agent. Preferably, the micro-expansive agent is a high-performance expansion and crack resistance agent with calcium and magnesium double expansion sources.

[0032] The water can be any suitable water. Preferably, the water is groundwater.

[0033] The 3d compressive strength, 28d compressive strength, and 60d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete can have any suitable compressive strength. Preferably, the 3d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 30 MPa but not greater than 35 MPa, the 28d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 50 MPa, and the 60d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 60 MPa.

[0034] Secondly, the present invention provides a preparation method of the above-mentioned low-carbon and high-corrosion-resistant cement-based marine concrete, comprising the following steps:

[0035] (1) Stir the limestone gravel with a particle size of 10 mm - 20 mm, the limestone gravel with a particle size of 5 mm - 10 mm, the river sand with a particle size of 1 mm - 5 mm, the fly ash, the slag powder, the metakaolin, the micro-expansive agent, and the ordinary Portland cement evenly;

[0036] (2) Add the water and the polycarboxylate water reducer, and stir evenly after standing to form a mixture.

[0037] In the step (1), the stirring can be carried out under any suitable conditions. Preferably, in the step (1), the stirring is carried out by a mixer for 120 s.

[0038] In the step (2), the standing time can be determined as needed. Preferably, in the step (2), the standing time is 120 s - 180 s.

[0039] In order to more clearly understand the technical content of the present invention, the following examples are specifically given for detailed description.

[0040] The experimental methods without specific conditions in the following examples are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0041] Unless otherwise defined or described, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0042] Example 1

[0043] Formulation of low-carbon and highly corrosion-resistant cement-based marine concrete:

[0044]

[0045]

[0046] The ordinary Portland cement is 42.5-grade ordinary Portland cement; the fly ash is first-class fly ash (purchased from Xingyi Power Plant in Guizhou, with a residue on a 45μm square-hole sieve of 8.7% by weight, a water demand ratio of 93%, and a specific surface area of 419m 2 / kg); the blast furnace slag powder is S95-grade granulated blast furnace slag powder (Nanjing Nangang Jiahua slag powder, purchased from Nanjing Nangang, with a specific surface area of 438m 2 / kg and a 28-day strength ratio of 99.5%); the micro-expansion agent is a high-performance expansion and crack-resistant agent with calcium and magnesium double expansion sources (purchased from Nanjing Jingleixing Building Materials Co., Ltd., with a specific surface area of 375m 2 / kg).

[0047] The preparation method of low-carbon and highly corrosion-resistant cement-based marine concrete is as follows:

[0048] (1) Pour limestone gravel with a particle size of 10mm - 20mm, limestone gravel with a particle size of 5mm - 10mm, river sand with a particle size of 1mm - 5mm, fly ash, blast furnace slag powder, metakaolin, micro-expansion agent, and ordinary Portland cement into a mixer and stir for 120s;

[0049] (2) Add groundwater and polycarboxylate water reducer, and after 120s, stir evenly to form a well-workable mixture, that is, low-carbon and highly corrosion-resistant cement-based marine concrete;

[0050] (3) Pour the mixture into a mold, and after hardening and curing, form a low-carbon and highly corrosion-resistant cement-based marine concrete structure.

[0051] Example 2

[0052] Formulation of low-carbon and highly corrosion-resistant cement-based marine concrete:

[0053]

[0054]

[0055] The ordinary Portland cement is 42.5-grade ordinary Portland cement; the fly ash is first-class fly ash (purchased from Xingyi Power Plant in Guizhou, with a residue on a 45μm square-hole sieve of 8.7% by weight, a water demand ratio of 93%, and a specific surface area of 419m 2 / kg); the blast furnace slag powder is S95-grade granulated blast furnace slag powder (Nanjing Nangang Jiahua slag powder, purchased from Nanjing Nangang, with a specific surface area of 438m 2 / kg, the 28-day strength ratio is 99.5%); the micro-expansion agent is a high-performance expansion and crack-resistant agent with calcium and magnesium double expansion sources (purchased from Nanjing Jingleixing Building Materials Co., Ltd., specific surface area is 375 m 2 / kg).

[0056] The preparation method of low-carbon and high-corrosion-resistant cement-based marine concrete is as follows:

[0057] (1) Pour limestone gravel with a particle size of 10 mm - 20 mm, limestone gravel with a particle size of 5 mm - 10 mm, river sand with a particle size of 1 mm - 5 mm, fly ash, slag powder, metakaolin, micro-expansion agent and ordinary Portland cement into a mixer and stir for 120 s;

[0058] (2) Add groundwater and polycarboxylate water reducer, and stir evenly after 150 s to form a well-workable mixture, that is, low-carbon and high-corrosion-resistant cement-based marine concrete;

[0059] (3) Pour the mixture into a mold, and form a low-carbon and high-corrosion-resistant cement-based marine concrete structure after hardening and curing.

[0060] Example 3

[0061] The formula of low-carbon and high-corrosion-resistant cement-based marine concrete:

[0062]

[0063]

[0064] The ordinary Portland cement is 42.5-grade ordinary Portland cement; the fly ash is first-class fly ash (purchased from Guizhou Xingyi Power Plant, the residue on a 45μm square-hole sieve is 8.7% by weight, the water demand ratio is 93%, and the specific surface area is 419 m 2 / kg); the slag powder is S95-grade granulated blast furnace slag powder (Nanjing Nangang Jiahua Slag Powder, purchased from Nanjing Nangang, specific surface area is 438 m 2 / kg); the micro-expansion agent is a high-performance expansion and crack-resistant agent with calcium and magnesium double expansion sources (purchased from Nanjing Jingleixing Building Materials Co., Ltd., specific surface area is 375 m 2 / kg).

[0065] The preparation method of low-carbon and high-corrosion-resistant cement-based marine concrete is as follows:

[0066] (1) Pour limestone gravel with a particle size of 10 mm - 20 mm, limestone gravel with a particle size of 5 mm - 10 mm, river sand with a particle size of 1 mm - 5 mm, fly ash, slag powder, metakaolin, micro-expansion agent and ordinary Portland cement into a mixer and stir for 120 s;

[0067] (2) Add groundwater and polycarboxylate water reducer, and stir evenly after 180 s to form a well-workable mixture, namely low-carbon and high-corrosion-resistant cement-based marine concrete;

[0068] (3) Pour and mold the mixture, and form a low-carbon and high-corrosion-resistant cement-based marine concrete structure after hardening and curing.

[0069] Example 4

[0070] Conduct relevant performance tests on the low-carbon and high-corrosion-resistant cement-based marine concrete prepared in Examples 1 to 3.

[0071] 1) Slump test method: The slump test is carried out according to the relevant regulations in the Standard Test Method for Performance of Ordinary Concrete Mixtures GB / T 50080-2016;

[0072] 2) Setting time test method: The setting time test is carried out and calculated according to the relevant regulations in the Standard Test Method for Performance of Ordinary Concrete Mixtures GB / T 50080-2016;

[0073] 3) Compressive strength test method: The concrete cube compressive strength test is carried out and calculated according to the relevant regulations in the Standard Test Method for Physical and Mechanical Properties of Concrete GB / T 50080-2016;

[0074] 4) Impermeability strength test method: The concrete cube compressive strength test is carried out and calculated according to the relevant regulations in the Standard Test Method for Physical and Mechanical Properties of Concrete GB / T 50080-2016;

[0075] 5) 56d electric flux and 56d Cl⁻ migration coefficient test method: The test and calculation are carried out according to the relevant regulations in the Standard Test Method for Long-Term and Durability Performance of Concrete GB / T50082-2024;

[0076] 6) Crack detection method: Visual inspection and a concrete crack detector are mainly used to detect the width and depth of cracks. The concrete crack detector used is the ZBL-F800 Comprehensive Crack Tester produced by Beijing Zhibolian.

[0077] The test results are shown in Tables 1 and 2 as follows:

[0078] Table 1:

[0079]

[0080] In terms of the initial setting time and final setting time, the setting time of the low-carbon and high-corrosion-resistant cement-based marine concrete disclosed in the present invention is normal, which can meet the needs of the construction site. Its early strength is relatively low, but the later strength is relatively high. It can be shown that the risk of early shrinkage and cracking of the concrete can be reduced, while ensuring relatively high strength in the later stage and improving its service life in harsh environments.

[0081] Table 2:

[0082]

[0083] From the data of the electricity passing amount and migration coefficient, it can be concluded that the low-carbon and high-corrosion-resistant cement-based marine concrete provided by the present invention has excellent durability, impermeability and corrosion resistance, and can effectively hinder the erosion of erosion ions in the seawater medium. The use of active mineral admixtures such as fly ash and slag powder can effectively improve the compactness of the concrete, showing a relatively high impermeability grade. Fewer permeation paths hinder the erosion medium from entering the interior of the concrete, thereby reducing the risk of steel bar corrosion. At the same time, it has an obvious effect on reducing concrete cracking.

[0084] In the present invention, by appropriately adding metakaolin, the transformation of ettringite to AFm phase can be effectively promoted, and the ability of the concrete to chemically solidify chloride ions can be greatly improved; through slag powder, the degree of protonation of the C-S-H structure in the hydration products can be effectively reduced, and at the same time, C-S-A-H can be formed, which can significantly improve the chloride ion solidification ability of the paste; through the micro-expansion agent, it is used to compensate for the shrinkage of the concrete and improve the crack resistance of the concrete.

[0085] The present invention introduces a composite active mineral admixture, studies the influence of morphological effects such as the composition, particle size distribution and surface structure of the composite high-activity mineral admixture on the hydration heat, mechanical properties and corrosion properties of the cement-based material, rationally distributes coarse aggregates with large particle size and small particle size as the filling of the cement-based based on the maximum packing density, forms a well-compacted mixture, and forms a structure with good mechanical properties with ordinary Portland cement and active mineral admixture, and establishes an optimized preparation method for low-carbon and high-corrosion-resistant cement-based marine engineering materials. The low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention is prepared, which has the characteristics of low carbon and excellent strength, durability, corrosion resistance and impermeability.

[0086] Compared with the prior art, the low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention has the following advantages:

[0087] 1. By selecting raw materials and their gradation distribution, a low-carbon and high-corrosion-resistant cement-based marine concrete can be obtained, which can delay the development of early strength of the concrete, reduce the cracking risk of the concrete structure, and has excellent later strength, durability, corrosion resistance and impermeability and other characteristics, and can be widely used in the construction of coastal buildings.

[0088] 2. The mineral powder and metakaolin adopted can greatly improve the chloride ion curing ability of concrete.

[0089] 3. The active mineral admixture adopted can replace the cement dosage and reduce carbon emissions.

[0090] The low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention is applicable to coastal buildings or underground structures rich in groundwater, delays the early strength development of concrete, reduces the cracking risk of concrete structures, improves the later strength of concrete, and improves the compactness, impermeability and later strength of concrete.

[0091] In summary, the low-carbon and high-corrosion-resistant cement-based marine concrete of the present invention can reduce carbon emissions, reduce the cracking risk of concrete, has excellent durability, impermeability and corrosion resistance, improves the service life of concrete, and is suitable for large-scale popularization and application.

[0092] In this specification, the present invention has been described with reference to its specific embodiments. However, it is obvious that various modifications and transformations can still be made without departing from the spirit and scope of the present invention. Therefore, the specification should be regarded as illustrative rather than restrictive.

Claims

1. A low-carbon, high-corrosion-resistant cement-based marine concrete, characterized in that: The invention comprises the following raw materials in parts by weight:

2. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The ordinary Portland cement is 180 to 280 parts by weight, the fly ash is 60 to 100 parts by weight, the mineral powder is 60 to 100 parts by weight, the metakaolin is 15 to 50 parts by weight, the micro-expansion agent is 40 to 60 parts by weight, the limestone crushed stone with a particle size of 10 mm to 20 mm is 800 to 900 parts by weight, the limestone crushed stone with a particle size of 5 mm to 10 mm is 130 to 180 parts by weight, the river sand with a particle size of 1 mm to 5 mm is 700 to 780 parts by weight, the polycarboxylate water reducer is 6 to 12 parts by weight, and the water is 120 to 180 parts by weight.

3. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The ordinary Portland cement is 42.5 grade ordinary Portland cement.

4. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The fly ash is first-class fly ash, the residue on a 45 μm square sieve of the first-class fly ash is not more than 10% by weight, the water requirement ratio of the first-class fly ash is not more than 95%, and the specific surface area of ​​the first-class fly ash is greater than 400 m 2 / kg.

5. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The mineral powder is S95 grade granulated blast furnace slag powder, and the specific surface area of ​​the S95 grade granulated blast furnace slag powder is greater than 400m 2 / kg, the 28d strength of the S95 grade granulated blast furnace slag powder is 99.5%.

6. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The micro-expansion agent is a high-performance expansion and anti-cracking agent with calcium and magnesium dual expansion sources.

7. The low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The 3d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 30MPa but not greater than 35MPa, the 28d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 50MPa, and the 60d compressive strength of the low-carbon and high-corrosion-resistant cement-based marine concrete is greater than 60MPa.

8. A method for preparing low-carbon, high-corrosion-resistant cement-based marine concrete according to claim 1, characterized in that: The following steps are involved: (1) mixing the limestone crushed stone with a particle size of 10 mm to 20 mm, the limestone crushed stone with a particle size of 5 mm to 10 mm, the river sand with a particle size of 1 mm to 5 mm, the fly ash, the mineral powder, the metakaolin, the micro-expansion agent and the ordinary Portland cement uniformly; (2) adding the water and the polycarboxylate water-reducing agent, allowing to stand and then stirring to form a mixture.

9. The preparation method according to claim 8, characterized in that: In the step (1), the stirring is carried out using a stirrer for 120 seconds.

10. The preparation method according to claim 8, characterized in that: In the step (2), the standing time is 120s to 180s.

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