Preparation process of marine concrete material resistant to chloride ion erosion

Abstract

The application relates to the field of concrete materials, and particularly discloses a preparation process of a marine concrete material resistant to chloride ion erosion, which comprises the following steps: (1) adding mixed powder formed by metastable modified powder, gamma-C2S or silicate powder and sodium alginate powder into a calcium nitrate solution, stirring until uniform, then separating the solid product, drying, mixing with oleic acid, grinding to obtain core powder; (2) adding the core powder into a coating liquid formed by sodium stearate, ethyl acetate, acrylic acid and an ethanol aqueous solution, stirring until uniform, then performing spray drying to obtain a self-repairing impermeability agent; (3) taking cement, fine aggregate, fly ash, the self-repairing impermeability agent, steel fiber and water reducing agent as raw materials, mixing the raw materials with water until uniform, and obtaining the concrete material. The concrete material can not only improve the chloride ion penetration resistance of the concrete material, but also solidify the entered chloride ions, and has the function of self-repairing cracks.

Description

Technical Field

[0001] This invention relates to the field of concrete materials, and specifically to a preparation process for a marine concrete material resistant to chloride ion corrosion. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Marine engineering is a key field supporting marine resource development, coastal protection, and maritime transportation. Concrete, as the most widely used and crucial building material, directly determines the safety and lifespan of marine engineering structures (such as cross-sea bridges, subsea tunnels, port terminals, and offshore wind power foundations) through its long-term durability. Compared to terrestrial environments, marine environments pose extremely harsh and complex multiple challenges to concrete structures. In particular, chloride ions, transported by moisture, penetrate into the concrete. When they reach the surface of the reinforcing steel and accumulate to a certain concentration, they damage the passivation film on the steel surface, leading to rapid corrosion. The volume of corrosion products increases by 2 to 4 times, and the resulting expansion stress causes cracks in the concrete structure, resulting in deterioration of its performance.

[0004] Adding hydrophobic agents to concrete can effectively improve its impermeability, which is one way to enhance its resistance to chloride ion attack. However, because hydrophobic agents coat the surface of cement particles to form a hydrophobic film, they hinder sufficient contact between cement particles and water, thus affecting the hydration reaction of cement particles and leading to insufficient strength development in the concrete. In addition, some hydrophobic agents can introduce a large number of air bubbles into the concrete material, resulting in a decrease in structural density, which also has an adverse effect on the strength of the concrete. Moreover, once cracks appear in the concrete structure due to shrinkage, load, etc., the pressure from seawater impact will accelerate the intrusion of chloride ions. Summary of the Invention

[0005] In view of this, the present invention provides a preparation process for a chloride-resistant marine concrete material, which not only improves the concrete material's resistance to chloride ion penetration but also solidifies the introduced chloride ions and has a self-repairing function for cracks. Specifically, the technical solution of the present invention is as follows.

[0006] A preparation process for a chloride ion-resistant marine concrete material includes the following steps:

[0007] (1) The layered bimetallic hydroxide powder is calcined to convert carbonate and hydroxide ions into water molecules and release carbon dioxide. Then, the obtained thermally modified layered bimetallic hydroxide is placed in a carbonate aqueous solution and stirred. After completion, the solid is separated and dried to obtain metastable modified powder.

[0008] (2) The mixed powder formed by the metastable modified powder, γ-C2S or calcium silicate powder and sodium alginate powder is added to calcium nitrate solution and stirred evenly. Then the solid product is separated, dried and mixed with oleic acid and ground to obtain the core powder.

[0009] (3) The core powder is added to the coating solution formed by sodium stearate, ethyl acetate, acrylic acid and ethanol aqueous solution and stirred evenly. Then the resulting solid-liquid mixture is spray-dried to obtain a self-healing impermeable agent.

[0010] (4) Take the following raw materials: cement, fine aggregate, fly ash, the self-healing impermeable agent, steel fiber, and water-reducing agent. Mix the above raw materials with mixing water to obtain concrete material.

[0011] Furthermore, in step (1), the fineness of the layered bimetallic hydroxide powder is 350~500 mesh.

[0012] Furthermore, in step (1), the calcination temperature is 400~450℃ and the time is 1~1.5 hours.

[0013] Further, in step (1), the ratio of the thermally modified layered bimetallic hydroxide to the carbonate aqueous solution is 1g: 20~40mL. Optionally, the mass fraction of the carbonate aqueous solution is 5~10%. The carbonate includes at least one of sodium carbonate, potassium carbonate, etc.

[0014] Further, in step (1), the stirring time is 30-50 minutes. Optionally, the drying temperature is 60-70°C.

[0015] Further, in step (2), the ratio of the metastable modified powder, γ-C2S or calcium silicate powder, and sodium alginate powder is 2~2.55g: 1~1.3g: 0.27~0.32g. Optionally, the fineness of the γ-C2S or calcium silicate powder is 300~500 mesh.

[0016] Further, in step (2), the ratio of the mixed powder to the calcium nitrate solution is 1g:30~40mL. Optionally, the mass fraction of the calcium nitrate solution is 10~16%.

[0017] Further, in step (2), the ratio of the solid product obtained after drying to oleic acid is 1g:0.12~0.18g. Optionally, the fineness of the core powder is 200~300 mesh.

[0018] Further, in step (3), the ethanol-water solution contains: sodium stearate in a saturated state, ethyl acetate with a mass fraction of 20-35%, acrylic acid with a mass fraction of 50-60%, and the concentration of the ethanol-water solution is 90-95 wt.%. That is, the coating solution is formed by distributing sodium stearate, ethyl acetate, and ethyl acetate in the ethanol-water solution as the base solution.

[0019] Further, in step (3), the ratio of the core powder to the coating liquid is 1g:7~10mL.

[0020] Further, in step (4), the proportions of cement, fine aggregate, fly ash, self-healing impermeable agent, steel fiber, and water-reducing agent are 170~190 parts by weight: 205~253 parts by weight: 15~25 parts by weight: 20~28 parts by weight: 4~7 parts by weight: 0.26~0.44 parts by weight.

[0021] Furthermore, in step (4), the total mass ratio of the mixing water to cement and fly ash is 0.37~0.41:1.

[0022] Further, in step (4), the steel fiber has a length of 5~15mm and a diameter of 0.18~0.23mm.

[0023] Further, in step (4), the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene water-reducing agent, aminosulfonate water-reducing agent, lignin sulfonate water-reducing agent, etc.

[0024] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0025] This invention first calcines a layered bimetallic hydroxide to convert the interlayer anions (carbonate and hydroxide) into water molecules and release carbon dioxide. Then, the resulting thermally modified layered bimetallic hydroxide is treated in a carbonate aqueous solution. The carbonate and hydroxide ions provided by the hydrolysis in this solution re-enter the interlayer space of the layered bimetallic hydroxide for structural reconstruction. These re-intercalated anions have reduced stability compared to the original interlayer anions, resulting in a metastable modified powder that is more susceptible to anion exchange. Next, this invention adds a mixed powder of this metastable modified powder with γ-C2S or calcium silicate powder and sodium alginate powder to a calcium nitrate solution for further treatment. During this process, the sodium alginate cross-links under the action of calcium ions, binding the powders together. Simultaneously, the cross-linked sodium alginate forms a gel, providing a storage space for subsequently added oleic acid. Finally, this invention coats the resulting core powder with an acrylic coating containing sodium stearate and ethyl acetate to form a self-healing impermeable agent. When incorporated into concrete, the cement components hydrate to form a large amount of calcium hydroxide, which reacts with the sodium stearate in the coating to form calcium stearate and sodium hydroxide. The ethyl acetate is hydrolyzed by the sodium hydroxide to release ethanol, thereby forming micropores on the coating. The oleic acid released therein diffuses rapidly under the drive of the ethanol and together with the calcium stearate, it forms a more comprehensive hydrophobic system, reducing the impermeability of the concrete and thus reducing the intrusion of chloride ions from seawater. On the other hand, during the service life of the concrete material of the present invention, the metastable modified powder in the self-healing impermeable agent exchanges with the carbonate ions in it after encountering invading chloride ions. This not only fixes the chloride ions in the metastable modified powder to prevent them from further diffusing and eroding the steel fibers in the concrete, but also the carbonate ions released after the ion exchange initiate a reaction with the γ-C2S or calcium silicate to form nano-silica gel. This gel further reacts with calcium hydroxide in the concrete to form hydrated calcium silicate cementitious products. This not only solidifies the chloride ions, but also repairs the microcracks in the concrete. Thus, once moisture carries chloride ions into the microcracks, the chloride ions can be used to activate the solidification and self-healing mechanisms, blocking the channels for chloride ion penetration and diffusion, and reducing the adverse effects. Attached Figure Description

[0026] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein:

[0027] Figure 1 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 1 below.

[0028] Figure 2 Cl is the concrete material prepared in Examples 1-7 below - Migration coefficient test chart.

[0029] Figure 3 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 2 below.

[0030] Figure 4 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 3 below.

[0031] Figure 5 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 4 below.

[0032] Figure 6 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 5 below.

[0033] Figure 7 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 6 below.

[0034] Figure 8 Figure (a) and flexural strength test results (b) of the self-healing impermeable agent sample prepared for Example 7 below. Detailed Implementation

[0035] The present invention is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention.

[0037] Example 1: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0038] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 400 mesh to 420℃ and keep it at that temperature for 1.5 hours. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with an 8% sodium carbonate solution at a ratio of 1g:35mL and stir for 40min. Then filter out the solid and dry it at 60℃ until the mass remains constant to obtain metastable modified powder.

[0039] (2) The metastable modified powder, 400-mesh γ-C2S powder and sodium alginate powder are mixed evenly in a ratio of 2.3g:1.2g:0.3g. The resulting mixed powder is then mixed with 15% calcium nitrate solution in a ratio of 1g:35mL and stirred for 2 minutes. After completion, the solid product is filtered out and dried at 60℃ until the mass remains constant. The resulting product is then mixed with oleic acid in a ratio of 1g:0.14g and ground for 1 hour. The mixture is then passed through a 200-mesh sieve to obtain the core powder.

[0040] (3) Sodium stearate, ethyl acetate, and acrylic acid are added to a 90 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution. The sodium stearate is saturated, the ethyl acetate has a mass fraction of 25%, and the acrylic acid has a mass fraction of 50%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 8 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 1 (as shown in a).

[0041] (4) Take the following raw materials in the following proportions: 175 parts by weight of 42.5 ordinary Portland cement, 220 parts by weight of fine aggregate, 20 parts by weight of Grade I fly ash, 24 parts by weight of the self-healing impermeable agent of this embodiment, 5 parts by weight of steel fiber, and 0.38 parts by weight of polycarboxylate superplasticizer. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 13mm and a diameter of 0.21mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 78 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0042] Performance Testing: 1. The Cl of the concrete material prepared in this embodiment was tested according to the "Standard for Test Methods of Long-Term Performance and Durability of Concrete" (GBT 50082-2024). - migration coefficient D RCM (like Figure 2(As shown). 2. Pour the concrete material of this embodiment into the mold, demold after hardening, and then cure according to standard for 28 days. After completion, immerse the obtained specimen in a 3.5% sodium chloride solution for 7 days, and then test the flexural strength of the obtained specimen after 10 days (e.g., ...). Figure 1 (as shown in b), the higher the value, the stronger the resistance to chloride ion corrosion. The results are shown in Table 1 below:

[0043]

[0044] Example 2: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0045] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 350 mesh to 450℃ and keep it at that temperature for 1 hour. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with a 10% sodium carbonate solution at a ratio of 1g:20mL and stir for 50min. Then filter out the solid and dry it at 70℃ until the mass remains constant to obtain metastable modified powder.

[0046] (2) The metastable modified powder, 300-mesh γ-C2S powder and sodium alginate powder are mixed evenly in a ratio of 2g:1g:0.27g. The resulting mixed powder is then mixed with 10% calcium nitrate solution in a ratio of 1g:40mL and stirred for 2min. After completion, the solid product is filtered out and dried at 65℃ until the mass remains constant. The resulting product is then mixed with oleic acid in a ratio of 1g:0.12g and ground for 1 hour. The mixture is then passed through a 200-mesh sieve to obtain the core powder.

[0047] (3) Sodium stearate, ethyl acetate, and acrylic acid are added to a 90 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution. The sodium stearate is saturated, the ethyl acetate has a mass fraction of 35%, and the acrylic acid has a mass fraction of 60%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 10 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 3 (as shown in a).

[0048] (4) Take the following raw materials in the following proportions: 190 parts by weight of 42.5 ordinary Portland cement, 253 parts by weight of fine aggregate, 25 parts by weight of Grade I fly ash, 28 parts by weight of the self-healing impermeable agent of this embodiment, 7 parts by weight of steel fiber, and 0.44 parts by weight of polycarboxylate superplasticizer. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 5mm and a diameter of 0.18mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 88.15 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0049] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 3 (as shown in b), the results are shown in Table 2 below:

[0050]

[0051] Example 3: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0052] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 500 mesh to 400℃ and keep it at that temperature for 1.5 hours. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with a sodium carbonate solution of 5% by mass at a ratio of 1g:40mL and stir for 30min. Then filter out the solid and dry it at 70℃ until the mass remains constant to obtain metastable modified powder.

[0053] (2) The metastable modified powder, 500-mesh calcium silicate powder, and sodium alginate powder are mixed evenly in a ratio of 2.55g:1.3g:0.32g. The resulting mixed powder is then mixed with a 16% calcium nitrate solution in a ratio of 1g:30mL and stirred for 2 minutes. After completion, the solid product is filtered out and dried at 70°C until the mass remains constant. The resulting product is then mixed with oleic acid in a ratio of 1g:0.18g and ground for 1.5 hours. The mixture is then passed through a 300-mesh sieve to obtain the core powder.

[0054] (3) Sodium stearate, ethyl acetate, and acrylic acid are added to a 95 wt.% ethanol aqueous solution and stirred until homogeneous to form a coating solution, wherein the sodium stearate is saturated, the ethyl acetate has a mass fraction of 20%, and the acrylic acid has a mass fraction of 50%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 7 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 4 (as shown in a).

[0055] (4) Take the following raw materials in the following proportions: 170 parts by weight of 42.5 ordinary Portland cement, 205 parts by weight of fine aggregate, 15 parts by weight of Grade I fly ash, 20 parts by weight of the self-healing impermeable agent of this embodiment, 4 parts by weight of steel fiber, and 0.26 parts by weight of sodium lignosulfonate water-reducing agent. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 15mm and a diameter of 0.23mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 68.45 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0056] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 4 (as shown in b), the results are shown in Table 3 below:

[0057]

[0058] Example 4: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0059] (1) Mix the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 400 mesh, γ-C2S powder with a fineness of 400 mesh, and sodium alginate powder in a ratio of 2.3g:1.2g:0.3g. Then mix the resulting powder with a 15% calcium nitrate solution in a ratio of 1g:35mL and stir for 2min. After completion, filter out the solid product and dry it at 60℃ until the mass remains constant. Then mix the resulting product with oleic acid in a ratio of 1g:0.14g and grind for 1 hour. Then pass it through a 200-mesh sieve to obtain the core powder.

[0060] (2) Sodium stearate, ethyl acetate, and acrylic acid are added to a 90 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution. The sodium stearate is saturated, the ethyl acetate has a mass fraction of 25%, and the acrylic acid has a mass fraction of 50%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 8 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 5 (as shown in a).

[0061] (3) Take the following raw materials in the following proportions: 175 parts by weight of 42.5 ordinary Portland cement, 220 parts by weight of fine aggregate, 20 parts by weight of Grade I fly ash, 24 parts by weight of the self-healing impermeable agent of this embodiment, 5 parts by weight of steel fiber, and 0.38 parts by weight of polycarboxylate superplasticizer. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 13mm and a diameter of 0.21mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 78 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0062] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 5 (as shown in b), the results are shown in Table 4 below:

[0063]

[0064] Example 5: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0065] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 500 mesh to 400℃ and keep it at that temperature for 1.5 hours. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with a sodium carbonate solution of 5% by mass at a ratio of 1g:40mL and stir for 30min. Then filter out the solid and dry it at 70℃ until the mass remains constant to obtain metastable modified powder.

[0066] (2) The metastable modified powder and sodium alginate powder were mixed evenly at a ratio of 2.55g:0.32g. The resulting mixed powder was then mixed with a 16% calcium nitrate solution at a ratio of 1g:30mL and stirred for 2 minutes. After completion, the solid product was filtered out and dried at 70℃ until the mass remained constant. The resulting product was then mixed with oleic acid at a ratio of 1g:0.18g and ground for 1.5 hours. The mixture was then passed through a 300-mesh sieve to obtain the core powder.

[0067] (3) Sodium stearate, ethyl acetate, and acrylic acid are added to a 95 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution. The sodium stearate is saturated, the ethyl acetate has a mass fraction of 20%, and the acrylic acid has a mass fraction of 50%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 7 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 6 (as shown in a).

[0068] (4) Take the following raw materials in the following proportions: 170 parts by weight of 42.5 ordinary Portland cement, 205 parts by weight of fine aggregate, 15 parts by weight of Grade I fly ash, 20 parts by weight of the self-healing impermeable agent of this embodiment, 4 parts by weight of steel fiber, and 0.26 parts by weight of sodium lignosulfonate water-reducing agent. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 15mm and a diameter of 0.23mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 68.45 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0069] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 6 (as shown in b), the results are shown in Table 5 below:

[0070]

[0071] Example 6: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0072] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 400 mesh to 420℃ and keep it at that temperature for 1.5 hours. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with an 8% sodium carbonate solution at a ratio of 1g:35mL and stir for 40min. Then filter out the solid and dry it at 60℃ until the mass remains constant to obtain metastable modified powder.

[0073] (2) The metastable modified powder, 400-mesh γ-C2S powder and sodium alginate powder are mixed evenly in a ratio of 2.3g:1.2g:0.3g. The resulting mixed powder is then mixed with 15% calcium nitrate solution in a ratio of 1g:35mL and stirred for 2 minutes. After completion, the solid product is filtered out and dried at 60℃ until the mass remains constant. The resulting product is then mixed with oleic acid in a ratio of 1g:0.14g and ground for 1 hour. The mixture is then passed through a 200-mesh sieve to obtain the core powder.

[0074] (3) Sodium stearate and acrylic acid are added to a 90 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution, wherein the sodium stearate is saturated and the acrylic acid has a mass fraction of 50%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 8 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 7 (as shown in a).

[0075] (4) Take the following raw materials in the following proportions: 175 parts by weight of 42.5 ordinary Portland cement, 220 parts by weight of fine aggregate, 20 parts by weight of Grade I fly ash, 24 parts by weight of the self-healing impermeable agent of this embodiment, 5 parts by weight of steel fiber, and 0.38 parts by weight of polycarboxylate superplasticizer. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 13mm and a diameter of 0.21mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 78 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0076] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 7 (as shown in b), the results are shown in Table 6 below:

[0077]

[0078] Example 7: A preparation process for a chloride ion-resistant marine concrete material, comprising the following steps:

[0079] (1) Heat the layered bimetallic hydroxide powder (Mg6Al2(OH)CO3·4H2O) with a fineness of 350 mesh to 450℃ and keep it at that temperature for 1 hour. After that, cool it to room temperature. Mix the obtained thermally modified layered bimetallic hydroxide with a 10% sodium carbonate solution at a ratio of 1g:20mL and stir for 50min. Then filter out the solid and dry it at 70℃ until the mass remains constant to obtain metastable modified powder.

[0080] (2) The metastable modified powder, 300-mesh γ-C2S powder and sodium alginate powder are mixed evenly in a ratio of 2g:1g:0.27g. The resulting mixed powder is then mixed with 10% calcium nitrate solution in a ratio of 1g:40mL and stirred for 2min. After completion, the solid product is filtered out and dried at 65℃ until the mass remains constant. The resulting product is then mixed with oleic acid in a ratio of 1g:0.12g and ground for 1 hour. The mixture is then passed through a 200-mesh sieve to obtain the core powder.

[0081] (3) Ethyl acetate and acrylic acid are added to a 90 wt.% aqueous ethanol solution and stirred until homogeneous to form a coating solution, wherein the mass fraction of ethyl acetate is 35% and the mass fraction of acrylic acid is 60%. Then, the core powder and the coating solution are mixed at a ratio of 1 g: 10 mL and stirred until homogeneous. The resulting solid-liquid mixture is then spray-dried to obtain a self-healing impermeable agent (such as...). Figure 8 (as shown in a).

[0082] (4) Take the following raw materials in the following proportions: 190 parts by weight of 42.5 ordinary Portland cement, 253 parts by weight of fine aggregate, 25 parts by weight of Grade I fly ash, 28 parts by weight of the self-healing impermeable agent of this embodiment, 7 parts by weight of steel fiber, and 0.44 parts by weight of polycarboxylate superplasticizer. Wherein: the fine aggregate is composed of river sand with particle sizes of 0.1~0.25mm, 0.3~0.6mm, and 0.7~1mm graded in a mass ratio of 1:1:2, and the steel fiber has a length of 5mm and a diameter of 0.18mm. Add the above raw materials to a mixer and mechanically mix for 4 minutes, then add 88.15 parts by weight of mixing water and continue mixing for 2 minutes to obtain the concrete material.

[0083] Performance testing: The Cl of the concrete material prepared in this embodiment was tested using the same method as in Example 1 above. - migration coefficient D RCM (like Figure 2 (as shown) and flexural strength (as shown) Figure 8 (as shown in b), the results are shown in Table 7 below:

[0084]

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for the production of a marine concrete material resistant to attack by chloride ions, characterised in that, Comprise the following steps: (1) the layered double hydroxide powder is calcined to make its carbonate and hydroxyl radical into water molecules and carbon dioxide release, then the obtained thermal modification layered double hydroxide is placed in carbonate aqueous solution and stirred, after completion, the solid product is separated and dried, to obtain a metastable modified powder; (2) the mixed powder formed by the metastable modified powder, γ-C2S or xonotlite powder, sodium alginate powder is added to calcium nitrate solution and stirred uniformly, then the solid product is separated, dried and mixed with oleic acid, and then ground to obtain an inner core powder; (3) the inner core powder is added to a coating liquid formed by sodium stearate, ethyl acetate, acrylic acid and ethanol aqueous solution and stirred uniformly, then the obtained solid-liquid mixture is spray dried to obtain a self-repairing impermeable agent; (4) take the following raw materials: cement, fine aggregate, fly ash, the self-repairing impermeable agent, steel fiber and water reducing agent;Mix the above raw materials with mixing water uniformly to obtain a concrete material.

2. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (1), the calcination temperature is 400-450℃, and the time is 1-1.5 hours;Or, in step (1), the fineness of the layered double hydroxide powder is 350-500 mesh.

3. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (1), the ratio of the thermal modification layered double hydroxide to the carbonate aqueous solution is 1g:20-40mL.

4. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (1), the carbonate includes at least one of sodium carbonate and potassium carbonate; Or, in step (1), the mass fraction of the carbonate aqueous solution is 5-10%; Or, in step (1), the stirring time is 30-50min; Or, in step (1), the drying temperature is 60-70℃.

5. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (2), the ratio of the metastable modified powder, γ-C2S or xonotlite powder and sodium alginate powder is 2-2.55g:1-1.3g:0.27-0.32g.

6. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (2), the ratio of the mixed powder to the calcium nitrate solution is 1g:30-40mL; Or, in step (2), the fineness of the γ-C2S or xonotlite powder is 300-500 mesh; Or, in step (2), the mass fraction of the calcium nitrate solution is 10-16%.

7. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (2), the ratio of the obtained solid product after drying to oleic acid is 1g:0.12-0.18g;Or, in step (2), the fineness of the inner core powder is 200-300 mesh.

8. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (3), in the ethanol aqueous solution, the sodium stearate is in a saturated state, the mass fraction of the ethyl acetate is 20-35%, the mass fraction of the acrylic acid is 50-60%, and the concentration of the ethanol aqueous solution is 90-95wt.%.

9. The process for preparing a marine concrete material resistant to chloride ion attack according to claim 1, characterized in that, In step (3), the ratio of the inner core powder to the coating liquid is 1g:7-10mL.

10. Process for the production of a marine concrete material resistant to chloride ion attack according to any one of claims 1 to 9, characterized in that, In step (4), the ratio of the cement, fine aggregate, fly ash, self-repairing impermeable agent, steel fiber and water reducing agent is 170-190 parts by weight:205-253 parts by weight:15-25 parts by weight:20-28 parts by weight:4-7 parts by weight:0.26-0.44 parts by weight. Or, in step (4), the total mass ratio of the mixing water to cement and fly ash is 0.37-0.41:

1. Or, in step (4), the length of the steel fiber is 5-15 mm, and the diameter is 0.18-0.23 mm. Or, in step (4), the water reducing agent includes at least one of polycarboxylic acid water reducing agent, naphthalene water reducing agent, amino sulfonate water reducing agent, and lignin sulfonate water reducing agent.

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