Preparation process of anti-cracking marine cement material based on carbide slag-based expanding agent

Abstract

The application relates to the field of marine cement materials, and particularly discloses a preparation process of a crack-resistant marine cement material based on a carbide slag-based expansion agent, which comprises the following steps: (1) uniformly mixing carbide slag and sodium silicate powder, and then performing calcination treatment; after the completion, grinding the calcination product, then adding the obtained powder into an anhydrous ethanol dispersion solution of nano silicon dioxide, sealing and then heating to react; after the completion, separating the solid product and drying to obtain modified micro powder of grade I; (2) uniformly mixing the modified micro powder of grade I with a silane coupling agent-anhydrous ethanol compound solution, and then drying to obtain modified micro powder of grade II; (3) adding the modified micro powder of grade II into an anhydrous ethanol solution of N,N,N-trimethylglycine, and then stirring; after the completion, separating the solid product and drying to obtain the carbide slag-based expansion agent; and the expansion agent is added into a cement-based material and uniformly mixed with water. The application effectively improves the matching degree of the expansion agent and the micro crack generation period, and improves the improvement effect of the expansion agent on the crack resistance of the cement structure.

Description

Technical Field

[0001] This invention relates to the field of marine cement materials, specifically to a preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expanding agent. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of this 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] Cement-based materials, as the cornerstone of modern construction, directly affect the safety and durability of engineering structures. However, the complex process of cement-based materials transforming from a plastic state to a hard solid (i.e., the hydration and hardening process) is often accompanied by the formation of microcracks. These subtle defects can evolve into macro-cracks during the service life of the building structure, ultimately jeopardizing the structural integrity and service life, especially for cement-based structures used in marine engineering. Therefore, reducing the formation of these microcracks is of great significance for improving the quality of marine engineering projects and extending their service life in marine environments.

[0004] One of the factors causing microcracks in cement during the hydration and hardening process is the shrinkage stress generated by autogenous shrinkage and drying shrinkage. Cement hydration is a chemical shrinkage process, meaning the total volume of the hydration products is less than the sum of the volumes of cement and water before the reaction. Under sealed conditions or when moisture cannot be replenished, this "self-drying" effect leads to the formation of negative pressure (meniscus effect) within the capillaries, thus generating autogenous shrinkage stress. Simultaneously, as moisture evaporates from the cement structure, drying shrinkage is further exacerbated. When the stress generated by shrinkage exceeds the tensile strength of the cement structure at this point, microcracks will form.

[0005] Adding expansive agents to cement-based materials to compensate for shrinkage is an effective way to reduce microcrack formation. For example, adding calcium oxide can cause it to expand due to the conversion of mixing water in the cement material into calcium hydroxide, thus offsetting the tensile stress caused by drying and temperature shrinkage. However, because calcium oxide reacts quickly with the mixing water, its compensatory effect is not well matched with the timing of microcrack formation in cement structures (usually the middle and late stages of hydration reaction), resulting in insufficient improvement in the crack resistance of cement structures. Summary of the Invention

[0006] This invention provides a preparation process for crack-resistant marine cement materials based on carbide slag-based expansive agents. This process effectively improves the matching degree between the carbide slag cement expansive agent and the microcrack initiation period, thereby enhancing the expansive agent's effect on improving the crack resistance of cement structures. Specifically, the technical solution of this invention is as follows.

[0007] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0008] (1) After mixing calcium carbide slag with sodium silicate powder, the mixture was calcined. After the calcination was completed, the product was ground and then the resulting powder was added to an anhydrous ethanol dispersion of nano-silica and heated to react. After the reaction was completed, the solid product was separated and dried to obtain Grade I modified micro powder.

[0009] (2) The modified micro powder is mixed with the silane coupling agent-anhydrous ethanol composite solution and then dried to obtain the grade II modified micro powder.

[0010] (3) The modified micro powder of grade II was added to anhydrous ethanol solution of N,N,N-trimethylglycine and stirred. After the mixture was completed, the solid product was separated and dried to obtain carbide slag-based expansion agent.

[0011] (4) Using silicate cement, coarse aggregate, fine aggregate, fly ash, silica fume, the aforementioned carbide slag-based expanding agent, water-reducing agent, and fiber as raw materials, mix them with mixing water to obtain the crack-resistant marine cement material.

[0012] Further, in step (1), the mass ratio of the carbide slag to the sodium silicate powder is 1g:0.14~0.2g.

[0013] Furthermore, in step (1), the calcination treatment is carried out at a temperature of 580~620℃ for 35~50 min.

[0014] Further, in step (1), the ratio of the powder, nano-silica, and anhydrous ethanol is 2.3~2.8g:1g:40~55mL. Optionally, the fineness of the powder is 100~150 mesh.

[0015] Furthermore, in step (1), the heating reaction is carried out at a temperature of 200~220℃ for 6~7.5 hours.

[0016] Further, in step (2), the ratio of the modified micro powder to the composite liquid is 1g:0.1~0.14mL.

[0017] Further, in step (2), the concentration of the silane coupling agent in the composite liquid is 0.5~1.0 wt.%. Optionally, the silane coupling agent includes at least one of A-171, KH-550, KH-580, ZQ-172, etc.

[0018] Further, in step (3), the ratio of the grade II modified micro powder to the anhydrous ethanol solution of N,N,N-trimethylglycine is 1g:10~20mL.

[0019] Further, in step (3), the mass fraction of N,N,N-trimethylglycine in the anhydrous ethanol is not less than 6%. Optionally, the stirring time is 15~25 min.

[0020] Further, in step (4), the proportions of each component in the raw materials are as follows: 110-120 parts by weight of silicate cement, 235-260 parts by weight of coarse aggregate, 152-170 parts by weight of fine aggregate, 9-13 parts by weight of fly ash, 10-15 parts by weight of silica fume, 8.5-14 parts by weight of the carbide slag-based expansive agent, 1.6-2.4 parts by weight of water-reducing agent, and 2-3.5 parts by weight of fiber.

[0021] Furthermore, in step (4), the mass ratio of the mixing water to the total of silicate cement, fly ash, and silica fume is 0.41~0.45:1.

[0022] Further, in step (4), the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene water-reducing agent, lignin sulfonate water-reducing agent, aminosulfonate water-reducing agent, aliphatic water-reducing agent, etc.

[0023] Further, in step (4), the fiber includes at least one of polyethylene fiber, polypropylene fiber, polyvinyl alcohol fiber, polyacrylonitrile fiber, etc.

[0024] Further, in step (4), the length of the fiber is 10~30mm and the diameter is 0.15~0.23mm.

[0025] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0026] This invention first mixes calcium carbide slag with sodium silicate powder and then calcines it, thereby obtaining not only sodium silicate-doped calcium oxide but also realizing the utilization of calcium carbide slag, an industrial solid waste. Further, this invention reacts the obtained powder with an anhydrous ethanol dispersion of nano-silica to form a primary modified micropowder with nano-silica particles loaded on its surface. Then, a silane coupling agent is loaded onto the primary modified micropowder particles before mixing with an anhydrous ethanol solution of N,N,N-trimethylglycine. On the one hand, the silane coupling agent molecules fill the gaps between the nano-silica particles on the particle surface, providing supplementary protection to the core and reducing contact with external water molecules, preventing premature reaction. On the other hand, the silane coupling agent molecules also help to form a denser N,N,N-trimethylglycine coating layer on the nano-silica shell, thus forming the calcium carbide slag-based expanding agent of this invention. When added to cementitious materials, the nano-silica shell and silane coupling agent effectively prevent the calcium oxide core doped with sodium silicate from contacting water molecules in the cementitious material. As the hydration reaction progresses to the middle and later stages, the calcium hydroxide hydrate product formed by the silicate cement hydration provides OH-... - After passing through the N,N,N-trimethylglycine coating layer, the agent reaches the nano-silica shell. During this process, the two gradually react to form hydrated calcium silicate (CSH). Simultaneously, the nano-silica shell is gradually dissolved, exposing the sodium silicate-doped calcium oxide core. This CSH not only enhances the bonding force between the expansive agent and the cementitious material, improving mechanical strength and reducing microcrack formation, but also, after the core is exposed, it comes into contact with the water molecules locked in by N,N,N-trimethylglycine, reacting to form the expansive product calcium hydroxide. This calcium hydroxide can fill the pores in the cementitious material, creating pre-stress to counteract shrinkage and reduce microcrack formation. Furthermore, due to the strong water-locking effect of N,N,N-trimethylglycine on the surface of the carbide slag-based expansive agent of this invention, it not only provides conditions for initiating the core reaction in the middle and later stages of the hydration reaction but also helps to delay the evaporation and loss of moisture in the cementitious material, reducing microcracks caused by drying shrinkage. In addition, when the calcium oxide core doped with sodium silicate comes into contact with water molecules, the sodium silicate is released and enters the cement-based material, which can also activate the fly ash and silica fume, improve their cementitious activity, form more cementitious components such as CSH, and improve the crack resistance of concrete materials. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, 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 improper limitation of the invention.

[0028] Figure 1The sample of the carbide slag-based expanding agent prepared in Example 1 below.

[0029] Figure 2 The following is a diagram of the flexural strength test in Example 1.

[0030] Figure 3 The following is a sample of a calcium carbide slag-based expanding agent prepared in Example 2.

[0031] Figure 4 The following is a diagram of the flexural strength test in Example 2.

[0032] Figure 5 The following is a sample of a calcium carbide slag-based expanding agent prepared in Example 3.

[0033] Figure 6 The following is a diagram of the flexural strength test in Example 3.

[0034] Figure 7 The following is a sample of calcium carbide slag-based expanding agent prepared as Comparative Example 1.

[0035] Figure 8 The following is a diagram of the flexural strength test for Comparative Example 1.

[0036] Figure 9 The sample of calcium oxide expanding agent used in Comparative Example 2 below.

[0037] Figure 10 The following is a diagram of the flexural strength test for Comparative Example 2.

[0038] Figure 11 The following is a sample of calcium carbide slag-based expanding agent prepared as Comparative Example 3.

[0039] Figure 12 The following is a diagram of the flexural strength test of Comparative Example 3.

[0040] Figure 13 The following is a sample of calcium carbide slag-based expanding agent prepared as Comparative Example 4.

[0041] Figure 14 The following is a diagram of the flexural strength test in Comparative Example 4.

[0042] Figure 15 The following is a sample of calcium carbide slag-based expanding agent prepared as Comparative Example 5.

[0043] Figure 16 The following is a diagram of the flexural strength test of Comparative Example 5. Detailed Implementation

[0044] The present invention will be 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.

[0045] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. The reagents or raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods or product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the methods of this invention. The technical solution of this invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0048] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.16g and stir until homogeneous. Then heat to 600℃ at a heating rate of 10℃ / min and hold for 45min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 100-mesh sieve to obtain powder. Then add the powder to an anhydrous ethanol dispersion of nano-silica and stir until homogeneous, wherein the ratio of powder, nano-silica and anhydrous ethanol is 2.5g:1g:50mL. Then transfer the obtained mixture to a reaction vessel, seal it and heat to 220℃ for 6 hours. After completion, filter to separate the solid product, dry it at 75℃ to remove residual ethanol, and obtain Grade I modified micro powder for later use.

[0049] (2) Add silane coupling agent KH-550 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 0.65 wt.%. Then mix the modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.12 mL and stir until homogeneous. Then filter to separate the solid product, dry it at 75 °C to remove residual ethanol, and obtain grade II modified micro powder for later use.

[0050] (3) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 7 wt.%. Then, the grade II modified micro powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 15 mL and stirred for 20 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 1 (As shown), for later use.

[0051] (4) Take the following raw materials in the following proportions: 110 parts by weight of cement powder (PO 42.5), 235 parts by weight of coarse aggregate, 152 parts by weight of fine aggregate, 9 parts by weight of fly ash, 10 parts by weight of silica fume, 8.5 parts by weight of the calcium carbide slag-based expansive agent prepared in this embodiment, 1.6 parts by weight of polycarboxylate superplasticizer, and 2 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polypropylene fiber with a length of 15 mm and a diameter of 0.18 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 52.9 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0052] Performance testing: The crack-resistant marine cement material prepared in this embodiment was poured into a mold to form specimens with dimensions of 40mm × 40mm × 160mm, and then transferred to a curing chamber for standard curing for 28 days. After completion, the flexural strength of the obtained specimens was tested using a testing machine (e.g., flexural strength of the specimens). Figure 2 As shown in the figure, the result is: 28d flexural strength = 20.17MPa.

[0053] Example 2

[0054] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0055] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.14g and stir until homogeneous. Then heat to 580℃ at a heating rate of 10℃ / min and hold for 50min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 150-mesh sieve to obtain powder. Then add the powder to an anhydrous ethanol dispersion of nano-silica and stir until homogeneous, wherein the ratio of powder, nano-silica and anhydrous ethanol is 2.3g:1g:40mL. Then transfer the obtained mixture to a reaction vessel, seal it and heat to 210℃ for 7 hours. After completion, filter to separate the solid product, dry it at 75℃ to remove residual ethanol, and obtain Grade I modified micro powder for later use.

[0056] (2) Add silane coupling agent KH-580 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 0.5 wt.%. Then mix the modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.14 mL and stir until homogeneous. Then filter to separate the solid product, dry it at 75 °C to remove residual ethanol, and obtain grade II modified micro powder for later use.

[0057] (3) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 8 wt.%. Then, the grade II modified micro-powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 10 mL and stirred for 15 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 3 (As shown), for later use.

[0058] (4) Take the following raw materials in the following proportions: 120 parts by weight of cement powder (PO 42.5), 260 parts by weight of coarse aggregate, 170 parts by weight of fine aggregate, 13 parts by weight of fly ash, 15 parts by weight of silica fume, 11 parts by weight of the calcium carbide slag-based expansive agent prepared in this embodiment, 2.4 parts by weight of polycarboxylate superplasticizer, and 3.5 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyethylene fiber with a length of 10 mm and a diameter of 0.15 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 66.6 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0059] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 4 As shown in the figure, the result is: 28d flexural strength = 18.04 MPa.

[0060] Example 3

[0061] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0062] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.2g and stir until homogeneous. Then heat to 620℃ at a heating rate of 10℃ / min and hold for 35min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 120-mesh sieve to obtain powder. Then add the powder to an anhydrous ethanol dispersion of nano-silica and stir until homogeneous, wherein the ratio of powder, nano-silica and anhydrous ethanol is 2.8g:1g:55mL. Then transfer the obtained mixture to a reaction vessel, seal it and heat to 200℃ for 7.5 hours. After completion, filter to separate the solid product, dry it at 75℃ to remove residual ethanol, and obtain Grade I modified micro powder for later use.

[0063] (2) Add silane coupling agent A-171 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 1.0 wt.%. Then mix the modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.1 mL and stir until homogeneous. Then filter to separate the solid product, dry it at 75 °C to remove residual ethanol, and obtain grade II modified micro powder for later use.

[0064] (3) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 6 wt.%. Then, the grade II modified micro-powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 20 mL and stirred for 25 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 5 (As shown), for later use.

[0065] (4) Take the following raw materials in the following proportions: 115 parts by weight of cement powder (PO 42.5), 253 parts by weight of coarse aggregate, 161 parts by weight of fine aggregate, 10 parts by weight of fly ash, 13 parts by weight of silica fume, 14 parts by weight of the calcium carbide slag-based expanding agent prepared in this embodiment, 2 parts by weight of sodium lignosulfonate water-reducing agent, and 3 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyvinyl alcohol fiber with a length of 30 mm and a diameter of 0.23 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 58 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0066] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 6 As shown in the figure, the result is: 28d flexural strength = 18.91 MPa.

[0067] Comparative Example 1

[0068] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0069] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.16g and stir until homogeneous. Then heat to 600℃ at a heating rate of 10℃ / min and hold for 45min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 100-mesh sieve to obtain powder. Then add the powder to an anhydrous ethanol dispersion of nano-silica and stir until homogeneous, wherein the ratio of powder, nano-silica and anhydrous ethanol is 2.5g:1g:50mL. Then transfer the obtained mixture to a reaction vessel, seal it and heat to 220℃ for 6 hours. After completion, filter to separate the solid product, dry it at 75℃ to remove residual ethanol, and obtain Grade I modified micro powder for later use.

[0070] (2) Add silane coupling agent KH-550 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 0.65 wt.%. Then, mix the modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.12 mL and stir until homogeneous. Then, filter to separate the solid product, and dry it at 75°C to remove residual ethanol to obtain the carbide slag-based expanding agent (e.g., Figure 7 (As shown), for later use.

[0071] (3) Take the following raw materials in the following proportions: 110 parts by weight of cement powder (PO 42.5), 235 parts by weight of coarse aggregate, 152 parts by weight of fine aggregate, 9 parts by weight of fly ash, 10 parts by weight of silica fume, 8.5 parts by weight of the calcium carbide slag-based expansive agent prepared in this embodiment, 1.6 parts by weight of polycarboxylate superplasticizer, and 2 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polypropylene fiber with a length of 15 mm and a diameter of 0.18 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 52.9 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0072] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 8 As shown in the figure, the result is: 28d flexural strength = 16.52 MPa.

[0073] Comparative Example 2

[0074] A preparation process for a crack-resistant marine cement material based on calcium oxide expanding agent includes the following steps:

[0075] Take the following proportions of raw materials: 115 parts by weight of cement powder (PO 42.5), 253 parts by weight of coarse aggregate, 161 parts by weight of fine aggregate, 10 parts by weight of fly ash, 13 parts by weight of silica fume, and 120-mesh calcium oxide expanding agent powder (e.g. Figure 9The mixture contains 14 parts by weight of coarse aggregate (as shown), 2 parts by weight of sodium lignosulfonate water-reducing agent, and 3 parts by weight of fiber. The coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyvinyl alcohol fiber with a length of 30 mm and a diameter of 0.23 mm. First, add the above raw materials to a mixer and stir for 3 minutes. Then, add 58 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0076] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 10 As shown in the figure, the result is: 28d flexural strength = 13.74 MPa.

[0077] Comparative Example 3

[0078] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0079] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.14g and stir until homogeneous. Then heat to 580℃ at a heating rate of 10℃ / min and hold for 50min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 150-mesh sieve to obtain powder. Then add the powder to an anhydrous ethanol dispersion of nano-silica and stir until homogeneous, wherein the ratio of powder, nano-silica and anhydrous ethanol is 2.3g:1g:40mL. Then transfer the obtained mixture to a reaction vessel, seal it and heat to 210℃ for 7 hours. After completion, filter to separate the solid product, dry it at 75℃ to remove residual ethanol, and obtain Grade I modified micro powder for later use.

[0080] (2) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 8 wt.%. Then, the Grade I modified micro-powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 10 mL and stirred for 15 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 11 (As shown), for later use.

[0081] (3) Take the following raw materials in the following proportions: 120 parts by weight of cement powder (PO 42.5), 260 parts by weight of coarse aggregate, 170 parts by weight of fine aggregate, 13 parts by weight of fly ash, 15 parts by weight of silica fume, 11 parts by weight of the calcium carbide slag-based expansive agent prepared in this embodiment, 2.4 parts by weight of polycarboxylate superplasticizer, and 3.5 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyethylene fiber with a length of 10 mm and a diameter of 0.15 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 66.6 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0082] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 12 As shown in the figure, the result is: 28d flexural strength = 16.27 MPa.

[0083] Comparative Example 4

[0084] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0085] (1) Mix calcium carbide slag and sodium silicate powder at a ratio of 1g:0.2g and stir evenly. Then heat to 620℃ at a heating rate of 10℃ / min and hold for 35min. After completion, cool to room temperature, grind the obtained calcined product and pass it through a 120-mesh sieve to obtain Grade I modified micro powder for later use.

[0086] (2) Add silane coupling agent A-171 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 1.0 wt.%. Then mix the Grade I modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.1 mL and stir until homogeneous. Then filter to separate the solid product, dry it at 75 °C to remove residual ethanol, and obtain Grade II modified micro powder for later use.

[0087] (3) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 6 wt.%. Then, the grade II modified micro-powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 20 mL and stirred for 25 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 13 (As shown), for later use.

[0088] (4) Take the following raw materials in the following proportions: 115 parts by weight of cement powder (PO 42.5), 253 parts by weight of coarse aggregate, 161 parts by weight of fine aggregate, 10 parts by weight of fly ash, 13 parts by weight of silica fume, 14 parts by weight of the calcium carbide slag-based expanding agent prepared in this embodiment, 2 parts by weight of sodium lignosulfonate water-reducing agent, and 3 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyvinyl alcohol fiber with a length of 30 mm and a diameter of 0.23 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 58 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0089] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 14 As shown in the figure, the result is: 28d flexural strength = 16.79 MPa.

[0090] Comparative Example 5

[0091] A preparation process for a crack-resistant marine cement material based on a calcium carbide slag-based expansive agent includes the following steps:

[0092] (1) The calcium carbide slag was heated to 580°C at a heating rate of 10°C and held for 50 min. After completion, it was cooled to room temperature, and the calcined product was ground and passed through a 150-mesh sieve to obtain powder. The powder was then added to an anhydrous ethanol dispersion of nano-silica and stirred evenly, wherein the ratio of powder, nano-silica, and anhydrous ethanol was 2.3 g: 1 g: 40 mL. The resulting mixture was then transferred to a reaction vessel, sealed, and heated to 210°C for 7 hours. After completion, the solid product was filtered to separate it, and dried at 75°C to remove residual ethanol, yielding Grade I modified micro powder for later use.

[0093] (2) Add silane coupling agent KH-580 to anhydrous ethanol and stir until homogeneous to form an anhydrous ethanol solution with a concentration of 0.5 wt.%. Then mix the modified micro powder with the anhydrous ethanol solution at a ratio of 1 g: 0.14 mL and stir until homogeneous. Then filter to separate the solid product, dry it at 75 °C to remove residual ethanol, and obtain grade II modified micro powder for later use.

[0094] (3) N,N,N-trimethylglycine was added to anhydrous ethanol and stirred until homogeneous to form an anhydrous ethanol solution with a concentration of 8 wt.%. Then, the grade II modified micro-powder was mixed with the anhydrous ethanol solution at a ratio of 1 g: 10 mL and stirred for 15 min. After completion, the solid product was filtered to separate it, and then dried at 75 °C to remove residual ethanol, yielding a carbide slag-based expanding agent (such as...). Figure 15 (As shown), for later use.

[0095] (4) Take the following raw materials in the following proportions: 120 parts by weight of cement powder (PO 42.5), 260 parts by weight of coarse aggregate, 170 parts by weight of fine aggregate, 13 parts by weight of fly ash, 15 parts by weight of silica fume, 11 parts by weight of the calcium carbide slag-based expansive agent prepared in this embodiment, 2.4 parts by weight of polycarboxylate superplasticizer, and 3.5 parts by weight of fiber. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, the fine aggregate is river sand with a particle size distribution between 1 and 3 mm, and the fiber is polyethylene fiber with a length of 10 mm and a diameter of 0.15 mm. First, add the above raw materials to the mixer and stir for 3 minutes, then add 66.6 parts by weight of mixing water and continue stirring for 2 minutes to obtain crack-resistant marine cement material.

[0096] Performance testing: The 28-day flexural strength (e.g., ) of the crack-resistant marine cement material prepared in this embodiment was tested using the same method as in Example 1 above. Figure 16 As shown in the figure, the result is: 28d flexural strength = 15.96 MPa.

[0097] 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 preparation process for crack-resistant marine cement material based on calcium carbide slag-based expansive agent, characterized in that, Includes the following steps: (1) After mixing calcium carbide slag with sodium silicate powder, the mixture is calcined. After the calcination is completed, the calcined product is ground and the resulting powder is added to anhydrous ethanol dispersion of nano-silica and heated to react. After the reaction is completed, the solid product is separated and dried to obtain Grade I modified micro powder. (2) The modified micro powder is mixed with the silane coupling agent-anhydrous ethanol composite solution and then dried to obtain Grade II modified micro powder; (3) The modified micro powder of grade II was added to anhydrous ethanol solution of N,N,N-trimethylglycine and stirred. After the mixture was completed, the solid product was separated and dried to obtain carbide slag-based expansion agent. (4) Using silicate cement, coarse aggregate, fine aggregate, fly ash, silica fume, the carbide slag-based expansion agent, water-reducing agent, and fiber as raw materials, and mixing them with mixing water, the crack-resistant marine cement material is obtained.

2. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (1), the mass ratio of carbide slag to sodium silicate powder is 1g:0.14~0.2g.

3. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (1), the calcination treatment is carried out at a temperature of 580~620℃ for 35~50 min.

4. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (1), the ratio of the powder, nano-silica, and anhydrous ethanol is 2.3~2.8g:1g:40~55mL; or, in step (1), the fineness of the powder is 100~150 mesh.

5. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (1), the heating reaction is carried out at a temperature of 200~220℃ for 6~7.5 hours.

6. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (2), the ratio of the modified micro powder to the composite liquid is 1g: 0.1~0.14mL; Alternatively, in step (2), the concentration of the silane coupling agent in the composite solution is 0.5~1.0 wt.%.

7. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (3), the ratio of the grade II modified micro powder to the anhydrous ethanol solution of N,N,N-trimethylglycine is 1g:10~20mL; Alternatively, in step (2), the silane coupling agent includes at least one of A-171, KH-550, KH-580, and ZQ-172.

8. The preparation process of the crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to claim 1, characterized in that, In step (3), the mass fraction of N,N,N-trimethylglycine in the anhydrous ethanol is not less than 6%; or, in step (3), the stirring time is 15~25 min.

9. The preparation process of crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to any one of claims 1-8, characterized in that, In step (4), the proportions of each component in the raw materials are as follows: 110-120 parts by weight of silicate cement, 235-260 parts by weight of coarse aggregate, 152-170 parts by weight of fine aggregate, 9-13 parts by weight of fly ash, 10-15 parts by weight of silica fume, 8.5-14 parts by weight of the calcium carbide slag-based expansive agent, 1.6-2.4 parts by weight of water-reducing agent, and 2-3.5 parts by weight of fiber.

10. The preparation process of crack-resistant marine cement material based on calcium carbide slag-based expansive agent according to any one of claims 1-8, characterized in that, In step (4), the water-reducing agent includes at least one of the following: polycarboxylate water-reducing agent, naphthalene-based water-reducing agent, lignin sulfonate water-reducing agent, aminosulfonate water-reducing agent, and aliphatic water-reducing agent; Alternatively, in step (4), the fiber includes at least one of polyethylene fiber, polypropylene fiber, polyvinyl alcohol fiber, and polyacrylonitrile fiber. Alternatively, in step (4), the fiber has a length of 10~30mm and a diameter of 0.15~0.23mm; Alternatively, in step (4), the mass ratio of the mixing water to the total of silicate cement, fly ash, and silica fume is 0.41 to 0.45:1.

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