Preparation method of solid waste-based early strength marine cement-based material

Abstract

The application relates to the field of marine cement materials, and particularly discloses a preparation method of a solid-waste-based early-strength marine cement-based material, which comprises the following steps: (1) uniformly mixing calcined recycled concrete micro powder and magnesium oxide whiskers, then mixing the mixture with water to form wet materials, and then standing; after hardening, crushing and grinding the obtained solidified body to obtain modified recycled micro powder; (2) uniformly mixing the modified recycled micro powder with a hot isopropyl alcohol solution of a stearate to obtain a waterproof agent after drying; (3) uniformly mixing magnesium oxide whiskers with a hot isopropyl alcohol solution of magnesium stearate to obtain modified magnesium oxide whiskers after drying; (4) uniformly mixing potassium dihydrogen phosphate, the waterproof agent and the modified magnesium oxide whiskers to obtain an early-strength agent; and (5) uniformly mixing granulated blast furnace slag powder, fly ash, solid-waste-based gypsum powder, carbide slag powder, coarse aggregate, fine aggregate, a water reducing agent, the early-strength agent and mixing water to obtain the solid-waste-based early-strength marine cement-based material. The early-strength additive can not only improve the early strength of the solid-waste-based cement-based material, but also improve the adaptability to the marine environment.

Description

Technical Field

[0001] This invention relates to the field of marine cement materials, specifically to a method for preparing a solid waste-based early-strength marine cement material. 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, as an essential material for modern construction, faces the dual challenges of dwindling high-quality limestone resources and a surge in industrial solid waste accumulation. Therefore, a new type of building material—solid waste-based cement—has emerged, using industrial solid waste (such as granulated blast furnace slag, steel slag, fly ash, and red mud) as its main raw material. This material not only eliminates the carbon emissions from limestone calcination and decomposition but also absorbs a large amount of waste residue from the steel, power, and chemical industries, providing a new solution for the green and low-carbon transformation of the building materials industry. Furthermore, utilizing the ability of calcium-based solid wastes such as steel slag to actively absorb and solidify carbon dioxide can also achieve a "carbon-negative" goal.

[0004] Among the many performance requirements of marine engineering cement materials, early strength is a crucial technical indicator. The unique construction environment of marine engineering projects, with construction windows limited by natural conditions such as tides, waves, and typhoons, necessitates that marine engineering cement materials harden rapidly after pouring and quickly reach a certain structural strength to withstand the impact of early environmental loads and buy time for subsequent processes. However, solid waste-based cement materials face a common technical bottleneck in practical engineering applications: slow early strength development. Compared to traditional silicate cement, solid waste-based cement exhibits a lower degree of hydration reaction in the early stages (1-3 days), resulting in a less dense hardened structure and insufficient strength growth to meet the demands of rapid construction. This restricts the large-scale application of solid waste-based cement materials in marine engineering construction. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing a solid waste-based early-strength marine cementitious material. By employing an early-strength admixture, this method not only enhances the early strength of the solid waste-based cementitious material but also improves its adaptability to the marine environment. Specifically, the technical solution of this invention is as follows.

[0006] A method for preparing a solid waste-based early-strength marine cementitious material includes the following steps:

[0007] (1) The calcined recycled concrete powder is mixed with magnesium oxide whiskers, and then mixed with water to form a wet material and left to stand. After hardening, the resulting solidified body is crushed and ground to obtain modified recycled powder for later use.

[0008] (2) The modified recycled micro powder is mixed with a hot aqueous solution of sodium stearate and / or potassium stearate, and dried to obtain a waterproofing agent for later use.

[0009] (3) Mix magnesium oxide whiskers with a hot isopropanol solution containing dissolved magnesium stearate and dry to obtain modified magnesium oxide whiskers for later use.

[0010] (4) Mix potassium dihydrogen phosphate, the waterproofing agent and the modified magnesium oxide whiskers to obtain an early strength agent for later use.

[0011] (5) Mix granulated blast furnace slag powder, fly ash, solid waste gypsum powder, carbide slag powder, coarse aggregate, fine aggregate, water reducing agent, and the aforementioned early strength agent evenly, and then add mixing water and mix evenly to obtain the solid waste-based early strength marine cement-based material.

[0012] Further, in step (1), the method for calcining the recycled concrete powder includes: heating the recycled concrete powder to 650~800℃ and holding it at that temperature for 1~2 hours, then rapidly cooling it to room temperature. Optionally, the fineness of the recycled concrete powder is not less than 100 mesh.

[0013] Further, in step (1), the ratio of the recycled concrete powder to magnesium oxide whiskers is 1 part by weight: 0.2~0.3 parts by weight.

[0014] Further, in step (1), the moisture content of the wet material is 24-28%. Optionally, the settling time is 5-7 days.

[0015] Furthermore, in step (1), the fineness of the modified recycled micro powder is 200~400 mesh.

[0016] Further, in step (2), the ratio of the modified regenerated micro powder to the hot aqueous solution of sodium stearate and / or potassium stearate is 1g:0.4~0.45mL. Optionally, the hot aqueous solution is saturated with sodium stearate and / or potassium stearate; the temperature of the hot aqueous solution is 60~80℃.

[0017] Further, in step (3), the ratio of the magnesium oxide whiskers to the hot isopropanol solution containing dissolved magnesium stearate is 1g:0.3~0.4mL. Optionally, the magnesium stearate in the hot isopropanol solution is saturated; the temperature of the hot isopropanol solution is 60~80℃.

[0018] Furthermore, in steps (2) and (3), the drying temperature is 90~110℃.

[0019] Further, in step (4), the ratio of potassium dihydrogen phosphate, waterproofing agent, and modified magnesium oxide whiskers is 1 part by weight: 0.19~0.23 parts by weight: 3~4.2 parts by weight.

[0020] Further, in step (5), the proportions of each component are as follows: 75-85 parts by weight of granulated blast furnace slag powder, 20-35 parts by weight of fly ash, 8-17 parts by weight of solid waste gypsum powder, 1-5 parts by weight of calcium carbide slag powder, 230-255 parts by weight of coarse aggregate, 120-140 parts by weight of fine aggregate, 3.5-6 parts by weight of early strength agent, and 1.5-2 parts by weight of water reducing agent.

[0021] Furthermore, in step (5), the mass ratio of the mixing water to the total mass of granulated blast furnace slag powder, fly ash, and solid waste gypsum powder is 0.42~0.46:1.

[0022] Furthermore, in step (5), the solid waste gypsum includes at least one of desulfurized gypsum, phosphogypsum, fluorogypsum, etc.

[0023] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0024] This invention utilizes potassium dihydrogen phosphate, a prepared waterproofing agent, and modified magnesium oxide whiskers to form an early-strength agent, which, when added to solid waste-based cement materials, not only improves the early strength of the cement materials but also overcomes the problem of insufficient water resistance of the formed early-strength component, struvite, while enhancing the adaptability of the solid waste-based cement materials to marine environments. To this end, this invention first uses calcined recycled concrete powder and magnesium oxide whiskers to prepare modified recycled powder. This not only realizes the utilization of recycled concrete powder, a large-scale construction waste, but also utilizes calcination to dehydrate the cementitious components such as hydrated calcium silicate in the recycled concrete powder, forming highly active β-C2S, which has rehydration properties. This allows the recycled concrete powder and magnesium oxide whiskers to be bonded together, resulting in a higher strength of the modified recycled powder / waterproofing agent, thus contributing to the improvement of the strength of solid waste-based cement materials. Furthermore, this invention utilizes the modified recycled powder to absorb sodium stearate and / or potassium stearate to form a waterproofing agent, and coats the surface of the magnesium oxide whiskers with magnesium stearate to form modified magnesium oxide whiskers. When the aforementioned early-strength agent is added to solid waste-based cement materials, on the one hand, the magnesium stearate on the surface of the modified magnesium oxide whiskers reacts with the hydrogen ions (H+) ionized from potassium dihydrogen phosphate. + The reaction forms stearic acid precipitate that adheres to the surface of magnesium oxide whiskers. Simultaneously, magnesium ions react with dihydrogen phosphate ions (H₂PO₄) ionized from potassium dihydrogen phosphate. -The process forms water-soluble magnesium dihydrogen phosphate, ensuring contact between potassium dihydrogen phosphate and magnesium oxide whiskers while limiting their contact area. This prevents rapid reaction and instantaneous setting, which would hinder construction. The resulting gelling product, struvite, exhibits high strength and strong adhesion, rapidly enhancing the early strength of solid waste-based cementitious materials. Simultaneously, as the reaction continues, the stearic acid formed on the surface of the magnesium oxide whiskers in the early stages of reaction forms a complex with the gelling product, improving its waterproofing ability. Furthermore, the modified magnesium oxide whiskers induce hydration of granulated blast furnace slag powder and fly ash, increasing their hydration rate and promoting early strength development. On the other hand, sodium stearate and / or potassium stearate in the waterproofing agent, due to their slow dissolution rate in room temperature water, are continuously released into the resulting gelling product, where residual potassium dihydrogen phosphate provides H₂. + Under the action of water, the stearic acid hydrophobic agent is converted and distributed in the cementitious product, further enhancing its waterproof ability. This results in the solid waste-based cementitious material of the present invention not only possessing good early strength but also helping to prevent the cementitious product from gradually decomposing under seawater erosion, leading to a decrease in strength. This improves the adaptability of the solid waste-based cementitious material to the marine environment. Furthermore, the process also utilizes the magnesium stearate on the surface of the magnesium oxide whiskers to consume potassium dihydrogen phosphate, and the sodium stearate and / or potassium stearate of the waterproofing agent to consume potassium dihydrogen phosphate. This mitigates the problem of excessive potassium dihydrogen phosphate dissolving upon contact with water during service, thus forming pores in the cementitious product and affecting strength. This further enhances the adaptability of the solid waste-based cementitious material of the present invention to the marine environment. Attached Figure Description

[0025] 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.

[0026] Figure 1 Early strength agent (a) and compressive strength test diagram (b) prepared for Example 1 below.

[0027] Figure 2 The early strength agent prepared for Example 2 is shown in (a) and the compressive strength test diagram is shown in (b).

[0028] Figure 3 Early strength agent (a) and compressive strength test diagram (b) prepared for Example 3 below.

[0029] Figure 4 The following is a diagram showing the compressive strength test results for Example 4.

[0030] Figure 5Early strength agent (a) and compressive strength test diagram (b) prepared for Example 5 below.

[0031] Figure 6 Early strength agent (a) and compressive strength test diagram (b) prepared for Example 6 below.

[0032] Figure 7 Early strength agent (a) and compressive strength test diagram (b) prepared for Example 7 below.

[0033] Figure 8 Early strength agent (a) and compressive strength test diagram (b) prepared for Example 8 below. Detailed Implementation

[0034] 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.

[0035] 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.

[0036] Example 1: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0037] (1) Heat recycled concrete powder with a fineness of 200 mesh to 700℃ and keep it at that temperature for 1.5 hours, then cool it rapidly (air-cooled) to room temperature to obtain calcined recycled concrete powder. Mix it with magnesium oxide whiskers at a ratio of 1 part by weight: 0.27 parts by weight and stir evenly. Then mix the resulting mixture with water and stir to form a wet material with a moisture content of 25%. After standing for 6 days, crush and grind the resulting solidified body and then pass it through a 350 mesh sieve to obtain modified recycled powder for later use.

[0038] (2) Add sodium stearate to hot water at 80°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, the modified regenerated micro powder and the saturated solution are mixed at a ratio of 1g:0.4mL and stirred evenly. The solution is then heated at 100°C to dry and remove moisture to obtain a waterproofing agent for later use.

[0039] (3) Add magnesium stearate to hot isopropanol at 80°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, magnesium oxide whiskers are mixed with the saturated solution at a ratio of 1g:0.3mL and stirred evenly. The solution is then heated and dried at 100°C to remove isopropanol, and modified magnesium oxide whiskers are obtained for later use.

[0040] (4) Potassium dihydrogen phosphate, the waterproofing agent of this embodiment, and the modified magnesium oxide whiskers of this embodiment are mixed in a ratio of 1 part by weight: 0.2 parts by weight: 3.8 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 1 (As shown in a), for later use.

[0041] (5) Take the following raw materials in the following proportions: 80 parts by weight of granulated blast furnace slag powder, 30 parts by weight of fly ash, 12 parts by weight of desulfurized gypsum powder, 3 parts by weight of calcium carbide slag powder, 245 parts by weight of coarse aggregate, 132 parts by weight of fine aggregate, 5 parts by weight of the early strength agent in this embodiment, and 1.8 parts by weight of polycarboxylate superplasticizer. Wherein: the coarse aggregate is crushed stone with a particle size distribution between 10 and 15 mm, and the fine aggregate is river sand with a particle size distribution between 1 and 3 mm. Add the above raw materials to a mixer and stir for 2 minutes, then add 53.5 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early strength marine cement-based material.

[0042] Performance Testing: 1. The marine cement-based material prepared in this embodiment was poured into a mold to form a specimen. After standard curing for 3 days, the 3-day compressive strength of the specimen was tested according to the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019). Figure 1 (as shown in b), i.e., early strength. 2. Pour the marine cement-based material prepared in this embodiment into a mold to make a specimen. After standard curing for 28 days, immerse it in water for 7 days. Then test the compressive strength of the specimen obtained by the above test method and calculate its compressive strength retention rate relative to the specimen before immersion. (3) Test the fluidity of the marine cement-based material according to the "Method for Determining the Flowability of Cement Mortar" (GBT2419-2005). The test results of the above performance indicators are: 3d compressive strength = 21.94MPa, retention rate = 99.46%, fluidity = 176mm.

[0043] Example 2: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0044] (1) Heat 100-mesh recycled concrete powder to 650℃ and keep it at that temperature for 2 hours, then cool it rapidly (air-cooled) to room temperature to obtain calcined recycled concrete powder. Mix it with magnesium oxide whiskers at a ratio of 1 part by weight: 0.3 parts by weight and stir evenly. Then mix the resulting mixture with water and stir to form a wet material with a moisture content of 24%. After standing for 5 days, crush and grind the resulting solidified body and then pass it through a 200-mesh sieve to obtain modified recycled powder for later use.

[0045] (2) Add sodium stearate to hot water at 60°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, the modified regenerated micro powder and the saturated solution are mixed at a ratio of 1g:0.4mL and stirred evenly. The solution is then heated at 110°C to dry and remove moisture to obtain a waterproofing agent for later use.

[0046] (3) Add magnesium stearate to hot isopropanol at 60°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, magnesium oxide whiskers are mixed with the saturated solution at a ratio of 1g:0.3mL and stirred evenly. The solution is then heated and dried at 100°C to remove isopropanol, and modified magnesium oxide whiskers are obtained for later use.

[0047] (4) Potassium dihydrogen phosphate, the waterproofing agent of this embodiment, and the modified magnesium oxide whiskers of this embodiment are mixed in a ratio of 1 part by weight: 0.19 parts by weight: 3 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 2 (As shown in a), for later use.

[0048] (5) Take the following raw materials in the following proportions: 85 parts by weight of granulated blast furnace slag powder, 20 parts by weight of fly ash, 8 parts by weight of phosphogypsum powder, 1 part by weight of calcium carbide slag powder, 230 parts by weight of coarse aggregate, 120 parts by weight of fine aggregate, 3.5 parts by weight of the early strength agent of this embodiment, and 1.5 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 47.5 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early strength marine cement-based material.

[0049] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 2 As shown in Figure b), the test results are: 3d compressive strength = 20.27 MPa, retention rate = 99.18%, and flowability = 174 mm.

[0050] Example 3: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0051] (1) Heat recycled concrete powder with a fineness of 150 mesh to 800℃ and keep it at that temperature for 1 hour, then cool it rapidly (air-cooled) to room temperature to obtain calcined recycled concrete powder. Mix it with magnesium oxide whiskers at a ratio of 1 part by weight: 0.2 parts by weight and stir evenly. Then mix the resulting mixture with water and stir to form a wet material with a moisture content of 28%. After standing for 7 days, crush and grind the resulting solidified body and then pass it through a 400-mesh sieve to obtain modified recycled powder for later use.

[0052] (2) Add potassium stearate to hot water at 75°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, the modified regenerated micro powder and the saturated solution are mixed at a ratio of 1g:0.42mL and stirred evenly. The solution is then heated and dried at 90°C to remove moisture, and a waterproofing agent is obtained for later use.

[0053] (3) Add magnesium stearate to hot isopropanol at 75°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, magnesium oxide whiskers are mixed with the saturated solution at a ratio of 1g:0.35mL and stirred evenly. The solution is then heated and dried at 90°C to remove isopropanol, and modified magnesium oxide whiskers are obtained for later use.

[0054] (4) Potassium dihydrogen phosphate, the waterproofing agent of this embodiment, and the modified magnesium oxide whiskers of this embodiment are mixed in a ratio of 1 part by weight: 0.23 parts by weight: 4.2 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 3 (As shown in a), for later use.

[0055] (5) Take the following raw materials in the following proportions: 75 parts by weight of granulated blast furnace slag powder, 35 parts by weight of fly ash, 17 parts by weight of desorbed paste powder, 5 parts by weight of calcium carbide slag powder, 255 parts by weight of coarse aggregate, 140 parts by weight of fine aggregate, 6 parts by weight of the early strength agent of this embodiment, and 2 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 58.42 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early strength marine cement-based material.

[0056] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 3 As shown in Figure b), the test results are: 3d compressive strength = 18.33 MPa, retention rate = 98.04%, and flowability = 179 mm.

[0057] Example 4: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0058] The following raw materials were prepared in the following proportions: 80 parts by weight of granulated blast furnace slag powder, 30 parts by weight of fly ash, 12 parts by weight of desulfurized gypsum powder, 3 parts by weight of calcium carbide slag powder, 245 parts by weight of coarse aggregate, 132 parts by weight of fine aggregate, and 1.8 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates were the same as those in Example 1 above. All the above raw materials were added to a mixer and stirred for 2 minutes. Then, 53.5 parts by weight of mixing water were added and stirring was continued for 3 minutes to obtain the solid waste-based early-strength marine cementitious material.

[0059] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 4 As shown in the figure, the test results are: 3d compressive strength = 15.42 MPa, retention rate = 91.37%, and flowability = 178 mm.

[0060] Example 5: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0061] (1) Potassium dihydrogen phosphate and the modified magnesium oxide whiskers of Example 1 above were mixed at a ratio of 1 part by weight to 3.8 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 5 (As shown in a), for later use.

[0062] (2) Take the following raw materials in the following proportions: 80 parts by weight of granulated blast furnace slag powder, 30 parts by weight of fly ash, 12 parts by weight of desulfurized gypsum powder, 3 parts by weight of calcium carbide slag powder, 245 parts by weight of coarse aggregate, 132 parts by weight of fine aggregate, 5 parts by weight of the early-strength agent of this embodiment, and 1.8 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 53.5 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early-strength marine cement-based material.

[0063] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 5 As shown in Figure b), the test results are: 3d compressive strength = 22.08 MPa, retention rate = 91.37%, and flowability = 167 mm.

[0064] Example 6: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0065] (1) Potassium dihydrogen phosphate, the waterproofing agent of Example 2 above, and unmodified magnesium oxide whiskers are mixed in a ratio of 1 part by weight: 0.19 parts by weight: 3 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 6 (As shown in a), for later use.

[0066] (2) Take the following raw materials in the following proportions: 85 parts by weight of granulated blast furnace slag powder, 20 parts by weight of fly ash, 8 parts by weight of phosphogypsum powder, 1 part by weight of calcium carbide slag powder, 230 parts by weight of coarse aggregate, 120 parts by weight of fine aggregate, 3.5 parts by weight of the early-strength agent of this embodiment, and 1.5 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 47.5 parts by weight of mixing water and continue stirring for 3 minutes to obtain the solid waste-based early-strength marine cement-based material.

[0067] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 6 As shown in Figure b), the test results are: 3d compressive strength = 20.85 MPa, retention rate = 94.43%, and flowability = 151 mm.

[0068] Example 7: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0069] (1) Heat recycled concrete powder with a fineness of 150 mesh to 800℃ and keep it at that temperature for 1 hour, then cool it rapidly (air-cooled) to room temperature to obtain calcined recycled concrete powder. Mix it with magnesium oxide whiskers at a ratio of 1 part by weight: 0.2 parts by weight and stir evenly. Then mix the resulting mixture with water and stir to form a wet material with a moisture content of 28%. After standing for 7 days, crush and grind the resulting solidified body and then pass it through a 400-mesh sieve to obtain a waterproofing agent for later use.

[0070] (2) Add magnesium stearate to hot isopropanol at 75°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, magnesium oxide whiskers are mixed with the saturated solution at a ratio of 1g:0.35mL and stirred evenly. The solution is then heated and dried at 90°C to remove isopropanol, and modified magnesium oxide whiskers are obtained for later use.

[0071] (3) Potassium dihydrogen phosphate, the waterproofing agent of this embodiment, and the modified magnesium oxide whiskers of this embodiment are mixed in a ratio of 1 part by weight: 0.23 parts by weight: 4.2 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 7 (As shown in a), for later use.

[0072] (4) Take the following raw materials in the following proportions: 75 parts by weight of granulated blast furnace slag powder, 35 parts by weight of fly ash, 17 parts by weight of desorbed paste powder, 5 parts by weight of calcium carbide slag powder, 255 parts by weight of coarse aggregate, 140 parts by weight of fine aggregate, 6 parts by weight of the early strength agent of this embodiment, and 2 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 58.42 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early strength marine cement-based material.

[0073] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 7 As shown in Figure b), the test results are: 3d compressive strength = 19.12 MPa, retention rate = 92.25%, and flowability = 172 mm.

[0074] Example 8: A method for preparing a solid waste-based early-strength marine cementitious material, comprising the following steps:

[0075] (1) Mix 100-mesh recycled concrete powder and magnesium oxide whiskers in a ratio of 1 part by weight: 0.3 parts by weight and stir evenly. Then mix the resulting mixture with water and stir to form a wet material with a moisture content of 24%. After standing for 5 days, crush and grind the solidified body and then pass it through a 200-mesh sieve to obtain modified recycled powder for later use.

[0076] (2) Add sodium stearate to hot water at 60°C and stir until fully dissolved. After filtering to remove insoluble matter, a saturated solution is obtained. Then, the modified regenerated micro powder and the saturated solution are mixed at a ratio of 1g:0.4mL and stirred evenly. The solution is then heated at 110°C to dry and remove moisture to obtain a waterproofing agent for later use.

[0077] (3) Potassium dihydrogen phosphate, the waterproofing agent of this embodiment, and the modified magnesium oxide whiskers of Example 2 above are mixed in a ratio of 1 part by weight: 0.19 parts by weight: 3 parts by weight and stirred evenly to obtain an early strength agent (such as...). Figure 8 (As shown in a), for later use.

[0078] (4) Take the following raw materials in the following proportions: 85 parts by weight of granulated blast furnace slag powder, 20 parts by weight of fly ash, 8 parts by weight of phosphogypsum powder, 1 part by weight of calcium carbide slag powder, 230 parts by weight of coarse aggregate, 120 parts by weight of fine aggregate, 3.5 parts by weight of the early strength agent of this embodiment, and 1.5 parts by weight of polycarboxylate superplasticizer. The coarse and fine aggregates are the same as those in Example 1 above. Add the above raw materials to a mixer and stir for 2 minutes, then add 47.5 parts by weight of mixing water and continue stirring for 3 minutes to obtain solid waste-based early strength marine cement-based material.

[0079] Performance testing: The various performance indicators of the marine cement-based material prepared in this embodiment were tested using the same method as in Example 1 above (wherein the compressive strength test is as follows). Figure 8 As shown in Figure b), the test results are: 3d compressive strength = 18.46 MPa, retention rate = 95.32%, and flowability = 171 mm.

[0080] 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 method for preparing a solid waste-based early-strength marine cement-based material, characterized in that, Includes the following steps: (1) The calcined recycled concrete powder is mixed with magnesium oxide whiskers, then mixed with water to form a wet material and left to stand; after hardening, the resulting solidified body is crushed and ground to obtain modified recycled powder for later use. (2) The modified recycled micro powder is mixed with a hot aqueous solution of sodium stearate and / or potassium stearate and then dried to obtain a waterproofing agent for later use; (3) Mix magnesium oxide whiskers with a hot isopropanol solution containing dissolved magnesium stearate and dry to obtain modified magnesium oxide whiskers for later use. (4) Mix potassium dihydrogen phosphate, the waterproofing agent, and the modified magnesium oxide whiskers to obtain an early strength agent for later use; (5) Mix granulated blast furnace slag powder, fly ash, solid waste gypsum powder, carbide slag powder, coarse aggregate, fine aggregate, water reducing agent, and the aforementioned early strength agent evenly, and then add mixing water and mix evenly to obtain the solid waste-based early strength marine cement-based material.

2. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In step (1), the method for calcining the recycled concrete powder includes: heating the recycled concrete powder to 650~800℃ and holding it for 1~2 hours, and then rapidly cooling it to room temperature; or, in step (1), the fineness of the recycled concrete powder is not less than 100 mesh.

3. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In step (1), the ratio of the recycled concrete powder to magnesium oxide whiskers is 1 part by weight: 0.2~0.3 parts by weight.

4. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In step (1), the moisture content of the wet material is 24-28%; Alternatively, in step (1), the settling time is 5 to 7 days; Alternatively, in step (1), the fineness of the modified recycled micro powder is 200~400 mesh.

5. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In step (2), the ratio of the modified regenerated micro powder to the hot aqueous solution of sodium stearate and / or potassium stearate is 1g: 0.4~0.45mL; Alternatively, in step (2), the hot aqueous solution contains sodium stearate and / or potassium stearate in a saturated state; Alternatively, in step (2), the temperature of the hot aqueous solution is 60~80℃.

6. The method for preparing solid waste-based early-strength marine cementitious materials according to claim 1, characterized in that, In step (3), the ratio of the magnesium oxide whiskers to the hot isopropanol solution containing dissolved magnesium stearate is 1g: 0.3~0.4mL; Alternatively, in step (3), the magnesium stearate in the hot isopropanol solution is saturated; Alternatively, in step (3), the temperature of the hot isopropanol solution is 60~80℃.

7. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In steps (2) and (3), the drying temperature is 90~110℃.

8. The preparation method of solid waste-based early-strength marine cementitious material according to claim 1, characterized in that, In step (4), the ratio of potassium dihydrogen phosphate, waterproofing agent, and modified magnesium oxide whiskers is 1 part by weight: 0.19~0.23 parts by weight: 3~4.2 parts by weight.

9. The method for preparing solid waste-based early-strength marine cementitious materials according to any one of claims 1-8, characterized in that, In step (5), the proportions of each component are as follows: 75-85 parts by weight of granulated blast furnace slag powder, 20-35 parts by weight of fly ash, 8-17 parts by weight of solid waste gypsum powder, 1-5 parts by weight of calcium carbide slag powder, 230-255 parts by weight of coarse aggregate, 120-140 parts by weight of fine aggregate, 3.5-6 parts by weight of early strength agent, and 1.5-2 parts by weight of water reducing agent.

10. The method for preparing solid waste-based early-strength marine cementitious materials according to any one of claims 1-8, characterized in that, In step (5), the mass ratio of the mixing water to the total of granulated blast furnace slag powder, fly ash, and solid waste gypsum powder is 0.42~0.46:1; or, in step (5), the solid waste gypsum includes at least one of desulfurized gypsum, phosphogypsum, and fluorogypsum.

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