Reinforcing agent for 3D printed concrete

Abstract

The application relates to the technical field of 3D printing concrete, and discloses a reinforcing agent for 3D printing concrete, which comprises a toughening component, a reinforcing component and a rheological component, wherein the toughening component is prepared from lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate and potassium sulfate through steaming, autoclaving, crushing and grinding; the reinforcing component comprises ethylenediaminetetraacetate, rice husk ash, sulphoaluminate cement and limestone powder; the rice husk ash is soaked in a low-concentration sulfuric acid solution, and then wet ground and dried after adjusting the pH value of the solution by using sodium hydroxide and ordinary Portland cement; and the rheological component comprises glue powder, water-absorbing resin, polyvinyl alcohol, wood fiber and polycarboxylate superplasticizer; the application can effectively improve the toughness of 3D printing concrete and reduce the drying shrinkage.

Description

Technical Field

[0001] This invention relates to the field of 3D printed concrete technology, and in particular to a reinforcing agent for 3D printed concrete. Background Technology

[0002] 3D printed concrete (3DCP) is a digital construction technology based on additive manufacturing principles. It involves using CNC extrusion equipment to stack layers of customized concrete slurry according to a three-dimensional model, directly forming buildings or components. Compared to traditional concrete construction processes, 3D printed concrete offers unique advantages. First, formwork-free construction significantly reduces construction costs; second, it can print complex shapes with high precision while maximizing material savings; and third, because 3D printing is an automated process, it saves manpower and shortens construction time.

[0003] While 3D printing technology offers numerous advantages, its development in the construction field still faces several limitations. Layer-by-layer printing is a key characteristic of 3D printing, resulting in poorer overall integrity between consecutive layers compared to monolithic casting. This layer-by-layer construction method inevitably leads to weak interlayer bonding in printed components. Without proper treatment, the bonding performance at the interface will be significantly lower than that of the matrix, thus affecting the overall integrity and structural performance of the printed component. Weak interlayer bonding is a major challenge hindering the widespread application of 3D printed components in the construction industry. Systematic research on interface performance and comprehensive improvement of the interface performance of 3D printed components are urgent issues that need to be addressed in 3D printed architecture.

[0004] In addition, to improve the plasticity of 3D printed concrete, the water-cement ratio of 3D printed concrete is low, and a large amount of highly absorbent materials (such as attapulgite clay, clay, recycled aggregates, recycled cementitious materials, etc.) are used, resulting in a lack of water inside the 3D printed concrete. In addition, in order to ensure that the 3D printed concrete does not collapse during the molding process, the humidity of the molding environment is low, and standard curing cannot be used during the curing process. Therefore, the large exposed surface of the 3D printed concrete during molding and subsequent processes leads to greater drying shrinkage.

[0005] To improve the performance of concrete, the main reinforcing agents currently used include the following patents: Patent 202310598508.5 describes a foam stabilizer and anti-carbonation reinforcing agent for all-solid-waste foamed concrete, its preparation method, and its application. It uses C3A and CaSO4·2H2O in a molar ratio of 1:3 to prepare ettringite, and uses polycarboxylate superplasticizer, thickener, and water as raw materials. First, nano-ettringite is obtained by wet grinding, and then it is mixed evenly with thickener to prepare the reinforcing agent.

[0006] Patent 202510488570.8 Permeable concrete reinforcing agent and its preparation method, wherein the concrete reinforcing agent is modified kaolin, water-retaining agent, active filler and sodium lignosulfonate aqueous solution, wherein the mass ratio of modified kaolin, water-retaining agent, active filler and sodium lignosulfonate aqueous solution is (4-7):3:(2-5):5.

[0007] Patent 202310582753.7 discloses a super-permeable concrete surface enhancer, its preparation method and application, wherein the raw materials for preparing the super-permeable concrete surface enhancer include dispersant, fluorosilicate, nano oxide, early strength agent and water.

[0008] Patent 202510113886.9 discloses a low-carbon cement concrete steam curing reinforcing agent and its application. The reinforcing agent comprises 0.5-5 parts of nano-calcium carbonate, 0.02-0.2 parts of an alcohol amine additive, 0-2 parts of an inorganic salt, and 0.01-0.2 parts of a surfactant. The alcohol amine additive is selected from diethanol monoisopropanolamine, monoethanol diisopropanolamine, triethanolamine, and triisopropanolamine. The inorganic salt is selected from aluminum sulfate, sodium aluminate, sodium chloride, sodium sulfate, and calcium chloride. The surfactant comprises at least one of polydimethylsiloxane, fluorosiloxane, and ethylene glycol siloxane.

[0009] Patent 202310491202.X discloses a crack-resistant reinforcing agent for concrete and its preparation method. The crack-resistant reinforcing agent for concrete comprises the following components: 1-10 parts of modified glass fiber, 1-5 parts of amino alcohol shrinkage reducing agent, 20-35 parts of fly ash, 1-5 parts of polyvinyl alcohol powder, and 1-5 parts of fiber dispersant. The preparation method of the modified glass fiber includes the following steps: hydroxylating the raw glass fiber with hydrogen peroxide to obtain hydroxylated glass fiber; impregnating the hydroxylated glass fiber in an ammonia solution and then freezing it to obtain the modified glass fiber.

[0010] Patent 202511989722.9 discloses a concrete reinforcing agent, its preparation method, and its application. The concrete reinforcing agent comprises: 20-30 parts of ultrafine silicate cement; 20-30 parts of ultrafine slag powder; 40-60 parts of ultrafine fly ash; 0.03-0.09 parts of alkanolamine components; 0.1-1 parts of salt activating components; 0.15-0.25 parts of nucleation inducing components; and 0.1-0.5 parts of catalytic components.

[0011] Patent 202010079901.X discloses a lithium-based penetrating liquid modified concrete surface enhancer and its preparation and application method. The lithium-based penetrating liquid modified concrete surface enhancer is composed of lithium-based penetrating liquid, sodium sulfate, latex powder, talc powder, film-forming aid, defoamer, and water. Using this invention, it can effectively repair the insufficient strength of structural concrete surfaces caused by "honeycomb surface", surface powdering and sanding, segregation and bleeding, etc., and has high repairability and adhesion.

[0012] Patent 202311152786.4 discloses an internally adsorbed concrete densifying agent and its preparation method. The internally adsorbed concrete densifying agent is obtained by a physicochemical reaction of a hydration product growth modifier, a cement mineral dissolution acceleration component, and a crystal growth inhibition component in a mass ratio of 1:1:1. The hydration product growth modifier is an alcohol amine, the cement mineral dissolution acceleration component is polyethyleneamine, and the crystal growth inhibition component is a sugar aqueous dispersion solution.

[0013] Patent 202010756760.0 discloses a two-component surface enhancer for prefabricated concrete and its application method. The surface enhancer includes component A and component B. Component A includes 5-25 parts of ethylenediaminetetraacetic acid tetrasodium, 1-10 parts of sodium citrate, 0.5-3 parts of triethanolamine, 1-10 parts of sodium gluconate, 1-10 parts of sodium gluconate, and 100-500 parts of water. Component B includes 5-20 parts of nano silica, 5-20 parts of polyacrylic acid modified nano silica, 10-30 parts of polycarboxylate modified nano silica, and 100-300 parts of water.

[0014] Although the aforementioned reinforcing agents have some effect on ordinary concrete, they are not suitable for 3D printed concrete.

[0015] Patent 202110148311.2 discloses an interlayer reinforcing binder for 3D printing using calcium vanadium whiskers and its application method. The binder comprises fly ash, steel slag powder, desulfurized gypsum, sodium silicate particles, and water. The molar ratio of aluminum to sulfur in all raw materials is 0.5–2, the molar ratio of calcium to aluminum is 2–6, and the molar ratio of calcium to aluminum is 1.5–3. The binder is sprayed onto the surface of the already printed lower layer of concrete during the printing process using a synchronous spraying method. As the upper layer of concrete is extruded and accumulates on top of the lower layer, its own gravity causes the sprayed binder to be evenly compressed between the layers. Under the alkaline environment of sodium silicate and the concrete surface, the desulfurized gypsum, fly ash, and steel slag generate N(C)-ASH gel and calcium vanadium whiskers. This gel-whisker combination provides interfacial strength, supplementing the strength of weak areas between layers, while simultaneously reducing moisture evaporation caused by excessively long intervals between printing layers.

[0016] Patent 202211370972.0 describes an interface reinforcing agent for 3D printed concrete, comprising, by weight: 1-2 parts of nano-silica, 25-40 parts of gypsum whiskers, and 100-150 parts of water.

[0017] Patent 202511962440.X discloses an interface reinforcing agent based on 3D printed cement-based materials and its application in 3D printed cement-based materials. The interface reinforcing agent of the present invention includes cement, nano-silica, EVA redispersible latex powder, POM polyoxymethylene fiber, mixing water, water-reducing agent and retarder. The cement is selected in the same way as the cement in the 3D printed cement-based materials, preferably ordinary silicate cement, and the cement strength grade is the same as the cement strength grade in the 3D printed cement-based materials.

[0018] While the above methods can effectively improve the performance of 3D printed concrete, the use of simultaneous spraying increases the difficulty of construction. Summary of the Invention

[0019] Purpose of the invention: To address the problems existing in the prior art, this invention provides a reinforcing agent for 3D printed concrete, which solves the problem of large shrinkage and easy cracking in 3D printed concrete.

[0020] Technical solution: In a first aspect, the present invention provides a reinforcing agent for 3D printed concrete, characterized in that: by weight, it comprises 70-80 parts of toughening component, 10-20 parts of reinforcing component, and 5-10 parts of rheological component; wherein, The toughening components include: 50-70 parts lithium slag, 30-50 parts steel slag, 5-15 parts sodium hydroxide, 5-10 parts sodium silicate, 3-10 parts magnesium nitrate, and 3-10 parts potassium sulfate; The reinforcing components include: 5-10 parts ethylenediaminetetraacetic acid salt, 10-30 parts rice husk ash, 20-30 parts sulfoaluminate cement, and 40-60 parts limestone powder; The rheological components include: 5-10 parts of adhesive powder, 20-30 parts of water-absorbing resin, 20-40 parts of polyvinyl alcohol, 20-30 parts of wood fiber, and 5-10 parts of polycarboxylate superplasticizer.

[0021] Furthermore, the specific surface area of ​​the reinforcing agent for 3D printed concrete is greater than 400 m². 2 / kg.

[0022] Secondly, the present invention provides a method for preparing a reinforcing agent for 3D printed concrete as described in any of the above claims, characterized in that it specifically includes the following steps: S1. Lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate, and potassium sulfate are mixed in proportion, steam-cured, pressure-steamed, crushed, and ground to obtain toughening components; S2. After soaking rice husk ash in a low-concentration sulfuric acid solution, the pH of the solution is adjusted with sodium hydroxide and ordinary silicate cement, followed by wet grinding and drying. Then, it is mixed and ground with ethylenediaminetetraacetate, sulfoaluminate cement, and limestone powder in a certain proportion until the specific surface area is greater than 400 m². 2 / kg, yielding the reinforcing component; S3. Mix and grind the toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component to obtain a reinforcing agent for 3D printed concrete.

[0023] Further, in S1, the specific preparation method of the toughening component is as follows: lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate, and potassium sulfate are mixed in proportion, molded under a water-cement ratio of 0.30~0.35, cured at 80~100℃ for 12-24 hours, demolded, then autoclaved under a pressure of 0.8~1.2MPa for 3~5 hours, and then crushed and ground to a specific surface area greater than 400 m². 2 / kg.

[0024] Further, in S2, the specific treatment method for the rice husk ash in the reinforcing component is as follows: The rice husk ash is soaked in a 0.005–0.05 mol / L sulfuric acid solution for 24–48 hours. Then, sodium hydroxide and ordinary silicate cement are added to the above solution to adjust the pH value to 12.5–13.5. Next, the rice husk ash is wet-milled and dried until the specific surface area is greater than 400 m². 2 / kg.

[0025] Furthermore, the mass ratio of sodium hydroxide to ordinary silicate cement is 1:2 to 1:4.

[0026] Thirdly, the present invention provides an application of the reinforcing agent for 3D printed concrete as described in any of the above claims, characterized in that the amount of the reinforcing agent for 3D printed concrete used in each cubic meter of concrete is 10~50kg.

[0027] Beneficial effects: Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate, and potassium sulfate generated during the sulfuric acid process for producing lithium carbonate to prepare a toughening component for 3D printed concrete. The gypsum-rich lithium slag and potassium sulfate form a large amount of monosulfide-type calcium vanadium stone under autoclaving conditions. When the toughening component comes into contact with water, it reacts rapidly with gypsum and other materials in the cementitious material to grow calcium vanadium stone, thereby changing the rheological properties of the 3D printed concrete and interpenetrating between the layers of the 3D printed concrete to enhance the interlayer bonding strength.

[0028] 2. Alkali-activated lithium slag and steel slag are used to form a large number of nano-sized hydrated calcium silicate, hydrated sodium aluminosilicate, and hydrated potassium aluminosilicate under pressure steaming conditions. Through substances such as magnesium nitrate and iron-rich phases in steel slag, the morphology and aspect ratio of the hydration products are changed under pressure steaming conditions, thereby improving their toughness.

[0029] 3. Adhesive powder, polyvinyl alcohol, and wood fiber can improve the consistency of the slurry and enhance the extrudability of concrete. The water absorption properties of water-absorbing resin and wood fiber can replenish water to the 3D printed concrete when it is short of water, thereby reducing the shrinkage of the concrete.

[0030] 4. This invention uses low-concentration sulfuric acid to soak rice husk ash to destroy its structure. Then, it is wet-milled in an alkaline environment prepared with sodium hydroxide and ordinary silicate cement. In addition to improving the grinding efficiency of rice husk ash, the sulfate ions in the solution react with cement during the wet milling process to form gypsum, ettringite, etc., which, together with highly dispersed cement hydration products, fill the pore structure on the surface of rice husk ash, reducing the water absorption rate of rice husk ash and providing nucleation sites for subsequent cement hydration. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the embodiments.

[0032] It should be noted that the steel slag and lithium slag in the following embodiments mainly come from Jiangsu Rongda New Material Co., Ltd. The steel slag used is converter steel slag, and the lithium slag used is waste residue discharged during the production of lithium carbonate from sulfate. Example 1

[0033] This embodiment provides a reinforcing agent for 3D printed concrete, comprising 70 parts toughening component, 20 parts reinforcing component, and 10 parts rheological component; wherein... The toughening components include: 70 parts lithium slag, 30 parts steel slag, 15 parts sodium hydroxide, 5 parts sodium silicate, 5 parts magnesium nitrate, and 5 parts potassium sulfate; The reinforcing components include: 5 parts ethylenediaminetetraacetate, 20 parts rice husk ash, 20 parts sulfoaluminate cement, and 55 parts limestone powder; The rheological components include: 5 parts adhesive powder, 30 parts water-absorbing resin, 30 parts polyvinyl alcohol, 30 parts wood fiber, and 5 parts polycarboxylate superplasticizer.

[0034] The preparation method of the above-mentioned reinforcing agent for 3D printed concrete is as follows: S1. According to the formula, each component of the toughening component is molded at a water-cement ratio of 0.30, cured at 80℃ for 24 hours, demolded, and then autoclaved at 0.8MPa for 3 hours. Finally, it is crushed and ground to a specific surface area of ​​420 m². 2 / kg yields the toughening component.

[0035] S2. Soak rice husk ash in a 0.005 mol / L sulfuric acid solution for 48 hours. Then, add sodium hydroxide and ordinary silicate cement to the solution to adjust the pH to 13.5. Next, wet-mill and dry the rice husk ash until the specific surface area reaches 420 m². 2 / kg, then mixed and ground with ethylenediaminetetraacetic acid salt, sulfoaluminate cement, and limestone powder in proportion to achieve a specific surface area of ​​420 m². 2 / kg, to obtain the reinforcing component; wherein, the mass ratio of sodium hydroxide to ordinary Portland cement is 1:2.

[0036] S3. Mix and grind the toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component to obtain a reinforcing agent for 3D printed concrete.

[0037] The specific surface area of ​​the reinforcing agent for 3D printed concrete prepared in this embodiment is 450 m². 2 / kg, and its dosage in each cubic meter of concrete is 10kg. Example 2

[0038] This embodiment provides a reinforcing agent for 3D printed concrete, mainly comprising 80 parts toughening component, 10 parts reinforcing component, and 10 parts rheological component; wherein... The toughening components include: 50 parts lithium slag, 50 parts steel slag, 10 parts sodium hydroxide, 10 parts sodium silicate, 3 parts magnesium nitrate, and 7 parts potassium sulfate; The reinforcing components include: 10 parts ethylenediaminetetraacetate, 10 parts rice husk ash, 20 parts sulfoaluminate cement, and 60 parts limestone powder; The rheological components include: 10 parts of adhesive powder, 20 parts of water-absorbing resin, 40 parts of polyvinyl alcohol, 25 parts of wood fiber, and 5 parts of polycarboxylate superplasticizer.

[0039] The preparation method of the above-mentioned reinforcing agent for 3D printed concrete is as follows: S1. According to the formula, each component of the toughening component is molded at a water-cement ratio of 0.35, cured at 100℃ for 12 hours, demolded, and then autoclaved at 1.2MPa for 5 hours. Finally, it is crushed and ground to a specific surface area of ​​430 m². 2 / kg yields the toughening component.

[0040] S2. Soak rice husk ash in a 0.05 mol / L sulfuric acid solution for 24 hours. Then, add sodium hydroxide and ordinary silicate cement to the solution to adjust the pH to 12.5. Next, wet-mill and dry the rice husk ash until the specific surface area reaches 430 m². 2 / kg, then mixed with ethylenediaminetetraacetic acid salt, sulfoaluminate cement, and limestone powder in proportion and ground to a specific surface area of ​​430 m². 2 / kg, to obtain the reinforcing component; wherein, the mass ratio of sodium hydroxide to ordinary Portland cement is 1:4.

[0041] S3. Mix and grind the toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component to obtain a reinforcing agent for 3D printed concrete.

[0042] The specific surface area of ​​the reinforcing agent for 3D printed concrete prepared in this embodiment is greater than 460 m². 2 / kg, and its dosage in each cubic meter of concrete is 30kg. Example 3

[0043] This embodiment provides a reinforcing agent for 3D printed concrete, mainly comprising 80 parts toughening component, 15 parts reinforcing component, and 5 parts rheological component; wherein... The toughening components include: 60 parts lithium slag, 40 parts steel slag, 10 parts sodium hydroxide, 8 parts sodium silicate, 9 parts magnesium nitrate, and 3 parts potassium sulfate; The reinforcing components include: 5 parts ethylenediaminetetraacetate, 20 parts rice husk ash, 25 parts sulfoaluminate cement, and 50 parts limestone powder; The rheological components include: 5 parts adhesive powder, 30 parts water-absorbing resin, 40 parts polyvinyl alcohol, 20 parts wood fiber, and 5 parts polycarboxylate superplasticizer.

[0044] The preparation method of the above-mentioned reinforcing agent for 3D printed concrete is as follows: S1. According to the formula, each component of the toughening component is molded at a water-cement ratio of 0.30, cured at 90℃ for 15 hours, demolded, and then autoclaved at 1.0 MPa for 4 hours. Finally, it is crushed and ground to a specific surface area of ​​420 m². 2 / kg yields the toughening component.

[0045] S2. Soak rice husk ash in a 0.01 mol / L sulfuric acid solution for 24 hours. Then, add sodium hydroxide and ordinary silicate cement to the solution to adjust the pH to 13.0. Next, wet-mill and dry the rice husk ash until the specific surface area reaches 420 m². 2 / kg, then mixed with ethylenediaminetetraacetic acid salt, sulfoaluminate cement, and limestone powder in proportion and ground until the specific surface area is greater than 420 m². 2 / kg, to obtain the reinforcing component; wherein, the mass ratio of sodium hydroxide to ordinary Portland cement is 1:3.

[0046] S3. The toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component are mixed and ground to obtain a reinforcing agent for 3D printed concrete.

[0047] The specific surface area of ​​the reinforcing agent for 3D printed concrete prepared in this embodiment is 450 m². 2 / kg, and its dosage in each cubic meter of concrete is 50kg. Example 4

[0048] This embodiment provides a reinforcing agent for 3D printed concrete, comprising 75 parts toughening component, 20 parts reinforcing component, and 5 parts rheological component; wherein... The toughening components consist of: 60 parts lithium slag, 40 parts steel slag, 5 parts sodium hydroxide, 10 parts sodium silicate, 10 parts magnesium nitrate, and 5 parts potassium sulfate. The reinforcing components include: 10 parts ethylenediaminetetraacetate, 10 parts rice husk ash, 20 parts sulfoaluminate cement, and 60 parts limestone powder; The rheological components include: 10 parts of adhesive powder, 30 parts of water-absorbing resin, 30 parts of polyvinyl alcohol, 20 parts of wood fiber, and 10 parts of polycarboxylate superplasticizer.

[0049] The preparation method of the above-mentioned reinforcing agent for 3D printed concrete is as follows: S1. According to the formula, each component of the toughening component is molded at a water-cement ratio of 0.30, cured at 80℃ for 15 hours, demolded, and then autoclaved at 1.0MPa for 3 hours. Finally, it is crushed and ground to a specific surface area of ​​450 m². 2 / kg yields the toughening component.

[0050] S2. Soak rice husk ash in a 0.02 mol / L sulfuric acid solution for 36 hours. Then, add sodium hydroxide and ordinary silicate cement to the solution to adjust the pH to 13.5. Next, wet grind and dry the rice husk ash until the specific surface area reaches 450 m². 2 / kg, then mixed and ground with ethylenediaminetetraacetic acid salt, sulfoaluminate cement, and limestone powder in proportion to achieve a specific surface area of ​​450 m². 2 / kg of reinforcing component; wherein, the mass ratio of sodium hydroxide to ordinary Portland cement is 1:3.

[0051] S3. Mix and grind the toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component to obtain a reinforcing agent for 3D printed concrete.

[0052] The specific surface area of ​​the reinforcing agent for 3D printed concrete prepared in this embodiment is 500 m². 2 / kg, and its dosage in each cubic meter of concrete is 50kg. Performance testing

[0053] Table 1 shows the performance evaluation indicators of this invention. The concrete compressive and flexural strength tests are performed according to the standards GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)" and GB / T 50082-2024 "Standard for Test Methods of Long-Term Performance and Durability of Concrete," etc. The compressive and flexural strength tests involve pouring 3D concrete into a 40mm×40mm×160mm mold, curing it according to standard for 24 hours, and then testing it after 3 days and 28 days. The splitting tensile strength test involves cutting the 3D-printed concrete into 150mm cube specimens. Concrete drying shrinkage is measured by pouring concrete into a 100mm × 100mm × 515mm mold. Extrudability is determined by visually inspecting the concrete to determine its condition.

[0054] The baseline mix proportion for 3D printed concrete is as follows: 1250 parts medium sand, 750 parts PII52.5 cement, 50 parts attapulgite clay, 50 parts fly ash, 300 parts water, 40 parts hydroxypropyl methylcellulose ether, and 20 parts water-reducing agent.

[0055] In the embodiments of the present invention, the fly ash in the 3D printed concrete of the comparative example is replaced by the same amount of reinforcing agent as the fly ash in the 3D printed concrete of the comparative example, and the amount of other materials is the same as that of the comparative example.

[0056]

[0057] As shown in Table 1, the embodiments of the present invention have higher early 3-day strength and later 28-day strength compared with the comparative examples, especially the flexural strength. They can significantly reduce the drying shrinkage of 3D printed concrete, reduce cracking, and improve the interlayer bond strength and extrudability of 3D printed concrete.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A reinforcing agent for 3D printed concrete, characterized in that: By weight, it comprises 70-80 parts toughening component, 10-20 parts reinforcing component, and 5-10 parts rheological component; wherein, The toughening components include: 50-70 parts lithium slag, 30-50 parts steel slag, 5-15 parts sodium hydroxide, 5-10 parts sodium silicate, 3-10 parts magnesium nitrate, and 3-10 parts potassium sulfate; The reinforcing components include: 5-10 parts ethylenediaminetetraacetic acid salt, 10-30 parts rice husk ash, 20-30 parts sulfoaluminate cement, and 40-60 parts limestone powder; The rheological components include: 5-10 parts of adhesive powder, 20-30 parts of water-absorbing resin, 20-40 parts of polyvinyl alcohol, 20-30 parts of wood fiber, and 5-10 parts of polycarboxylate superplasticizer.

2. The reinforcing agent for 3D printed concrete according to claim 1, characterized in that: The specific surface area of ​​the reinforcing agent for 3D printed concrete is greater than 400 m². 2 / kg.

3. The method for preparing the reinforcing agent for 3D printed concrete according to any one of claims 1-2, characterized in that, Specifically, the steps include: S1. Lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate, and potassium sulfate are mixed in proportion, steam-cured, pressure-steamed, crushed, and ground to obtain toughening components; S2. After soaking rice husk ash in a low-concentration sulfuric acid solution, the pH of the solution is adjusted with sodium hydroxide and ordinary silicate cement, followed by wet grinding and drying. Then, it is mixed and ground with ethylenediaminetetraacetate, sulfoaluminate cement, and limestone powder in a certain proportion until the specific surface area is greater than 400 m². 2 / kg, yielding the reinforcing component; S3. Mix and grind the toughening component obtained in S1, the reinforcing component obtained in S2, and the rheological component to obtain a reinforcing agent for 3D printed concrete.

4. The method for preparing the reinforcing agent for 3D printed concrete according to claim 3, characterized in that: In S1, the specific preparation method of the toughening component is as follows: lithium slag, steel slag, sodium hydroxide, sodium silicate, magnesium nitrate, and potassium sulfate are mixed in proportion, molded under a water-cement ratio of 0.30~0.35, cured at 80~100℃ for 12-24 hours, demolded, then autoclaved under a pressure of 0.8~1.2MPa for 3~5 hours, and then crushed and ground to a specific surface area greater than 400 m². 2 / kg.

5. The method for preparing the reinforcing agent for 3D printed concrete according to claim 3, characterized in that: In S2, the specific treatment method for the rice husk ash in the reinforcing component is as follows: Soak the rice husk ash in a 0.005–0.05 mol / L sulfuric acid solution for 24–48 hours. Then, add sodium hydroxide and ordinary silicate cement to the above solution to adjust the pH value to 12.5–13.

5. Next, wet grind and dry the rice husk ash until the specific surface area is greater than 400 m². 2 / kg.

6. The method for preparing the reinforcing agent for 3D printed concrete according to claim 5, characterized in that: The mass ratio of sodium hydroxide to ordinary silicate cement is 1:2 to 1:

4.

7. The application of the reinforcing agent for 3D printed concrete according to any one of claims 1-2, characterized in that: The amount of the reinforcing agent used in the 3D printed concrete is 10~50kg per cubic meter of concrete.

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