A method for preparing chloride ion-resistant 3D-printed concrete and its components.

Abstract

This invention discloses a method for preparing chloride ion-resistant 3D-printed concrete and its components. The invention comprises the following components in parts by weight: 230-250 parts silicate cement, 40-80 parts fly ash, 30-60 parts mineral powder, 60-100 parts wind turbine blade powder, 0-25 parts wind turbine blade fiber, 550-575 parts fine aggregate, 1.35-1.75 parts water-reducing agent, 0.225-0.35 parts cellulose ether, 0.25%-0.35% wetting agent, and 135-155 parts water. The 3D-printed concrete prepared by this invention is low-cost, easy to produce, and possesses excellent strength and superior chloride ion resistance, while also being environmentally friendly. Applying an anti-corrosion mixture to the surface of the reinforcing steel and the prepared 3D-printed concrete components further enhances the resistance of the reinforcing steel and concrete to seawater erosion.

Description

Technical Field

[0001] This invention relates to the field of 3D printed concrete materials technology, specifically to a method for preparing chloride ion-resistant 3D printed concrete and its components. Background Technology

[0002] Marine reinforced concrete has always faced various problems, such as seawater corrosion, cracking, and abrasion damage, posing a significant challenge to the durability and chloride ion penetration resistance of concrete. Among the many factors affecting the durability of reinforced concrete structures, cracking caused by steel corrosion is considered one of the most significant causes of durability failure. For marine reinforced concrete structures, cracking is primarily due to chloride ion attack.

[0003] Generally, the surface of reinforcing steel bars within concrete is in a stable passivated state due to the presence of highly alkaline concrete pore solutions. When external chloride ions penetrate the concrete, the pH value of the pore solution decreases, the chloride ion content increases, leading to the destruction of the passivation film and corrosion. Since the volume of corrosion products after rusting is 2 to 4 times the original volume, its volume expansion is restricted by the surrounding concrete, generating pressure at the reinforced concrete interface, i.e., steel bar rust expansion force. As the amount of steel bar corrosion increases, the gradually increasing rust expansion force will cause the concrete cover to crack under tension. Rust expansion cracks first appear at the concrete interface around the reinforcing steel bars and gradually expand from the inside out. When rust expansion cracks penetrate the concrete cover, harmful media from the environment directly penetrate the concrete interior through the cracks, contacting the reinforcing steel bars, greatly accelerating the corrosion rate, further exacerbating the expansion of rust expansion cracks in the concrete, and even causing the concrete cover to peel off, seriously affecting the durability of the concrete structure. Therefore, how to improve the density of the concrete cover and resist chloride ion erosion of marine reinforced concrete has become an urgent problem to be solved. Therefore, how to improve the resistance of concrete to chloride ion corrosion of marine reinforced concrete has become an urgent problem to be solved.

[0004] Currently, the common methods to enhance the corrosion resistance of marine concrete can be broadly divided into two types. One is to add a special coating to the outside of the concrete, but this is problematic because the toxicity of the coating could threaten the safety of construction workers and cause serious environmental pollution. The other is to improve the quality of the concrete, but existing formulas use complex components, are costly, and require high research and development costs.

[0005] In recent years, 3D printing technology has seen significant development in the construction field due to its distinct advantages, including the elimination of templates, the ability to personalize concrete components through computer programming, and the ability to ensure component precision and quality through computer program control, as well as faster and more efficient production. The key to the engineering practice of 3D printing technology lies in 3D-printed concrete. The most basic requirement for 3D-printed concrete is high printability, while also better meeting the durability requirements of marine concrete structures, making the preparation of chloride ion-resistant 3D-printed concrete essential.

[0006] Wind turbine blades, as a thermosetting composite material, are extremely difficult to degrade naturally. If left to accumulate in nature, they will become persistent organic pollutants, easily causing significant white pollution as the number of retired blades increases. How to dispose of retired blades has become a crucial issue that the wind power industry needs to consider and address in the future.

[0007] To date, researchers have formulated cement mortars resistant to chloride ion penetration, and some scholars have also formulated 3D-printed colored concrete with strong chloride ion penetration resistance, such as in application number 202110149025.8, where carbon nanotube fibers are added to improve the strength, ductility, toughness, and chloride ion penetration resistance of the concrete material, achieving a chloride ion penetration coefficient of 1.52 × 10⁻⁶. -12 -2.76×10 -12 m 2 / s; Application No. 202010230796.5 Through the filling and reinforcing effects of densifying agents and microsilica, as well as the adjustment of water-reducing agents and modified fibers, the internal voids of concrete are filled densely, thereby improving the chloride ion penetration resistance of concrete, with a chloride ion penetration coefficient of 1.5×10 -12 -2.22×10 -12 m 2 / s; In summary, the highest existing level of resistance to chloride ion penetration can reach is Level IV.

[0008] However, 3D printed concrete does not yet meet the requirements of being able to dispose of solid waste, being environmentally friendly, having high mechanical strength, good printing performance, and having a chloride ion penetration resistance level of V. Summary of the Invention

[0009] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0010] Therefore, the purpose of this invention is to provide a method for preparing 3D printed concrete and its components that are resistant to chloride ion penetration. The method is low in cost and easy to prepare, and has excellent strength and ultra-high resistance to chloride ion penetration. At the same time, it can dispose of industrial solid waste that is difficult to biodegrade naturally.

[0011] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0012] A method for preparing chloride ion-resistant 3D-printed concrete, the specific steps of which are as follows:

[0013] S101. Material Preparation: Prepare materials according to the following weight proportions: 230-250 parts of 42.5 silicate cement, 60-100 parts of decommissioned wind turbine blade powder, 40-80 parts of fly ash, 30-60 parts of mineral powder, 0-25 parts of wind turbine blade fiber, 550-575 parts of fine aggregate, 1.35-1.75 parts of water-reducing agent, 0.225-0.35 parts of cellulose ether, 0.1-0.2 parts of air-entraining agent, 0.25-0.35 parts of wetting agent, and 135-155 parts of water.

[0014] S102. Preparation of decommissioned wind turbine blade powder dispersion: Mix 50% of the water and wetting agent from step S101, then add 50% of the decommissioned wind turbine blade powder, stir for 5 minutes, add to an ultrasonic disperser, disperse for 1 hour and set aside.

[0015] S103. Preparation of modified decommissioned wind turbine blade fibers: Dry mix the remaining 50% wind turbine powder, 50% mineral powder and decommissioned wind turbine blade fibers from step S101 for 5 minutes, then perform autoclaving treatment at a temperature of 90℃±10℃ for 1 hour, and then take them out for later use.

[0016] S104. Dry mix the cement, fly ash, remaining 50% mineral powder and fine aggregate, water-reducing agent, cellulose ether and air-entraining agent from step S101 for 5 minutes, then add the remaining 30% of the total water and stir at low speed for 3 minutes.

[0017] S105. Add the decommissioned wind turbine blade powder dispersion prepared in step S102 to the mixture in step S104, continue to stir at low speed for 3 minutes, then add the modified decommissioned wind turbine blade fiber prepared in step S103, stir at low speed again for 5 minutes, add water equal to 20% of the total water volume, stir at high speed for 3 minutes, and then let stand to obtain 3D printed concrete resistant to chloride ion penetration.

[0018] As a preferred embodiment of the method for preparing chloride ion-resistant 3D printed concrete according to the present invention, in step S1, the materials are prepared according to the following parts by weight: 250 parts of 42.5 silicate cement, 80 parts of decommissioned wind turbine blade powder, 40 parts of fly ash, 30 parts of mineral powder, 25 parts of wind turbine blade fiber, 575 parts of fine aggregate, 1.45 parts of water-reducing agent, 0.3 parts of cellulose ether, 0.1 parts of air-entraining agent, 0.25 parts of wetting agent, and 140 parts of water.

[0019] In a preferred embodiment of the method for preparing chloride ion-resistant 3D printed concrete according to the present invention, the average particle size of the decommissioned wind turbine blade powder is 50.98 μm, and the decommissioned wind turbine blade powder contains transparent glass fiber filaments.

[0020] As a preferred embodiment of the method for preparing chloride ion-resistant 3D printed concrete according to the present invention, the single filament length of the decommissioned wind turbine blade fiber is 3μm-15μm, and it contains a small amount of glass fiber powder and resin particles.

[0021] In a preferred embodiment of the method for preparing chloride ion-resistant 3D printed concrete according to the present invention, the fine aggregate includes fine river sand and / or tailings sand, wherein the fineness modulus of the fine river sand is 1.36.

[0022] In a preferred embodiment of the method for preparing chloride ion-resistant 3D-printed concrete according to the present invention, the water-reducing agent is a retarded polycarboxylate superplasticizer powder, the cellulose ether is hydroxyethyl cellulose ether with a viscosity of 25000 mPa·s at 20°C, and the air-entraining agent is industrial-grade sodium dodecyl sulfate. The wetting agent is a type of polyoxyethylene alkylphenol ether.

[0023] A method for preparing a 3D-printed concrete component resistant to chloride ion penetration, the specific steps of which are as follows:

[0024] S201. Material preparation: Prepare materials according to the following weight proportions: 300-350 parts silicate cement, 5-100 parts sulfoaluminate cement, 100-150 parts decommissioned wind turbine blade powder, 550-600 parts quartz sand, 1.8-2.2 parts water-reducing agent, 5-10 parts dispersible colloid powder, 2.2-3 parts water-repellent agent, 30-60 parts organosilicon additive, and 160-180 parts water.

[0025] S202. Dry mix the silicate cement, sulfoaluminate cement, decommissioned wind turbine blade powder, quartz sand, water-reducing agent, dispersible colloid powder and water-repellent agent from step S201 for 5 minutes.

[0026] S203. After mixing the organosilicon additive and water evenly, add it to the mixture of S202 and continue to stir at low speed for 5 minutes to obtain waterproof and seepage-proof mortar for later use.

[0027] S204. Cut the steel bars required for the printed concrete components into shape, and spray a layer of epoxy resin on the surface. After the surface dries, use a brush to apply the prepared waterproof and seepage-proof mortar to the surface of the steel bars. After the surface dries, it is ready for use.

[0028] S205. Add the prepared 3D printed concrete into the 3D printer with the printing path set, and print and stack the required components according to the printing path; at the same time, place the steel bars prepared in step S204 into the 3D printed concrete components according to the design reinforcement, and cure the 3D printed concrete components for 28 days.

[0029] S206. Apply two more coats of the waterproof and seepage-resistant mortar prepared in step S203 to the surface of the 3D printed concrete component prepared in step S205.

[0030] As a preferred embodiment of the method for preparing a chloride ion-resistant 3D printed concrete component according to the present invention, in step S201, the following materials are prepared in parts by weight: 300 parts of silicate cement, 50 parts of sulfoaluminate cement, 100 parts of decommissioned wind turbine blade powder, 600 parts of quartz sand, 1.9 parts of water-reducing agent, 10 parts of dispersible colloid powder, 2.8 parts of water-repellent agent, 40 parts of organosilicon admixture, and 170 parts of water.

[0031] As a preferred embodiment of the method for preparing a chloride ion-resistant 3D printed concrete component according to the present invention, in step S206, the waterproof and seepage-resistant mortar is first applied parallel to the printing direction of the 3D printed concrete component and covers the weak joints of each printed strip in an S-shape, and is then applied in a second S-shape perpendicular to the printing direction, with a coating thickness of 3mm-5mm.

[0032] In a preferred embodiment of the method for preparing a chloride ion-resistant 3D-printed concrete component according to the present invention, the quartz sand has a particle size of 0.106mm-0.15mm, and the organosilicon admixture is water glass with a solid content of 42.17%, containing 21.25% Na2O, 21.82% SiO2 and 58.83% water, and a modulus of 2.1.

[0033] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention pre-mixes retired wind turbine blade powder with a wetting agent and water, and through ultrasonic dispersion, modifies the hydrophobic wind turbine blade powder into a more easily mixed material, resulting in more uniform powder dispersion. Furthermore, it pre-disperses and mixes retired wind turbine fibers with retired wind turbine powder and mineral powder, followed by high-temperature autoclaving treatment, coating the surface of the wind turbine fibers with a layer of hydrophilic powder. This increases the friction on the fiber surface, improving adhesion to other powder materials and increasing the overall strength of the concrete. Important chemical reactions are pre-processed and carried out separately, ensuring each reaction is more complete and thorough, thus stabilizing the quality of the concrete. Finally, applying an anti-corrosion, waterproof, and impermeable mortar to the surface of the reinforcing steel and the prepared 3D-printed concrete component further enhances the resistance of the reinforcing steel and concrete materials to seawater erosion. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0035] Figure 1 This is a flowchart of a method for preparing chloride ion-resistant 3D-printed concrete according to the present invention;

[0036] Figure 2 This is a flowchart illustrating a method for preparing a chloride ion-resistant 3D-printed concrete component according to the present invention.

[0037] Figure 3 TG images of decommissioned wind turbine blade powder and fibers provided for this invention. Detailed Implementation

[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0041] This invention provides a method for preparing 3D-printed concrete and its components that are resistant to chloride ion penetration. The preparation method is low-cost and easy, and has excellent strength and high resistance to chloride ion penetration. At the same time, it can dispose of industrial solid waste that is difficult to biodegrade naturally.

[0042] Please see Figure 1 The specific steps of the preparation method of chloride ion-resistant 3D printed concrete of the present invention are as follows:

[0043] S101. Material preparation: Prepare materials according to the weight proportions shown in Table 1.

[0044] The powder of the decommissioned wind turbine blades has an average particle size of 50.98 μm, is white, and contains a small amount of transparent glass fiber filaments.

[0045] The fibers of the retired wind turbine blades have a single filament length of 3μm-15μm and contain a small amount of glass fiber powder and resin particles.

[0046] The silicate cement is Zhonglian PO 42.5 grade produced in Anhui.

[0047] The fly ash is Grade I fly ash sold in Nanjing, and the mineral powder is S95 grade mineral powder sold in the market.

[0048] The fine aggregate is selected from local fine river sand in Anhui Province, and the fineness modulus of the fine river sand is 1.36.

[0049] The water-reducing agent is Sika 540P retarded polycarboxylate superplasticizer powder. The cellulose ether is hydroxyethyl cellulose ether produced by Dow, with a viscosity of 25000 mPa·s at 20°C. The air-entraining agent is industrial-grade sodium dodecyl sulfate.

[0050] The sulfoaluminate cement mentioned is commercially available grade 42.5 rapid-hardening sulfoaluminate cement.

[0051] The quartz sand is produced in Nanjing and has a particle size of 0.106mm-0.15mm. The redispersible polymer powder is 5044 polymer powder produced by Wacker Chemie. The water repellent is commercially available Dow Corning SHP-50 silicone water repellent.

[0052] The organosilicon additive is commercially available water glass with a solid content of 42.17%, containing 21.25% Na2O, 21.82% SiO2 and 58.83% water, and a modulus of 2.1.

[0053] S102. Preparation of decommissioned wind turbine blade powder dispersion: Mix 50% of the water and wetting agent from step S101, then add 50% of the decommissioned wind turbine blade powder, stir for 5 minutes, add to an ultrasonic disperser, disperse for 1 hour and set aside.

[0054] S103. Preparation of modified decommissioned wind turbine blade fibers: Dry mix the remaining 50% wind turbine powder, 50% mineral powder and decommissioned wind turbine blade fibers from step S101 for 5 minutes, then perform autoclaving treatment at a temperature of 90℃±10℃ for 1 hour, and then take them out for later use.

[0055] S104. Dry mix the cement, fly ash, remaining 50% mineral powder and fine aggregate, water-reducing agent, cellulose ether and air-entraining agent from step S101 for 5 minutes, then add the remaining 30% of the total water and stir at low speed for 3 minutes.

[0056] S105. Add the decommissioned wind turbine blade powder dispersion prepared in step S102 to the mixture in step S104, continue to stir at low speed for 3 minutes, then add the modified decommissioned wind turbine blade fiber prepared in step S103, stir at low speed again for 5 minutes, add water equal to 20% of the total water volume, stir at high speed for 3 minutes, and then let stand to obtain 3D printed concrete resistant to chloride ion penetration.

[0057] Table 1. Weight parts of each component in the preparation example of chloride ion-resistant 3D printed concrete.

[0058]

[0059] The concrete prepared in the above example was added to a desktop 3D printer for building construction. The printing strip width was 15cm, the layer height was 10cm, and 10 layers were printed. The compressive strength was tested according to T / CBMF 183-2022 "Test Method for Basic Mechanical Properties of 3D Printed Concrete". The frost resistance, impermeability, and chloride ion penetration resistance were determined according to GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". The specific test results are shown in Table 2.

[0060] Table 2. Performance test results of concrete prepared using 3D-printed concrete resistant to chloride ion penetration.

[0061]

[0062] As shown in Table 2, the concrete prepared according to the above method, by replacing traditional cement clinker with decommissioned wind turbine blades and reinforcing fibers with decommissioned wind turbine blade fibers, reduces the amount of cement required, increases the utilization of industrial solid waste such as decommissioned wind turbine blades, fully utilizes the physical and chemical properties of the crushed decommissioned wind turbine blades, stimulates the performance of each raw material, and promotes mutual influence and synergy, thereby reducing the amount of admixtures used. The resulting compressive strength can reach 50 MPa, and the chloride ion diffusion coefficient in the chloride ion penetration test is 0.25 × 10⁻⁶. -12 m 2 / s, with excellent concrete strength and resistance to chloride ion penetration, making it more suitable for harsh application environments such as the ocean; the antifreeze test shows that the concrete has good antifreeze properties, which greatly improves the corrosion resistance and durability of the concrete.

[0063] Table 3 Material composition of powder and fiber from decommissioned wind turbine blades

[0064]

[0065]

[0066] As shown in Table 3, the inorganic phases in both the decommissioned wind turbine blade powder and the decommissioned wind turbine blade fibers belong to alkali-free glass fibers, with a sodium content of less than 2%. The mass ratio of alumina to silica in both materials is close to 1:4, consistent with the composition of aluminosilicate glass. The chemical composition of both materials is similar to that of cement, containing SiO2, Al2O3, Fe2O3, CaO, etc., accounting for approximately 95% of the total composition. The decommissioned wind turbine blade powder contains abundant chemical components similar to pozzolanic materials, with SiO2 content approximately twice that of cement, exhibiting high hydration activity, and can be used as a partial cement admixture.

[0067] Depend on Figure 3 It can be seen that both materials begin to lose mass at 300℃, which is due to the combustion of epoxy resin in the air. The calculated resin mass fraction in the recycled micro powder is 28.44%, and the resin mass fraction in the recycled fiber is 34.61%, indicating that both materials contain hydrophobic resin components, which can reduce water absorption and improve impermeability.

[0068] This invention involves pre-mixing decommissioned wind turbine blade powder with a wetting agent and water, followed by ultrasonic dispersion to ensure more uniform dispersion of the powder within the system. Decommissioned wind turbine fibers are also pre-dispersed and mixed with the decommissioned wind turbine powder and mineral powder. After high-temperature autoclaving, a layer of powder coats the surface of the wind turbine fibers, increasing surface friction and improving adhesion to other powder materials, thus increasing the overall strength of the concrete. Furthermore, important chemical reactions are pre-processed and carried out separately to ensure each reaction is more complete and thorough, resulting in stable concrete quality.

[0069] This invention uses a mixture of decommissioned wind turbine powder, fly ash, and mineral powder to partially replace traditional cement clinker. The chemical composition of the decommissioned wind turbine blade powder is mainly composed of glass fiber and resin, which can undergo secondary hydration with sodium hydroxide generated after cement hydration, thereby increasing the hardness of the hydration products, making the hydration products more compact, improving mechanical strength and resistance to chloride ion penetration, and at the same time, the resin component improves the waterproof and antifreeze properties of the material.

[0070] Preparation of comparative examples

[0071] Comparative Example 1

[0072] Step 1: Prepare the ingredients. Prepare the ingredients according to the weight proportions of Comparative Example 1 in Table 4.

[0073] The other steps are the same as in the preparation example, except that in step five, dispersion is carried out for 30 minutes before use.

[0074] Comparative Example 2

[0075] Step 1: Prepare the ingredients. Prepare the ingredients according to the comparative proportion of 1 part by weight in Table 4.

[0076] The other steps are the same as those in Comparative Example 1, except that in step five, the sample is dispersed for 1.5 hours and then set aside.

[0077] Comparative Example 3

[0078] Step 1: Prepare the materials. The weight proportions of Comparative Example 3 are the same as those of Comparative Example 1.

[0079] The other steps are the same as in Comparative Example 1, except that the temperature in step six is ​​set to 110℃±10℃; Comparative Example 4

[0080] Step 1: Prepare the materials. The weight proportions of Comparative Example 4 are the same as those of Comparative Example 1.

[0081] The other steps are the same as in Comparative Example 1, except that the temperature in step six is ​​set to 70℃±10℃; Comparative Example 5

[0082] The preparation steps are the same as in the preparation example. The difference between Comparative Example 5 and Comparative Example 1 is that the amount of retired wind turbine blade powder is 150 parts.

[0083] Comparative Example 6

[0084] The preparation steps are the same as in the preparation example. The difference between Comparative Example 6 and Comparative Example 1 is that the amount of retired wind turbine blade powder is 40 parts.

[0085] Comparative Example 7

[0086] The preparation steps are the same as in the preparation example. The difference between Comparative Example 7 and Comparative Example 1 is that the amount of fiber in the decommissioned wind turbine blade is 50 parts.

[0087] Comparative Example 8

[0088] The preparation steps are the same as in the preparation example. The difference between Comparative Example 8 and Comparative Example 1 is that the fiber of the decommissioned wind turbine blade is 75 parts.

[0089] Comparative Example 9

[0090] The preparation steps are the same as in the preparation example. The difference between Comparative Example 9 and Comparative Example 1 is that the wetting agent is 0.15 parts.

[0091] Comparative Example 10

[0092] The preparation steps are the same as in the preparation example. The difference between Comparative Example 10 and Comparative Example 1 is that the wetting agent is 0.35 parts.

[0093] Table 4. Weight proportions of each component in the comparative example of chloride ion-resistant 3D-printed concrete.

[0094]

[0095] The 3D-printed concrete prepared in the above comparative example was added to a desktop 3D architectural printer. The printing strip width was 15cm, the layer height was 10cm, and 10 layers were printed. The compressive strength was tested according to T / CBMF 183-2022 "Test Method for Basic Mechanical Properties of 3D Printed Concrete". The frost resistance, impermeability, and chloride ion penetration resistance were determined according to GB / T50082-2009 "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete". The specific test results are shown in Table 5.

[0096] Table 5. Comparative test results of chloride ion penetration resistant 3D printed concrete.

[0097]

[0098]

[0099] As shown in Table 5, the performance test results indicate that the concrete prepared according to the above method was not superior to that of Comparative Examples 1-10 in terms of performance. This demonstrates that only appropriate ultrasonic dispersion time, reasonable steam curing time, suitable amounts of decompressed wind turbine blade powder and fiber, and appropriate wetting agent dosage can produce 3D-printed concrete and components with excellent compressive strength, good durability, and resistance to chloride ion penetration.

[0100] Please see Figure 1 The present invention also provides a method for preparing a 3D-printed concrete component resistant to chloride ion penetration, the specific steps of which are as follows:

[0101] S201. Material preparation: Prepare materials according to the weight proportions shown in Table 2.

[0102] S202. Dry mix the silicate cement, sulfoaluminate cement, decommissioned wind turbine blade powder, quartz sand, water-reducing agent, dispersible colloid powder and water-repellent agent from step S201 for 5 minutes.

[0103] S203. After mixing the organosilicon additive and water evenly, add it to the mixture of S202 and continue to stir at low speed for 5 minutes to obtain waterproof and seepage-proof mortar for later use.

[0104] S204. Cut the steel bars required for the printed concrete components into shape, and spray a layer of epoxy resin on the surface. After the surface dries, use a brush to apply the prepared waterproof and seepage-proof mortar to the surface of the steel bars. After the surface dries, it is ready for use.

[0105] S205. Add the 3D printed concrete prepared above into the 3D printer with the printing path set, and print and stack it into the required component according to the printing path; at the same time, place the steel bars prepared in step S204 into the 3D printed concrete component according to the design reinforcement, and cure the 3D printed concrete component for 28 days.

[0106] S206. Apply two more coats of the waterproof and seepage-resistant mortar prepared in step S203 to the surface of the 3D printed concrete component prepared in step S205.

[0107] Table 6 shows the weight parts of each component in the preparation example of waterproof and impermeable mortar for 3D printed concrete components resistant to chloride ion penetration.

[0108] raw materials Preparation Example 5 Preparation Example 6 Preparation Example 7 Preparation Example 8 Silicate cement 300 300 450 450 Sulfoaluminate cement 100 50 50 100 retired wind turbine blade powder 50 100 100 50 Quartz sand 600 600 550 550 Inorganic silicon additives 50 40 30 20 Water reducing agent 1.8 1.9 2.1 2.2 Dispersible adhesive powder 8 10 6 5 Water repellent 3 2.8 2.5 2.2 water 160 170 175 180

[0109] The mortar prepared in the above example was tested according to the test and testing methods in GB 18445-2012 "Cement-based Penetrating Crystalline Waterproofing Materials", and the test items in Table 7 were tested. The specific test results are shown in Table 7.

[0110]

[0111]

[0112] As shown in Table 7, the performance test results indicate that all performance indicators of the waterproof and seepage-resistant mortar applied to the surface of the chloride ion-resistant 3D-printed concrete components have met or exceeded national standards. In particular, its seepage resistance, a key indicator of waterproofing materials, is excellent, and its secondary seepage pressure resistance far exceeds national standards. This demonstrates that the waterproof and seepage-resistant mortar applied to the surface of the chloride ion-resistant 3D-printed concrete components can serve as an excellent waterproofing material. Furthermore, it imparts strong waterproof and seepage-resistant capabilities to the concrete matrix. Applying this material to the surface of reinforcing steel and the finished 3D-printed concrete components further enhances the resistance of both steel and concrete to seawater erosion.

[0113] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for the production of a 3D printed concrete component which is resistant to penetration by chloride ions, characterized in that The specific steps are as follows: S201, preparation: according to the following weight parts, Portland cement 300-350 parts, sulphoaluminate cement 5-100 parts, retired fan blade powder 100-150 parts, quartz sand 550-600 parts, water reducing agent 1.8-2.2 parts, dispersible glue powder 5-10 parts, water repellent agent 2.2-3 parts, organic silicon additive 30-60 parts and water 160-180 parts; S202, dry mixing the Portland cement, sulphoaluminate cement, retired fan blade powder, quartz sand, water reducing agent, dispersible glue powder and water repellent agent in step S201 for 5 minutes; S203, after stirring the organic silicon additive and water uniformly, add the mixture of S202, continue to stir at low speed for 5 minutes to prepare the waterproof and impermeable mortar, and standby; S204, cut the steel bars needed for printing the concrete member into shape, and spray a layer of epoxy resin on the surface. After the surface is dry, use a brush to brush the prepared waterproof and impermeable mortar on the surface of the steel bars, and standby after the surface is dry; S205, add the 3D printed concrete prepared by the method for preparing the 3D printed concrete resistant to chloride ion penetration to the 3D printer with the set printing path, and print the 3D printed concrete according to the printing path to stack into the required member; at the same time, place the steel bars prepared in step S204 in the 3D printed concrete member according to the design reinforcement, and maintain the 3D printed concrete member for 28 days; S206, brush the waterproof and impermeable mortar prepared in step S203 on the surface of the 3D printed concrete member prepared in step S205 again for two times; The specific steps of the method for preparing the 3D printed concrete resistant to chloride ion penetration are as follows: S101, preparation: according to the following weight parts, 42.5 Portland cement 230-250 parts, retired fan blade powder 60-100 parts, fly ash 40-80 parts, mineral powder 30-60 parts, fan blade fiber 0-25 parts, fine aggregate 550-575 parts, water reducing agent 1.35-1.75 parts, cellulose ether 0.225-0.35 parts, air entraining agent 0.1-0.2 parts, wetting agent 0.25-0.35 parts, and water 135-155 parts; S102, preparation of retired fan blade powder dispersion liquid: mix 50% of the water in step S101 with the wetting agent, then add 50% of the retired fan blade powder, stir for 5 minutes, and then add to the ultrasonic dispersing instrument, and disperse for 1 hour to standby; S103, preparation of modified retired fan blade fiber: dry mix 50% of the remaining retired fan blade powder in step S101, 50% of the mineral powder, and the retired fan blade fiber for 5 minutes, and then perform autoclave treatment, with the temperature set to 90℃±10℃, and take out after 1 hour to standby; S104, dry mix the cement, fly ash, 50% of the remaining mineral powder and fine aggregate, water reducing agent, cellulose ether and air entraining agent in step S101 for 5 minutes, then add 30% of the total water amount, and stir at low speed for 3 minutes; S105, the retired fan blade powder dispersion liquid prepared in step S102 is added to the mixture of step S104, low-speed stirring is continued for 3 min, then the modified retired fan blade fiber prepared in step S103 is added, low-speed stirring is continued for 5 min, 20% of the total water amount of water is added, high-speed stirring is continued for 3 min, and then standing is performed to obtain the 3D printing concrete with anti-chloride ion penetration.

2. A method of producing a 3D printed concrete component resistant to chloride penetration according to claim 1, characterized in that, In the step S1, the following weight parts are prepared: 250 parts of 42.5 Portland cement, 80 parts of retired fan blade powder, 40 parts of fly ash, 30 parts of mineral powder, 25 parts of fan blade fiber, 575 parts of fine aggregate, 1.45 parts of water reducing agent, 0.3 parts of cellulose ether, 0.1 parts of air entraining agent, 0.25 parts of wetting agent, and 140 parts of water.

3. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, The average particle size of the retired fan blade powder is 50.98 µm, and the retired fan blade powder contains transparent glass fiber filaments.

4. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, The single filament length of the retired fan blade fiber is 3 µm-15 µm, and contains a small amount of glass fiber powder and resin particles.

5. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, The fine aggregate includes fine river sand and / or tailings sand, and the fineness modulus of the fine river sand is 1.

36.

6. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, The water reducing agent is a retarding type polycarboxylic acid water reducing agent powder, the cellulose ether is a hydroxyethyl cellulose ether with a viscosity of 25000 mPa·s at 20°C, the air entraining agent is an industrial grade sodium dodecyl sulfate, and the wetting agent is one of polyoxyethylene alkyl phenol ethers.

7. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, In the step S201, the following weight parts are prepared: 300 parts of Portland cement, 50 parts of sulphoaluminate cement, 100 parts of retired fan blade powder, 600 parts of quartz sand, 1.9 parts of water reducing agent, 10 parts of dispersible glue powder, 2.8 parts of hydrophobic agent, 40 parts of silicone additive, and 170 parts of water.

8. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, In the step S206, the waterproof anti-permeation mortar is brushed in the first pass parallel to the printing direction of the 3D printing concrete component, and in the second pass perpendicular to the printing direction, and the coating thickness is 3 mm-5 mm.

9. A method of producing a 3D printed concrete component resistant to chloride ion penetration according to claim 1, characterized in that, The particle size of the quartz sand is 0.106 mm-0.15 mm, and the silicone additive is water glass with a solid content of 42.17%, containing 21.25% Na2O, 21.82% SiO2, and 58.83% water, and a modulus of 2.1.

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