Composite geopolymer torsade and 3D printing method

Abstract

This invention discloses a 3D printing method for composite geopolymer twisted character blocks, comprising the following steps: S100. Kaolin is calcined at high temperature to obtain metakaolin micro powder; S200. Blast furnace slag is ground to obtain blast furnace slag micro powder; S300. A low-modulus water glass solution is obtained by mixing a high-modulus water glass solution and a sodium hydroxide solution as an alkaline activator; S400. Metakaolin micro powder, blast furnace slag micro powder and alkaline activator are mixed and stirred at high speed to produce a three-dimensional network structure N-A-S-H gel; S500. Mixed fibers, water-reducing agent, antibacterial agent and waterproofing agent are added and stirred at low speed to obtain a fluid paste mixture; S600. The 3D printing nozzle is driven to move along the twisted character block in the X, Y and Z directions, while the delivery pump drives the paste mixture to be quantitatively ejected from the 3D printing nozzle to print the twisted character block. The 3D-printed Twisted King blocks produced using this method use geopolymers as a substitute for concrete, resulting in environmental friendliness, energy efficiency, enhanced durability, and improved resistance to seawater erosion.

Description

Technical Field

[0001] This invention relates to the field of twisted letter blocks, and in particular provides a composite geopolymer twisted letter block and a 3D printing method. Background Technology

[0002] Twisted blocks are a type of protective block on breakwaters, typically placed on the outermost layer of the breakwater to protect it by reducing the impact of waves.

[0003] Currently, Twisted King blocks are generally manufactured from plain concrete using traditional casting techniques. The production process requires multiple steps, including mold setup, casting, and demolding, resulting in a long solidification time and a labor-intensive manufacturing process. Furthermore, since the core and surface layers of Twisted King blocks are made from plain concrete with the same cement content, a higher cement content is usually added to achieve overall solidification and prevent structural loosening. This increases concrete production costs, and cement production has a significant environmental impact, which is detrimental to environmental protection.

[0004] When traditionally manufactured T-shaped blocks are used to pave breakwaters, the cyclical impact of waves can damage them due to seawater erosion. Furthermore, the presence of chlorides and microorganisms in seawater can lead to poor durability of these concrete T-shaped blocks, making them susceptible to microbial invasion and corrosion, which is detrimental to the long-term service life of the concrete. Summary of the Invention

[0005] Based on this, the present invention provides a composite geopolymer twisted block and a 3D printing method, which improves its durability during use, enhances its resistance to seawater erosion, simplifies the manufacturing process, reduces production costs, and achieves the purpose of environmental protection and energy saving.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for 3D printing composite geopolymer twisted block, comprising the following steps:

[0007] S100. Kaolin is calcined at high temperature to obtain metakaolin, which is then ground and filtered to obtain metakaolin powder; S200. Blast furnace slag is ground and filtered to obtain blast furnace slag powder.

[0008] S300. Mix high-modulus water glass solution and sodium hydroxide solution according to the specified ratio to obtain low-modulus water glass solution as an alkaline activator;

[0009] S400. Mix the obtained metakaolin powder, blast furnace slag powder and alkaline activator and stir at high speed to produce a three-dimensional network structure NASH gel.

[0010] S500. Add mixed fibers, water-reducing agent, antibacterial agent and waterproofing agent, stir at low speed until uniform, to obtain a fluid paste-like mixture;

[0011] The S600 3D printing building equipment drives the 3D printing nozzle to move along the Twisted King block in the X, Y, and Z directions, while the delivery pump drives the paste mixture to be quantitatively ejected from the 3D printing nozzle to print the Twisted King block.

[0012] Furthermore, kaolin is ground into powder and calcined at 800-900℃ for 3.5-4.5 hours with a heating rate of 2-10℃ / min to obtain metakaolin. The metakaolin is then ground and filtered through an 80-120 mesh sieve to obtain metakaolin micro powder, which is rich in Si and Al. After activation with an alkaline activator, it mainly produces NASH gel, which has a three-dimensional network structure. Compared with silicate cementitious materials, it has higher strength after hardening.

[0013] Furthermore, the blast furnace slag is cleaned and dried to obtain dried granulated blast furnace slag. This dried granulated blast furnace slag is then ground and filtered through a 60-140 mesh sieve to obtain blast furnace slag micro powder. Granulated blast furnace slag powder (GGBS) contains a large amount of Ca. After activation with an alkaline activator, the products are mainly chain-structured CASH and NASH phase gels, thus significantly reducing the setting time and significantly enhancing early strength. Using an equal mass of GGBS to replace metakaolin in the curing reaction, the final setting time can be controlled within 30 minutes, and the strength can increase by approximately 150%.

[0014] Furthermore, the preparation steps of the alkaline activator include:

[0015] S310. The preset modulus of the low-modulus water glass solution to be prepared is 1.3. Calculate the mass of sodium hydroxide required to prepare the low-modulus water glass solution using the following formula:

[0016]

[0017] In the formula, G is the mass of sodium hydroxide added, G0 is the mass of the high-modulus water glass solution, M1 is the modulus of the high-modulus water glass solution, M0 is the modulus of the water glass solution to be prepared, N is the mass of sodium hydroxide in the high-modulus water glass solution, and P is the purity of sodium hydroxide.

[0018] S320. Based on the principle that the mass of sodium hydroxide solid remains unchanged, convert it to the mass of 8.0 mol / L sodium hydroxide solution, and prepare an 8.0 mol / L sodium hydroxide solution;

[0019] S330. Dissolve the prepared 8.0 mol / L sodium hydroxide solution in high-modulus water glass and stir until homogeneous to obtain low-modulus water glass.

[0020] Furthermore, during the printing of the Twisted King block using a 3D printing nozzle, the content of the mixed fiber in the paste mixture at the nozzle inlet is dynamically adjusted so that the concentration of mixed fiber on the periphery of the Twisted King block is lower than that in the core, thereby improving the overall structural support and cohesion of the Twisted King block.

[0021] Furthermore, a first storage tank for storing a paste-like mixture of low-concentration mixed fibers and a second storage tank for storing a paste-like mixture of high-concentration mixed fibers are provided. The first storage tank is connected to the 3D printing nozzle inlet via a first delivery pump, and the second storage tank is connected to the 3D printing nozzle inlet via a second delivery pump. During the 3D printing of the Twisted King character block, the delivery speed of the first and second delivery pumps is dynamically adjusted to regulate the concentration of mixed fibers entering the 3D printing nozzle.

[0022] Furthermore, during the 3D printing of torsion blocks at different heights, the concentration of the mixed fibers in the paste-like mixture delivered to the 3D printing nozzle is dynamically adjusted. The steps include:

[0023] S610. When printing the bottom of the twisted block, increase the conveying speed of the first conveying pump and decrease the conveying speed of the second conveying pump to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle and reduce the mixed fiber content at the bottom of the twisted block.

[0024] S620. When printing the middle part of the Twisted King block, reduce the conveying speed of the first conveying pump and increase the conveying speed of the second conveying pump to increase the mixed fiber concentration of the paste mixture input to the 3D printing nozzle and increase the mixed fiber content in the middle part of the Twisted King block;

[0025] S630. When printing the top of the Twisted King block, increase the delivery speed of the first delivery pump and decrease the delivery speed of the second delivery pump to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle and reduce the mixed fiber content at the top of the Twisted King block.

[0026] Furthermore, when printing the middle of the Twisted King character block, the concentration of the mixed fibers in the paste-like mixture delivered to the 3D printing nozzle is dynamically adjusted at different positions at the same height. The steps include:

[0027] S660. When printing the outer periphery of the middle part of the twisted character block, reduce the mixed fiber content of the paste mixture input to the 3D printing nozzle to reduce the mixed fiber content of the outer periphery of the middle part of the twisted character block;

[0028] S670. When printing the inner core of the twisted character block, increase the mixed fiber content of the paste mixture input to the 3D printing nozzle to improve the mixed fiber content of the inner core of the twisted character block.

[0029] To achieve the above objectives, in a second aspect, the present invention provides a composite geopolymer twisted kingpin, which is produced using the 3D printing method according to any one of claims 1 to 8, wherein the raw materials comprise, by weight proportion:

[0030] The composition consists of 45-55% metakaolin powder, 44-55% blast furnace slag powder, 10-15% alkaline activator, 5-10% mixed fiber, 2-5% water-reducing agent, 2-5% waterproofing agent, and 1-2% antibacterial and bactericidal agent, with the remainder being water.

[0031] Furthermore, the composite fiber concentration at the bottom and top of the composite geopolymer twisted block is lower than that in the middle; in the middle of the geopolymer twisted block, the composite fiber concentration on the outer periphery is lower than that in the inner core.

[0032] The technical advantages of the composite geopolymer twisted block and 3D printing method provided by this invention are at least as follows:

[0033] The provided composite geopolymer twisted block and 3D printing method use geopolymers such as kaolin and blast furnace slag as main raw materials. Alkaline activation with an alkaline activator generates a three-dimensional network structure of NASH fluid paste. The curing process involves the breaking and re-condensation of -OS iO-Al-O- bonds in the silicate material to form a tetrahedral network structure. This results in a short setting time, improved structural solidification force, and high early strength. Furthermore, the addition of mixed fibers enhances load-bearing capacity, water-reducing agents improve rapid setting, antibacterial agents enhance antibacterial properties, and waterproofing agents improve waterproofing performance. This results in a high resistance to seawater erosion, making the produced twisted blocks suitable for use on seawalls.

[0034] Furthermore, using geopolymer materials as raw materials not only provides a wide range of sources, but also results in a paste-like mixture with good fluidity and a short setting time, making it suitable for 3D printing processes. Based on this, using the designed 3D model of the twisted U-shaped block, the block is manufactured by adding material layer by layer through 3D printing equipment. This 3D printing process replaces the traditional casting process for rapid production of the twisted U-shaped block, eliminating the mold setup, casting, and demolding steps required in traditional concrete casting. This saves time and labor, and the production process consumes less energy and emits less carbon, making it highly environmentally friendly and offering significant advantages compared to traditional concrete processes. Attached Figure Description

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 A flowchart illustrating an embodiment of the provided composite geopolymer twisted block 3D printing method;

[0037] Figure 2 A flowchart illustrating an embodiment of the preparation steps of the provided alkaline activator;

[0038] Figure 3 A structural schematic diagram of an embodiment of the provided 3D printing building equipment;

[0039] Figure 4 A flowchart illustrating an embodiment of dynamically adjusting the concentration of mixed fibers in a paste mixture during the process of 3D printing twisted character blocks at different heights;

[0040] Figure 5 A flowchart illustrating an embodiment of dynamically adjusting the concentration of mixed fibers in a paste mixture when printing the middle of a twisted character block;

[0041] Figure 6 A schematic front view of an embodiment of the provided composite geopolymer twisted block;

[0042] Figure 7 for Figure 6 A sectional view of section 1-1'.

[0043] Explanation of reference numerals in the attached diagram:

[0044] 1-Twisted King-shaped block, 11-Bottom, 12-Middle, 13-Top, 121-Outer perimeter of the middle, 122-Inner core of the middle;

[0045] 21 - 3D printing building equipment; 22 - 3D printing nozzles;

[0046] 31-First transfer pump, 32-First storage tank;

[0047] 41 - Second transfer pump, 42 - Second storage tank. Detailed Implementation

[0048] Currently, U-shaped concrete blocks are generally manufactured using traditional casting techniques with plain concrete. This process is time-consuming and labor-intensive, with a long setting time. The cement content is consistent between the core and the surface layers. To achieve overall strength and prevent structural loosening, a higher cement content is typically added, resulting in high concrete production costs. Cement production also has a significant environmental impact, hindering environmental protection. Furthermore, the recurring impact of ocean waves can damage the U-shaped concrete blocks due to seawater erosion. The presence of chlorides and microorganisms in seawater also leads to poor durability, making these concrete U-shaped blocks susceptible to microbial invasion and corrosion, thus limiting their long-term usability.

[0049] Therefore, the present invention provides a composite geopolymer twisted block, the raw materials comprising, by weight proportion: 45-55% metakaolin powder, 44-55% blast furnace slag powder, 10-15% alkaline activator, 5-10% mixed fiber, 2-5% water-reducing agent, 2-5% waterproofing agent, and 1-2% antibacterial and bactericidal agent, with the remainder being water. Simultaneously, a method for 3D printing composite geopolymer twisted letter blocks is provided, comprising the following steps: S100. Kaolin is calcined at high temperature to obtain metakaolin micro powder; S200. Blast furnace slag is ground to obtain blast furnace slag micro powder; S300. A low-modulus water glass solution is obtained by mixing a high-modulus water glass solution and a sodium hydroxide solution as an alkaline activator; S400. Metakaolin micro powder, blast furnace slag micro powder, and alkaline activator are mixed and stirred at high speed to produce a three-dimensional network structure of NASH gel; S500. Mixed fibers, water-reducing agent, antibacterial agent, and waterproofing agent are added and stirred at low speed to obtain a fluid paste mixture; S600. The 3D printing nozzle is driven to move along the twisted letter block in the X, Y, and Z directions, while the delivery pump drives the paste mixture to be quantitatively ejected from the 3D printing nozzle to print the twisted letter block. The twisted letter blocks 3D printed by this method use geopolymer as a substitute for concrete material, which is environmentally friendly and energy-saving, and has enhanced durability and resistance to seawater erosion.

[0050] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0051] like Figure 1 As shown, the present invention provides a method for 3D printing composite geopolymer twisted block, the steps of which include:

[0052] S100. Kaolin is calcined at high temperature to obtain metakaolin, which is then ground and filtered to obtain metakaolin micro powder; in the specific implementation process, kaolin is ground into powder and calcined at 800-900℃ for 3.5-4.5h with a heating rate of 2-10℃ / min to obtain metakaolin, which is then ground and filtered through an 80-120 mesh sieve to obtain metakaolin micro powder;

[0053] S200. Blast furnace slag is ground and filtered to obtain blast furnace slag powder; in the specific implementation process, blast furnace slag is cleaned and dried to obtain dried granulated blast furnace slag, and the dried granulated blast furnace slag is ground and filtered through a 60-140 mesh sieve to obtain blast furnace slag powder.

[0054] S300. Mix high-modulus water glass solution and sodium hydroxide solution according to the specified ratio to obtain low-modulus water glass solution as an alkaline activator;

[0055] like Figure 2 As shown, in the specific implementation process, the preparation steps of the alkaline activator include:

[0056] S310. The preset modulus of the low-modulus water glass solution to be prepared is 1.3. Calculate the mass of sodium hydroxide required to prepare the low-modulus water glass solution using the following formula:

[0057]

[0058] In the formula, G is the mass of sodium hydroxide added, G0 is the mass of the high-modulus water glass solution, M1 is the modulus of the high-modulus water glass solution, M0 is the modulus of the water glass solution to be prepared, N is the mass of sodium hydroxide in the high-modulus water glass solution, and P is the purity of sodium hydroxide.

[0059] S320. Based on the principle that the mass of sodium hydroxide solid remains unchanged, convert it to the mass of 8.0 mol / L sodium hydroxide solution, and prepare an 8.0 mol / L sodium hydroxide solution;

[0060] S330. Dissolve the prepared 8.0 mol / L sodium hydroxide solution in high modulus water glass and stir until homogeneous to obtain low modulus water glass;

[0061] S400. Mix the obtained metakaolin powder, blast furnace slag powder and alkaline activator and stir at high speed to produce a three-dimensional network structure NASH gel.

[0062] S500. Add mixed fibers, water-reducing agent, antibacterial agent and waterproofing agent, stir at low speed until uniform, to obtain a fluid paste-like mixture;

[0063] The S600 3D printing building equipment 21 drives the 3D printing nozzle 22 to move along the Twisted King block in the X, Y, and Z directions, while the delivery pump drives the paste mixture to be quantitatively ejected from the 3D printing nozzle 22 to print the Twisted King block.

[0064] The composite geopolymer twisted-roof blocks manufactured using the above methods incorporate water-reducing agents, increasing the fluidity of the geopolymer slurry and reducing its cohesiveness. This allows for proper extrusion during 3D printing. The material itself has high strength, ensuring sufficient strength to withstand its own load and the subsequent loads from the upper parts during printing, preventing collapse. Manufactured layer by layer using 3D printing equipment, compared to ordinary concrete twisted-roof blocks, the twisted-roof blocks of this invention exhibit significantly improved strength, enhanced durability, and increased resistance to seawater and microbial erosion. They possess high strength and multifunctionality, contributing to their long-term service life.

[0065] In a preferred embodiment, the composite geopolymer twisted block provided by the present invention comprises, by weight proportion: 45-55% metakaolin powder, 44-55% blast furnace slag powder, 10-15% alkaline activator, 5-10% mixed fiber, 2-5% water-reducing agent, 2-5% waterproofing agent, and 1-2% antibacterial and bactericidal agent, with the remainder being water.

[0066] The provided composite geopolymer twisted block 3D printing method uses geopolymers such as kaolin and blast furnace slag as the main raw materials. It generates a three-dimensional network structure of NASH fluid paste mixture through alkaline activation with an alkaline activator. The curing process is a process in which the -OS iO-Al-O- bonds in the silicate material break and recombine to form a tetrahedral network structure, which promotes the rapid setting time of the generated material, improves the structural solidification force, and has high early strength. At the same time, the addition of mixed fibers improves the load-bearing capacity, the addition of water-reducing agents improves the rapid setting, the addition of antibacterial agents improves the antibacterial ability, and the addition of waterproofing agents improves the waterproof performance, thereby improving the durability and continuity during the use of breakwaters. It has a high resistance to seawater erosion and is suitable for use on seashore breakwaters.

[0067] 3D printing materials require not only a certain degree of fluidity during extrusion but also the ability to harden and achieve high strength within a short time. This ensures the printed material has sufficient strength to withstand its own load and the load from subsequent printing, preventing collapse during printing. Therefore, geopolymer materials are highly suitable for the requirements of 3D printed building materials. Specifically, the resulting fluid paste-like mixture is suitable for 3D printing. Based on the designed 3D model of the Twisted King block, the material is added layer by layer using 3D printing equipment to manufacture the Twisted King block. Replacing the traditional casting process with 3D printing eliminates the need for mold setup, casting, and demolding, saving time and labor. Furthermore, the material sources are widely available, and the production process consumes less energy and emits less carbon, offering significant advantages compared to traditional cement.

[0068] The mixed fiber is a mixture of basalt fiber and PVA fiber. This mixed fiber can significantly improve the tensile and flexural strength of geopolymer materials, and also makes a significant contribution to compressive strength.

[0069] The water-reducing agent material is one of naphthalene-based high-efficiency water-reducing agent and polycarboxylate high-performance water-reducing agent. The water-reducing agent can significantly enhance the flowability of fresh polymer materials and reduce their cohesiveness, ensuring successful extrusion during 3D printing.

[0070] The waterproofing agent is one of acrylate and polydimethylsiloxane (PDMS). Adding the waterproofing agent can enhance the erosion resistance and durability of the geopolymer material, and extend its service life when it is used to prepare the T-shaped blocks for breakwaters.

[0071] The antibacterial and bactericidal material is either nano-TiO2 or hexadecylmethylammonium bromide. Adding the antibacterial and bactericidal material can prevent the invasion and corrosion of microorganisms and extend the service life of the geopolymer material.

[0072] This technical solution example increases the fluidity of the geopolymer slurry and reduces its cohesiveness by adding water-reducing agent materials, enabling normal extrusion during 3D printing. By adding fiber materials, waterproofing agents, and antibacterial materials to the 3D printing material in layers, the strength of the geopolymer toggle block is greatly improved, its durability is enhanced, and its resistance to seawater erosion and microbial erosion is strengthened. It has high strength and multiple functions, which is conducive to its long-term service.

[0073] In some preferred embodiments, during the printing of the twisted king block using the 3D printing nozzle 22, the mixed fiber content of the paste mixture at the inlet of the 3D printing nozzle 22 is dynamically adjusted so that the mixed fiber concentration on the periphery of the twisted king block is lower than that in the core, thereby improving the overall structural support and peripheral cohesion of the twisted king block. Through this structure, the low mixed fiber concentration on the periphery of the twisted king block ensures the continuity and density of the outer surface, avoiding surface roughness and incompleteness caused by the mixed fibers, thus improving surface quality and seawater erosion resistance. Simultaneously, the high mixed fiber concentration in the core of the twisted king block, with its strong tensile strength, enhances the cohesion of the core, thereby increasing the structural strength of the twisted king block. In other words, by achieving a structure with a low mixed fiber concentration in the core and a high mixed fiber concentration on the periphery, the surface quality of the composite geopolymer twisted king block is improved, and the cohesion of the core is enhanced, thus improving the overall structural strength and seawater erosion resistance of the twisted king block.

[0074] like Figure 3As shown, in order to achieve accurate and rapid adjustment of the concentration of the paste mixture during the 3D printing process, this invention provides a 3D printing device specifically for composite geopolymer twisted blocks. It includes a first storage tank 32 for storing a paste mixture of low-concentration mixed fibers and a second storage tank 42 for storing a paste mixture of high-concentration mixed fibers. The first storage tank 32 is connected to the inlet of the 3D printing nozzle 22 via a first delivery pump 31, and the second storage tank 42 is connected to the inlet of the 3D printing nozzle 22 via a second delivery pump 41. During the 3D printing of the twisted blocks, the delivery speeds of the first and second delivery pumps 31 are dynamically adjusted to regulate the concentration of the mixed fibers entering the 3D printing nozzle 22. Through the above structure, the first delivery pump directly controls the input amount of the low-concentration mixed fiber paste mixture in the first storage tank, and the second delivery pump directly controls the input amount of the high-concentration mixed fiber paste mixture in the second storage tank. By controlling the start / stop or output speed of the first and second delivery pumps, the concentration of mixed fibers in the paste mixture can be accurately controlled. Furthermore, the first and second delivery pumps are directly connected to the 3D printing nozzle inlet, facilitating rapid adjustment of the mixed fiber content at the 3D printing nozzle inlet and improving the adjustment response speed. This allows for accurate adjustment of the mixed fiber content in a short time, precisely controlling the mixed fiber content at different positions of the Twisted King block during the 3D printing process, improving structural quality, and thus enhancing the overall structural strength.

[0075] like Figure 4 As shown, in some preferred embodiments, the specific implementation process involves dynamically adjusting the concentration of the mixed fibers in the paste-like mixture delivered to the 3D printing nozzle 22 during the process of 3D printing the Twisted King character blocks at different heights. The steps include:

[0076] S610. When printing the bottom 11 of the twisted block 1, increase the conveying speed of the first conveying pump 31 and decrease the conveying speed of the second conveying pump 41 to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle 22 and reduce the mixed fiber content of the bottom 11 of the twisted block.

[0077] S620. When printing the middle part 12 of the twisted block 1, reduce the conveying speed of the first conveying pump 31 and increase the conveying speed of the second conveying pump 41 to increase the mixed fiber concentration of the paste mixture input to the 3D printing nozzle 22 and increase the mixed fiber content of the middle part 12 of the twisted block.

[0078] S630. When printing the top 13 of the twisted block 1, increase the conveying speed of the first conveying pump 31 and decrease the conveying speed of the second conveying pump 41 to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle 22 and reduce the mixed fiber content of the top 13 of the twisted block.

[0079] like Figure 5As shown, in some preferred embodiments, the specific implementation process is as follows: when printing the middle 12 of the Twisted King block 1, the concentration of the mixed fiber of the paste-like mixture delivered to the 3D printing nozzle 22 is dynamically adjusted at different positions at the same height. The steps include:

[0080] S660. When printing the outer periphery 121 of the middle part of the twisted block 1, reduce the mixed fiber content of the paste mixture input to the 3D printing nozzle 22 to reduce the mixed fiber content of the outer periphery 121 of the middle part of the twisted block.

[0081] S670. When printing the inner core 122 of the twisted king block 1, the mixed fiber content of the paste mixture input to the 3D printing nozzle 22 is increased to improve the mixed fiber content of the inner core 122 of the twisted king block.

[0082] like Figure 6 and Figure 7 As shown, in the composite geopolymer twisted block formed by the above method, the composite fiber concentration at the bottom 11 and top 13 of the composite geopolymer twisted block is lower than that in the middle 12. In the middle 12 of the geopolymer twisted block, the composite fiber concentration on the outer periphery is lower than that in the inner core. The low concentration of mixed fibers on the outer periphery of the twisted block avoids surface roughness and incompleteness caused by the mixed fibers, ensuring the continuity and density of the outer surface of the twisted block and improving its resistance to seawater erosion. The high concentration of mixed fibers in the core provides strong tensile strength, thereby improving the structural strength and cohesion of the twisted block. This method improves both the surface quality of the composite geopolymer twisted block and the cohesion of the core, thus enhancing the overall structural strength of the twisted block.

[0083] Based on the above embodiments, a composite geopolymer twisted U-shaped block is provided, using metasoil micro powder and blast furnace slag micro powder as main raw materials. Alkaline activation with an alkaline activator generates a three-dimensional network structure of NASH gel, improving structural coagulation strength. Adding mixed fibers enhances load-bearing capacity, and adding a water-reducing agent improves rapid setting, making it suitable for 3D printing. Simultaneously, adding an antibacterial agent enhances antibacterial ability, and adding a waterproofing agent improves waterproof performance. In the manufacturing process, 3D printing replaces the traditional casting process, eliminating the need for mold setting, casting, and demolding, saving time and labor, and eliminating the need for concrete cement, thus being environmentally friendly. The 3D-printed twisted U-shaped block has high durability and strong resistance to seawater erosion, making it suitable for use in seawalls.

[0084] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for 3D printing composite geopolymer twisted kingpin blocks, characterized by the following steps: include: S100. Kaolin is calcined at high temperature to obtain metakaolin, which is then ground and filtered to obtain metakaolin powder. S200. Blast furnace slag is ground and filtered to obtain blast furnace slag powder; S300. Mix high-modulus water glass solution and sodium hydroxide solution according to the specified ratio to obtain low-modulus water glass solution as an alkaline activator; S400. Mix the obtained metakaolin powder, blast furnace slag powder and alkaline activator and stir at high speed to produce a three-dimensional network structure NASH gel. S500. Add mixed fibers, water-reducing agent, antibacterial agent and waterproofing agent, stir at low speed until uniform, to obtain a fluid paste-like mixture; The S600 3D printing building equipment (21) drives the 3D printing nozzle (22) to move along the Twisted King block in the X, Y, and Z directions. At the same time, the delivery pump drives the paste mixture to be quantitatively ejected from the 3D printing nozzle (22) to print the Twisted King block. During the process of printing the Twisted King block using the 3D printing nozzle (22), the mixed fiber content of the paste mixture at the inlet of the 3D printing nozzle (22) is dynamically adjusted so that the mixed fiber concentration on the periphery of the Twisted King block is less than that in the core, thereby improving the overall structural support and periphery cohesion of the Twisted King block.

2. The method for 3D printing composite geopolymer twisted block according to claim 1, characterized in that, Kaolin is ground into powder and calcined at 800-900℃ for 3.5-4.5 hours with a heating rate of 2-10℃ / min to obtain metakaolin. The metakaolin is then ground and filtered through an 80-120 mesh sieve to obtain metakaolin micro powder.

3. The method for 3D printing composite geopolymer twisted block according to claim 2, characterized in that, Blast furnace slag is cleaned and dried to obtain dried granulated blast furnace slag. The dried granulated blast furnace slag is then ground into powder and filtered through a 60-140 mesh sieve to obtain blast furnace slag micro powder.

4. The method for 3D printing composite geopolymer twisted block according to claim 2 or 3, characterized in that, The preparation steps of the alkaline activator include: S310. The preset modulus of the low-modulus water glass solution to be prepared is 1.

3. Calculate the required mass of sodium hydroxide for preparing the low-modulus water glass solution using the following formula: In the formula, G is the mass of sodium hydroxide added, G0 is the mass of the high-modulus water glass solution, M1 is the modulus of the high-modulus water glass solution, M0 is the modulus of the water glass solution to be prepared, N is the mass of sodium hydroxide in the high-modulus water glass solution, and P is the purity of sodium hydroxide. S320. Based on the principle that the mass of sodium hydroxide solid remains unchanged, convert it to the mass of 8.0 mol / L sodium hydroxide solution, and prepare an 8.0 mol / L sodium hydroxide solution; S330. Dissolve the prepared 8.0 mol / L sodium hydroxide solution in high-modulus water glass and stir until homogeneous to obtain low-modulus water glass.

5. The method for 3D printing composite geopolymer twisted block according to claim 1, characterized in that, A first storage tank (32) for storing a paste-like mixture of low-concentration mixed fibers and a second storage tank (42) for storing a paste-like mixture of high-concentration mixed fibers are provided. The first storage tank (32) is connected to the inlet of the 3D printing nozzle (22) via a first delivery pump (31), and the second storage tank (42) is connected to the inlet of the 3D printing nozzle (22) via a second delivery pump (41). During the 3D printing of the Twisted King block, the delivery speed of the first delivery pump (31) and the second delivery pump (41) is dynamically adjusted to regulate the concentration of mixed fibers entering the 3D printing nozzle (22).

6. The method for 3D printing composite geopolymer twisted block according to claim 5, characterized in that, During the process of 3D printing Twisted King character blocks at different heights, the concentration of the mixed fibers in the paste-like mixture delivered to the 3D printing nozzle (22) is dynamically adjusted, including the following steps: S610. When printing the bottom (11) of the twisted block (1), increase the conveying speed of the first conveying pump (31) and decrease the conveying speed of the second conveying pump (41) to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle (22) and reduce the mixed fiber content of the bottom (11) of the twisted block. S620. When printing the middle (12) of the twisted block (1), reduce the conveying speed of the first conveying pump (31) and increase the conveying speed of the second conveying pump (41) to increase the mixed fiber concentration of the paste mixture input to the 3D printing nozzle (22) and increase the mixed fiber content of the middle (12) of the twisted block; S630. When printing the top (13) of the Twisted King block (1), increase the conveying speed of the first conveying pump (31) and decrease the conveying speed of the second conveying pump (41) to reduce the mixed fiber concentration of the paste mixture input to the 3D printing nozzle (22) and reduce the mixed fiber content of the top (13) of the Twisted King block.

7. The method for 3D printing composite geopolymer twisted block according to claim 5, characterized in that, When printing the middle (12) of the Twisted King block (1), the concentration of the mixed fibers of the paste mixture delivered to the 3D printing nozzle (22) is dynamically adjusted at different positions at the same height, the steps of which include: S660. When printing the middle outer periphery (121) of the twisted king block (1), reduce the mixed fiber content of the paste mixture input to the 3D printing nozzle (22) to reduce the mixed fiber content of the middle outer periphery (121) of the twisted king block; S670. When printing the central core (122) of the twisted king block (1), the mixed fiber content of the paste mixture input to the 3D printing nozzle (22) is increased to improve the mixed fiber content of the central core (122) of the twisted king block.

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