Construction method of multi-material printing concrete arch structure based on 3D printing

Abstract

The invention relates to a building method of a multi-material printing concrete arch structure based on 3D printing, comprising the following steps: S1, determining the shape and size of the arch structure, and determining a printing code; s2, printing of the part, close to the bottom, of the concrete arch structure is completed through concrete with the high performance and the mixing proportion in a side-lying printing mode; s3, when the printing part in the S2 has certain strength, the printing part is erected to serve as a bottom template when the remaining part is printed; s4, concrete with a weak mixing ratio is adopted, and concrete printing is conducted on the concrete bottom formwork layer by layer; and S5, curing is completed, and the two concrete materials are integrated. And the two parts are maintained together. Compared with the prior art, the method has the advantages of improving the construction efficiency of the concrete arch structure, reducing the construction cost of the concrete arch structure and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and in particular to a method for constructing a multi-material printed concrete arch structure based on 3D printing. Background Art

[0002] For the construction of building structural concrete components, especially structures that require openings, such as arch structures, the common practice is to first use other materials to make a template of the same size as the opening, and then pour concrete with the help of the template, or use concrete 3D printing technology as the bottom template to print the concrete structure. The disadvantages of this construction method are as follows: (1) Construction with the help of templates made of other materials consumes a lot of materials, especially for 3D printing concrete technology, which fails to reflect its advantage of being moldless. (2) Traditional auxiliary templates made of foam, plastic, wood, steel, etc. are difficult to construct, the construction process is complicated, the construction cost is high, and the construction period is long. (3) Traditional foam, plastic, wood, and steel templates can only meet certain specific construction needs. When faced with needs of different shapes and sizes, the reuse rate is low. Templates of a single model are often discarded after being used a few times, which is a serious waste.

[0003] Therefore, there is an urgent need for a method that can improve the construction efficiency of concrete arch structures, reduce the construction cost of concrete arch structures, and be more environmentally friendly. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a construction method of multi-material printed concrete arch structure based on 3D printing, improve the construction efficiency of concrete arch structure, reduce the construction cost of concrete arch structure, and be more in line with the concept of green environmental protection.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The present invention provides a method for constructing a multi-material printed concrete arch structure based on 3D printing, comprising the following steps:

[0007] S1: determine the shape and size of the arch structure and determine the printing code;

[0008] S2: Printing in sideways mode, using a high-performance mix of concrete to print the bottom part of the concrete arch structure;

[0009] S3: When the printed part in S2 has a certain strength, it is erected and used as the bottom template for printing the remaining parts. When the concrete bottom template has the ability to bear the upper concrete structure, the printing of the remaining parts can be started without long-term maintenance.

[0010] S4: Use a concrete with a weak mix ratio to print concrete layer by layer on the above concrete bottom template;

[0011] S5: Curing is completed and the two concrete materials become one. The two parts are cured together.

[0012] Furthermore, the concrete arch structure needs to satisfy the requirement that, except for the main arch opening, there are no other openings or suspended parts. The shape of the concrete arch structure is required to be a parabola, an arc, a catenary, or other more complex shapes.

[0013] Furthermore, the arch structure includes: a concrete bottom template and an upper concrete structure. The concrete layer constituting the concrete bottom template is a thicker layer or layers, while the concrete layer constituting the upper concrete is a thinner layer. The concrete materials used when printing the two parts can be different.

[0014] Furthermore, in S1, according to the shape and size of the arch structure and in combination with a specific printing method, printing codes for the concrete bottom formwork and the upper concrete structure in the concrete arch structure are respectively written.

[0015] Furthermore, in S2, when printing the concrete bottom formwork, the concrete material used is a fiber-reinforced material, which is a part of the structure and also remains at the bottom of the structure as a reinforcing material.

[0016] Furthermore, in S2, a circular print head with a small diameter is used, and the print head diameter is equal to the thickness of the concrete bottom template. The concrete bottom template is printed layer by layer in the form of side printing. The shape of the concrete bottom template is determined according to the shape of the arch structure opening. The final printing height of the side printing is equal to the width of the rectangular cross-section of the arch structure in the middle span.

[0017] Furthermore, in S4, recycled aggregate concrete can be used when printing the upper concrete structure.

[0018] Furthermore, in S4, a wider rectangular print head is used, the print head width is equal to the width of the rectangular cross-section of the arch structure, and the print head height is equal to the thickness of the concrete layer printed layer by layer.

[0019] Furthermore, in S4, according to the specific force requirements of the structure, when printing the upper concrete structure, more concrete materials with different mix ratios are used, that is, gradient concrete arches are printed to meet the gradient force requirements; when printing the two parts, the same concrete material can also be used for printing according to the specific bearing capacity requirements.

[0020] Furthermore, in S4, when printing concrete layer by layer, if grid reinforcement is required, the grid reinforcement material can be laid when the required number of layers are printed.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) Compared with traditional wood, steel, plastic and other templates, the concrete bottom template printed in the present invention is integrated with the entire structure and does not need to be disassembled. This method of constructing a concrete arch does not consume templates of other materials, reduces construction costs, improves construction efficiency, and complies with the green and low-carbon concept.

[0023] (2) The construction method proposed in the present invention can use materials with different properties when printing the two parts: the concrete bottom template uses a stronger material, which can be used as a part of the structure and also as a reinforcing material of the structure; the upper concrete structure uses a material with lower performance requirements, such as recycled aggregate concrete, which reduces construction costs, provides an application scenario for recycled materials, and complies with the concept of green construction.

[0024] (3) The concrete arch structure construction method provided by the present invention can meet various construction requirements for arch structures of different shapes and sizes by only adjusting the printing code. It is difficult to freely adjust the template size according to the needs of traditional templates. The same template is used to construct one or a type of structure of one shape and size, which is easy to cause great waste. Especially for construction requirements with a large number of sizes and a small number of components of a single size, the construction method of the present invention can improve construction efficiency, save construction costs, and comply with the green and low-carbon concept.

[0025] (4) Currently, gradient concrete materials are mostly used in structures such as plates and beams. The present invention provides a method for applying gradient materials in more complex special-shaped structures.

[0026] (5) The concrete arch structure construction method provided by the present invention, combined with concrete 3D printing technology, has high construction efficiency and is suitable for the construction and prefabrication of a large number of components, facilitating streamlined construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1a It is a schematic diagram of the dimensions of the side of the arch structure of the present invention;

[0028] Figure 1b It is a schematic diagram of two parts of the arch structure of the present invention;

[0029] Figure 2 It is a cross-sectional view at the mid-span position of the catenary linear concrete arch structure constructed in the present invention, namely, the AA cross-sectional view;

[0030] Figure 3a The process of printing the concrete bottom formwork;

[0031] Figure 3b The appearance of the concrete bottom formwork after it has a certain strength and stands upright;

[0032] Figure 3c The process of printing upper concrete layer by layer on the concrete bottom formwork.

[0033] Figure numerals: 1 - concrete bottom formwork; 2 - upper concrete structure. DETAILED DESCRIPTION

[0034] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0035] Example 1

[0036] This embodiment provides a method for constructing a multi-material printed concrete arch structure based on 3D printing, comprising the following steps:

[0037] S1: determine the shape and size of the arch structure and determine the printing code;

[0038] S2: Print sideways, using a high-performance mix of concrete to print the bottom portion of the concrete arch structure, such as Figure 3a As shown;

[0039] S3: When the printed part in S2 has a certain strength, stand it upright and use it as the bottom template for printing the remaining parts, such as Figure 3b shown.

[0040] S4: Use a concrete with a weak mix ratio, and print the concrete layer by layer on the bottom template of the above concrete, such as Figure 3c As shown;

[0041] S5: Curing is completed and the two concrete materials become one. The two parts are cured together.

[0042] In a specific implementation, the concrete arch structure needs to meet the requirement that, except for the main arch opening, there are no other openings or suspended parts. The shape of the concrete arch structure is required to be a parabola, an arc, a catenary, or other more complex shapes.

[0043] like Figure 1b As shown, the arch structure includes: a concrete bottom template 1 and an upper concrete structure 2. The concrete layer constituting the concrete bottom template 1 is a relatively thick layer or several layers, while the concrete layer constituting the upper concrete 2 is a relatively thin multiple layers. The concrete materials used when printing the two parts can be different.

[0044] In this embodiment:

[0045] l-span of the arch structure; l0-clear span of the arch structure; l1-total span of the arch structure; f-rise of the arch structure; f0-clear rise of the arch structure; H-total height of the arch structure; d-width of the arch foot of the arch structure; n-number of concrete layers constituting the upper concrete part of the arch structure; h0-single layer thickness of the concrete layer constituting the upper concrete part of the arch structure; h1-layer thickness of the concrete layer constituting the bottom formwork part of the arch structure; b-width of the cross-sectional rectangle of the arch structure span; h-height of the cross-sectional rectangle of the arch structure span.

[0046] In this example, the thickness of a single concrete layer is h0=10 mm, and the thickness of the concrete at the bottom concrete formwork 1 is h1=20 mm, which is equal to the thickness of two layers of the upper concrete structure 2.

[0047] In this example, the arch size is selected as span l = 600mm and sagitta f = 150mm. With the axis of symmetry as the y-axis and the line connecting the arch feet as the x-axis, the unit is mm, a plane rectangular coordinate system is established, and the equation of the arch axis is obtained as follows:

[0048]

[0049] In this example, the mid-span cross-sectional dimensions of the arch structure are selected as b×h=120mm×90mm, that is, the number of concrete layers is n=9.

[0050] The dimensions of the side and cross-section of the arch structure are as follows: Figure 1b , Figure 2 shown.

[0051] In order to determine the size of the concrete arch structure and write the printing code, the axis equations of each concrete layer and the axis equation of the concrete bottom formwork part are determined by translation based on the obtained arch axis equation. For special-shaped curves that cannot be expressed by formulas, the printing code is written in the form of microelement.

[0052] According to the shape and size of the arch structure and the specific printing method, the printing codes of the two parts of the concrete arch structure are written separately. Among them, the concrete bottom template 1 is printed in a side-lying manner, while the upper concrete structure 2 is printed in an upright manner.

[0053] When printing the concrete bottom template 1, a concrete material with strong performance, such as fiber-reinforced material, is used. In the end, the concrete bottom template 1 is a part of the structure and also remains in the structure as a reinforcing material. Since the concrete bottom template 1 is located at the bottom of the structure, a concrete material with high tensile strength, such as fiber-reinforced material, should be selected according to the structural stress characteristics.

[0054] The printing material in this example is ECC material (engineering cement-based composite material), the fiber mixed is 12mm PE fiber, and the fiber content is 1.5%.

[0055] When printing the concrete bottom template 1, a circular print head with a smaller diameter is used. In order to make the printing strip meet the requirements, the print head diameter is equal to the thickness of the concrete bottom template 1, and the concrete bottom template 1 is printed layer by layer in the form of side-lying printing. The shape of the concrete bottom template 1 is determined according to the shape of the arch structure opening, and the final printing height is equal to the width of the rectangular cross-section of the arch structure.

[0056] In this example, when printing the concrete bottom template 1, a 20mm circular print head is used. By setting the height during extrusion, the printed strip size is controlled to be 20mm in width and 10mm in height. In order to meet the requirements of the mid-span cross-section size of the arch structure, 12 layers are printed with a total layer height of 120mm.

[0057] When the concrete bottom formwork 1 has the ability to bear the upper concrete structure, the printing of the remaining parts can begin without long-term maintenance.

[0058] When printing the upper concrete structure 2, due to the small tensile strength requirement of the upper concrete structure 2, concrete with poorer performance, such as recycled aggregate concrete, can be used. At the same time, according to the specific force requirements of the structure, when printing the upper concrete structure 2, more concrete materials with different mix ratios can also be used, that is, gradient concrete arches can be printed.

[0059] When printing the two parts, the same concrete material can also be used for printing according to the specific bearing capacity requirements. If the same material is used, the method proposed in the present invention will be used as a printing method for a homogeneous arch structure.

[0060] The upper concrete structure 2 is printed using the same material as the concrete bottom formwork 1 .

[0061] When printing the upper concrete structure 2, in order to improve construction efficiency, a wider rectangular print head is used. The print head width is equal to the width of the rectangular cross-section of the arch structure, and the print head height is equal to the thickness of the concrete layer printed layer by layer.

[0062] The print head size used in this example is a rectangular print head with a width of 120 mm and a height of 10 mm. The printed concrete strips have the same size and a total of 7 layers are printed.

[0063] At the same time, when printing concrete layer by layer, if grid reinforcement is required, the grid reinforcement material can be laid when the required number of layers are printed.

[0064] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0065] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for constructing a multi-material printed concrete arch structure based on 3D printing, characterized in that: The following steps are involved: S1: determine the shape and size of the arch structure and determine the printing code; S2: Printing in sideways mode, using a high-performance mix of concrete to print the bottom part of the concrete arch structure; S3: When the printed part in S2 has a certain strength, it is placed upright and used as a bottom template for printing the remaining parts; S4: Use a concrete with a weak mix ratio to print concrete layer by layer on the above concrete bottom template; S5: Curing is completed and the two concrete materials become one.

2. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: The concrete arch structure needs to meet the requirement that, except for the main arch opening, there are no other openings or suspended parts.

3. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: The arch structure comprises: a concrete bottom formwork (1) and an upper concrete structure (2).

4. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S1, according to the shape and size of the arch structure and in combination with a specific printing method, the printing codes of the concrete bottom template (1) and the upper concrete structure (2) in the concrete arch structure are respectively written.

5. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S2, when printing the concrete bottom template (1), the concrete material used is a fiber-reinforced material, which is a part of the structure and also remains at the bottom of the structure as a reinforcing material.

6. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S2, a circular printing head with a small diameter is used, and the printing head diameter is equal to the thickness of the concrete bottom template (1). The concrete bottom template (1) is printed layer by layer in the form of side-lying printing. The shape of the concrete bottom template (1) is determined according to the shape of the arch structure opening. The final printing height of the side-lying printing is equal to the width of the rectangular cross-section of the arch structure.

7. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S4, recycled aggregate concrete can be used when printing the upper concrete structure (2).

8. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S4, a wider rectangular print head is used, the print head width is equal to the width of the rectangular cross-section of the arch structure, and the print head height is equal to the thickness of the concrete layer printed layer by layer.

9. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S4, according to the specific force requirements of the structure, when printing the upper concrete structure (2), a gradient concrete arch is printed to meet the gradient force requirements; when printing the two parts, according to the specific bearing capacity requirements, the same concrete material can be used for printing.

10. The method for constructing a multi-material printed concrete arch structure based on 3D printing according to claim 1, characterized in that: In S4, when printing concrete layer by layer, if mesh reinforcement is required, the mesh reinforcement material can be laid when the required number of layers are printed.

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