A 3D-printed FRP-concrete hollow composite pile

Abstract

This invention relates to a 3D-printed FRP-concrete hollow composite pile. The FRP-concrete hollow composite pile consists of a 3D-printed hollow concrete pile and an outer GFRP fabric covering. By using adhesive bonding, the continuous GFRP fabric is completely adhered to the surface of the 3D-printed hollow concrete composite pile, thereby compensating for the inherent weak interlayer bonding of 3D-printed concrete and the structural instability of hollow concrete piles, thus improving the overall mechanical properties of the structure. This invention utilizes 3D printing technology to print layer by layer, achieving a staggered distribution of layers, which significantly improves the friction between the pile and the soil during construction.

Description

Technical Field

[0001] This utility model relates to the field of intelligent construction technology, and in particular to a 3D-printed FRP-concrete hollow composite pile. Background Technology

[0002] Concrete, as one of the most widely used structural materials in the construction industry, generates significant amounts of carbon dioxide during its production, causing severe climate change and environmental damage. Simultaneously, some major industrial cities inevitably generate large quantities of solid waste, such as coal gangue and tailings, leading to land occupation, environmental pollution, and safety threats. In the field of civil engineering, traditional solid concrete piles require large quantities of concrete, representing high carbon emissions and a high demand for natural resources such as cement, sand, and stone, which is detrimental to resource conservation and sustainable development.

[0003] 3D printing technology, also known as rapid prototyping, is based on three-dimensional data and utilizes the layering principle of points, lines, and surfaces to improve many of the challenges in traditional construction processes. Compared to traditional construction methods, this technology significantly reduces construction waste, lowers labor costs, and shortens construction cycles. Its practicality and efficiency have been proven in numerous real-world projects, such as the 3D-printed park in Bao'an, Shenzhen, and the 3D-printed bridge in Taopu, Shanghai. It also shows great potential for application in space infrastructure construction and extreme environment construction. However, 3D-printed concrete technology currently has some drawbacks, such as weak interlayer bonding (the layer-by-layer stacking method used in 3D-printed concrete leads to insufficient bonding between layers, affecting the overall strength and durability of the structure), and insufficient strength in 3D-printed concrete hollow pile structures.

[0004] In the field of composite structures, hollow concrete composite structures, compared to traditional solid structures, exhibit significant structural advantages and environmental benefits due to their lightweight design, which reduces building weight, engineering costs, and carbon dioxide emissions. In recent years, an increasing number of studies have introduced fiber-reinforced polymer (FRP) materials as a key element in composite structures. FRP, with its superior properties such as high strength, corrosion resistance, and low density, can effectively constrain concrete structures, further enhancing the overall mechanical properties and durability of the structure while reducing the amount of building materials used and environmental impact. Therefore, FRP-constrained hollow concrete composite piles based on 3D printing technology combine the advantages of 3D printing technology, hollow concrete composite structures, and FRP materials, providing an efficient and environmentally friendly solution for modern technology. Utility Model Content

[0005] The purpose of this invention is to provide a 3D-Printed Hybrid FRP-Concrete Hollow Pile (3D HFCH pile) based on 3D printing, which aims to improve the overall stability, impermeability, and bearing capacity of the structure while reducing or maintaining the amount of material used, thus providing an efficient and environmentally friendly solution for modern technology.

[0006] The technical solution adopted to achieve the purpose of this utility model is as follows:

[0007] A 3D-printed FRP-concrete hollow composite pile includes a 3D-printed concrete hollow pile and a layer of FRP fabric tightly attached to its outer surface.

[0008] Furthermore, an FRP fabric is tightly attached to the outer surface of the 3D printed concrete hollow pile, a 3D printed concrete layer is set around the FRP fabric, and another FRP fabric is set on the outer surface of the 3D printed concrete layer, forming an alternating structure of FRP fabric and 3D printed concrete layer. The outermost layer of the 3D printed FRP-concrete hollow composite pile is FRP fabric, and the number of 3D printed concrete layers is 1-4.

[0009] Furthermore, an adhesive layer is provided between the FRP fabric and the 3D printed concrete layer; the FRP fabric is at least one of GFRP fabric or CFRP fabric.

[0010] Furthermore, the 3D printed hollow concrete pile and the 3D printed concrete layer are made of 3D printed concrete material containing at least one of antimony tailings, iron tailings, and coal slag.

[0011] Furthermore, the 3D printed concrete hollow pile and the wall thickness of the 3D printed concrete layer are 20-48mm, such as 24mm, 36mm, 48mm, etc.

[0012] Furthermore, at least one layer of FRP fabric is also tightly bonded to the inner layer of the 3D printed concrete hollow pile through an adhesive layer.

[0013] Furthermore, the thickness of the FRP fabric is 0.1-0.8 mm.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0015] 1. Compared with traditional solid structures, the FRP-concrete hollow composite pile of this utility model reduces the building's self-weight, engineering cost, and carbon dioxide emissions while improving its performance, demonstrating significant structural advantages and environmental benefits.

[0016] 2. In this invention, each layer of FRP fabric is tightly bonded to the concrete surface, thereby compensating for the inherent interlayer bonding defects and structural instability of ordinary 3D printed hollow concrete piles, and improving the overall mechanical properties of the structure while reducing weight.

[0017] 3. The 3D HFCH composite pile of this utility model uses 3D printing technology to improve the flexibility and manufacturing efficiency of the structure, broaden the application range of composite structures, save labor costs, reduce construction waste and shorten the construction cycle. While meeting the complexity of component shapes, it also improves the stability and strength of the components.

[0018] 4. The concrete material of this utility model is made using 3D printing technology. Except for grinding down obvious protrusions, the non-uniform distribution characteristics of the interlayer stepped structure formed by the layer-by-layer printing process are completely preserved in the finished product. Its original three-dimensional printing texture is accurately inherited through the FRP composite process. While significantly enhancing the friction between the pile and the soil, the presence of FRP fabric can significantly improve the stability, corrosion resistance, and bearing capacity of the pile. Attached Figure Description

[0019] Figure 1 This is a structural diagram of a 3D HFCH composite pile according to an embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional view of a 3D HFCH composite pile according to an embodiment of the present invention.

[0021] Figure 3 This is a structural diagram of a 3D HFCH composite pile according to another embodiment of the present invention.

[0022] In the image, 1 represents a 3D-printed hollow concrete pile; 2 represents FRP fabric; and 3 represents a 3D-printed concrete layer. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described examples are only a part of the embodiments of the present utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0024] Example 1

[0025] like Figure 1As shown, a 3D-printed FRP-concrete hollow composite pile includes a 3D-printed concrete hollow pile 1 and an FRP fabric 2 tightly attached to its outer surface. The FRP fabric is made of GFRP (glass fiber reinforced composite plastic) fabric with a thickness of 0.2 mm.

[0026] Example 2

[0027] The specific manufacturing process of the combined pile in Example 1 consists of 9 steps:

[0028] 1) Use SketchUp software to draw a cylindrical printing model with an outer circle and inner square, and an outer circle and inner circle, with a height of 450mm and a diameter of 150mm, and output it as an STL file; then use Simplify3D software to open this STL file, set the printing parameters (print position, print size, print height, print speed, print path, nozzle extrusion rate, etc.): layer height 5mm; output as a gcode file;

[0029] 2) Add 12kg of cement, 1.2kg of silica fume, and 12.8g of HPMC to a mixer and mix for 60s; then add 4.2kg of water, 55ml of water-reducing agent solution, and 10g of PP fiber in sequence and mix for 120s; finally add 3.34kg of quartz sand and 8.65kg of antimony tailings and mix for 180s to obtain the material required for printing.

[0030] 4) Select the appropriate 3D printing concrete nozzle according to the required size and assemble the 3D concrete printing head.

[0031] 5) Start printing using the 3D concrete printer.

[0032] 6) After the 3D printed hollow concrete piles have been left to stand for about 2 hours to allow them to gain sufficient strength, move them to the concrete curing area and number them according to their production order, ensuring that no two piles are duplicated.

[0033] 7) Cover the 3D-printed hollow concrete pile with a plastic film and place it in an environment with a temperature of 20±5℃ and a relative humidity of more than 50% for 24 hours. After it hardens, immediately place it in a standard curing room or curing box with a temperature of 20±2℃ and a relative humidity of more than 95% for curing or steam curing.

[0034] 8) Processing of 3D printed concrete hollow piles: After the piles are cured, the visible protruding edges of the 3D printed concrete hollow piles are ground off. The grinding process does not damage the 3D printed layer texture itself, and avoids uneven stress on the pile body due to damage to the GFRP fabric when it is wrapped around the 3D printed concrete hollow pile.

[0035] 9) Use a composite process (adhere the pre-treated 3D printed hollow concrete pile to GFRP fabric with epoxy resin, wrap it with heat shrink tape, and finally heat the treated 3D printed hollow concrete pile with a heating gun (200℃) to shrink the heat shrink tape so that the GFRP fabric can tightly fit the gap of the 3D printed hollow concrete pile) to process the 3D printed hollow concrete pile.

[0036] 10) Move the treated 3D printed concrete hollow pile to the concrete curing area and lay it flat. Turn it over every half hour (6 times in total) to avoid the epoxy resin glue depositing on one side of the 3D printed FRP-concrete hollow composite pile due to gravity, which would affect the adhesion between GFRP and the pile body.

[0037] 11) After the epoxy resin has fully cured for 24 hours, the heat-shrinkable tape on the surface of the 3D printed concrete hollow pile is peeled off, and the FRP-concrete hollow composite pile based on 3D printing described in this utility model is finally obtained.

[0038] This embodiment uses a hand lay-up process to treat 3D-printed hollow concrete piles and GFRP fabric, followed by wrapping heat-shrinkable tape around the pile surface. The treated 3D-printed FRP-concrete hollow composite pile is heated using a heat gun (200℃) to shrink the heat-shrinkable tape. After the heat-shrinkable tape has shrunk, the 3D-printed FRP-concrete hollow composite pile is moved to a concrete curing area and laid flat, being turned over every half hour (a total of 6 times). After 24 hours, the heat-shrinkable tape is removed from the 3D-printed hollow concrete pile, resulting in a 3D-printed FRP-concrete hollow composite pile.

[0039] Example 3

[0040] This embodiment is based on 3D-printed FRP-concrete hollow composite piles. Based on embodiment 1, it has an alternating structure on its periphery. A layer of GFRP fabric is tightly attached to the outer surface of the 3D-printed concrete hollow pile 1. A layer of 3D-printed concrete 3 is set on the periphery of the GFRP fabric. Another layer of GFRP fabric is set on the outer surface of the 3D-printed concrete layer, forming an alternating structure of GFRP fabric and 3D-printed concrete layers. The outermost layer of the 3D-printed FRP-concrete hollow composite pile is GFRP fabric, and the number of 3D-printed concrete layers is 2.

[0041] The GFRP fabric is tightly bonded to the 3D-printed concrete layer via an adhesive layer made of epoxy resin (a mixture of epoxy resin (A) and catalyst (B) in a 2:1 mass ratio), ensuring no gaps during bonding. Then, heat-shrinkable tape is wrapped layer by layer. Heating with a heat gun (200℃) causes the tape to shrink, ensuring its tightness and allowing the GFRP fabric to adhere closely to the concrete surface, thus guaranteeing uniform stress distribution. This enhances the load-bearing capacity and corrosion resistance of the concrete pile while maintaining the spiral texture characteristic of the pile surface.

[0042] After the surface has cooled, move it to the concrete curing area and lay it flat, turning it over every half hour (a total of 6 times) to prevent the epoxy resin from depositing on one side due to gravity, which could cause poor adhesion. After 24 hours, remove the heat-shrink tape and prepare the next 3D printed concrete layer. Repeat the bonding process until the required number of 3D printed concrete layers is reached.

[0043] Example 4

[0044] This embodiment is based on 3D printed FRP-concrete hollow composite piles. Based on embodiment 1, a layer of GFRP fabric is tightly attached inside the 3D printed concrete hollow pile.

[0045] Any aspects not covered in this utility model are applicable to the prior art.

Claims

1. A 3D printing based FRP-concrete hollow composite pile, characterized in that: It includes 3D-printed hollow concrete piles and a layer of FRP fabric tightly attached to their outer surface; The outer surface of the 3D printed concrete hollow pile is tightly attached with an FRP fabric, a 3D printed concrete layer is set around the FRP fabric, and another FRP fabric is set on the outer surface of the 3D printed concrete layer, forming an alternating structure of FRP fabric and 3D printed concrete layer. The outermost layer of the 3D printed FRP-concrete hollow composite pile is FRP fabric, and the number of 3D printed concrete layers is 1-4.

2. The 3D printing based FRP-concrete hollow composite pile according to claim 1, characterized in that: An adhesive layer is provided between the FRP fabric and the 3D printed concrete layer; the FRP fabric is at least one of GFRP fabric or CFRP fabric.

3. The 3D printing based FRP-concrete hollow composite pile according to claim 1, characterized in that: The 3D printed concrete hollow pile and the wall thickness of the 3D printed concrete layer are 20-48mm.

4. The 3D printing based FRP-concrete hollow composite pile according to claim 1, characterized in that: The inner layer of the 3D printed concrete hollow pile is also tightly bonded with at least one layer of FRP fabric through an adhesive layer.

5. The 3D-printed FRP-concrete hollow composite pile according to any one of claims 1-4, characterized in that: The thickness of the FRP fabric is 0.1-0.8 mm.

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