Modified ultra-high performance concrete for 3d printing and method for reinforcing a bridge pier

Abstract

The present application relates to bridge pier reinforcing technology, in particular to modified ultra-high performance concrete for 3D printing and a bridge pier reinforcing method, comprising 3D printed ultra-high performance concrete, luminescent powder, reflective powder and BSSON:Eu 2+ material; the luminescent component of the luminescent powder is Ca2SnO4:Tb 3+ ; the addition amount of the luminescent powder is 7.0-8.0% of the cement mass in the 3D printed ultra-high performance concrete, the addition amount of the reflective powder is 2.1-2.5% of the cement mass in the 3D printed ultra-high performance concrete, and the addition amount of the BSSON:Eu 2+ material is 0.5-0.8% of the cement mass in the 3D printed ultra-high performance concrete. After the modified ultra-high performance concrete for 3D printing is used to reinforce the bridge pier, not only good mechanical properties are obtained, but also a warning sign effect is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pier reinforcement, in particular to modified ultra-high performance concrete for 3D printing and a pier reinforcement method. BACKGROUND

[0002] The information disclosed in this Background section is only for the purpose of increasing an understanding of the general background of the application and does not necessarily constitute an admission by the patent applicant or the patent owner that this information forms part of the prior art that is already known in this field.

[0003] As an important support structure of a bridge, the stability and reliability of a pier play an important role in the safe operation of the bridge. Ordinary piers such as overpass bridges are at risk of being hit by vehicles during use, and water-crossing piers are at risk of being hit by passing ships during water navigation. Therefore, it is of great practical significance to improve the anti-impact ability of the pier and the warning sign effect at night. When a large ship or a large vehicle collides with the pier, the anti-impact performance of the concrete pier is required to ensure the structural stability of the pier. The existing ordinary concrete cannot efficiently meet the instantaneous anti-impact ability, and the use of 3D printing technology to repair and reinforce the existing concrete pier can enhance the anti-impact performance of the pier and prolong the service life by taking advantage of the tensile and compressive strength of ultra-high performance concrete.

[0004] However, the 3D printed ultra-high performance concrete does not have a warning sign effect at night. In order to make it have a warning sign effect at night, luminescent powder and reflective powder can be added, which can be added to the surface of the pier in the form of a coating or added to the 3D printed ultra-high performance concrete. If only a coating is provided, the strength of the coating is low and the anti-impact performance is poor, which is not conducive to long-term application of the warning sign effect. Although the luminescent powder and reflective powder are added to the 3D printed ultra-high performance concrete, the performance of the 3D printed ultra-high performance concrete can be used to improve the long-term use of the warning sign effect, but the inventors have found through research that the commonly used luminescent powder mainly contains SrAl2O4:Eu 2+ ,Dy 3+ The main component of the reflective powder is SiO2. The luminescent time of this luminescent powder is limited, which is not conducive to the use of the pier reinforcement shell with a long period, and the luminescent brightness decreases significantly over time. The addition of reflective powder has a certain attenuation on the compressive strength of the concrete, which has certain limitations as a reinforcement shell material. SUMMARY

[0005] In order to solve the problems of the prior art, the present application aims to provide modified ultra-high performance concrete for 3D printing and a pier reinforcement method, which has good mechanical properties and forms a warning sign effect, and the luminescent powder is BSSON:Eu 2+The addition of the material can significantly reduce the influence of traditional reflective powder on the compressive strength of the concrete material after being added, can make the concrete material continuously emit light, and after being impacted, continuously form strengthened brightness, so that the reinforced shell achieves better warning and identification effect.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application is:

[0007] In one aspect, a modified ultra-high performance concrete for 3D printing, comprising 3D printed ultra-high performance concrete, luminescent powder, reflective powder and BSSON:Eu 2+ material; the luminescent component of the luminescent powder is Ca2SnO4:Tb 3+ ;

[0008] The addition amount of the luminescent powder is 7.0-8.0% of the cement quality in the 3D printed ultra-high performance concrete, the addition amount of the reflective powder is 2.1-2.5% of the cement quality in the 3D printed ultra-high performance concrete, and the addition amount of the BSSON:Eu 2+ material is 0.5-0.8% of the cement quality in the 3D printed ultra-high performance concrete.

[0009] The 3D printed ultra-high performance concrete requires good thixotropy, that is, it is necessary to ensure that the concrete has good fluidity when extruded by mechanical vibration, facilitating printing work; after being extruded from the printing head, the mechanical vibration disappears, and the fluidity is immediately lost, facilitating the control and generation of the printed shape. At the same time, it requires high strength performance, that is, the strength grade is above C100. In order to make the 3D printed ultra-high performance concrete have luminescent performance, luminescent material needs to be added first, however, the composition system of each raw material determines its thixotropy and mechanical properties, and the addition of luminescent material will change its composition system, thereby changing its thixotropy and mechanical properties. Therefore, the present application adds 7.0-8.0% of the cement quality of the luminescent powder whose main component is Ca2SnO4:Tb 3+ and 2.1-2.5% of the cement quality of the reflective powder, a small amount of luminescent powder and reflective powder can reduce the influence on the composition system of the raw material, thereby ensuring its thixotropy and mechanical properties. However, a small amount of luminescent powder and reflective powder also affects its luminescent performance, and even if the amount of reflective powder added is small, it still affects its compressive performance, therefore, the present application further adds a small amount (0.5-0.8% of the cement quality) of BSSON:Eu 2+ material, which can not only significantly reduce the influence of traditional reflective powder on the compressive strength of the concrete material after being added, but also make the concrete material continuously emit light, and after being impacted, continuously form strengthened brightness, so that the reinforced shell achieves better warning and identification effect.

[0010] On the other hand, a method for reinforcing bridge piers involves using the modified ultra-high performance concrete described above for 3D printing to 3D print the area of ​​the bridge pier to be reinforced, forming a base layer.

[0011] The beneficial effects of this invention are as follows:

[0012] 1. This invention utilizes 3D-printed ultra-high performance concrete to reinforce existing bridge piers, improving their resistance to impacts from ships, floating debris such as ice floes, and vehicles, extending the lifespan of the piers, and significantly enhancing their compressive and tensile strength. Furthermore, it incorporates luminescent powder, reflective powder, and BSSON:Eu into the 3D-printed ultra-high performance concrete. 2+ The material can create warning signs for passing ships and vehicles; at the same time, it can greatly reduce the impact on the thixotropic and mechanical properties of the original 3D-printed ultra-high performance concrete.

[0013] 2. This invention integrates the pier reinforcement shell with 3D printing technology, which can effectively reinforce existing piers, newly built piers and irregularly shaped piers, improve the efficiency of pier reinforcement, and enhance practicality and durability. Attached Figure Description

[0014] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0015] Figure 1 Top view of the shell for reinforcement;

[0016] Among them, 1. Bridge pier, 2. Anti-collision shell, 3. Bolts. Detailed Implementation

[0017] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0018] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] A typical embodiment of the present invention provides a modified ultra-high performance concrete for 3D printing, comprising 3D-printed ultra-high performance concrete, luminescent powder, reflective powder, and BSSON:Eu2+ Materials; the luminescent component of the luminescent powder is Ca2SnO4:Tb 3+ ;

[0020] The amount of luminescent powder added is 7.0–8.0% of the cement mass in the 3D-printed ultra-high performance concrete, and the amount of reflective powder added is 2.1–2.5% of the cement mass in the 3D-printed ultra-high performance concrete. BSSON:Eu 2+ The amount of material added is 0.5 to 0.8% of the cement mass in the 3D-printed ultra-high performance concrete.

[0021] In some embodiments, the amount of luminescent powder added is 7.4–7.6% of the cement mass in the 3D-printed ultra-high performance concrete. Studies have shown that under these conditions, the amount of luminescent powder incorporated is beneficial for crystal stacking on the concrete surface, enabling the formation of granular gel particles with some unhydrated particles, thereby improving the concrete strength.

[0022] In some embodiments, BSSON:Eu 2+ In the material, Eu 2+ The relative content is 5.0%–7.0%. Studies have shown that Eu 2 + When the relative content of Eu is 5.0-6.2%, it can further improve the luminous brightness, and in Eu 2+ When the relative content is 5.9% to 6.1%, the brightness is higher.

[0023] In some embodiments, the gel material in the 3D-printed ultra-high performance concrete comprises, by weight, the following raw materials: cement: 62,000–68,000 parts; silica fume: 450–550 parts; mineral powder: 1,400–1,600 parts; fly ash: 900–1,200 parts; gypsum: 400–550 parts; fiber: 180–220 parts; water-reducing agent: 45–55 parts; setting regulator: 0.8–1 part; early-strength agent: 4–6 parts; thickener: 0.8–1 part. This 3D-printed ultra-high performance concrete exhibits better thixotropy and ultra-high performance.

[0024] In one or more embodiments, the cement is silicate cement and sulfoaluminate cement. Specifically, the mass ratio of silicate cement to sulfoaluminate cement is 0.45:0.1 to 0.3. Modified ultra-high performance concrete for 3D printing formed under these conditions exhibits better performance.

[0025] In one or more embodiments, the fiber is steel fiber. Using steel fiber can improve the toughness of the matrix.

[0026] In one or more embodiments, the water-reducing agent is a powdered polycarboxylate high-performance water-reducing agent with a water reduction rate ≥35%.

[0027] In one or more embodiments, the setting agent is sodium gluconate.

[0028] In one or more embodiments, the early strength agent is lithium carbonate.

[0029] In one or more embodiments, the thickener is xanthan gum.

[0030] In some embodiments, the aggregate used in the 3D-printed ultra-high performance concrete has a particle size of 40–120 mesh. Specifically, the aggregate particle size is 40–70 mesh or 70–120 mesh. The aggregate used in this invention is, for example, quartz sand.

[0031] In some embodiments, the water-binder ratio is 0.15–0.25. Under these conditions, the modified ultra-high performance concrete used for 3D printing exhibits better performance. The water-binder ratio described in this invention refers to the ratio of the mass of water to the mass of the 3D-printed ultra-high performance concrete, luminescent powder, reflective powder, and BSSON:Eu. 2+ The ratio of the total mass of the materials.

[0032] In some embodiments, the sand-to-binder ratio is 1:0.9 to 1.1. Under these conditions, the modified ultra-high performance concrete used for 3D printing exhibits better performance. The sand-to-binder ratio described in this invention refers to the ratio of the mass of aggregate (e.g., quartz sand) to the mass of the 3D-printed ultra-high performance concrete, luminescent powder, reflective powder, and BSSON:Eu. 2+ The ratio of the total mass of the materials.

[0033] In another embodiment of the present invention, a method for reinforcing bridge piers is provided, wherein the modified ultra-high performance concrete used for 3D printing is used to 3D print the area of ​​the bridge pier to be reinforced to form a base layer.

[0034] In some embodiments, cement, quartz sand, silica fume, mineral powder, water, fly ash, gypsum, water-reducing agent, setting regulator, early strength agent, thickener, luminescent powder, reflective powder, and BSSON:Eu2 are included. + Mix and stir to obtain a mixture; then add the fibers in batches to prevent clumping, and adjust the stirring time appropriately according to the fiber content to ensure that the steel fibers are evenly dispersed in the mixture.

[0035] In some embodiments, the parameters for 3D printing are: horizontal printing speed of 45-55 mm / s, vertical printing speed of 8-12 mm / s, and extrusion speed of 1.3-1.7 L / min.

[0036] In some embodiments, a superhydrophobic coating is applied to the substrate surface to form a top layer.

[0037] In one or more embodiments, the superhydrophobic coating material is obtained by adding fluorosilane material during the hydrolysis of tetraethyl orthosilicate and then performing fluorination treatment.

[0038] In one or more embodiments, after the surface layer is formed, a reinforcing shell is installed.

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0040] Example 1

[0041] Modified ultra-high performance concrete for 3D printing, comprising the following raw materials by weight fraction:

[0042] Cement: 65,000 parts; Quartz sand: 68,500 parts; Silica fume: 500 parts; Mineral powder: 1,500 parts; Water: 13,700 parts; Fly ash: 1,000 parts; Gypsum: 500 parts; Fiber: 200 parts; Water-reducing agent: 50 parts; Setting regulator: 1 part; Early strength agent: 5 parts; Thickener: 1 part; Luminescent powder: 4,900 parts (luminescent powder content relative to cement is 7.5%); Reflective powder: 1,500 parts; BSSON:Eu 2+ (Eu 2+ (Relative content of 6%): 400 portions.

[0043] The cement used is silicate cement and sulfoaluminate cement. The mass ratio of silicate cement to sulfoaluminate cement is 0.45:0.2, i.e., 48,750 parts silicate cement and 16,250 parts sulfoaluminate cement are used. The quartz sand has a particle size of 40-70 mesh; steel fiber is used; the water-reducing agent is powdered polycarboxylate high-performance water-reducing agent with a water reduction rate ≥35%; the setting regulator is sodium gluconate; the early strength agent is lithium carbonate; and the thickener is xanthan gum. The luminescent component of the luminescent powder is Ca2SnO4:Tb. 3+ The product is available in commercially available form with a 400-mesh specification and a center particle size of 10μm. The reflective powder is composed of glass microspheres, which are spherical glass microspheres with a high refractive index and a 200-mesh specification.

[0044] BSSON:Eu 2+ The main components of the material are BaCO3, SrCO3, EuF3 and α-Si3N4. It is a powdered solid and is prepared by the traditional solid-state method. Specifically, the materials are weighed according to the stoichiometric ratio, placed in a prepared agate mortar, and an appropriate amount of anhydrous ethanol is added. After grinding for 30 minutes, the mixture is transferred to a corundum crucible. Finally, the crucible is placed in a tube furnace (90% N2, 10% H2). The heating rate of the tube furnace is 5℃ / min. The reaction is carried out at 1650℃ for 4 hours. Finally, the mixture is cooled to room temperature and ground into powder.

[0045] Ingredients include cement, quartz sand, silica fume, mineral powder, water, fly ash, gypsum, water-reducing agent, setting regulator, early-strength agent, thickener, luminescent powder, reflective powder, and BSSON:Eu. 2+ The materials are mixed and stirred to obtain a mixture; then the fibers are added in batches to prevent clumping. The stirring time is adjusted appropriately according to the fiber content to ensure that the steel fibers are evenly dispersed in the mixture.

[0046] In 3D printing, the parameters are: horizontal printing speed of 50 mm / s, vertical printing speed of 10 mm / s, and extrusion speed of 1.5 L / min.

[0047] After obtaining the base layer, a superhydrophobic coating is applied to the surface of the base layer to form the top layer. The superhydrophobic coating material is obtained by adding fluorosilane material during the hydrolysis of tetraethyl orthosilicate and then performing fluorination treatment.

[0048] according to Figure 1 As shown, two anti-collision shells 2 are attached to the surface of the reinforced bridge pier 1, and then bolts 3 are used to connect the two anti-collision shells 2, completing the installation of the reinforcement shell. The anti-collision shells 2 can be manufactured by scanning the bridge pier and generating drawings based on the pier's appearance.

[0049] Example 2

[0050] This embodiment is the same as Embodiment 1, except that: the amount of luminescent powder is 4500 parts, and the content of luminescent powder relative to cement is 7.0%.

[0051] Example 3

[0052] This embodiment is the same as Embodiment 1, except that: the amount of luminescent powder is 5200 parts, and the content of luminescent powder relative to cement is 8.0%.

[0053] Example 4

[0054] This embodiment is the same as Embodiment 1, except that: BSSON:Eu 2+ Eu 2+ The relative content is 5%.

[0055] Example 5

[0056] This embodiment is the same as Embodiment 1, except that: BSSON:Eu 2+ Eu 2+ The relative content is 7%.

[0057] Example 6

[0058] This embodiment is the same as Embodiment 1, except that: cement: 62,000 parts; quartz sand: 65,800 parts; silica fume: 550 parts; mineral powder: 1,400 parts; water: 13,100 parts; fly ash: 1,200 parts; gypsum: 400 parts; fiber: 220 parts; water-reducing agent: 45 parts; setting regulator: 1 part; early strength agent: 4 parts; thickener: 1 part; luminescent powder: 4,600 parts (the content of luminescent powder relative to cement is 7.5%); reflective powder: 1,200 parts; BSSON:Eu 2+ (Eu 2+ (Relative content of 6%): 450 portions.

[0059] Example 7

[0060] This embodiment is the same as Embodiment 1, except that: cement: 68,000 parts; quartz sand: 71,700 parts; silica fume: 450 parts; mineral powder: 1,600 parts; water: 14,300 parts; fly ash: 900 parts; gypsum: 550 parts; fiber: 180 parts; water-reducing agent: 55 parts; setting regulator: 0.8 parts; early strength agent: 6 parts; thickener: 0.8 parts; luminescent powder: 5,100 parts (the content of luminescent powder relative to cement is 7.5%); reflective powder: 1,700 parts; BSSON:Eu 2+ (Eu 2+ (Relative content of 6%): 500 portions.

[0061] Comparative Example 1

[0062] This comparative example is the same as Example 1, except that no luminescent powder, reflective powder, or BSSON:Eu was added. 2+ .

[0063] Comparative Example 2

[0064] This comparative example is the same as Example 1, except that the luminescent powder is mainly composed of SrAl2O4:Eu. 2+ ,Dy 3+ And BSSON:Eu was not added. 2+ Material.

[0065] Comparative Example 3

[0066] This comparative example is the same as Example 1, except that BSSON:Eu was not added. 2+ Material.

[0067] The mechanical and luminescent properties of the substrates prepared in Examples 1-5 and Comparative Examples 1-3 were tested.

[0068] The effect of adding luminescent and reflective powders on the mechanical properties of bridge pier concrete:

[0069] The results are shown in Table 1. With the same amount of reflective powder, the flexural strength gradually increased at 7 days as the relative content ratio of cement to reflective powder increased; at 28 days, the flexural strength first increased and then decreased, reaching the optimal value when the relative content of concrete and reflective powder was 3%.

[0070] Table 1. Effect of luminescent powder addition amount on the flexural strength of the substrate.

[0071] 7d flexural strength 28d flexural strength Example 2 (relative content of luminescent powder 7.0%) 10.2 MPa 21.7 MPa Example 1 (relative content of luminescent powder 7.5%) 11.5 MPa 23.6 MPa Example 3 (relative content of luminescent powder 8.0%) 12.8 MPa 22.4 MPa Comparative Example 1 11.1 MPa 22.9 MPa Comparative Example 2 10.9 MPa 22.7 MPa Comparative Example 3 11.3 MPa 23.2 MPa

[0072] With the same amount of reflective powder, the relative content of cement and reflective powder gradually increases, and the changes in compressive strength are shown in Table 2 below.

[0073] Table 2. Effect of luminescent powder addition amount on the compressive strength of the substrate.

[0074]

[0075]

[0076] As can be seen from Tables 1 and 2, firstly, the mechanical properties of Comparative Examples 1 and 3 show that the addition of SrAl2O4:Eu as the main component is effective. 2+ ,Dy 3+ The addition of luminescent powder can lead to a decrease in the mechanical properties of modified concrete, while the addition of luminescent components such as Ca2SnO4:Tb... 3+ The luminescent powder can enhance the mechanical properties of modified concrete.

[0077] Secondly, as the relative content of luminescent powder gradually increases, the compressive strength of concrete first increases and then decreases. Therefore, the optimal relative content of luminescent powder is around 7.5%.

[0078] Microscopic observation revealed that when the amount of luminescent powder added was 7.0%, the concrete surface had more and uneven crystals; when the amount of luminescent powder added was 7.5%, the concrete surface had stacked crystals, with granular gel and some unhydrated particles, which was beneficial to the formation of concrete strength; when the amount of luminescent powder added was 8.0%, the luminescent powder on the concrete surface continued to hydrolyze, which easily caused crystal expansion and was not conducive to improving the concrete strength.

[0079] Therefore, when preparing concrete materials, the relative content of luminescent powder is 7.5%, which has the best effect on the flexural and compressive strength of concrete. The quality of water in the material should be strictly controlled, and the water content should be controlled by setting the concrete printing speed to avoid excessive reaction.

[0080] For materials BSSON:Eu 2+ Eu 2+ The relative content of the components was subjected to tensile testing, and the changes in luminescence were observed, as shown in Table 3.

[0081] Table 3 Eu 2+ Relative content affects the luminous intensity of the substrate

[0082]

[0083]

[0084] Table 3 shows that, firstly, only the luminescent component Ca2SnO4:Tb is added. 3+ The luminescent powder has a low spectral brightness; adding BSSON:Eu 2+ The material can improve spectral brightness.

[0085] Secondly, BSSON:Eu 2+ Eu 2+ The sample exhibits optimal mechanoluminescence properties when the content is 6%.

[0086] Based on Tables 1-3, the added luminescent component is Ca2SnO4:Tb. 3+ After adding the luminescent powder, add BSSON:Eu 2+ The material can not only improve spectral brightness, but also further improve mechanical properties such as compressive strength.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A modified ultra-high performance concrete for 3D printing, characterized in that, Including 3D-printed ultra-high performance concrete, luminescent powder, reflective powder, and BSSON:Eu 2+ Materials; the luminescent component of the luminescent powder is Ca2SnO4:Tb 3+ ; The amount of luminescent powder added is 7.0-8.0% of the cement mass in the 3D-printed ultra-high performance concrete, and the amount of reflective powder added is 2.1-2.5% of the cement mass in the 3D-printed ultra-high performance concrete. BSSON:Eu 2+ The amount of material added is 0.5~0.8% of the cement mass in the 3D-printed ultra-high performance concrete; In the 3D-printed ultra-high performance concrete, the gel material, by weight, includes the following raw materials: Cement: 62,000~68,000 parts; Silica fume: 450~550 parts; Mineral powder: 1400~1600 parts; Fly ash: 900~1200 parts; Plaster: 400-550 parts; Fiber: 180~220 parts; Water-reducing agent: 45-55 parts; Setting regulator: 0.8~1 part; Early strength agent: 4-6 parts; Thickener: 0.8~1 part.

2. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, The cement is silicate cement and sulfoaluminate cement.

3. The modified ultra-high performance concrete for 3D printing as described in claim 2, characterized in that, The mass ratio of silicate cement to sulfoaluminate cement is 0.45:0.1~0.

3.

4. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, The amount of luminescent powder added is 7.4~7.6% of the cement mass in the 3D printed ultra-high performance concrete.

5. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, BSSON:Eu 2+ In the material, Eu 2+ The relative content is 5.0~7.0%.

6. The modified ultra-high performance concrete for 3D printing as described in claim 5, characterized in that, Eu 2+ The relative content is 5.0~6.2%.

7. The modified ultra-high performance concrete for 3D printing as described in claim 6, characterized in that, Eu 2+ The relative content is 5.9-6.1%.

8. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, The aggregate used in the 3D-printed ultra-high performance concrete has a particle size of 40-120 mesh.

9. The modified ultra-high performance concrete for 3D printing as described in claim 8, characterized in that, The aggregate particle size is 40~70 mesh or 70~120 mesh.

10. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, The water-to-binder ratio is 0.15~0.

25.

11. The modified ultra-high performance concrete for 3D printing as described in claim 1, characterized in that, The sand-to-rubber ratio is 1:0.9~1.

1.

12. A method for reinforcing bridge piers, characterized in that, The modified ultra-high performance concrete for 3D printing as described in any one of claims 1 to 11 is used to 3D print the base layer at the point to be reinforced on the bridge pier.

13. The method for reinforcing bridge piers as described in claim 12, characterized in that, Ingredients include cement, quartz sand, silica fume, mineral powder, water, fly ash, gypsum, water-reducing agent, setting regulator, early-strength agent, thickener, luminescent powder, reflective powder, and BSSON:Eu. 2+ Mix and stir to obtain a mixture; then add the fibers in batches.

14. The method for reinforcing bridge piers as described in claim 12, characterized in that, in 3D printing, the parameters are: horizontal printing speed of 45~55 mm / s, vertical printing speed of 8~12 mm / s, and extrusion speed of 1.3~1.7 L / min.

15. The method for reinforcing bridge piers as described in claim 12, characterized in that, A superhydrophobic coating is applied to the base surface to form a surface layer.

16. The method for reinforcing bridge piers as described in claim 15, characterized in that, The superhydrophobic coating material is obtained by adding fluorosilane material during the hydrolysis of tetraethyl orthosilicate and then performing fluorination treatment.

17. The method for reinforcing bridge piers as described in claim 15, characterized in that, After the surface layer is formed, a reinforcing shell is installed.

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