High-strength repairing material for highway bridge expansion joints and preparation method of high-strength repairing material

Abstract

The invention relates to the technical field of building materials, and particularly discloses a high-strength repairing material for a highway bridge expansion joint and a preparation method of the high-strength repairing material. The high-strength repairing material for the highway bridge expansion joint comprises the following raw materials in parts by weight: 10-20 parts of modified epoxy resin, 20-30 parts of silica fume, 3-5 parts of carbon nanotubes, 30-40 parts of cement, 3-8 parts of polyvinyl alcohol fibers, 0.5-1.5 parts of a water reducing agent, 0.5-1 part of a curing agent and 10-20 parts of water, and the modified epoxy resin is modified epoxy resin into which dynamic covalent bonds are introduced. The composition disclosed by the invention can be used for repairing the expansion joint of the highway bridge and has the advantage of high compressive strength.

Description

Technical Field

[0001] This application relates to the technical field of building materials, and more specifically, it relates to a high-strength repair material for highway bridge expansion joints and its preparation method. Background Art

[0002] In the field of highway bridge construction and maintenance, expansion joints, as key components of bridge structures, play a crucial role in ensuring the overall safety of bridges and extending their service life. The main design purpose of expansion joints is to effectively adapt to the deformation of bridges under various complex conditions such as temperature changes and load actions, and at the same time be able to withstand the continuous and repeated actions of wheel loads. However, when exposed to variable loads and harsh environmental conditions for a long time, the expansion joint parts are extremely vulnerable to damage, such as frequent cracking and peeling. These damages not only damage the aesthetics of the bridge, reduce the driving comfort, but also potentially threaten the structural safety of the bridge, and urgently need to be repaired in a timely and effective manner.

[0003] Although there are currently some repair materials for bridge expansion joints available in the market, these materials generally have obvious shortcomings in performance. Specifically, their strength is often insufficient to meet the high requirements in practical applications, their toughness performance is poor, and their self-healing ability is weak when facing damage. Summary of the Invention

[0004] To solve the above problems, this application provides a high-strength repair material for highway bridge expansion joints and its preparation method.

[0005] In the first aspect, a high-strength repair material for highway bridge expansion joints provided by this application adopts the following technical solution: A high-strength repair material for highway bridge expansion joints includes the following raw materials by weight: 10 - 20 parts of modified epoxy resin, 20 - 30 parts of silica fume, 3 - 5 parts of carbon nanotubes, 30 - 40 parts of cement, 3 - 8 parts of polyvinyl alcohol fiber, 0.5 - 1.5 parts of water reducer, 0.5 - 1 part of curing agent, and 10 - 20 parts of water. The modified epoxy resin is a modified epoxy resin introduced with dynamic covalent bonds.

[0006] By adopting the above technical solutions, epoxy resin has excellent mechanical properties, adhesion and chemical stability. However, traditional epoxy resin lacks self-healing ability and cannot recover its performance automatically after being damaged during long-term use. By introducing dynamic covalent bonds to endow the material with self-healing ability, when the material is damaged, the dynamic covalent bonds can undergo reversible reactions under certain conditions to reconnect the structure of the material and achieve self-healing. Furthermore, carbon nanotubes are uniformly dispersed in the repair material. Their photothermal effect can absorb light energy and convert it into heat energy under the irradiation of near-infrared light, thus effectively heating the modified epoxy resin and triggering the self-healing of dynamic covalent bonds. The modified epoxy resin acts synergistically with raw materials such as silica fume, polyvinyl alcohol fiber and cement, improving the strength and toughness of the material, enabling it to withstand greater loads and deformations and enhancing the repair effect.

[0007] Optionally, the preparation of the modified epoxy resin includes the following steps: (1) Take polyether polyol and epoxy resin, mix them evenly, heat to 60 - 70 °C, add a catalyst and react for 2 - 3 h. Then add an acetone solution containing 4-vinyl-2,3-dihydrobenzofuran and continue to react for 4 - 6 h. After adding glycidyl cinnamate, raise the temperature to 70 - 80 °C and perform vacuum degassing to obtain preliminarily modified epoxy resin; (2) Mix the above preliminarily modified epoxy resin with N,N'-methylenebismaleimide evenly and pre-react at 55 - 65 °C for 1 - 1.5 h. The addition amount ratio of N,N'-methylenebismaleimide to the added weight of epoxy resin is 1:1.2 - 1.5; add benzoyl peroxide accounting for 0.1 - 0.3 wt% of the epoxy resin and raise the temperature to 120 °C and keep it for 1.5 - 2.5 h to react to obtain the modified epoxy resin.

[0008] By adopting the above technical solutions, polyether polyol has good flexibility and a low glass transition temperature. Through modification, the toughness of epoxy resin can be improved, thereby enhancing the flexibility of epoxy resin, enabling the material to better absorb energy when subjected to external forces and reducing the generation and expansion of cracks. Furthermore, cinnamic acid groups are introduced, which have good photosensitivity. When the material is damaged, it can be repaired by activating the reaction and crosslinking at the damaged part through light irradiation. And through the Diels-Alder addition reaction, dynamic covalent bonds are introduced into the epoxy resin to form a crosslinked network structure, enabling the material to undergo reversible bonding when subjected to external forces and improving the repair ability and durability of the material.

[0009] Optionally, the addition weight ratio of polyether polyol to epoxy resin in the preparation process is 1:3 - 5; the molecular weight of polyether polyol is between 1500 - 2000; The addition weight ratio of glycidyl cinnamate to epoxy resin is 0.2 - 0.3:1.

[0010] By adopting the above technical solution, the grafting reaction between polyether polyol and epoxy resin improves the molecular structure of epoxy resin, enabling the material to better absorb energy when subjected to external forces, reducing the generation and propagation of cracks. Meanwhile, the polyether polyol within this molecular weight range endows the grafted product with appropriate flexibility and reactivity.

[0011] Optionally, the catalyst is dibutyltin dilaurate catalyst, and its addition amount is 0.1 - 0.2 wt% of the addition amount of epoxy resin.

[0012] Optionally, the mass concentration of the acetone solution containing 4 - vinyl - 2,3 - dihydrobenzofuran is 35 - 45 wt%, and the weight ratio of the acetone solution to the added epoxy resin is 0.3 - 0.5:1.

[0013] Optionally, a nano - scale reinforcing material is further added during the modification process. The nano - scale reinforcing material is nano - silica, and its addition amount accounts for 1 - 3 wt% of the epoxy resin.

[0014] By adopting the above technical solution, nano - silica forms a nano - scale network structure inside the material with its good reinforcing effect, restricting the slippage of polymer molecular chains and improving the compressive strength of the material. Meanwhile, the surface active sites of nano - silica promote the exchange reaction of dynamic covalent bonds, enhancing the self - healing ability of the material.

[0015] Optionally, 8 - 12 parts of acrylate emulsion are further added to the raw materials.

[0016] By adopting the above technical solution, the acrylate monomers in the acrylate emulsion react with the functional groups in the epoxy resin to form a cross - linked structure, improving the compressive strength of the material.

[0017] In a second aspect, the present application provides a preparation method for a high - strength repair material for highway bridge expansion joints, adopting the following technical solution: A preparation method for a high - strength repair material for highway bridge expansion joints includes the following steps: Dry - mix and stir cement, silica fume and carbon nanotubes for 3 - 5 min, add polyvinyl alcohol fiber and continue stirring for 5 - 8 min, then add modified epoxy resin, water - reducing agent and curing agent and continue stirring for 10 - 15 min to obtain the repair material.

[0018] By adopting the above technical solution, during the preparation process, various raw materials form a cross - linked structure through physical mixing and chemical reactions, endowing the repair material with excellent mechanical properties and self - healing ability.

[0019] In summary, the present application has the following beneficial effects: 1. Due to the synergistic effect of modified epoxy resin, silica fume, polyvinyl alcohol fiber, cement and other raw materials used in this application, the strength and toughness of the repair material are significantly improved. The addition of polyether polyol improves the flexibility of epoxy resin, allowing the material to better absorb energy when subjected to external forces, reducing the generation and expansion of cracks. At the same time, the addition of nano-silica and acrylic emulsion further enhances the material's deformation resistance and adhesion. These characteristics enable the repair material to withstand large loads and deformations, and is suitable for complex environments such as highway bridge expansion joints.

[0020] 2. In this application, by introducing dynamic covalent bonds, the repair material can restore its performance by itself when damaged. Dynamic covalent bonds can undergo reversible reactions under certain conditions, allowing the structure of the material to reconnect, thereby achieving self-repair. In addition, the photothermal effect of carbon nanotubes can absorb light energy and convert it into heat energy under the irradiation of near-infrared light, effectively heating the modified epoxy resin, and further initiating the self-repair process of dynamic covalent bonds. This self-repairing ability extends the service life of the repair material and reduces maintenance costs. DETAILED DESCRIPTION

[0021] The present application is further described in detail below with reference to the embodiments.

[0022] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased from the market.

[0023] Bisphenol A epoxy resin (E-51), epoxy value is 0.44-0.48eq / 100g; polyether polyol is purchased from Wudi Dexin Chemical Co., Ltd., SE-220E, molecular weight is 2000; nano-silica particle size is 15nm; pure acrylic emulsion is purchased from Zhonghe Chemical (Shandong) Co., Ltd., model BA-201; carbon nanotubes are purchased from Xi'an Qiyue Biotechnology Co., Ltd., diameter 20-30nm, length 10-30nm; polyvinyl alcohol fiber is purchased from Tai'an Haili New Materials Co., Ltd., fiber diameter 15μm±3, length 6mm; polycarboxylic acid water reducer model DH-4005; curing agent is purchased from Jinan Chenghao Chemical Co., Ltd., brand T31.

[0024] Preparation examples of raw materials and / or intermediates Preparation Example 1 A modified epoxy resin, the preparation of which comprises the following steps: (1) Take 10 kg of polyether polyol and 30 kg of bisphenol A epoxy resin (E-51), stir and mix them evenly at a speed of 500 rpm, heat up to 60 - 70 °C, add 0.03 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2 - 3 h; dropwise add 12 kg of acetone solution containing 4-vinyl-2,3-dihydrobenzofuran with a mass concentration of 35 wt%, disperse it under ultrasonic wave at 40 KHz and 200 w, add 6 kg of glycidyl cinnamate, gradually heat up to 80 °C and continue the reaction for 4 - 6 h, and carry out vacuum defoaming for 30 min under -0.08 MPa to remove solvent residues, obtaining a preliminarily modified epoxy resin with a viscosity controlled at 2500 - 3000 mPa·s; (2) Mix the above preliminarily modified epoxy resin with 25 kg of N,N'-methylenebismaleimide evenly, carry out a pre-reaction at 55 - 65 °C for 1 - 1.5 h, add 0.03 kg of benzoyl peroxide, heat up to 120 °C and keep it for 1.5 - 2.5 h to obtain the modified epoxy resin by reaction.

[0025] Preparation Example 2 A modified epoxy resin, the preparation comprises the following steps: (1) Take 6 kg of polyether polyol and 30 kg of bisphenol A epoxy resin (E-51), stir and mix them evenly at a speed of 500 rpm, heat up to 60 - 70 °C, add 0.06 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2 - 3 h; dropwise add 9 kg of acetone solution containing 4-vinyl-2,3-dihydrobenzofuran with a mass concentration of 40 wt%, disperse it under ultrasonic wave at 40 KHz and 200 w, add 9 kg of glycidyl cinnamate, gradually heat up to 80 °C and continue the reaction for 4 - 6 h, and carry out vacuum defoaming for 30 min under -0.08 MPa to remove solvent residues, obtaining a preliminarily modified epoxy resin with a viscosity controlled at 2500 - 3000 mPa·s; (2) Mix the above preliminarily modified epoxy resin with 20 kg of N,N'-methylenebismaleimide evenly, carry out a pre-reaction at 55 - 65 °C for 1 - 1.5 h, add 0.09 kg of benzoyl peroxide, heat up to 120 °C and keep it for 1.5 - 2.5 h to obtain the modified epoxy resin by reaction.

[0026] Preparation Example 3 A modified epoxy resin, the preparation comprises the following steps: (1) Take 7.5 kg of polyether polyol and 30 kg of bisphenol A epoxy resin (E-51), stir and mix them evenly at a speed of 500 rpm, heat up to 60 - 70 °C, add 0.04 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2 - 3 h; dropwise add 15 kg of acetone solution containing 4-vinyl-2,3-dihydrobenzofuran with a mass concentration of 45 wt%, disperse it under ultrasonic wave at 40 KHz and 200 w, add 7.5 kg of glycidyl cinnamate, gradually heat up to 80 °C and continue the reaction for 4 - 6 h, carry out vacuum degassing for 30 min under -0.08 MPa to remove solvent residues, and obtain a preliminarily modified epoxy resin with viscosity controlled at 2500 - 3000 mPa·s; (2) Mix the above preliminarily modified epoxy resin with 22.5 kg of N,N'-methylenebismaleimide evenly, carry out a pre-reaction at 55 - 65 °C for 1 - 1.5 h, add 0.06 kg of benzoyl peroxide, heat up to 120 °C and keep it for 1.5 - 2.5 h to obtain the modified epoxy resin.

[0027] Preparation Example 4 A modified epoxy resin, different from Preparation Example 1 in that 0.3 kg of nano-silica is further added in this preparation example. The preparation includes the following steps: (1) Take 6 kg of polyether polyol and 30 kg of bisphenol A epoxy resin (E-51), stir and mix them evenly at a speed of 500 rpm, add 0.3 kg of nano-silica and stir evenly, then heat up to 60 - 70 °C, add 0.06 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2 - 3 h; dropwise add 9 kg of acetone solution containing 4-vinyl-2,3-dihydrobenzofuran with a mass concentration of 40 wt%, disperse it under ultrasonic wave at 40 KHz and 200 w, add 9 kg of glycidyl cinnamate, gradually heat up to 80 °C and continue the reaction for 4 - 6 h, carry out vacuum degassing for 30 min under -0.08 MPa to remove solvent residues, and obtain a preliminarily modified epoxy resin with viscosity controlled at 2500 - 3000 mPa·s; (2) Mix the above preliminarily modified epoxy resin with 20 kg of N,N'-methylenebismaleimide evenly, carry out a pre-reaction at 55 - 65 °C for 1 - 1.5 h, add 0.09 kg of benzoyl peroxide, heat up to 120 °C and keep it for 1.5 - 2.5 h to obtain the modified epoxy resin.

[0028] Preparation Example 5 A modified epoxy resin, different from Preparation Example 4 in that 0.6 kg of nano-silica is further added in this preparation example.

[0029] Preparation Example 6 A modified epoxy resin, which is different from Preparation Example 4 in that 0.9 kg of nano-silica is further added in this preparation example.

[0030] Comparative Preparation Example 1 A modified epoxy resin is different from Preparation Example 1 in that glycidyl cinnamate is not added in this preparation example.

[0031] Comparative Preparation Example 2 A modified epoxy resin is different from Preparation Example 1 in that 4-vinyl-2,3-dihydrobenzofuran is not added in this preparation example. The preparation includes the following steps: (1) Take 10 kg of polyether polyol and 30 kg of bisphenol A epoxy resin (E-51), stir and mix them evenly at a speed of 500 rpm, heat up to 60 - 70 °C, add 0.03 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2 - 3 h; dropwise add 12 kg of acetone solution, disperse it under ultrasonic wave at 40 KHz and 200 w, add 6 kg of glycidyl cinnamate, gradually heat up to 80 °C and continue the reaction for 4 - 6 h, and conduct vacuum degassing for 30 min at -0.08 MPa to remove solvent residues, obtaining a preliminarily modified epoxy resin with viscosity controlled at 2500 - 3000 mPa·s; (2) Mix the above preliminarily modified epoxy resin with 25 kg of N,N'-methylenebismaleimide evenly, pre-react at 55 - 65 °C for 1 - 1.5 h, add 0.03 kg of benzoyl peroxide, heat up to 120 °C and keep it for 1.5 - 2.5 h to obtain the modified epoxy resin. Examples

[0032] Example 1 A high-strength repair material for highway bridge expansion joints, and the preparation includes the following steps: Dry-mix and stir 35 kg of cement, 25 kg of silica fume and 4 kg of carbon nanotubes for 3 - 5 min, add 3 kg of polyvinyl alcohol fiber and continue to stir for 5 - 8 min, then add 15 kg of the modified epoxy resin prepared in Preparation Example 1, 1 kg of polycarboxylate water reducer and 0.5 kg of curing agent, and continue to stir for 10 - 15 min to obtain the repair material.

[0033] Example 2 A high-strength repair material for highway bridge expansion joints, and the preparation includes the following steps: Dry-mix and stir 40 kg of cement, 20 kg of silica fume and 5 kg of carbon nanotubes for 3 - 5 min, add 8 kg of polyvinyl alcohol fiber and continue to stir for 5 - 8 min, then add 20 kg of the modified epoxy resin prepared in Preparation Example 1, 0.5 kg of polycarboxylate water reducer and 1 kg of curing agent, and continue to stir for 10 - 15 min to obtain the repair material.

[0034] Example 3 A high-strength repair material for highway bridge expansion joints, the preparation of which comprises the following steps: Dry-mix and stir 30 kg of cement, 30 kg of silica fume and 5 kg of carbon nanotubes for 3 - 5 min, add 8 kg of polyvinyl alcohol fibers and continue stirring for 5 - 8 min, then add 20 kg of the modified epoxy resin prepared in Preparation Example 1, 0.5 kg of polycarboxylate water reducer and 1 kg of curing agent and continue stirring for 10 - 15 min to obtain the repair material.

[0035] Example 4 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin used in this example is prepared in Preparation Example 2.

[0036] Example 5 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin used in this example is prepared in Preparation Example 3.

[0037] Example 6 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin used in this example is prepared in Preparation Example 4.

[0038] Example 7 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin used in this example is prepared in Preparation Example 5.

[0039] Example 8 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin used in this example is prepared in Preparation Example 6.

[0040] Example 9 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that this example further contains 8 kg of pure acrylic emulsion (acrylate emulsion), and the preparation comprises the following steps: Dry-mix and stir 35 kg of cement, 25 kg of silica fume and 4 kg of carbon nanotubes for 3 - 5 min, add 3 kg of polyvinyl alcohol fibers and continue stirring for 5 - 8 min, then add 15 kg of the modified epoxy resin prepared in Preparation Example 1, 8 kg of pure acrylic emulsion, 1 kg of polycarboxylate water reducer and 0.5 kg of curing agent and continue stirring for 10 - 15 min to obtain the repair material.

[0041] Example 10 A high-strength repair material for highway bridge expansion joints, which is different from Example 9 in that this example also contains 10 kg of pure acrylic emulsion (acrylate emulsion).

[0042] Example 11 A high-strength repair material for highway bridge expansion joints, which is different from Example 9 in that this example also contains 12 kg of pure acrylic emulsion (acrylate emulsion).

[0043] Control Example Control Example 1 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that unmodified epoxy resin is added in this control example.

[0044] Control Example 2 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that modified epoxy resin is not added in this control example.

[0045] Control Example 3 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin prepared in Comparative Preparation Example 1 is used in this control example.

[0046] Control Example 4 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that the modified epoxy resin prepared in Comparative Preparation Example 2 is used in this control example.

[0047] Control Example 5 A high-strength repair material for highway bridge expansion joints, which is different from Example 1 in that carbon nanotubes are not added in this control example.

[0048] Performance Detection Test Detection Method Compressive strength: Test the 28-day compressive strength and flexural strength according to the standard of "GB / T 17671-2021"; Fatigue test: Use the MTS hydraulic servo system to simulate traffic load (frequency 5 Hz, stress ratio 0.1), and test the remaining strength retention rate after 10 6 cycles of irradiation with light greater than 700 nm for 2 h; Freeze-thaw cycle: Carry out 300 freeze-thaw cycles (-20°C - 20°C) according to the standard of "JTG 3420-2020", and detect the mass loss rate (%) and relative dynamic elastic modulus attenuation (%) after irradiating with light greater than 700 nm for 2 h.

[0049] Table 1 Test Detection Data Compressive strength / MPa Strength retention rate / % Mass loss rate / % Relative dynamic elastic modulus attenuation / % Example 1 93.25 96.00 0.18 4.50 Example 2 92.48 95.71 0.20 4.82 Example 3 92.76 95.86 0.22 4.92 Example 4 92.12 95.07 0.19 4.74 Example 5 92.33 95.21 0.17 4.78 Example 6 95.89 97.16 0.14 4.12 Example 7 95.56 97.09 0.16 4.27 Example 8 95.67 97.12 0.15 4.19 Example 9 96.78 99.00 0.12 3.86 Example 10 97.54 100.00 0.10 3.51 Example 11 97.98 101.00 0.08 3.27 Comparative example 1 85.67 88.00 3.50 8.00 Comparative example 2 82.23 84.00 3.85 10.00 Comparative example 3 87.12 90.00 1.77 7.00 Comparative example 4 86.45 89.00 3.20 7.50 Comparative example 5 82.98 85.00 2.19 8.15 Combining Examples 1-3 and Comparative Examples 1-2 and referring to Table 1, it can be seen that all the experimental data of Example 1 are better than those of Comparative Examples 1-2. In Comparative Example 1, unmodified epoxy resin was added, and in Comparative Example 2, no modified epoxy resin was added. Compared with the unmodified or completely non-added cases, the modified epoxy resin can significantly improve the performance of the repair material.

[0050] Combining Examples 1-3 and Comparative Examples 3-4 and referring to Table 1, it can be seen that all the experimental data of Examples 1-3 are better than those of Comparative Examples 3-4, indicating that the modification effect cannot be achieved without adding 4-vinyl-2,3-dihydrobenzofuran and glycidyl cinnamate during the modification process of epoxy resin, thus affecting the overall performance of the repair material.

[0051] Combining Examples 1-3 and Comparative Example 5 and referring to Table 1, it can be seen that all the experimental data of Examples 1-3 are better than those of Comparative Example 5. Carbon nanotubes as the reinforcing phase can improve the strength and durability of the repair material.

[0052] Combining Examples 1-8 and referring to Table 1, it can be seen that all the experimental data of Examples 6-8 are better than those of Examples 1-5, indicating that adding nano-silica during the modification process of modified epoxy resin can form a nano-scale network structure inside the epoxy resin, restrict the slippage of polymer molecular chains, improve the strength of the epoxy resin, and thus improve the compressive strength of the material.

[0053] Combining Examples 1-3 and Examples 9-11 and referring to Table 1, it can be seen that all the experimental data of Examples 9-11 are better than those of Examples 1-3, indicating that adding acrylate emulsion can improve the overall performance of the repair material and react with epoxy resin to form a cross-linked structure to improve the compressive strength of the material.

[0054] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A high-strength repair material for expansion joints of highway bridges, characterized in that: The composition comprises the following raw materials in parts by weight: 10-20 parts of modified epoxy resin, 20-30 parts of silica fume, 3-5 parts of carbon nanotubes, 30-40 parts of cement, 3-8 parts of polyvinyl alcohol fiber, 0.5-1.5 parts of water reducer, 0.5-1 part of curing agent and 10-20 parts of water. The modified epoxy resin is a modified epoxy resin introduced with dynamic covalent bonds.

2. The high-strength repair material for expansion joints of highway bridges according to claim 1, characterized in that: The modified epoxy resin preparation comprises the following steps: (1) Mix the polyether polyol and epoxy resin evenly, heat to 60-70°C, add the catalyst and react for 2-3 hours, then add the acetone solution containing 4-vinyl-2,3-dihydrobenzofuran and continue to react for 4-6 hours, add glycidyl cinnamate and heat to 70-80°C, vacuum degassing to obtain a preliminarily modified epoxy resin; (2) The above-mentioned preliminarily modified epoxy resin and N,N'-methylenebismaleimide are uniformly mixed and pre-reacted at 55-65°C for 1-1.5 hours, wherein the ratio of the added amount of N,N'-methylenebismaleimide to the added weight of the epoxy resin is 1:1.2-1.5; 0.1-0.3wt% of benzoyl peroxide in the epoxy resin is added, and the temperature is raised to 120°C and maintained for 1.5-2.5 hours to obtain the modified epoxy resin.

3. The high-strength repair material for expansion joints of highway bridges according to claim 2, characterized in that: The weight ratio of the polyether polyol to the epoxy resin in the preparation process is 1:3-5; the molecular weight of the polyether polyol is between 1500-2000; The weight ratio of the glycidyl cinnamate to the epoxy resin is 0.2-0.3:

1.

4. The high-strength repair material for expansion joints of highway bridges according to claim 2, characterized in that: The catalyst is a dibutyltin dilaurate catalyst, and the added amount thereof is 0.1-0.2 wt % of the added amount of the epoxy resin.

5. The high-strength repair material for expansion joints of highway bridges according to claim 2, characterized in that: The mass concentration of the acetone solution containing 4-vinyl-2,3-dihydrobenzofuran is 35-45wt%, and the weight ratio of the acetone solution to the epoxy resin is 0.3-0.5:

1.

6. The high-strength repair material for expansion joints of highway bridges according to claim 2, characterized in that: During the modification process, a nano-scale reinforcing material is added. The nano-scale reinforcing material is nano-silicon dioxide, and the amount added accounts for 1-3wt% of the epoxy resin.

7. The high-strength repair material for expansion joints of highway bridges according to claim 1, characterized in that: 8-12 parts of acrylic emulsion are also added to the raw materials.

8. A method for preparing a high-strength repair material for expansion joints of highway bridges according to any one of claims 1 to 7, characterized in that: The steps include: The cement, silica fume and carbon nanotubes are dry-mixed and stirred for 3-5 minutes, polyvinyl alcohol fibers are added and stirred for 5-8 minutes, and then modified epoxy resin, water reducing agent and curing agent are added and stirred for 10-15 minutes to obtain a repair material.