High-strength repairing material for highway bridge expansion joint and preparation method thereof

Abstract

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

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, and more particularly to a high-strength repairing material for highway bridge expansion joints and a preparation method thereof. BACKGROUND

[0002] In the field of highway bridge construction and maintenance, expansion joints, as a key component of bridge structures, have a crucial significance in ensuring the overall safety and extending the service life of bridges. The main design purpose of expansion joints is to effectively adapt to the deformation of bridges under various temperature changes, load actions and other complex conditions, while being able to withstand the continuous and repeated action of wheel loads. However, long-term exposure to variable loads and harsh environmental conditions, expansion joint parts are prone to damage, such as cracking, falling off and other phenomena. These damages not only damage the aesthetics of the bridge and reduce the driving comfort, but also potentially threaten the structural safety of the bridge, which needs to be repaired in a timely and effective manner.

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

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

[0005] In the first aspect, the present application provides a high-strength repairing material for highway bridge expansion joints, which adopts the following technical solution:

[0006] A high-strength repairing material for highway bridge expansion joints, comprising the following raw materials by weight:

[0007] 10-20 parts of modified epoxy resin, 20-30 parts of silica ash, 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 reducing agent, 0.5-1 part of curing agent and 10-20 parts of water, wherein the modified epoxy resin is a modified epoxy resin with dynamic covalent bonds.

[0008] By adopting the technical scheme, the epoxy resin has excellent mechanical properties, adhesion and chemical stability, but the traditional epoxy resin lacks self-repairing ability and cannot restore performance after damage in long-term use. By introducing dynamic covalent bonds, the material has self-repairing ability. When the material is damaged, the dynamic covalent bonds can reversibly react under certain conditions, so that the structure of the material is reconnected, and self-repairing is realized. Further, the carbon nanotubes are uniformly dispersed in the repair material, and the photothermal effect of the carbon nanotubes can absorb light energy and convert it into heat energy under the irradiation of near-infrared light, thereby effectively heating the modified epoxy resin and initiating the self-repairing of the dynamic covalent bonds. The modified epoxy resin cooperates with silica ash, polyvinyl alcohol fiber and cement and other raw materials to improve the strength and toughness of the material, so that the material can withstand larger load and deformation, and the repair effect is improved.

[0009] Optionally, the preparation of the modified epoxy resin comprises the following steps:

[0010] (1) uniformly mix polyether polyol and epoxy resin, heat to 60-70℃, add catalyst, react for 2-3h, then add 4-vinyl-2,3-dihydrobenzofuran acetone solution and continue to react for 4-6h, then add glycidyl cinnamate, heat to 70-80℃, and vacuum degassing to obtain a preliminary modified epoxy resin;

[0011] (2) uniformly mix the preliminary modified epoxy resin with N,N'-methylene bis-maleimide, pre-react at 55-65℃ for 1-1.5h, the addition amount of N,N'-methylene bis-maleimide is 1:1.2-1.5 by weight ratio of the addition amount of epoxy resin; add 0.1-0.3wt% of benzoyl peroxide based on the epoxy resin, heat to 120℃ and keep for 1.5-2.5h to prepare the modified epoxy resin.

[0012] By adopting the technical scheme, the polyether polyol has good flexibility and low glass transition temperature, and the toughness of the epoxy resin can be improved by modification, thereby improving the flexibility of the epoxy resin, so that the material can better absorb energy when subjected to external force, and the generation and expansion of cracks are reduced. Further, the cinnamic acid group is introduced, which has good photosensitivity, and when the material is damaged, the reaction is activated by light to crosslink and repair the damaged part. The Diels-Alder addition reaction introduces dynamic covalent bonds into the epoxy resin, forming a crosslinked network structure, so that the material can reversibly bond when subjected to external force, improving the repairability and durability of the material.

[0013] Optionally, the addition amount of polyether polyol and epoxy resin in the preparation process is 1:3-5 by weight ratio; the molecular weight of the polyether polyol is 1500-2000;

[0014] The weight ratio of the cinnamic acid glycidyl ester to the epoxy resin is 0.2-0.3:1.

[0015] By adopting the technical scheme, the grafting reaction of the polyether polyol and the epoxy resin improves the molecular structure of the epoxy resin, so that the material can better absorb energy when subjected to external force, and the generation and expansion of cracks are reduced, and the polyether polyol in the molecular weight range makes the product after grafting have appropriate flexibility and reactivity.

[0016] Optionally, the catalyst is dibutyl tin dilaurate, and the amount of the catalyst is 0.1-0.2wt% of the amount of the epoxy resin.

[0017] Optionally, 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.

[0018] Optionally, a nanoscale reinforcing material is further added in the modification process, and the nanoscale reinforcing material is nanoscale silicon dioxide, and the amount of the nanoscale silicon dioxide is 1-3wt% of the epoxy resin.

[0019] By adopting the technical scheme, the nanoscale silicon dioxide forms a nanoscale network structure in the material due to its good reinforcing effect, limits the slippage of the polymer molecular chain, and improves the compressive strength of the material. Meanwhile, the surface active sites of the nanoscale silicon dioxide promote the exchange reaction of the dynamic covalent bond, and the self-repairing ability of the material is enhanced.

[0020] Optionally, 8-12 parts of an acrylic emulsion are further added in the raw materials.

[0021] By adopting the technical scheme, the acrylic ester monomer in the acrylic emulsion reacts with the functional groups in the epoxy resin to form a crosslinked structure, and the compressive strength of the material is improved.

[0022] In the second aspect, the application provides a preparation method of a high-strength repairing material for highway bridge expansion joints.

[0023] The preparation method of the high-strength repairing material for highway bridge expansion joints comprises the following steps:

[0024] The cement, silica fume and carbon nanotubes are dry mixed and stirred for 3-5min, the polyvinyl alcohol fiber is added and stirred for 5-8min, then the modified epoxy resin, the water reducing agent and the curing agent are added and stirred for 10-15min to obtain the repairing material.

[0025] By adopting the technical scheme, in the preparation process, various raw materials form a cross-linked structure through physical mixing and chemical reaction, so that the repairing material has excellent mechanical properties and self-repairing ability.

[0026] In summary, the present application has the following beneficial effects:

[0027] 1. Due to the synergistic effect of the modified epoxy resin, silica ash, polyvinyl alcohol fiber and cement and other raw materials, the strength and toughness of the repairing material are significantly improved. The addition of polyether polyol improves the flexibility of the epoxy resin, so that the material can better absorb energy when subjected to external force, reducing the generation and expansion of cracks. At the same time, the addition of nano-silicon dioxide and acrylic emulsion further enhances the anti-deformation ability and adhesion of the material. These characteristics enable the repairing material to withstand greater load and deformation, making it suitable for complex environments such as highway bridge expansion joints.

[0028] 2. In the present application, by introducing dynamic covalent bonds, the repairing material can restore its performance when damaged. Dynamic covalent bonds can undergo reversible reactions under certain conditions, allowing the material's structure to reconnect and thus achieve self-repairing. In addition, the photothermal effect of carbon nanotubes can absorb light energy and convert it into heat energy under near-infrared light irradiation, effectively heating the modified epoxy resin and further triggering the self-repairing process of dynamic covalent bonds. This self-repairing ability extends the service life of the repairing material and reduces maintenance costs. DETAILED DESCRIPTION

[0029] The present application is further described in detail below in conjunction with the examples.

[0030] Unless otherwise specified in the examples, the procedures were carried out under conventional conditions or according to the manufacturer's recommendations. The reagents or instruments used were not specified by the manufacturer, but were conventional products that could be purchased on the market.

[0031] Bisphenol A type epoxy resin (E-51) with an epoxy value of 0.44-0.48 eq / 100g; polyether polyol purchased from Shandong Desheng Chemical Co., Ltd., SE-220E, molecular weight 2000; nano-silicon dioxide particle size 15 nm; pure acrylic emulsion purchased from Zhonghe Chemical (Shandong) Co., Ltd., model BA-201; carbon nanotubes purchased from Xi'an Qiyue Biological Technology Co., Ltd., diameter 20-30 nm, length 10-30 nm; polyvinyl alcohol fiber purchased from Taian Haili New Material Co., Ltd., fiber diameter 15 μm ± 3, length 6 mm; polycarboxylic acid water reducer type DH-4005; curing agent purchased from Jinan Chenghao Chemical Co., Ltd., brand T31.

[0032] Preparation example of raw materials and / or intermediates

[0033] Preparation example 1

[0034] A modified epoxy resin, the preparation comprising the following steps:

[0035] (1) Take 10 kg of polyether polyol and 30 kg of bisphenol A type epoxy resin (E-51) and mix them uniformly at a stirring speed of 500 rpm, heat to 60-70°C, add 0.03 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2-3 h; add 12 kg of 35 wt% acetone solution containing 4-vinyl-2,3-dihydrobenzofuran, disperse under ultrasonic wave 40 KHz, 200 w, add 6 kg of glycidyl cinnamate, gradient heat to 80°C and continue the reaction for 4-6 h, vacuum degassing at -0.08 MPa for 30 min to remove solvent residues, and obtain a preliminary modified epoxy resin with viscosity controlled at 2500-3000 mPa·s;

[0036] (2) Mix the above preliminary modified epoxy resin with 25 kg of N,N'-methylene bis-maleimide uniformly, pre-react at 55-65°C for 1-1.5 h, add 0.03 kg of benzoyl peroxide, heat to 120°C and maintain for 1.5-2.5 h, and prepare the modified epoxy resin by reaction.

[0037] Preparation Example 2

[0038] A modified epoxy resin, the preparation comprising the following steps:

[0039] (1) Take 6 kg of polyether polyol and 30 kg of bisphenol A type epoxy resin (E-51) and mix them uniformly at a stirring speed of 500 rpm, heat to 60-70°C, add 0.06 kg of dibutyltin dilaurate catalyst and maintain the reaction for 2-3 h; add 9 kg of 40 wt% acetone solution containing 4-vinyl-2,3-dihydrobenzofuran, disperse under ultrasonic wave 40 KHz, 200 w, add 9 kg of glycidyl cinnamate, gradient heat to 80°C and continue the reaction for 4-6 h, vacuum degassing at -0.08 MPa for 30 min to remove solvent residues, and obtain a preliminary modified epoxy resin with viscosity controlled at 2500-3000 mPa·s;

[0040] (2) Mix the above preliminary modified epoxy resin with 20 kg of N,N'-methylene bis-maleimide uniformly, pre-react at 55-65°C for 1-1.5 h, add 0.09 kg of benzoyl peroxide, heat to 120°C and maintain for 1.5-2.5 h, and prepare the modified epoxy resin by reaction.

[0041] Preparation Example 3

[0042] A modified epoxy resin, the preparation comprising the following steps:

[0043] (1) Take 7.5 kg of polyether polyol and 30 kg of bisphenol A type epoxy resin (E-51) and mix them uniformly at a stirring speed of 500 rpm, heat to 60-70°C, add 0.04 kg of dibutyl tin dilaurate catalyst and maintain the reaction for 2-3 h; add 15 kg of 4-vinyl-2,3-dihydrobenzofuran-containing acetone solution with a mass concentration of 45 wt%, disperse under ultrasonic wave 40 KHz, 200 w, add 7.5 kg of glycidyl cinnamate, gradient heat to 80°C and continue the reaction for 4-6 h, vacuum degassing at -0.08 MPa for 30 min to remove solvent residues, and obtain the preliminary modified epoxy resin with a viscosity controlled at 2500-3000 mPa·s;

[0044] (2) Mix the above preliminary modified epoxy resin with 22.5 kg of N,N'-methylene bis-maleimide uniformly, pre-react at 55-65°C for 1-1.5 h, add 0.06 kg of benzoyl peroxide, heat to 120°C and maintain for 1.5-2.5 h, and react to prepare the modified epoxy resin.

[0045] Preparation Example 4

[0046] A modified epoxy resin, which is different from Preparation Example 1 in that 0.3 kg of nano-silica is further added in the present preparation example, is prepared including the following steps:

[0047] (1) Take 6 kg of polyether polyol and 30 kg of bisphenol A type epoxy resin (E-51) and mix them uniformly at a stirring speed of 500 rpm, add 0.3 kg of nano-silica and mix uniformly, heat to 60-70°C, add 0.06 kg of dibutyl tin dilaurate catalyst and maintain the reaction for 2-3 h; add 9 kg of 4-vinyl-2,3-dihydrobenzofuran-containing acetone solution with a mass concentration of 40 wt%, disperse under ultrasonic wave 40 KHz, 200 w, add 9 kg of glycidyl cinnamate, gradient heat to 80°C and continue the reaction for 4-6 h, vacuum degassing at -0.08 MPa for 30 min to remove solvent residues, and obtain the preliminary modified epoxy resin with a viscosity controlled at 2500-3000 mPa·s;

[0048] (2) Mix the above preliminary modified epoxy resin with 20 kg of N,N'-methylene bis-maleimide uniformly, pre-react at 55-65°C for 1-1.5 h, add 0.09 kg of benzoyl peroxide, heat to 120°C and maintain for 1.5-2.5 h, and react to prepare the modified epoxy resin.

[0049] Preparation Example 5

[0050] A modified epoxy resin, which is different from Preparation Example 4 in that 0.6 kg of nano-silica is further added in the present preparation example.

[0051] Preparation Example 6

[0052] A modified epoxy resin, different from Preparation Example 4 is that 0.9 kg of nano-silica is added in the present preparation example.

[0053] Comparative Preparation Example 1

[0054] A modified epoxy resin, different from Preparation Example 1 is that no glycidyl cinnamate is added in the present preparation example.

[0055] Comparative Preparation Example 2

[0056] A modified epoxy resin, different from Preparation Example 1 is that no 4-vinyl-2,3-dihydrobenzofuran is added in the present preparation example, the preparation comprising the following steps:

[0057] (1) 10 kg of polyether polyol and 30 kg of bisphenol A type epoxy resin (E-51) are mixed uniformly at a stirring speed of 500 rpm, and heated to 60-70 °C, and 0.03 kg of dibutyltin dilaurate catalyst is added to maintain the reaction for 2-3 h; 12 kg of acetone solution is added dropwise, dispersed under ultrasonic wave at 40 KHz and 200 w, 6 kg of glycidyl cinnamate is added, and the temperature is increased to 80 °C in stages, and the reaction is continued for 4-6 h, and the residual solvent is removed by vacuum degassing at -0.08 MPa for 30 min to obtain a preliminary modified epoxy resin with a viscosity controlled at 2500-3000 mPa·s;

[0058] (2) The above preliminary modified epoxy resin is mixed uniformly with 25 kg of N,N'-methylene bis-maleimide, and pre-reacted at 55-65 °C for 1-1.5 h, and 0.03 kg of benzoyl peroxide is added, and heated to 120 °C for 1.5-2.5 h, and the reaction is prepared to obtain the modified epoxy resin.

[0059] Example

[0060] Example 1

[0061] A high-strength repair material for highway bridge expansion joints, the preparation comprising the following steps:

[0062] 35 kg of cement, 25 kg of silica fume and 4 kg of carbon nanotubes are dry mixed and stirred for 3-5 min, 3 kg of polyvinyl alcohol fiber is added and stirred for 5-8 min, then 15 kg of modified epoxy resin prepared in Preparation Example 1, 1 kg of polycarboxylic acid water reducer and 0.5 kg of curing agent are added and stirred for 10-15 min to obtain the repair material.

[0063] Example 2

[0064] A high-strength repair material for highway bridge expansion joints, the preparation comprising the following steps:

[0065] Mix 40 kg cement, 20 kg silica fume and 5 kg carbon nanotube dry for 3-5 min, add 8 kg polyvinyl alcohol fiber and continue to stir for 5-8 min, then add 20 kg modified epoxy resin prepared in Preparation Example 1, 0.5 kg polycarboxylate superplasticizer and 1 kg curing agent and continue to stir for 10-15 min to obtain the repair material.

[0066] Example 3

[0067] A high-strength repair material for highway bridge expansion joints, the preparation comprising the following steps:

[0068] Mix 30 kg cement, 30 kg silica fume and 5 kg carbon nanotube dry for 3-5 min, add 8 kg polyvinyl alcohol fiber and continue to stir for 5-8 min, then add 20 kg modified epoxy resin prepared in Preparation Example 1, 0.5 kg polycarboxylate superplasticizer and 1 kg curing agent and continue to stir for 10-15 min to obtain the repair material.

[0069] Example 4

[0070] 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.

[0071] Example 5

[0072] 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.

[0073] Example 6

[0074] 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.

[0075] Example 7

[0076] 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.

[0077] Example 8

[0078] 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.

[0079] Example 9

[0080] A high-strength repairing material for highway bridge expansion joints, which differs from Example 1 in that it further contains 8 kg of pure acrylic emulsion (acrylate emulsion), and is prepared by the following steps:

[0081] The cement, silica fume and carbon nanotubes are dry mixed and stirred for 3-5 min, the polyvinyl alcohol fibers are added and stirred for another 5-8 min, then the modified epoxy resin prepared in Preparation Example 1, the pure acrylic emulsion, the polycarboxylic acid water reducer and the curing agent are added and stirred for another 10-15 min to obtain the repairing material.

[0082] Example 10

[0083] A high-strength repairing material for highway bridge expansion joints, which differs from Example 9 in that it further contains 10 kg of pure acrylic emulsion (acrylate emulsion).

[0084] Example 11

[0085] A high-strength repairing material for highway bridge expansion joints, which differs from Example 9 in that it further contains 12 kg of pure acrylic emulsion (acrylate emulsion).

[0086] Comparative Example

[0087] Comparative Example 1

[0088] A high-strength repairing material for highway bridge expansion joints, which differs from Example 1 in that it contains unmodified epoxy resin in this comparative example.

[0089] Comparative Example 2

[0090] A high-strength repairing material for highway bridge expansion joints, which differs from Example 1 in that it does not contain modified epoxy resin in this comparative example.

[0091] Comparative Example 3

[0092] A high-strength repairing material for highway bridge expansion joints, which differs from Example 1 in that it uses the modified epoxy resin prepared in Comparative Preparation Example 1 in this comparative example.

[0093] Comparative Example 4

[0094] A high-strength repairing material for highway bridge expansion joints, which differs from Example 1 in that it uses the modified epoxy resin prepared in Comparative Preparation Example 2 in this comparative example.

[0095] Comparative Example 5

[0096] A high-strength repair material for highway bridge expansion joints differs from Example 1 in that no carbon nanotubes are added in the present comparative example.

[0097] Performance detection test

[0098] Detection method

[0099] Compressive strength: test the compressive strength and flexural strength at 28 days according to the standard GB / T 17671-2021;

[0100] Fatigue test: simulate traffic load (frequency 5 Hz, stress ratio 0.1) using MTS hydraulic servo system, test the residual strength retention rate after 10 6 cycles of illumination with light greater than 700 nm for 2 h;

[0101] Freeze-thaw cycle: 300 freeze-thaw cycles (-20℃-20℃) according to the standard JTG 3420-2020, test the mass loss rate (%) and relative dynamic elastic modulus attenuation (%) after 2 h of illumination with light greater than 700 nm.

[0102] Table 1 Test data

[0103] Compressive strength / MPa Strength retention / % 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

[0104] In combination with Examples 1-3 and Comparative Examples 1-2 and in combination with Table 1, it can be seen that the experimental data of Example 1 is better than that of Comparative Example 1-2, in which unmodified epoxy resin is added in Comparative Example 1 and no modified epoxy resin is added in Comparative Example 2. The modified epoxy resin can significantly improve the performance of the repair material compared to the unmodified or completely not added case.

[0105] In combination with Examples 1-3 and Comparative Examples 3-4 and in combination with Table 1, it can be seen that the experimental data of Examples 1-3 is better than that of Comparative Examples 3-4, indicating that neither 4-vinyl-2,3-dihydrobenzofuran nor cinnamic acid glycidyl ester can achieve good modification effect in the modification process of the epoxy resin, thereby affecting the overall performance of the repair material.

[0106] In combination with Examples 1-3 and Comparative Example 5 and in combination with Table 1, it can be seen that the experimental data of Examples 1-3 is better than that of Comparative Example 5, and carbon nanotubes as a reinforcing phase can improve the strength and durability of the repair material.

[0107] In combination with Examples 1-8 and in combination with Table 1, it can be seen that the experimental data of Examples 6-8 is better than that of Examples 1-5, indicating that adding nano-silica in the modification process of the modified epoxy resin can form a nano-scale network structure inside the epoxy resin, limit the slipping of polymer molecular chains, and improve the strength of the epoxy resin, thereby improving the compressive strength of the material.

[0108] As can be seen from the combination of Embodiments 1-3 and Embodiments 9-11 and Table 1, the experimental data of Embodiments 9-11 is better than that of Embodiments 1-3, indicating that the addition of the acrylic ester emulsion can improve the overall performance of the repair material, and the reaction with the epoxy resin forms a cross-linked structure to improve the compressive strength of the material.

[0109] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments according to the needs after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high strength patching material for highway bridge expansion joints, characterized in that, The raw materials include the following weight parts: modified epoxy resin 10-20 parts, silica ash 20-30 parts, carbon nanotube 3-5 parts, cement 30-40 parts, polyvinyl alcohol fiber 3-8 parts, water reducing agent 0.5-1.5 parts, curing agent 0.5-1 part and water 10-20 parts, wherein the modified epoxy resin is a modified epoxy resin with dynamic covalent bond; The preparation of the modified epoxy resin includes the following steps: (1) uniformly mix polyether polyol and epoxy resin, heat to 60-70℃, add catalyst, react for 2-3h, then add 4-vinyl-2,3-dihydrobenzofuran acetone solution, continue to react for 4-6h, then add glycidyl cinnamate, heat to 70-80℃, vacuum degassing, to obtain preliminary modified epoxy resin; (2) uniformly mix the preliminary modified epoxy resin with N,N'-methylene bis-maleimide, pre-react at 55-65℃ for 1-1.5h, the ratio of the added amount of N,N'-methylene bis-maleimide to the added weight parts of epoxy resin is 1:1.2-1.5, add 0.1-0.3wt% of the epoxy resin of benzoyl peroxide, heat to 120℃ and keep for 1.5-2.5h, to obtain the modified epoxy resin.

2. A high strength patching material for highway bridge expansion joints as claimed in claim 1, wherein: The ratio of the added weight parts of polyether polyol to the added weight parts of epoxy resin is 1:3-5, and the molecular weight of polyether polyol is 1500-2000; The ratio of the added weight parts of glycidyl cinnamate to the added weight parts of epoxy resin is 0.2-0.3:

1.

3. A high strength patching material for highway bridge expansion joints as claimed in claim 1, wherein: The catalyst is dibutyltin dilaurate catalyst, and the added amount is 0.1-0.2wt% of the added amount of epoxy resin.

4. A high strength patching material for highway bridge expansion joints as claimed in claim 1, wherein: The mass concentration of the 4-vinyl-2,3-dihydrobenzofuran acetone solution is 35-45wt%, and the ratio of the added weight parts of acetone solution to the added weight parts of epoxy resin is 0.3-0.5:

1.

5. A high strength patching material for highway bridge expansion joints as claimed in claim 1, wherein: In the modification process, nano-scale reinforcing material is also added, and the nano-scale reinforcing material is nano-silica, and the added amount is 1-3wt% of the epoxy resin.

6. A high strength patching material for highway bridge expansion joints as claimed in claim 1, wherein: 8-12 parts of acrylic emulsion are also added in the raw materials.

7. A process for the preparation of a high strength patching material for highway bridge expansion joints as claimed in any one of claims 1 to 5, wherein, The method includes the following steps: dry mix cement, silica ash and carbon nanotube for 3-5min, add polyvinyl alcohol fiber, continue to stir for 5-8min, then add modified epoxy resin, water reducing agent and curing agent, continue to stir for 10-15min, to obtain the repair material.