An epoxy repair material, its preparation method and use

Abstract

The present application relates to the technical field of patching material utilization, and provides an epoxy patching material, a preparation method and application thereof.The epoxy patching material comprises modified epoxy glue and aggregate; the modified epoxy glue comprises component A and component B; the components of the component A comprise epoxy resin, toughening agent, active diluent and adhesion promoter, and the components of the component B comprise curing accelerator and curing agent.The selected curing agent is not water-soluble curing agent, and the active diluent and adhesion promoter used have hydrophobic structures, have good dispersion prevention effect, and still have excellent interfacial bonding performance on steel or concrete base surface after high-temperature boiling experiment.The epoxy patching material can be used on water and underwater, especially has good curing performance underwater, is not easy to scatter in water, has good water resistance, excellent interfacial bonding performance and excellent comprehensive performance, and has wide application prospect in underwater / on-water repair of concrete structure.

Description

Technical Field

[0001] This invention relates to the field of repair materials technology, and in particular to an epoxy repair material, its preparation method, and its application. Background Technology

[0002] In recent years, with the development of infrastructure such as roads, transportation, water conservancy, and hydropower, more and more infrastructure is entering its maintenance period. Some of these maintenance-required infrastructure structures, such as bridge piers and dams, are concrete structures that are submerged for extended periods, placing higher demands on repair materials and processes. In the maintenance of roads, such as tunnels, situations often arise where water cannot be completely drained from the base surface, necessitating underwater operations. Therefore, research on underwater repair materials has significant practical implications and economic benefits.

[0003] Underwater repair requires materials to not crumble underwater, while also possessing excellent interfacial adhesion and resistance to water aging. Most existing repair materials for concrete structures are suitable for normal, waterless environments, but suffer from poor application quality or short service life in humid or wet conditions.

[0004] Chinese patent CN110615639A discloses an epoxy mortar for underwater repair, focusing on the material's adhesion and durability, but it does not mention the interfacial adhesion performance after water aging. Chinese patent CN100355816A discloses an epoxy / polyurethane interpenetrating polymer network underwater repair material, which has good pourability, mechanical properties, and moderate toughness, and can be neutralized in water and cured at low temperatures. However, its adhesive strength is not high, approximately 1 MPa after 48 hours, and it does not mention the change in adhesive strength after water aging. Chinese patent CN111875321A discloses an underwater repair material based on seawater and coral sand, which combines cement mortar and epoxy resin to improve the adhesion performance of the underwater repair material, but it lacks research on the material's aging resistance under the influence of water, heat, and other environmental factors.

[0005] Underwater repair materials, due to their special usage conditions, are required to have good construction performance underwater, as well as good aging resistance, especially water resistance. However, current epoxy repair materials in this field can usually only be used in waterless environments. The aforementioned patents are insufficient in terms of water resistance or lack corresponding research, and cannot ensure the bonding durability of the repair materials under the influence of hydrothermal and other factors. Summary of the Invention

[0006] In view of this, the present invention provides an epoxy repair material, its preparation method, and its application. The epoxy repair material provided by the present invention can be used both above and below water, and in particular, it has good water resistance, can cure underwater, does not disperse in water, and maintains excellent adhesion performance underwater.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] An epoxy repair compound includes a modified epoxy adhesive and aggregate; the modified epoxy adhesive includes component A and component B;

[0009] Component A comprises the following components in parts by weight: 100 parts epoxy resin, 5-15 parts toughening agent, 5-20 parts reactive diluent, and 0.5-2 parts adhesion promoter; the reactive diluent is a hydrophobic epoxy compound with reactive epoxy groups; the adhesion promoter is one or more of epoxy-containing silane compounds and long-chain alkyl-containing silane compounds.

[0010] Component B comprises the following components in parts by weight: 2-8 parts of curing accelerator and 92-98 parts of curing agent; the curing agent is at least two of cashew phenol amine curing agent, cashew phenol amide curing agent and modified amine curing agent.

[0011] Preferably, the hydrophobic epoxy compound having reactive epoxy groups is one or both of cashew phenol glycidyl ether and castor oil triglycidyl ether.

[0012] Preferably, the epoxy-containing silane compound is 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; the long-chain alkyl silane compound is hexadecyl glycidyl ether.

[0013] Preferably, the cashew phenol amine curing agent is at least one of NX-6032 and NC558; the cashew phenol amide curing agent is at least one of LITE-3040 and LITE3117; and the modified amine curing agent is at least one of SX-3637L-3 and SX-3637M-6.

[0014] Preferably, the epoxy resin is one or both of bisphenol A type epoxy resin and bisphenol F type epoxy resin; the toughening agent is terminal epoxy group liquid nitrile rubber; and the curing accelerator is an organic acid.

[0015] Preferably, the epoxy resin is a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, wherein the mass ratio of bisphenol A type epoxy resin to bisphenol F type epoxy resin in the mixture is (50-90):(10-50).

[0016] Preferably, the mass ratio of component A to component B is 1:(0.3 to 0.5).

[0017] Preferably, the aggregate is one or both of natural sand and manufactured sand; the mass ratio of the modified epoxy resin to the aggregate is 1:(2-6).

[0018] The present invention also provides a method for preparing the epoxy repair material described above, comprising the following steps:

[0019] Component A is obtained by mixing epoxy resin, toughening agent, reactive diluent and adhesion promoter;

[0020] The curing accelerator and the curing agent are mixed to obtain component B;

[0021] The modified epoxy resin is obtained by mixing the components A and B.

[0022] The modified epoxy adhesive and aggregate are mixed to obtain an epoxy repair material.

[0023] The present invention also provides the application of the epoxy repair material described in the above-described scheme or the epoxy repair material prepared by the preparation method described in the above-described scheme in the above-described scheme for the repair of concrete structures above or below water.

[0024] This invention provides an epoxy repair material, comprising a modified epoxy adhesive and aggregates; the modified epoxy adhesive comprises component A and component B; component A comprises the following components in parts by weight: 100 parts epoxy resin, 5-15 parts toughening agent, 5-20 parts reactive diluent, and 0.5-2 parts adhesion promoter; the reactive diluent is a hydrophobic epoxy compound having reactive epoxy groups; the adhesion promoter is one or more of epoxy-containing silane compounds and long-chain alkyl-containing silane compounds; component B comprises the following components in parts by weight: 2-8 parts curing accelerator and 92-98 parts curing agent; the curing agent is at least two of cashew phenol aldehyde amine curing agent, cashew phenol aldehyde amide curing agent, and modified amine curing agent. The active diluent selected in this invention has a hydrophobic structure, which not only dilutes the epoxy but also prevents it from dispersing underwater. The curing agents selected in this invention are all non-water-soluble, effectively improving the underwater curing performance of the epoxy resin. Furthermore, by introducing a curing agent with a cashew phenol structure and an adhesion promoter with epoxy groups or long-chain alkyl groups, this invention effectively improves the water resistance of the epoxy resin, ensuring excellent interfacial adhesion to both steel and concrete substrates after high-temperature boiling tests. In addition, the epoxy repair material provided by this invention has a wide range of applications, suitable for both underwater and above-water construction: the selected modified amine and cashew phenol-containing curing agent maintain excellent curing performance in both underwater and air (above-water) environments, thus enabling underwater / above-water repair construction while maintaining excellent overall performance.

[0025] In summary, the epoxy repair material provided by this invention can be applied above or below water. In particular, it has good water resistance, good underwater curing performance, does not easily disperse in water, has excellent interfacial adhesion performance, and excellent overall performance. It overcomes the shortcomings of traditional epoxy repair materials that can only be used in a waterless environment and has broad application prospects in underwater / above-water repair of concrete structures. Attached Figure Description

[0026] Figure 1 The image shows the damage to a mortar block sample using the repair material from Example 1 after boiling in water at 65°C for 7 days.

[0027] Figure 2 Photographs showing the damage to a mortar block sample using the repair material from Comparative Example 1 after boiling in water at 65°C for 7 days.

[0028] Figure 3 Photographs showing the damage to a mortar block sample using the repair material from Comparative Example 2 after boiling in water at 65°C for 7 days.

[0029] Figure 4 Photographs showing the damage to a mortar block sample using the repair material of Comparative Example 3 after boiling in water at 65°C for 7 days.

[0030] Figure 5 A photograph of the epoxy repair material prepared for Example 1 placed in water. Detailed Implementation

[0031] This invention provides an epoxy repair material, comprising a modified epoxy adhesive and aggregate; the modified epoxy adhesive comprises component A and component B;

[0032] Component A comprises the following components in parts by weight: 100 parts epoxy resin, 5-15 parts toughening agent, 5-20 parts reactive diluent, and 0.5-2 parts adhesion promoter; the reactive diluent is a hydrophobic epoxy compound with reactive epoxy groups; the adhesion promoter is one or more of epoxy-containing silane compounds and long-chain alkyl-containing silane compounds.

[0033] Component B comprises the following components in parts by weight: 2-8 parts of curing accelerator and 92-98 parts of curing agent; the curing agent is at least two of cashew phenol amine curing agent, cashew phenol amide curing agent and modified amine curing agent.

[0034] The epoxy repair material provided by the present invention includes a modified epoxy adhesive, which comprises component A and component B. Component A and component B are described in detail below.

[0035] By weight, component A comprises 100 parts of epoxy resin. In this invention, the epoxy resin is preferably one or both of bisphenol A type epoxy resin and bisphenol F type epoxy resin; the bisphenol A type epoxy resin is preferably E-51, and the bisphenol F type epoxy resin is preferably GEFR170; further, the epoxy resin is preferably a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, wherein the mass ratio of bisphenol A type epoxy resin to bisphenol F type epoxy resin in the mixture is preferably (50-90):(10-50), more preferably (60-80):(20-40); the bisphenol F type epoxy resin, due to its structural characteristics, has excellent heat resistance, solvent resistance, adhesion and mechanical properties, and also has low viscosity and is not prone to crystallization; the raw material of bisphenol A type epoxy resin is readily available and low in cost. By using the two epoxy resins in combination, their advantages and disadvantages are complemented, and excellent comprehensive performance can be obtained.

[0036] Based on the mass fraction of the epoxy resin, component A includes 5 to 15 parts, preferably 8 to 12 parts, of a toughening agent. In this invention, the toughening agent is preferably terminal epoxy-based liquid nitrile rubber; the terminal epoxy-based liquid nitrile rubber has epoxy groups that can participate in the crosslinking structure, improving flexibility while maintaining strength.

[0037] Based on the mass fraction of the epoxy resin, component A comprises 5-20 parts, preferably 10-15 parts, of an reactive diluent. In this invention, the reactive diluent is a hydrophobic epoxy compound with reactive epoxy groups, and the hydrophobic epoxy compound with reactive epoxy groups is one or both of cashew phenol glycidyl ether and castor oil triglycidyl ether. The reactive diluent selected in this invention itself has a hydrophobic structure, and thus not only has a diluting effect but also a certain degree of anti-dispersion effect.

[0038] Based on the mass fraction of the epoxy resin, component A includes 0.5 to 2 parts, preferably 1 to 1.5 parts, of an adhesion promoter. In this invention, the adhesion promoter is one or more of an epoxy-containing silane compound and a long-chain alkyl silane compound; the epoxy-containing silane compound is preferably 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (A186); the long-chain alkyl silane compound is preferably hexadecyl glycidyl ether (Dynasylan9116); in a specific embodiment of this invention, the adhesion promoter is preferably a mixture of A186 and Dynasylan9116, and the mass ratio of A186 to Dynasylan9116 is preferably (1-5):(1-4), more preferably 1:1, 2:1, 4:3, or 5:4; the adhesion promoter selected in this invention has epoxy groups or long carbon chains, which can further improve interfacial adhesion, and at the same time, it has a hydrophobic structure and also has a good anti-dispersion effect.

[0039] By weight, component B comprises 2 to 8 parts, preferably 3 to 6 parts, of a curing accelerator. In this invention, the curing accelerator is preferably an organic acid, specifically one or more of salicylic acid, oxalic acid, and benzoic acid. This invention uses an organic acid as a curing accelerator, which provides a moderate accelerating effect, allowing the material to retain a longer working period without curing too slowly.

[0040] Based on the mass fraction of the curing accelerator, component B comprises 92 to 98 parts of curing agent, preferably 93 to 95 parts. In this invention, the curing agent is preferably at least two of cashew phenol aldehyde amine curing agent, cashew phenol aldehyde amide curing agent, and modified amine curing agent; the cashew phenol aldehyde amine curing agent is preferably at least one of NX-6032 and NC558; the cashew phenol aldehyde amide curing agent is preferably at least one of LITE-3040 and LITE3117; the modified amine curing agent is preferably at least one of SX-3637L-3 and SX-3637M-6, preferably two. The source of the cashew phenol aldehyde amide curing agent and the modified amine curing agent in this invention is not particularly required; commercially available curing agents can be used. In a specific embodiment of this invention, SX-3637L-3 and SX-3637M-6 were purchased from Changzhou Shanfeng Chemical Co., Ltd., and NX-6032, NC558, LITE-3040, and LITE3117 were purchased from Cardley Chemical Co., Ltd.; in a specific embodiment of this invention, the curing agent is preferably NC558, S... A mixture of X-3637L-3 and SX-3637M-6, wherein the mass ratio of NC558, SX-3637L-3, and SX-3637M-6 is preferably (40-50):(25-35):(20-26), more preferably 50:26:20, 40:35:22, or 45:25:26; or, the curing agent is preferably a mixture of LITE-3040, SX-3637L-3, and SX-3637M-6. The preferred mass ratio of LITE-3040, SX-3637L-3, and SX-3637M-6 is 42:25:25; or, the preferred curing agent is a mixture of NC558, LITE-3040, SX-3637L-3, and SX-3637M-6, wherein the preferred mass ratio of NC558, LITE-3040, SX-3637L-3, and SX-3637M-6 is 24:30:20:20. In this invention, the cashew phenol aldehyde amine curing agent possesses cashew phenol side chains that provide excellent water resistance, adhesion, wet / underwater curing ability, and a long working period, and also exhibits good adhesion to untreated substrates; the cashew phenol aldehyde amide curing agent possesses cashew phenol side chains that provide excellent water resistance, adhesion, wet / underwater curing ability, and a long working period, and also has good mechanical strength and heat resistance; the modified amine curing agent cures quickly, has good adhesion, and high strength, and can improve the mechanical properties of materials and regulate curing characteristics.

[0041] In this invention, the mass ratio of component A to component B is preferably 1:(0.3 to 0.5), more preferably 1:0.35, 1:0.4 or 1:0.45.

[0042] The epoxy repair material provided by this invention includes aggregate. In this invention, the aggregate is preferably one or both of natural sand and manufactured sand; the mud (dust) content of the aggregate is preferably less than 1 wt% (natural sand is expressed as mud content, manufactured sand as dust content), and the moisture content is preferably less than 0.5 wt%. The aggregate is preferably medium sand with a fineness modulus of 2.3 to 3.0; the mass ratio of the modified epoxy adhesive to the aggregate is preferably 1:(2 to 6), more preferably 1:2.5, 1:3, 1:3.5, 1:4, or 1:5.5.

[0043] The present invention also provides a method for preparing the epoxy repair material described above, comprising the following steps:

[0044] Component A is obtained by mixing epoxy resin, toughening agent, reactive diluent and adhesion promoter;

[0045] The curing accelerator and the curing agent are mixed to obtain component B;

[0046] The modified epoxy resin is obtained by mixing the components A and B.

[0047] The modified epoxy adhesive and aggregate are mixed to obtain an epoxy repair material.

[0048] This invention does not have special requirements for the mixing method, as long as the components are mixed evenly. In a specific embodiment of this invention, it is preferable to first prepare component A and component B, package component A, component B and aggregate separately, and then mix component A, component B and aggregate evenly at the construction site.

[0049] This invention also provides the application of the epoxy repair material described in the above-described scheme or the epoxy repair material prepared by the preparation method described in the above-described scheme in the repair of concrete structures above or below water. This invention has no special requirements for the concrete structure. Specifically, bridge piers, dams, tunnels, etc. can all be repaired using the epoxy repair material of this invention. In particular, underwater parts can be effectively repaired using the epoxy repair material of this invention. This invention has no special requirements for the repair method. The epoxy repair material of this invention can be directly spread on the area to be repaired and then smoothed.

[0050] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] Example 1

[0052] The epoxy repair material provided in this embodiment consists of modified epoxy adhesive and aggregate. The modified epoxy adhesive is composed of two components, A and B, in a mass ratio of 1:0.4. The raw material proportions of components A and B are as follows:

[0053] Component A:

[0054] Component B: Salicylic acid, 4 parts by weight;

[0055] Cashew phenolic amide NC558 50 parts by weight;

[0056] Modified amine SX-3637L-3 26 parts by weight;

[0057] Modified amine SX-3637M-6, 20 parts by weight;

[0058] The aggregate is natural sand with a mud (dust) content of less than 1 wt%, a moisture content of less than 0.5 wt%, and a fineness modulus of 2.3 to 3.0.

[0059] The preparation method of this epoxy repair material is as follows:

[0060] (1) Select epoxy resin, toughening agent, reactive diluent and adhesion promoter according to the above dosage relationship, mix them evenly to obtain component A for later use;

[0061] (2) Select curing accelerator and curing agent according to the above dosage relationship, mix them evenly, and prepare component B for later use;

[0062] (3) Take component A and component B according to the above dosage relationship, mix them evenly to obtain modified epoxy adhesive, and mix the modified epoxy adhesive and aggregate evenly in a mass ratio of 1:2.5 to obtain epoxy repair material.

[0063] Example 2

[0064] The epoxy repair material provided in this embodiment includes a modified epoxy adhesive and aggregate. The modified epoxy adhesive is composed of two components, A and B, in a mass ratio of 1:0.35. The raw material proportions of components A and B are as follows:

[0065] Component A:

[0066] Component B:

[0067] The aggregate is natural sand with a mud (dust) content of less than 1 wt%, a moisture content of less than 0.5 wt%, and a fineness modulus of 2.3 to 3.0.

[0068] The preparation method of this epoxy repair material is as follows:

[0069] (1) Select epoxy resin, toughening agent, reactive diluent and adhesion promoter according to the above dosage relationship, mix them evenly to obtain component A for later use;

[0070] (2) Select curing accelerator and curing agent according to the above dosage relationship, mix them evenly, and prepare component B for later use;

[0071] (3) Take component A and component B according to the above dosage relationship, mix them evenly to obtain modified epoxy adhesive, and mix the modified epoxy adhesive and aggregate evenly in a mass ratio of 1:2.5 to obtain epoxy repair material.

[0072] Example 3

[0073] The epoxy repair material provided in this embodiment is composed of modified epoxy adhesive and aggregate. The modified epoxy adhesive consists of two components, A and B, in a mass ratio of 1:0.45. The raw material proportions of components A and B are as follows:

[0074] Component A:

[0075]

[0076] Component B:

[0077] The aggregate is natural sand with a mud (dust) content of less than 1 wt%, a moisture content of less than 0.5 wt%, and a fineness modulus of 2.3 to 3.0.

[0078] The preparation method of this epoxy repair material is as follows:

[0079] (1) Select epoxy resin, toughening agent, reactive diluent and adhesion promoter according to the above dosage relationship, mix them evenly to obtain component A for later use;

[0080] (2) Select curing accelerator and curing agent according to the above dosage relationship, mix them evenly, and prepare component B for later use;

[0081] (3) Take component A and component B according to the above dosage relationship, mix them evenly to obtain modified epoxy adhesive, and mix the modified epoxy adhesive and aggregate evenly in a mass ratio of 1:3 to obtain epoxy repair material.

[0082] Example 4

[0083] The epoxy repair material provided in this embodiment is composed of modified epoxy adhesive and aggregate. The modified epoxy adhesive consists of two components, A and B, in a mass ratio of 1:0.45. The raw material proportions of components A and B are as follows:

[0084] Component A:

[0085]

[0086] Component B:

[0087] The aggregate is natural sand with a mud (dust) content of less than 1 wt%, a moisture content of less than 0.5 wt%, and a fineness modulus of 2.3 to 3.0.

[0088] The preparation method of this epoxy repair material is as follows:

[0089] (1) Select epoxy resin, toughening agent, reactive diluent and adhesion promoter according to the above dosage relationship, mix them evenly to obtain component A for later use;

[0090] (2) Select curing accelerator and curing agent according to the above dosage relationship, mix them evenly, and prepare component B for later use;

[0091] (3) Take component A and component B according to the above dosage relationship, mix them evenly to obtain modified epoxy adhesive, mix the modified epoxy adhesive and aggregate evenly in a mass ratio of 1:4 to obtain epoxy repair material.

[0092] Example 5

[0093] The epoxy repair material provided in this embodiment is composed of modified epoxy adhesive and aggregate. The modified epoxy adhesive consists of two components, A and B, in a mass ratio of 1:0.4. The raw material proportions of components A and B are as follows:

[0094] Component A:

[0095] Component B:

[0096] The aggregate is manufactured sand with a mud (dust) content of less than 1 wt%, a moisture content of less than 0.5 wt%, and a fineness modulus of 2.3 to 3.0.

[0097] The preparation method of this epoxy repair material is as follows:

[0098] (1) Select epoxy resin, toughening agent, reactive diluent and adhesion promoter according to the above dosage relationship, mix them evenly to obtain component A for later use;

[0099] (2) Select curing accelerator and curing agent according to the above dosage relationship, mix them evenly, and prepare component B for later use;

[0100] (3) Take component A and component B according to the above dosage relationship, mix them evenly to obtain modified epoxy adhesive, mix the modified epoxy adhesive and aggregate evenly at a mass ratio of 1:5.5 to obtain epoxy repair material.

[0101] Comparative Example 1

[0102] A commercially available underwater curing agent product 7120 from a certain company is used to form an epoxy adhesive according to the following proportions.

[0103] Component A:

[0104] Component B: 7120 100 parts by weight;

[0105] Weigh all raw materials according to the above mass ratio. First, add components A and B to a mixing tank at a ratio of m(A):m(B) = 1:0.45 and stir evenly to obtain epoxy adhesive. Then, mix the epoxy adhesive and aggregate evenly at a mass ratio of 1:2.5 to obtain underwater repair material. The aggregate used is the same as in Example 1.

[0106] Comparative Example 2

[0107] Epoxy adhesive composition:

[0108] Component A:

[0109] Component B: 2 parts by weight of tertiary amine accelerator DMP-30;

[0110] Cashew phenolamine NX6032 55 parts by weight;

[0111] Modified amine SX-3637L-3, 43 parts by weight;

[0112] Weigh all raw materials according to the above mass ratio. First, add components A and B to a mixing tank at a ratio of m(A):m(B) = 1:0.4 and stir evenly to obtain epoxy adhesive. Then, mix the epoxy adhesive and aggregate evenly at a mass ratio of 1:2.5 to obtain repair material. The aggregate used is the same as in Example 1.

[0113] Comparative Example 3

[0114] The epoxy adhesive composition is m(A):m(B) = 1:0.7.

[0115] Component A:

[0116] Component B:

[0117] The preparation method of cashew phenol modified hexamethylenediamine is as follows: under continuous stirring, 302.5g of cashew phenol and 144.25g of hexamethylenediamine are mixed, heated to 80℃, and 39g of paraformaldehyde is added in portions. The reaction temperature is controlled at 80-95℃. After reacting for 2 hours, the water generated in the reaction is removed under vacuum to obtain cashew phenol modified hexamethylenediamine.

[0118] Weigh all raw materials according to the above mass ratio. First, add components A and B to a mixing tank at a ratio of m(A):m(B) = 1:0.7 and stir evenly to obtain epoxy adhesive. Then, mix the epoxy adhesive and aggregate evenly at a mass ratio of 1:2.5 to obtain repair material. The aggregate used is the same as in Example 1.

[0119] Performance testing:

[0120] (1) Mortar block bonding test: Soak the mortar block (70*70*30mm) in water for 48h, prepare the repair material according to Examples 1 to 5 and the comparative proportion, and spread the repair material evenly on the bonding area of ​​the mortar block. After the sample preparation is completed, immediately immerse the sample completely underwater and cure for 72h. After taking out the sample, align the steel joint with the bonding area and bond it. Test the bonding strength according to GB / T16777-2008 standard.

[0121] Underwater tensile shear strength: After the steel sheet is removed by immersion in water and bonded as required, the sample is immediately completely immersed underwater. After curing for 72 hours, the tensile shear strength is determined in accordance with GB / T7124-2008.

[0122] Water boiling aging test: After curing, the steel-steel tensile shear and mortar block samples prepared according to the above method are boiled in 65℃ hot water for 7 days, and then the changes in tensile shear strength and mortar block bonding strength are detected.

[0123] The test results of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1.

[0124] Table 1. Changes in adhesive properties before and after water boiling aging (unit: MPa)

[0125]

[0126] Note: *Mortar block refers to failure occurring on the mortar block side; interface failure refers to failure occurring at the bonding surface between the mortar block and the adhesive; composite failure refers to failure that combines both mortar block and interface failure.

[0127] Figure 1 The image shows the damage to a mortar block sample using the repair material from Example 1 after boiling in water at 65°C for 7 days.

[0128] Figures 2-4The images show the damage to mortar block samples after being boiled in water at 65°C for 7 days using the repair materials from Comparative Examples 1, 2, and 3.

[0129] As shown in Table 1, the epoxy repair material prepared by this invention possesses good underwater curing performance, interfacial adhesion performance, and water resistance. Under underwater curing conditions, the bond strength of the mortar blocks in Examples 1-3 is all above 2.5 MPa, and the failure mode is mortar block failure. In contrast, the bond strength of Comparative Example 2 is only 1.92 MPa and is a composite failure, while the bond strength of Comparative Example 3 is only 1.79 MPa and is also a composite failure. After aging in water at 65°C for 7 days, the bond strength of the mortar blocks in Examples 1-3 remains around 2.5 MPa, and the failure mode is still mortar block failure. However, the bond strength of Comparative Examples 1 and 2 decreases to around 1.1 MPa, and the failure mode changes to composite or interfacial failure. The decrease is more significant in Comparative Example 3, with the bond strength less than 1 MPa after aging. Furthermore, combined with... Figures 1-4 It can be clearly seen that after boiling and aging, the failure mode of the sample in Example 1 is mortar block failure, while the failure modes of the samples in Comparative Examples 1, 2 and 3 are composite failure, interface failure and interface failure, respectively.

[0130] Furthermore, as can be seen from Table 1, the tensile shear strength of Examples 1 to 3 all reached above 15 MPa, while that of Comparative Examples 1 and 2 was only about 11 MPa, and that of Comparative Example 3 was also below 15 MPa. After aging in water at 65°C for 7 days, the tensile shear strength of Examples 1 to 3 decreased, but still remained above 14.5 MPa, with a decrease of only about 0.6 MPa. In contrast, the tensile shear strength of Comparative Examples 1 and 2 decreased to less than 6.5 MPa, with a significantly greater decrease than that of Examples 1 to 3. Although the tensile shear strength of Comparative Example 3 did not decrease, its absolute value was still lower than that of Examples 1 to 3.

[0131] In addition, the same tests were performed on Examples 4-5, and the results were similar to those of Examples 1-3. The failure mode was mortar block, and the bonding strength was high, with a small decrease in bonding strength after aging.

[0132] (2) Gel time test: The gel time of components A and B in Examples 1-3 and Comparative Examples 1-3 was measured according to ASTM C881-13 after mixing in the specified ratio.

[0133] Mechanical property testing: Components A and B in Examples 1-3 and Comparative Examples 1-3 were mixed according to the specified ratio, and after curing, the tensile strength and elongation at break were determined according to GB / T1040.3-2006.

[0134] Dispersion test: Prepare the repair materials according to Examples 1 to 5 and comparative proportions, take a small amount of the repair materials and place them in water, and observe whether the repair materials disperse in the water.

[0135] The test results of Examples 1-3 and Comparative Examples 1-3 are shown in Table 2.

[0136] Table 2 Gel Time and Mechanical Properties of Epoxy Binders

[0137]

[0138] Note: 1. Gel time and mechanical properties are data obtained by curing modified epoxy resin AB components according to the proportions of Examples 1-3 or comparative examples; 2. The results in water state are obtained by measuring epoxy repair materials prepared by modified epoxy resin (AB components) and aggregate according to the proportions of Examples 1-3 or comparative examples.

[0139] Figure 5 A photograph of the epoxy repair material prepared for Example 1 placed in water.

[0140] As can be seen from Table 2, the epoxy repair material prepared by this invention has the characteristics of long working time, high strength, and certain toughness. For example, in Example 1, the modified epoxy adhesive has a gel time of 32 min, a tensile strength of 51.5 MPa, an elongation of 5.6%, and the prepared repair material can be directly cured in water without dispersion (e.g., ...). Figure 5 (As shown). The epoxy adhesives obtained in Comparative Examples 1 to 3 had shorter gel times and poorer mechanical properties. In particular, the epoxy adhesive in Comparative Example 3 had a tensile strength of only 18.9 MPa, and it was difficult to cure in water, easily dispersed, and could not be used for underwater repair.

[0141] Furthermore, the same tests were performed on Examples 4-5, and the results were similar to those of Examples 1-3, all showing a longer gel time, higher tensile strength and elongation, and easy solidification in water, making them difficult to disperse.

[0142] In summary, the epoxy adhesive prepared by this invention has excellent underwater curing performance, mechanical properties, interfacial adhesion performance, water resistance, and underwater non-dispersion properties, and can realize the repair of concrete structures above or below water, with a wide range of applications.

[0143] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Application of epoxy repair material in underwater repair of concrete structures; characterized in that, The epoxy repair material cures underwater and does not disperse in water; the epoxy repair material includes modified epoxy adhesive and aggregate; the modified epoxy adhesive includes component A and component B; the mass ratio of component A to component B is 1:(0.3~0.5); Component A comprises the following components in parts by weight: 100 parts epoxy resin, 5-15 parts toughening agent, 5-20 parts reactive diluent, and 0.5-2 parts adhesion promoter; the reactive diluent is a hydrophobic epoxy compound with reactive epoxy groups; the adhesion promoter is a mixture of A186 and Dynasylan 9116, with a mass ratio of (1-5):1; the epoxy resin is a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, with a mass ratio of (60-90):(10-40); the hydrophobic epoxy compound with reactive epoxy groups is one or both of cashew nut shell glycidyl ether and castor oil triglycidyl ether; the toughening agent is terminal epoxy group liquid nitrile rubber. Component B comprises the following components in parts by weight: 2-8 parts of curing accelerator and 92-98 parts of curing agent; the curing agent is cashew phenol aldehyde amine curing agent and cashew phenol aldehyde amide curing agent; the curing accelerator is an organic acid; the organic acid is salicylic acid; and all curing agents are non-water-soluble curing agents. The aggregate is one or both of natural sand and manufactured sand; the aggregate is medium sand with a fineness modulus of 2.3 to 3.

0. The mass ratio of the modified epoxy adhesive to the aggregate is 1:(2~6).

2. The application according to claim 1, characterized in that, The cashew phenol amide curing agent is at least one of NX-6032 and NC558; the cashew phenol amide curing agent is at least one of LITE-3040 and LITE 3117.

3. The application according to claim 1 or 2, characterized in that, The preparation method of the epoxy repair material includes the following steps: Component A is obtained by mixing epoxy resin, toughening agent, reactive diluent and adhesion promoter; The curing accelerator and the curing agent are mixed to obtain component B; The modified epoxy resin is obtained by mixing the components A and B. The modified epoxy adhesive and aggregate are mixed to obtain an epoxy repair material.

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