Heat-resistant self-repairing epoxy asphalt binder and its preparation and application

Abstract

This invention belongs to the field of asphalt modification and specifically discloses a method for preparing a temperature-resistant, self-healing epoxy asphalt binder. The binder is obtained by curing a modified epoxy binder with asphalt. The modified epoxy binder is a solidified mixture of raw materials comprising an epoxy resin and a dynamic curing agent, which undergoes a curing reaction. The dynamic curing agent comprises a disulfide curing agent. The invention also includes the epoxy asphalt binder obtained by the preparation method and its application. The asphalt obtained by the method has excellent high-temperature fluidity and self-healing properties.

Description

Technical Field

[0001] The present invention belongs to the field of modified asphalt, and in particular relates to a temperature-resistant self-repairing epoxy asphalt binder. Background Art

[0002] Asphalt pavement, as the interface that directly interacts with vehicles, plays a vital role in the entire pavement structure. During long-term use, asphalt pavement is prone to various degrees of damage, including rutting, cracks, subsidence, potholes, and delamination. Once damaged, it not only hinders driving but also causes a certain degree of damage to the steel plates, shortening the service life of the bridge. Therefore, it is particularly important to effectively repair problems such as minor cracks in asphalt pavement. Epoxy resin-modified asphalt has the advantages of good flexibility, strong crack resistance, good temperature stability, strong fatigue resistance, and corrosion resistance, and is extremely advantageous for asphalt modification.

[0003] Existing research has primarily focused on the selection of epoxy systems and curing agents, epoxy system dosage, preparation processes, and the mixing process of the mixture. Epoxy asphalt is prepared by adding epoxy resin to asphalt. This curing reaction with the curing agent forms an irreversible solid, which modifies the asphalt's thermoplastic properties to a certain extent. Asphalt itself is a naturally self-healing and self-repairing material. The introduction of an epoxy binder increases structural strength, but also reduces its self-healing ability. Damage and cracking that occur in epoxy asphalt pavements during use are primarily addressed through manual repairs, which involve filling with external materials. This approach fails to prevent or repair the damage at its root. Microcapsules are introduced into asphalt mixtures. When cracks develop, the microcapsules are stimulated, rupturing their walls. The released substances combine with catalysts in the system, reacting within the cracks and achieving a repair effect. However, limitations of this approach are that the addition of microcapsules reduces the overall strength of the asphalt system and the bonding between the two is poor, hindering its further application and development.

[0004] Among existing technologies, limited research has been conducted on the high-temperature self-healing properties of hot-mix epoxy asphalt systems, particularly those used in steel box girder bridge decks. Furthermore, there is virtually no research on epoxy asphalt systems that can maintain fluidity for a certain period of time during high-temperature curing without solidifying, while also exhibiting good mechanical properties after curing. Traditional amine curing agents irreversibly crosslink with epoxy resins, creating an irreversible covalent network that prevents reprocessing, recycling, reshaping, and reconfiguration. Consequently, most aged, damaged, and discarded epoxy resins are disposed of through incineration or landfill, resulting in significant environmental pollution and resource waste. Summary of the Invention

[0005] In view of the problems of existing epoxy asphalt binders in terms of high-temperature fluidity, self-healing performance and unsatisfactory mechanical properties, the first purpose of the present invention is to provide a method for preparing a temperature-resistant and self-healing epoxy asphalt binder, aiming to prepare an epoxy asphalt binder with good high-temperature fluidity, high-temperature self-healing ability and mechanical properties.

[0006] The second purpose of the present invention is to provide a temperature-resistant self-repairing epoxy asphalt binder prepared by the preparation method and its application as an epoxy asphalt binder for hot-mix steel box girders.

[0007] In order to solve the problems of epoxy asphalt binder, such as easy solidification at high temperature, poor fluidity, poor self-repair performance at high temperature, and poor mechanical ability, the present invention previously attempted to use epoxy binders with good fluidity and high performance resistance as modifiers for the modification of the asphalt. However, research found that there were compatibility issues between asphalt and epoxy binders. Not all epoxy binders with good fluidity and temperature resistance could volatilize in asphalt to achieve the expected modification effect. Therefore, the present invention conducted further in-depth research and proposed the following solutions:

[0008] A method for preparing a temperature-resistant self-repairing epoxy asphalt binder, which is obtained by curing a modified epoxy adhesive and asphalt;

[0009] The modified epoxy adhesive is a solidified mixture of raw materials including epoxy resin and dynamic curing agent after curing reaction;

[0010] The dynamic curing agent comprises a disulfide curing agent (also referred to as disulfide in the present invention).

[0011] The present invention innovatively discovered that by modifying asphalt with a modified epoxy binder containing disulfide as a curing agent, an unexpectedly good adaptation synergistic effect can be obtained. While ensuring the fluidity of the epoxy asphalt mixture during the curing process, the overall mechanical properties are taken into account, giving it the ability to self-repair at high temperatures, while improving the material strength and hardness, meeting the transportation operation requirements of the construction site and the performance requirements of actual applications.

[0012] In the present invention, the epoxy binder formed by using the disulfide as a curing component is the key to unexpectedly synergistically improving the high-temperature fluidity, high-temperature self-healing performance and mechanical properties of the epoxy asphalt binder.

[0013] The disulfide curing agent is a compound having a structure of formula 1

[0014] R1-SS-R1

[0015] Formula 1

[0016] R1 is a substituted alkyl or aromatic group; wherein the substituent is an ester group, a carboxyl group, an amino group, or a hydroxyl group. The substituted alkyl group is, for example, a C1-C10 alkyl group with one or more substituents. The substituted aryl group is, for example, a group with one or more substituents on an aromatic ring. The aromatic ring is, for example, a benzene ring, a five-membered heterocycle, or a six-membered heterocycle.

[0017] Preferably, the disulfide is a compound of formula 1-A:

[0018] In the present invention, the preferred formula 1-A can further improve the high-temperature fluidity and self-repairing effect of asphalt.

[0019] The dynamic curing agent further comprises an auxiliary curing agent, and the auxiliary curing agent is an aliphatic amine; the aliphatic amine is preferably at least one of polyetheramine, diethyltoluenediamine, m-phenylenediamine, and octadecylamine.

[0020] The present invention also found that the combination of disulfide and the auxiliary curing agent can further cooperate to help further improve the high-temperature fluidity, self-repairing ability and mechanical ability of the modified asphalt binder.

[0021] Preferably, in the dynamic curing agent, the weight content of the auxiliary curing agent is below 60 wt.%, preferably 30-50 wt.%.

[0022] In the present invention, the content of the dynamic curing agent in the raw materials is 40-50wt%.

[0023] In the present invention, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, p-aminophenol triglycidyl epoxy resin, and 4,4'-diaminodiphenyl ether tetraglycidyl epoxy resin.

[0024] In the present invention, the modified epoxy adhesive is a curing mixture of the raw materials that is thermally cured at 100 to 300° C. (preferably 150 to 200° C.);

[0025] Preferably, the thermal curing time is 4-10 minutes.

[0026] In the present invention, the modified epoxy adhesive and asphalt are mixed and solidified to obtain the binder.

[0027] In the present invention, the curing temperature is above 150°C, preferably 160-250°C;

[0028] Preferably, the curing time is more than 1 hour, preferably 1 to 10 hours, and further can be 2 to 5 hours.

[0029] In the present invention, after high-temperature curing, conventional curing treatment may be performed, and the temperature of the oxidation treatment may be, for example, 40 to 80° C. The curing time may be more than 1 day, preferably 2 to 5 days.

[0030] The present invention also provides a temperature-resistant self-repairing epoxy asphalt binder prepared by the preparation method.

[0031] The present invention also provides an application of the temperature-resistant self-repairing epoxy asphalt binder prepared by the preparation method. For example, it can be used in any application scenario that requires flow construction at high temperature or requires high-temperature self-repairing ability. For example, it can be used as hot-mix steel box girder epoxy asphalt.

[0032] Beneficial effects:

[0033] The present invention innovatively utilizes a disulfide-cured epoxy resin binder to modify asphalt, achieving unexpected synergy and resolving the issues of easy curing during asphalt processing and suboptimal mechanical and high-temperature self-healing properties. The present invention further discovered that combining disulfide with the aforementioned auxiliary curing agent can further improve the compatibility of the resulting modified epoxy binder with asphalt, contributing to further improvements in the high-temperature fluidity, mechanical, and self-healing properties of the asphalt composition. DETAILED DESCRIPTION

[0034] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] In the present invention, the epoxy resin can be any brand of epoxy resin known in the industry. For example, in the following cases, unless otherwise stated, the bisphenol A epoxy resin is Macklin E51 resin.

[0036] The 4,4'-diaminodiphenyl ether tetraglycidyl epoxy resin is Adamas' AG-80.

[0037] The polyetheramine is Aladdin D2000.

[0038] test:

[0039] Fluidity at high temperatures is determined by direct observation;

[0040] The tensile rate of the mechanical test was 500 mm / min;

[0041] Self-repair is achieved by creating scratches on the sample with a blade, and then allowing it to rest at a high temperature of 180°C for repair. After repair, the mechanical properties of the sample are measured, compared with the original sample, and the repair ratio is calculated.

[0042] Example 1

[0043] A bisphenol A epoxy resin and a curing agent (4,4'-diaminodiphenyl disulfide) in a mass ratio of 56:44 were placed in a container and dissolved at 180°C with mechanical stirring for 5 minutes to form a uniform mixture Y1. The epoxy resin mixture Y1 in a mass ratio of 40:60 was mixed with a base asphalt Y2 that had been conditioned at 180°C for approximately 1 hour, stirred for approximately 5 minutes, and cured in an oven at 180°C for 3 hours. The mixture was then transferred to a 60°C oven for 3-4 days and then conditioned at room temperature for 1-2 days to obtain an epoxy asphalt binder.

[0044] At high temperature of 180℃, it solidifies in 2.5 hours and has basically no fluidity. Its mechanical properties are 3.4MPa-254%, and its self-repairing ability is 64% at 180℃ for 1 hour.

[0045] Example 2

[0046] Compared with Example 1, the only difference is that the curing agent is 4,4'-diaminodiphenyl disulfide and polyetheramine in a weight ratio of 1:1. Other operations and parameters are the same as those in Example 1.

[0047] The epoxy asphalt binder does not solidify at high temperature of 180℃ for 3 hours, maintains good fluidity, and its mechanical properties reach 2.3MPa-505%. Its self-repairing ability at 180℃ for 1 hour is about 88%.

[0048] Example 3

[0049] Compared with Example 1, the only difference is that the curing agent is 4,4'-diaminodiphenyl disulfide and octadecylamine in a weight ratio of 2:1. Other operations and parameters are the same as those in Example 1.

[0050] The epoxy asphalt binder does not solidify at high temperature of 180℃ for 3 hours, maintains good fluidity, and its mechanical properties reach 3.0MPa-276%. The self-repair ability at 180℃ for 1 hour is about 82%.

[0051] Example 4

[0052] Compared with Example 1, the only difference is that the epoxy resin is 4,4'-diaminodiphenyl ether tetraglycidyl epoxy resin, the weight ratio of epoxy resin to curing agent is 60:40; and the weight ratio of epoxy resin mixture Y1 to asphalt Y2 is 50:50.

[0053] The epoxy asphalt binder does not solidify at high temperature of 180℃ for 3 hours, maintains a good fluidity, and has mechanical properties of 3.4MPa-409%. The self-repairing ability at 180℃ for 1 hour is about 68%. The addition of asphalt weakens the mechanical strength of the binder and improves its elongation at break to a certain extent.

[0054] Example 5

[0055] Compared with Example 1, the only difference is that the curing agent is 3,3'-dithiodipropionic acid, and the other operations and parameters are the same as Example 1.

[0056] At high temperature of 180℃, it is cured for 1.5 hours, and its mechanical properties are 2.6MPa-232%, and its self-repairing ability is 58% at 180℃ for 1 hour.

[0057] Comparative Example 1

[0058] Compared with Example 1, the only difference is that the curing agent is diethyltoluenediamine, and the other operations and parameters are the same as Example 1.

[0059] The epoxy asphalt binder is completely cured in 0.5 hours at a high temperature of 180°C and has no fluidity. The mechanical properties of the sample after curing reach 4.3MPa-128%, and the self-repairing ability at 180°C for 1 hour is less than 30%.

[0060] Comparative Example 2

[0061] Compared with Example 1, the only difference is that the curing agent is glutaric anhydride and polyetheramine in a weight ratio of 9:1, and other operations and parameters are the same as Example 1.

[0062] The epoxy asphalt binder was essentially cured after one hour at 180°C. However, the binder lacked fluidity (not meeting construction site requirements) and was susceptible to damage and cracking in actual use. After curing, the sample's mechanical properties reached 3.4 MPa-89%, and its self-healing capacity at 180°C for one hour was approximately 52%.

Claims

1. A method for preparing a heat-resistant self-repairing epoxy asphalt binder, characterized in that: Curing the modified epoxy adhesive and asphalt; The modified epoxy adhesive is a solidified mixture of raw materials including epoxy resin and dynamic curing agent after curing reaction; The dynamic curing agent includes a disulfide curing agent and an auxiliary curing agent; The disulfide curing agent is a compound of formula 1-A: Formula 1-A; The auxiliary curing agent is aliphatic amine.

2. The preparation method according to claim 1, wherein The aliphatic amine is at least one of polyetheramine, diethyltoluenediamine, m-phenylenediamine and octadecylamine.

3. The preparation method according to claim 1, wherein In the dynamic curing agent, the weight content of the auxiliary curing agent is below 60wt.%.

4. The preparation method according to claim 3, wherein In the dynamic curing agent, the weight content of the auxiliary curing agent is 30-50wt%.

5. The preparation method according to any one of claims 1 to 4, wherein In the raw materials, the content of the dynamic curing agent is 40-50wt%.

6. The preparation method according to claim 1, wherein The epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, p-aminophenol triglycidyl epoxy resin, and 4,4'-diaminodiphenyl ether tetraglycidyl epoxy resin.

7. The preparation method according to claim 1, wherein The modified epoxy adhesive is a curing mixture of the raw materials thermally cured at 100-300°C.

8. The preparation method according to claim 7, wherein The heat curing time is 4-10 minutes.

9. The preparation method according to claim 1, wherein The curing temperature is above 150°C.

10. The preparation method according to claim 9, characterized in that The curing temperature is 160~250℃.

11. The preparation method according to claim 1, wherein The curing time is more than 1 hour.

12. The preparation method according to claim 11, characterized in that The curing time is 1~10h.

13. A temperature-resistant self-repairing epoxy asphalt binder prepared by the preparation method according to any one of claims 1 to 12.

14. An application of a heat-resistant self-repairing epoxy asphalt binder prepared by the preparation method according to any one of claims 1 to 12, characterized in that: Use it as hot mix steel box girder epoxy asphalt.

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