Three-vinylon rib and microcapsule self-repairing concrete and preparation method thereof

Abstract

The invention provides three-vinylon rib and microcapsule self-repairing concrete and a preparation method thereof, and belongs to the technical field of building materials. Basalt fibers and polyvinyl alcohol fibers are blended, and obtained blended fibers are subjected to determinant three-dimensional weaving to prepare three-dimensional composite fibers; and soaking the three-dimensional composite fiber in epoxy resin, coating a mixture of diethylenetriamine and ethylenediamine, drying and curing to obtain the three-vinylon rib. And coating the epoxy resin with polyphenylene sulfide to prepare the microcapsule. And then mixing the three-vinylon rib and the microcapsule with concrete slurry to prepare the three-vinylon rib and microcapsule self-repairing concrete. The compressive strength and breaking strength of the three-vinylon rib and microcapsule self-repairing concrete obtained by adopting the method are remarkably improved, and meanwhile, the three-vinylon rib and microcapsule self-repairing concrete also has excellent self-repairing capability.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a three-dimensional polyvinyl alcohol fiber and microcapsule self-healing concrete and a preparation method thereof. Background Technique

[0002] During the use and service process of concrete in projects such as building construction, bridges, roads, and dams, due to its low elastic modulus and tensile strength, cracks often occur. These cracks not only reduce the overall strength of the concrete structure, but may also lead to safety hazards and accelerate the corrosion of internal steel bars, shortening the service life of the concrete. For strictly required infrastructure such as underground projects and hydropower stations, traditional crack repair methods (such as plastering, grouting, etc.) are often difficult to quickly and effectively solve the problem, and the cost is high. Therefore, making concrete have self-healing function by adding self-healing materials to concrete has become a research direction for solving concrete crack problems.

[0003] Chinese Patent Application Publication Text CN111268937A discloses a self-healing concrete, which contains self-healing microcapsules including a capsule core and a capsule wall. The capsule wall material of the self-healing microcapsules is obtained by copolymerization of acrylate monomers without substituents and methyl-substituted acrylate monomers; the capsule core is at least one of sulfoaluminate-based expansive agents, calcium oxide-based expansive agents, and magnesium oxide-based expansive agents. By adding the self-healing microcapsules to the concrete, self-healing of concrete cracks can be achieved, effectively improving the safety and durability of the concrete structure. However, the concrete prepared by this method can only repair cracks after they occur, and cannot improve the crack resistance of the concrete before cracks are formed. Summary of the Invention

[0004] Therefore, in order to improve the crack resistance of concrete before cracks occur and enable the concrete to have self-healing performance after cracks occur, the present invention provides a three-dimensional polyvinyl alcohol fiber and microcapsule self-healing concrete and a preparation method thereof. By simultaneously incorporating a three-dimensional polyvinyl alcohol fiber structure and microcapsules into the concrete slurry, the strength of the concrete can be effectively improved before cracks occur, and at the same time, self-healing function can be achieved after cracks appear.

[0005] To achieve the above object, the present invention specifically adopts the following technical solutions: A three-dimensional polyvinyl alcohol fiber and microcapsule self-healing concrete, in which three-dimensional polyvinyl alcohol fibers and microcapsules are distributed inside the self-healing concrete; The preparation method of the three-dimensional synthetic fiber reinforcement includes the following steps: P1. Blending basalt fibers and polyvinyl alcohol fibers to obtain blended fibers, and then performing row-column three-dimensional braiding on the blended fibers to obtain three-dimensional composite fibers; P2. Immersing the three-dimensional composite fibers in epoxy resin, taking them out, coating a mixture of diethylenetriamine and ethylenediamine on their surfaces, and drying and curing to obtain the three-dimensional synthetic fiber reinforcement. The microcapsules are obtained by coating polyphenylene sulfide on the surface of epoxy resin.

[0006] In a preferred embodiment, the three-dimensional synthetic fiber reinforcement and self-healing concrete containing microcapsules include the following components in parts by mass: 100 parts of cement, 40-50 parts of fly ash, 100-150 parts of fine aggregate, 2-5 parts of water reducing agent, 30-60 parts of water, 3-6 parts of microcapsules, 1.5-2 parts of initiator, and 7-20 parts of three-dimensional synthetic fiber reinforcement.

[0007] In a further preferred embodiment, the cement is P·O 32.5 or P·O 42.5 cement.

[0008] In a further preferred embodiment, the fine aggregate is standard sand conforming to the regulations in JB / T 9224-1999 "Standard Sand for Verifying Foundry Binders".

[0009] In a further preferred embodiment, the water reducing agent is a polycarboxylate water reducing agent with a water reducing rate > 30%.

[0010] In a further preferred embodiment, the initiator is azobisisobutyronitrile.

[0011] In a preferred embodiment, in step P1, the mass ratio of basalt fibers to polyvinyl alcohol fibers is 1:2 to 2:1.

[0012] In a preferred embodiment, in step P2, the mass ratio of diethylenetriamine to ethylenediamine is 1:3 to 3:2.

[0013] In a preferred embodiment, in step P2, the drying and curing temperature is 40-60 °C and the drying time is 6 hours.

[0014] In a preferred embodiment, the preparation method of the microcapsules includes the following steps: S1. Taking 8-16 parts of polyphenylene sulfide by mass, heating it, adding 10-18 parts of epoxy resin under stirring, and continuously stirring under heating to make the polyphenylene sulfide and epoxy resin mix evenly; S2. Stopping heating, increasing the stirring speed, adding perfluorotributylamine to the mixture obtained in step S1 to obtain a suspension of microcapsules; subjecting the suspension to ultrasonic treatment, filtering, and drying the separated microcapsules to obtain polyphenylene sulfide-coated epoxy resin, which is the microcapsule.

[0015] In a further preferred embodiment, in step S1, the polyphenylene sulfide is heated to 300 - 310 °C, and after adding epoxy resin, the temperature is maintained at 300 - 320 °C.

[0016] In a further preferred embodiment, the stirring speed in step S1 is 700 - 1500 rpm, and the stirring speed in step S2 is 2000 - 2500 rpm.

[0017] In a further preferred embodiment, the ultrasonic frequency in step S2 is 60 kHz, and the ultrasonic time is 15 - 30 minutes.

[0018] The preparation method of the 3D vinylon bars and microcapsule self - healing concrete comprises the following steps: uniformly mixing cement, fly ash, fine aggregate, initiator, and water - reducing agent; adding water and the microcapsules to the obtained mixture and continuing to mix uniformly to obtain concrete slurry; adding the 3D vinylon bars into a mold, pouring the concrete slurry into the mold, and drying to obtain the 3D vinylon bars and microcapsule self - healing concrete.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) In the present invention, basalt fibers and PVA fibers are blended into blended fibers, and a three - dimensional composite fiber is made by using a row - type three - dimensional braiding technique. Then, the three - dimensional composite fiber is soaked in epoxy resin and coated with a mixture of diethylenetriamine and ethylenediamine to obtain 3D vinylon bars. Incorporating the 3D vinylon bars into the concrete slurry forms a three - dimensional network structure in the prepared concrete, which helps to disperse stress and enhance toughness, and can significantly improve the tensile strength, shear strength, and ductility of the concrete, comprehensively reflected in significantly improving the crack resistance of the concrete, reducing the self - weight and construction cost of the concrete (the 3D vinylon bars can replace part of the steel bar usage, reducing the material cost by 15% - 20%). When micro - cracks occur in the concrete, the three - dimensional network structure can limit the further rapid expansion of existing cracks.

[0020] (2) During service, concrete structures are prone to cracking under the influence of external loads or temperature stresses and other factors. If not repaired in time, it is easy to cause crack extension and the collapse of the concrete structure. Therefore, in the present invention, microcapsules formed by coating epoxy resin with polyphenylene sulfide are also added to the concrete slurry. The microcapsules have the advantages of fast flow rate and strong adhesion. When cracks occur in the concrete, the microcapsules can flow to the cracks, and the stress concentration at the crack tip causes the polyphenylene sulfide layer wrapped outside the microcapsules to rupture, and the internal epoxy resin flows out, thereby repairing the cracks.

[0021] (3) The concrete prepared by simultaneously incorporating three-dimensional synthetic fiber bars and microcapsules in the present invention has excellent impact resistance and fatigue resistance. Before cracks occur in the concrete, it can reduce the probability of crack generation; when microcracks just occur in the concrete, it can reduce the crack propagation speed; after the cracks expand into larger cracks, it can self-repair the cracks. Therefore, the three-dimensional synthetic fiber bars and microcapsule self-repairing concrete provided in the present invention can reduce the structural damage problems caused by long-term loads.

[0022] (4) Compared with the planar fibers in the prior art that can only enhance the crack resistance in one direction, the three-dimensional network structure in the present invention can achieve multi-directional crack resistance enhancement and can extend the crack propagation path to inhibit the rapid expansion of cracks. Moreover, the three-dimensional synthetic fiber bars with a three-dimensional network structure optimize the distribution of fibers, avoiding the agglomeration problem of planar fibers. Therefore, the interfacial bonding strength with the concrete matrix is significantly improved, the slump loss < 15%, and the construction performance of the concrete is better.

[0023] (5) In the prior art, in the scheme of physically mixing single fibers and microcapsules, the doping amount of microcapsules is relatively large (>5%), and the repair of the concrete depends on random contact (the triggering rate ≤ 60%); while in the present invention, the microcapsules are loaded at the nodes of the three-dimensional synthetic fiber bars, the demand for microcapsules is less, the cracks preferentially expand along the network and precisely trigger the release of microcapsules (the triggering rate ≥ 90%), and a 0.32 mm crack can be completely repaired in 7 days.

[0024] (6) The mass loss rate of the microcapsules in the present invention in an alkaline environment (pH = 13.5) in 30 days is only 1.23%; while traditional microcapsules are easily degraded in alkaline concrete, and the survival rate < 50%. Coating with polyphenylene sulfide can enhance the adhesion of microcapsules and improve the weather resistance of microcapsules (the microcapsules can remain stable even above 300 °C), and it is applicable to high-temperature or corrosive environments (such as marine engineering). While traditional epoxy resin microcapsules are easily washed away by water and cause more losses when directly exposed, and the adhesion < 1 MPa.

[0025] (7) The repair efficiency of traditional microcapsules drops to < 50% after freeze-thaw cycles, while the three-dimensional synthetic fiber bars in the present invention can protect the microcapsules from freeze-thaw erosion and can increase the durability of the concrete by more than 3 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic three-dimensional structure diagram of the three-dimensional synthetic fiber bars and microcapsule self-repairing concrete prepared in the present invention; Figure 2 is a result diagram of the self-repair experiment of the three-dimensional synthetic fiber bars and microcapsule self-repairing concrete prepared in Example 3 of the present invention.

[0027] In the figure: 1. Microcapsule; 2. Three-dimensional synthetic fiber bar; 3. Concrete. Detailed implementation mode

[0028] The following content describes the technical solutions of this application clearly and completely in combination with embodiments, so that those skilled in the art can fully understand this application. Obviously, the described embodiments are only some preferred embodiments of this application, rather than all embodiments. Any equivalent transformation or substitution made to the following implementation manners by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0029] In the following embodiments, unless otherwise specified, all parts are by mass. In the following embodiments, the fine aggregate used is the standard sand specified in JB / T 9224-1999 "Standard Sand for Verifying Foundry Binders". The mechanical and physical property parameters of the basalt fiber and polyvinyl alcohol (PVA) fiber used are shown in Table 1 and Table 2 respectively.

[0030] Table 1 Mechanical and Physical Properties of Basalt Fiber

[0031] Table 2 Mechanical and Physical Properties of Polyvinyl Alcohol Fiber

[0032] The polycarboxylate superplasticizer model used in the following examples and comparative examples is the HLX standard type, purchased from Shanxi Feike New Material Technology Co., Ltd., and the water reduction rate > 30%.

[0033] Example 1 A three-dimensional fiber-reinforced and microcapsule self-healing concrete, comprising the following components: 100 parts of cement, 45 parts of fly ash, 130 parts of fine aggregate, 2 parts of polycarboxylate superplasticizer, 30 parts of water, 3 parts of microcapsules, 2 parts of azobisisobutyronitrile (initiator), and 7 parts of three-dimensional fiber reinforcement.

[0034] The preparation method of the microcapsules includes the following steps: S1. Heat 16 parts of PPS (polyphenylene sulfide) to 305 °C, stir at a speed of 1000 rpm for 20 min, then add 15 parts of epoxy resin (such as epoxy resin E44), keep the temperature at 310 °C, and continue to stir at a speed of 1000 rpm for 30 min to obtain a mixture of PPS and epoxy resin.

[0035] S2. Stop heating, increase the stirring speed to 2300 rpm, add perfluorotributylamine (coolant, the addition amount is in a ratio of 1:3 to the total mass of the PPS and epoxy resin mixture) to the mixture obtained in step S1 to obtain a suspension of microcapsules. Ultrasonically treat this suspension at an ultrasonic frequency of 60 kHz for 30 min. Filter, and dry the separated microcapsules at 60 °C for more than 12 hours to obtain epoxy resin coated with PPS, which is the microcapsule. The particle size of this microcapsule is 100 - 110 μm, and the percentage of the mass of epoxy resin (core material) in the microcapsule to the mass of the microcapsule is 60 wt%.

[0036] The preparation method of the three-dimensional aramid fiber bars includes the following steps: P1. Blend basalt fibers and PVA fibers in a mass ratio of 1:1 to obtain blended fibers. Using the method of three-dimensional braiding in a determinant pattern, fix the blended fibers on the yarn carrier and move them along the path of the two-dimensional Cartesian coordinate plane on the chassis to drive the blended fibers to interweave in space to form a corresponding three-dimensional structure preform, thereby obtaining three-dimensional composite fibers.

[0037] P2. Immerse the three-dimensional composite fibers in epoxy resin (such as epoxy resin E44) for 2 hours. After taking them out, evenly coat the surface with a mixture composed of diethylenetriamine and ethylenediamine in a mass ratio of 1:3, and finally cure at 40 °C for 6 hours to obtain three-dimensional aramid fiber bars with a wire diameter of 20 - 25 μm.

[0038] The preparation method of the three-dimensional aramid fiber bars and microcapsule self-healing concrete includes the following steps: Add the cement, fly ash, fine aggregate, initiator, and water reducing agent to a concrete mixer and stir at a speed of 800 rpm for 1 minute; add water and the microcapsules to the concrete mixer and stir at a speed of 600 rpm for 2 minutes to ensure that the microcapsules are evenly distributed in the concrete slurry to obtain concrete slurry. Place the three-dimensional aramid fiber bars in the center of the mold, pour the concrete slurry into the mold, and after drying, obtain a self-healing concrete 3 with a three-dimensional structure as Figure 1 shown, including three-dimensional aramid fiber bars 2 and microcapsules 1.

[0039] Example 2 A three-dimensional aramid fiber bars and microcapsule self-healing concrete, comprising the following components: 100 parts of cement, 50 parts of fly ash, 100 parts of fine aggregate, 5 parts of polycarboxylate water reducing agent, 60 parts of water, 6 parts of microcapsules, 1.8 parts of azobisisobutyronitrile (initiator), and 20 parts of three-dimensional aramid fiber bars.

[0040] The preparation method of the microcapsules includes the following steps: S1. Heat 8 parts of PPS (polyphenylene sulfide) to 300 °C, stir at a speed of 1500 rpm for 30 min, then add 10 parts of epoxy resin (such as epoxy resin E135), keep the temperature at 300 °C, and continue to stir at a speed of 1500 rpm for 40 min to obtain a mixture of PPS and epoxy resin.

[0041] S2. Stop heating, increase the stirring speed to 2500 rpm, add perfluorotributylamine to the mixture obtained in step S1 to obtain a suspension of microcapsules. Ultrasonically treat this suspension at an ultrasonic frequency of 60 kHz for 15 min. Filter, and dry the separated microcapsules at 60 °C for more than 24 hours to obtain epoxy resin coated with PPS, which is the microcapsule. The particle size of this microcapsule is 70 - 80 μm, and the mass percentage of epoxy resin in the microcapsule accounts for 59 wt% of the mass of the microcapsule.

[0042] The preparation method of the three-dimensional polyester fiber bars is basically the same as that in Example 1, the difference is that in step P1, the mass ratio of basalt fiber to PVA fiber is 1:2; in step P2, the mass ratio of diethylenetriamine to ethylenediamine is 1:1, and the three-dimensional composite fiber treated with epoxy resin and the mixture of diethylenetriamine and ethylenediamine is cured at 60 °C for 6 hours to obtain three-dimensional polyester fiber bars with a wire diameter of 15 - 20 μm. The preparation method of the three-dimensional polyester fiber bar and microcapsule self-healing concrete is the same as that in Example 1.

[0043] Example 3 A three-dimensional polyester fiber bar and microcapsule self-healing concrete, comprising the following components: 100 parts of cement, 40 parts of fly ash, 150 parts of fine aggregate, 3 parts of polycarboxylate water reducer, 40 parts of water, 5 parts of microcapsules, 1.5 parts of azobisisobutyronitrile (initiator), 18 parts of three-dimensional polyester fiber bars.

[0044] The preparation method of the microcapsule comprises the following steps: S1. Heat 9 parts of PPS (polyphenylene sulfide) to 310 °C, stir at a speed of 700 rpm for 25 min, then add 18 parts of epoxy resin (such as epoxy resin E44), keep the temperature at 320 °C, and continue to stir at a speed of 700 rpm for 35 min to obtain a mixture of PPS and epoxy resin.

[0045] S2. Stop heating, increase the stirring speed to 2000 rpm, add perfluorotributylamine to the mixture obtained in step S1 to obtain a suspension of microcapsules. Ultrasonically treat this suspension at an ultrasonic frequency of 60 kHz for 20 min. Filter, and dry the separated microcapsules at 60 °C for more than 36 hours to obtain epoxy resin coated with PPS, which is the microcapsule. The particle size of this microcapsule is 110 - 120 μm, and the mass percentage of epoxy resin in the microcapsule accounts for 61 wt% of the mass of the microcapsule.

[0046] The preparation method of the three-dimensional polyvinyl alcohol fiber is basically the same as that in Example 1, except that in step P1, the mass ratio of basalt fiber to PVA fiber is 2:1; in step P2, the mass ratio of diethylenetriamine to ethylenediamine is 3:2, and the three-dimensional composite fiber treated with epoxy resin and the mixture of diethylenetriamine and ethylenediamine is cured at 55°C for 6 hours to obtain a three-dimensional polyvinyl alcohol fiber with a filament diameter of 25-30 μm. The preparation method of the three-dimensional polyvinyl alcohol fiber and the microcapsule self-healing concrete is the same as that in Example 1.

[0047] The performance of the microcapsules prepared in this example is shown in Table 3.

[0048] Table 3 Performance of the microcapsules prepared in Example 3

[0049] Comparative Example 1 A self-healing concrete, comprising the following components: 100 parts of cement, 40 parts of fly ash, 150 parts of fine aggregate, 3 parts of polycarboxylate water reducer, 40 parts of water, 1.5 parts of azobisisobutyronitrile (initiator), and 18 parts of three-dimensional polyvinyl alcohol fiber. Among them, the preparation method of the three-dimensional polyvinyl alcohol fiber is the same as that in Example 1. The preparation method of the self-healing concrete is the same as that in Example 1 except for the different components. That is, compared with Example 3, the self-healing concrete in this comparative example does not contain microcapsules.

[0050] Comparative Example 2 A self-healing concrete, comprising the following components: 100 parts of cement, 40 parts of fly ash, 150 parts of fine aggregate, 3 parts of polycarboxylate water reducer, 40 parts of water, 1.5 parts of azobisisobutyronitrile (initiator), and 5 parts of microcapsules. Among them, the preparation method of the microcapsules is the same as that in Example 3. The preparation method of the self-healing concrete is the same as that in Example 1 except for the different components. That is, compared with Example 3, the self-healing concrete in this comparative example does not contain three-dimensional polyvinyl alcohol fiber.

[0051] Comparative Example 3 A concrete, comprising the following components: 100 parts of cement, 40 parts of fly ash, 150 parts of fine aggregate, 3 parts of polycarboxylate water reducer, 40 parts of water, 1.5 parts of azobisisobutyronitrile (initiator). The preparation method of this concrete is prepared by the conventional concrete preparation method in the art. That is, compared with Example 3, the concrete in this comparative example does not contain microcapsules and three-dimensional polyvinyl alcohol fiber.

[0052] Comparative Example 4 A self-healing concrete, comprising the following components: 100 parts of cement, 40 parts of fly ash, 150 parts of fine aggregate, 3 parts of polycarboxylate water reducer, 40 parts of water, 5 parts of microcapsules, 1.5 parts of azobisisobutyronitrile (initiator), and 18 parts of three-dimensional vinylon bars. Among them, the preparation method of the microcapsules is the same as that in Example 3. The preparation method of this self-healing concrete is the same as that in Example 3. The preparation method of the three-dimensional vinylon bars comprises the following steps: P1. Blend basalt fibers and PVA fibers in a mass ratio of 2:1 to obtain blended fibers. Using the method of three-dimensional braiding in a determinant pattern, fix the blended fibers on the yarn carrier and move them along the path of the two-dimensional Cartesian coordinate plane on the chassis, driving the blended fibers to interweave in space to form a corresponding three-dimensional structural preform, thereby obtaining three-dimensional composite fibers.

[0053] P2. Immerse the three-dimensional composite fibers in epoxy resin E44 for 2 hours. After taking them out, evenly coat ethylenediamine on their surfaces, and finally cure them at 55 °C for 6 hours to obtain three-dimensional vinylon bars with a wire diameter of 25 - 30 μm.

[0054] Referring to the method in T / CECS 913-2021 "Test Method Standard for Self-Healing Performance of Cement Concrete", test the mechanical properties of the concretes prepared in Examples 1 - 3 and Comparative Examples 1 - 4 respectively. The results are shown in Table 4.

[0055] Table 4 Test Results of Mechanical Properties of Concretes with Different Compositions

[0056] It can be seen from the mechanical property data in Table 4 that for the concrete with only three-dimensional vinylon bars added (Comparative Example 1), compared with ordinary concrete (Comparative Example 3), the compressive strength and flexural strength are significantly improved; for the concrete with only microcapsules added (Comparative Example 2), compared with ordinary concrete (Comparative Example 3), the compressive strength is significantly improved, and the flexural strength changes little; however, the degree of improvement in compressive strength is not as large as that in the examples. For the concrete in Example 3 with both three-dimensional vinylon bars and microcapsules added, compared with the concretes in Comparative Example 1 and Comparative Example 2, both the compressive strength and flexural strength are significantly improved. Compared with Comparative Example 3, for the self-healing concrete prepared in Comparative Example 4 with both three-dimensional vinylon bars and microcapsules added, the compressive strength and flexural strength are significantly improved; however, compared with Example 3, the compressive strength and flexural strength in Comparative Example 4 are significantly decreased. This shows that adding both three-dimensional vinylon bars and microcapsules to the concrete is beneficial to simultaneously improving the compressive strength and flexural strength of the concrete. And the three-dimensional vinylon bars treated with a mixture of diethylenetriamine and ethylenediamine have a greater degree of improvement in the compressive strength and flexural strength of the concrete than the three-dimensional vinylon bars treated with a single amine (such as ethylenediamine).

[0057] The following method is used to conduct self-healing experiments on the three-dimensional fiber-reinforced bars and microcapsule self-healing concrete prepared in Example 3: (1)Preparation, molding and curing of self-healing concrete: Pour the three-dimensional fiber-reinforced bars and microcapsule self-healing concrete prepared in Example 3 into a mold of 100mm×100mm×110mm, vibrate and level it, demold after 24 hours, move the specimen to the curing room, and take it out after curing at a temperature of 25°C and a humidity of 95% for 28 days.

[0058] (2)Crack prefabrication and self-healing: Using the splitting test method (refer to T / CECS 913-2021 "Test Method Standard for Self-healing Performance of Cement Concrete"), generate microcracks on the surface of the specimen, immediately remove the specimen, measure the initial crack width, place it at room temperature for 7 days, and then test the width of the crack. The results are as Figure 2 shown. Figure 2 Figure (a) in it is the concrete with initial cracks, and figure (b) is the concrete placed at room temperature for 7 days. It can be seen from the Figure 2 experimental results that cracks with a width of 0.32mm can self-heal.

[0059] The above-described embodiments are only the preferred embodiments of the present application and are not used to limit the protection scope of the present application. For any person skilled in the art, various changes and modifications can be made to the present application. Any simple equivalent changes and modifications made based on the protection scope of the present application and the content of the specification shall be included in the protection scope of the present application.

Claims

1. A three-dimensional polyvinyl alcohol fiber and microcapsule self-healing concrete, characterized in that, The self-healing concrete is internally distributed with three-dimensional polyester fibers and microcapsules; The preparation method of the three-dimensional polyester fibers includes the following steps: P1. Blend basalt fibers and polyvinyl alcohol fibers to obtain blended fibers, and then perform determinant three-dimensional braiding on the blended fibers to obtain three-dimensional composite fibers; P2. Immerse the three-dimensional composite fibers in epoxy resin, take them out, coat a mixture of diethylenetriamine and ethylenediamine on their surfaces, and dry and cure them to obtain three-dimensional polyester fibers; The microcapsules are obtained by coating polyphenylene sulfide on the surface of epoxy resin.

2. The three-dimensional synthetic fiber reinforcement and microcapsule self-healing concrete according to claim 1, characterized in that, It includes the following components in parts by mass: 100 parts of cement, 40 - 50 parts of fly ash, 100 - 150 parts of fine aggregate, 2 - 5 parts of water reducing agent, 30 - 60 parts of water, 3 - 6 parts of microcapsules, 1.5 - 2 parts of initiator, and 7 - 20 parts of three-dimensional polyester fibers.

3. The three-dimensional polyvinyl alcohol fiber and microcapsule self-healing concrete according to claim 2, characterized in that, The cement is P·O 32.5 or P·O 42.5 cement; and / or the fine aggregate is the standard sand specified in JB / T 9224-1999 "Standard Sand for Verifying Foundry Binders".

4. The three-dimensional polyester fiber and microcapsule self-healing concrete according to claim 2, characterized in that, The water reducing agent is a polycarboxylate water reducing agent with a water reduction rate > 30%; and / or the initiator is azobisisobutyronitrile.

5. The three-dimensional polyester fiber reinforcement and microcapsule self-healing concrete according to claim 1, characterized in that, In step P1, the mass ratio of basalt fibers to polyvinyl alcohol fibers is 1:2 - 2:

1.

6. The three-dimensional polyester fiber reinforcement and microcapsule self-healing concrete according to claim 1, characterized in that In step P2, the mass ratio of the diethylenetriamine to the ethylenediamine is 1:3 - 3:

2.

7. The three-dimensional polyvinyl alcohol fiber-reinforced and microcapsule self-healing concrete according to claim 1, wherein The preparation method of the microcapsules includes the following steps: S1. By mass, heat 8 - 16 parts of polyphenylene sulfide, add 10 - 18 parts of epoxy resin under stirring, and continue stirring under heating to make the polyphenylene sulfide and epoxy resin mix evenly; S2. Stop heating, increase the stirring speed, add perfluorotributylamine to the mixture obtained in step S1 to obtain a suspension of microcapsules; subject the suspension to ultrasonic treatment, filter, and dry the separated microcapsules to obtain the epoxy resin coated with polyphenylene sulfide, which is the microcapsule.

8. The three-dimensional synthetic fiber reinforcement and microcapsule self-healing concrete according to claim 7, characterized in that, In step S1, heat the polyphenylene sulfide to 300 - 310°C, and keep the temperature at 300 - 320°C after adding the epoxy resin.

9. The three-dimensional synthetic fiber and microcapsule self-healing concrete according to claim 7, characterized in that, The stirring speed in step S1 is 700 - 1500 rpm, and the stirring speed in step S2 is 2000 - 2500 rpm.

10. The preparation method of the three-dimensional vinylon tendon and microcapsule self-healing concrete according to any one of claims 1 to 9, characterized in that, It includes the following steps: Mix the cement, fly ash, fine aggregate, initiator, and water reducing agent evenly; add water and the microcapsules to the obtained mixture and continue to mix evenly to obtain concrete slurry; add the three-dimensional polyester fibers into a mold, pour the concrete slurry into the mold, and dry to obtain the three-dimensional polyester fiber and microcapsule self-healing concrete.

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