Preparation process of concrete crack self-healing repairing agent and concrete material thereof
Through surface-modified nanosilicate and microbial spore composite repair agent, the microcapsule core prepared by combining expanded perlite and microfluidic control technology, the self-healing of concrete cracks is achieved, which improves compressive strength and permeability, extends service life, and reduces maintenance costs.
Patent Information
- Application Number
- CN202510590122.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2025-08-15
AI Technical Summary
Existing concrete crack repair methods are difficult to effectively repair internal cracks, and the construction is complex or costly, which cannot meet the self-repair and long-life needs of large buildings.
Surface-modified nanosilicates are used to recombinate with microbial spores, cracks are repaired through metabolic secretion of calcium carbonate and other substances, and expanded perlite is used to adjust humidity, and crack repair is performed by microcapsule core prepared in combination with microfluidic control technology.
It improves the compressive strength and flexural strength of concrete, reduces the invasion of harmful substances, extends service life, reduces maintenance costs, and meets green and environmental protection requirements.
Smart Images
Figure CN120483574A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of concrete, and in particular to a preparation process of a concrete crack self-healing repair agent and a concrete material thereof. Background Art
[0002] As the most widely used structural material in modern construction projects, concrete's mechanical properties and durability play a decisive role in project quality. However, in actual service, concrete structures are prone to cracking due to factors such as external loads, temperature changes, dry-wet cycles, and chemical erosion. The presence of these cracks not only reduces the concrete's bearing capacity but also accelerates the intrusion of harmful substances such as moisture, chloride ions, and sulfates, leading to problems such as steel corrosion and concrete carbonization, seriously threatening the safety and service life of the structure.
[0003] At present, common methods for repairing concrete cracks include surface repair, grouting and replacement of damaged components. The surface repair method can only deal with shallow cracks and it is difficult to effectively repair internal cracks. Although the grouting method can fill cracks to a certain extent, the repair effect on small cracks is limited, and the construction process is complicated and the cost is high. Replacing damaged components requires a lot of manpower, material resources and time. As construction projects develop towards large-scale and complex directions, traditional repair methods can no longer meet the needs of self-repair and long life of concrete structures. Therefore, the present invention proposes a preparation process of a concrete crack self-healing repair agent and a concrete material thereof to solve the problems existing in the prior art. Summary of the Invention
[0004] To address the above issues, the present invention proposes a preparation process for a self-healing repair agent for concrete cracks and its concrete material. In the repair agent prepared by this preparation process, the surface-modified nanosilicate has a high specific surface area and activity, and can undergo a secondary hydration reaction with cement hydration products to generate more CSH gel, effectively filling the crack pores. Microbial spores serve as a load. After cracks form, they are activated by water and secrete substances such as calcium carbonate through metabolism, further repairing the cracks. Expanded perlite has good water absorption and water retention properties, which can regulate the internal humidity of concrete and provide a suitable environment for the self-healing reaction.
[0005] To achieve the purpose of the present invention, the present invention is implemented by the following technical solution: a preparation process of a concrete crack self-healing repair agent, comprising the following steps:
[0006] S1: Silica fume and hexadecyltrimethylammonium bromide were modified in a 60°C water bath at a mass ratio of 100:1 to obtain surface-modified nanosilicate, which was then loaded with microbial spores and composited with expanded perlite to form component one.
[0007] S2: Ethyl cellulose and hydroxypropyl methyl cellulose are dissolved in anhydrous ethanol and mixed with chitosan acetate solution to form a composite wall material, which is then coated with a core material containing modified calcium sulfoaluminate. Microcapsules with dual particle sizes of 20-50 μm and 50-100 μm are prepared by microfluidic technology to form component two;
[0008] S3: Mix component 1 and component 2 in a mass ratio of 1:2-1:3.
[0009] A further improvement is that in S1, silica fume and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 100:1, stirred at a speed of 200-300 r / min for 2 hours in a 60°C water bath, centrifuged at 4000-5000 r / min for 15-20 minutes, and dried at 80-100°C for 6-8 hours to obtain surface-modified nano-silicate.
[0010] A further improvement is that in S1, the preparation method of the microbial spores is: mixing a microbial culture liquid with a sodium alginate solution with a mass fraction of 2%-3% in a volume ratio of 1:2-1:3, and dropping the mixture into a calcium chloride solution with a mass fraction of 3%-4% to form gel beads. After soaking the gel beads in the calcium chloride solution for 2-3 hours, the gel beads are washed with deionized water for 3-4 times, and dried at 30-40° C. to constant weight to obtain the microbial spores.
[0011] A further improvement is that in S1, expanded perlite with a particle size of 0.1-1 mm is selected, and the surface-modified nano-silicate, microbial spores and expanded perlite are mixed in a mass ratio of (10-20): (5-10): (15-25) to obtain component one.
[0012] A further improvement is that in S2, ethyl cellulose and hydroxypropyl methyl cellulose are dissolved in anhydrous ethanol in a mass ratio of (1.5-2.5): (0.8-1.2), and stirred at 150-200 r / min in a 50-60°C water bath until completely dissolved to obtain a wall material solution; chitosan is dissolved in an acetic acid solution with a mass fraction of 2%-3% to prepare a chitosan solution with a mass fraction of 1%-2%; the wall material solution and the chitosan solution are mixed in a volume ratio of (2.5-3.5): (0.8-1.2), and stirred for 30-40 minutes to form a composite wall material.
[0013] A further improvement is that in S2, modified calcium sulfoaluminate powder, nano-silica, sodium gluconate, and calcium lactate are evenly mixed in a mass ratio of (30-40): (10-15): (5-8): (10-15) to obtain a core material, the core material is wrapped in the composite wall material, and capsules with two particle sizes of 20-50 μm and 50-100 μm are prepared by microfluidic technology to obtain a second component.
[0014] A further improvement is that the modified calcium sulfoaluminate powder is prepared by mixing calcium sulfoaluminate powder and magnesium stearate in a mass ratio of 100:5 and stirring at 80° C. for 30 minutes.
[0015] A concrete material comprises the following components in a mass ratio: 50-80 parts of Portland cement, 30-60 parts of medium sand, 50-80 parts of crushed stone with a particle size of 5-25 mm, 20-40 parts of water, and 5-15 parts of a repair agent.
[0016] A further improvement is that the silicate cement is selected to have a strength grade of 42.5 or above.
[0017] A further improvement is that the fineness modulus of the medium sand is controlled to be 2.3-3.0, and the content of the needle-shaped particles of the crushed stone is controlled to be no more than 10%.
[0018] The beneficial effects of the present invention are:
[0019] 1. In the repair agent prepared by the present invention, the surface-modified nano-silicate has a high specific surface area and activity, can undergo a secondary hydration reaction with cement hydration products, generate more CSH gel, and effectively fill the crack pores; the microbial spores serve as a load, and after the cracks are formed, they are activated by water and secrete substances such as calcium carbonate through metabolism to further repair the cracks; the expanded perlite has good water absorption and water retention, can adjust the internal humidity of the concrete, and provide a suitable environment for the self-healing reaction; the 20-50μm capsules are used to repair microcracks, and the 50-100μm capsules are used to repair macrocracks. The modified calcium sulfoaluminate powder in the core material expands when exposed to water to generate filling pressure, the nano-silica refines the cement hydration products, and the sodium gluconate and calcium lactate synergistically regulate the hydration reaction rate to ensure the efficient progress of the self-healing process.
[0020] 2. The present invention improves the microstructure of concrete by adding a repair agent, making the cement stone more compact. According to tests, compared with ordinary concrete, the compressive strength and flexural strength are higher, which effectively improves the bearing capacity of concrete, greatly reduces the intrusion of harmful substances into the interior of the concrete, improves the impermeability and erosion resistance, and extends the service life of the concrete.
[0021] 3. The preparation process of the present invention does not produce harmful substances, which meets the requirements of green environmental protection. The self-healing properties of concrete reduce the cost of subsequent maintenance and repair. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION
[0023] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.
[0024] Example 1
[0025] according to Figure 1 As shown, this embodiment proposes a preparation process of a concrete crack self-healing repair agent, comprising the following steps:
[0026] Preparation of the first component: 100g of silica fume (SiO2 content ≥90%) was mixed with 1g of cetyltrimethylammonium bromide (CTAB). The mixture was stirred at 250 rpm in a 60°C water bath for 2 hours, then centrifuged at 4500 rpm for 18 minutes and dried at 85°C for 7 hours to obtain surface-modified nanosilicate. Preparation of the immobilized microbial carrier: The microbial culture was mixed with a 2.5% sodium alginate solution at a volume ratio of 1:2.5 and added dropwise to a 3.5% calcium chloride solution. The gel beads were soaked for 2.5 hours, washed four times, and dried at 35°C to constant weight. Expanded perlite with a particle size of 0.5mm was selected and 15g of the surface-modified nanosilicate, 8g of the immobilized microbial carrier, and 20g of the expanded perlite were mixed to obtain the first component.
[0027] Preparation of the second component: Dissolve 20g of ethyl cellulose and 10g of hydroxypropyl methylcellulose in anhydrous ethanol and stir at 180 rpm in a 55°C water bath until dissolved to obtain a wall material solution. Dissolve chitosan in a 2.5% acetic acid solution to prepare a 1.5% chitosan solution. Mix the wall material solution and chitosan solution in a 3:1 volume ratio and stir for 35 minutes to form a composite wall material solution. Combine 35g of modified calcium sulfoaluminate powder, 12g of nanosilica, 6g of sodium gluconate, and 12g of calcium lactate as the core material. Microfluidic technology was used to prepare capsules with particle sizes of 20-50μm and 50-100μm to obtain the second component.
[0028] Mixing: Mix the first component and the second component in a mass ratio of 1:2 to obtain a concrete crack self-healing repair agent.
[0029] Preparation of concrete material: add the components into a concrete mixer according to the proportion of 60 parts of silicate cement, 45 parts of medium sand, 70 parts of crushed stone, 28 parts of water, and 10 parts of concrete crack self-healing repair agent, and stir for 3-5 minutes to prepare concrete material.
[0030] Example 2
[0031] according to Figure 1 As shown, this embodiment proposes a preparation process of a concrete crack self-healing repair agent, comprising the following steps:
[0032] Preparation of the first component: Surface-modified nanosilicate was prepared in the same manner, by mixing 18 g of surface-modified nanosilicate, 9 g of immobilized microorganism carrier and 22 g of expanded perlite to obtain the first component.
[0033] Preparation of the second component: Dissolve 22g of ethyl cellulose and 11g of hydroxypropyl methylcellulose in anhydrous ethanol and stir at 190 rpm in a 58°C water bath until dissolved to obtain a wall material solution. Dissolve chitosan in a 2.8% acetic acid solution to prepare a 1.8% chitosan solution. Mix the wall material solution and chitosan solution in a volume ratio of 3.2:1.1 and stir for 38 minutes to form a composite wall material solution. A core material, 38g of modified calcium sulfoaluminate powder, 13g of nanosilica, 7g of sodium gluconate, and 13g of calcium lactate, was mixed and prepared using microfluidic technology to form capsules, obtaining the second component.
[0034] Mixing: Mix the first component and the second component in a mass ratio of 1.2:2.1 to obtain a concrete crack self-healing repair agent.
[0035] Preparation of concrete materials: Prepare concrete materials according to the proportions of 70 parts of Portland cement, 50 parts of medium sand, 75 parts of crushed stone, 32 parts of water, and 12 parts of concrete crack self-healing repair agent.
[0036] Example 3
[0037] according to Figure 1 As shown, this embodiment proposes a preparation process of a concrete crack self-healing repair agent, comprising the following steps:
[0038] Preparation of the first component: 20 g of surface-modified nanosilicate, 10 g of immobilized microorganism carrier and 25 g of expanded perlite were mixed to obtain the first component.
[0039] Preparation of the second component: Dissolve 25g of ethyl cellulose and 12.5g of hydroxypropyl methylcellulose in anhydrous ethanol and stir at 200 rpm in a 60°C water bath until dissolved to obtain a wall material solution. Dissolve chitosan in a 3% acetic acid solution to prepare a 2% chitosan solution. Mix the wall material solution and chitosan solution in a volume ratio of 3.5:1.2 and stir for 40 minutes to form a composite wall material solution. A core material of 40g of modified calcium sulfoaluminate powder, 15g of nanosilica, 8g of sodium gluconate, and 15g of calcium lactate was mixed and prepared using microfluidic technology to form capsules, obtaining the second component.
[0040] Mixing: Mix the first component and the second component in a mass ratio of 1.3:2.3 to obtain a concrete crack self-healing repair agent.
[0041] Preparation of concrete materials: Prepare concrete materials according to the proportions of 80 parts of Portland cement, 60 parts of medium sand, 80 parts of crushed stone, 35 parts of water, and 13 parts of concrete crack self-healing repair agent.
[0042] Comparative Example
[0043] Ordinary concrete was prepared, the components of which were as follows by weight: 60 parts of Portland cement, 45 parts of medium sand, 70 parts of crushed stone, and 28 parts of water, without adding a concrete crack self-healing repair agent.
[0044] Experimental data:
[0045] Compressive strength test: The concrete prepared in Examples 1, 2, 3 and the comparative example was made into 150 mm × 150 mm × 150 mm cubic test blocks. After 28 days of standard curing, the compressive strength was tested as follows:
[0046]
[0047]
[0048] Permeability Test: The water seepage height method was used to test the water seepage performance of the concretes of Examples 1, 2, and 3, as well as the comparative example. Concrete was formed into truncated cone-shaped test blocks with a diameter of 175 mm and a height of 185 mm. After 28 days of standard curing, the water seepage test was conducted. The results showed that the water seepage height of the comparative example concrete was 35 mm, while the water seepage heights of the concretes of Examples 1, 2, and 3 were 20 mm, 18 mm, and 16 mm, respectively.
[0049] Micro-crack repair: Prefabricated 0.05mm cracks, Examples 1, 2, and 3 achieved a crack closure rate of 85% and a compressive strength recovery rate of 92% after 24 hours.
[0050] Macro crack repair: Prefabricated 0.3mm crack, Example 1, 2, 3 after 28 days of calcium carbonate deposition of 1.2g / cm 2 , strength recovery rate 96%;
[0051] Durability: After 50 freeze-thaw cycles, the mass loss rate of Examples 1, 2, and 3 was less than 1.5%.
[0052] In the repair agent prepared by the present invention, the surface-modified nano-silicate has a high specific surface area and activity, and can undergo a secondary hydration reaction with cement hydration products to generate more CSH gel, effectively filling crack pores. The microbial spores serve as a load. After the cracks are formed, they are activated by water and secrete substances such as calcium carbonate through metabolism to further repair the cracks. The expanded perlite has good water absorption and water retention properties, which can regulate the internal humidity of the concrete and provide a suitable environment for the self-healing reaction. The 20-50μm capsules are used to repair microcracks, and the 50-100μm capsules are used to repair macrocracks. The modified calcium sulfoaluminate powder in the core material expands when exposed to water to generate filling pressure. The nano-silica refines the cement hydration products. The sodium gluconate and calcium lactate synergistically regulate the hydration reaction rate to ensure the efficient progress of the self-healing process. At the same time, the addition of a repair agent improves the concrete's microstructure, making the cement stone more compact. Tests have shown that compared to ordinary concrete, it has higher compressive and flexural strengths, effectively improving the concrete's load-bearing capacity. It also significantly reduces the intrusion of harmful substances into the concrete, improving its impermeability and corrosion resistance, and extending its service life. Furthermore, the preparation process of this invention produces no harmful substances, meeting environmental protection requirements. The concrete's self-healing properties reduce subsequent maintenance and repair costs.
[0053] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.
Claims
1. A preparation process of a concrete crack self-healing repair agent, characterized in that: The following steps are involved: S1: Silica fume and hexadecyltrimethylammonium bromide were modified in a 60°C water bath at a mass ratio of 100:1 to obtain surface-modified nanosilicate, which was then loaded with microbial spores and composited with expanded perlite to form component one. S2: Ethyl cellulose and hydroxypropyl methyl cellulose are dissolved in anhydrous ethanol and mixed with chitosan acetate solution to form a composite wall material, which is then coated with a core material containing modified calcium sulfoaluminate. Microcapsules with dual particle sizes of 20-50 μm and 50-100 μm are prepared by microfluidic technology to form component two; S3: Mix component 1 and component 2 in a mass ratio of 1:2-1:
3.
2. The preparation process of a concrete crack self-healing repair agent according to claim 1, characterized in that: In the S1, silica fume and hexadecyltrimethylammonium bromide are mixed in a mass ratio of 100:1, stirred at 200-300 rpm in a 60°C water bath for 2 hours, centrifuged at 4000-5000 rpm for 15-20 minutes, and dried at 80-100°C for 6-8 hours to obtain surface-modified nano-silicate.
3. The preparation process of a concrete crack self-healing repair agent according to claim 2, characterized in that: In S1, the preparation method of microbial spores is as follows: a microbial culture liquid is mixed with a sodium alginate solution having a mass fraction of 2% to 3% in a volume ratio of 1:2 to 1:3, and the mixture is added dropwise to a calcium chloride solution having a mass fraction of 3% to 4% to form gel beads. After the gel beads are soaked in the calcium chloride solution for 2 to 3 hours, they are washed with deionized water for 3 to 4 times and dried at 30 to 40° C. to constant weight to obtain microbial spores.
4. The preparation process of a concrete crack self-healing repair agent according to claim 3, characterized in that: In S1, expanded perlite with a particle size of 0.1-1 mm is selected, and surface-modified nanosilicate, microbial spores and expanded perlite are mixed in a mass ratio of (10-20): (5-10): (15-25) to obtain component one.
5. The preparation process of a concrete crack self-healing repair agent according to claim 1, characterized in that: In the S2, ethyl cellulose and hydroxypropyl methyl cellulose are dissolved in anhydrous ethanol in a mass ratio of (1.5-2.5): (0.8-1.2), and stirred at 150-200 r / min in a 50-60°C water bath until completely dissolved to obtain a wall material solution; chitosan is dissolved in an acetic acid solution with a mass fraction of 2%-3% to prepare a chitosan solution with a mass fraction of 1%-2%; the wall material solution and the chitosan solution are mixed in a volume ratio of (2.5-3.5): (0.8-1.2), and stirred for 30-40 minutes to form a composite wall material.
6. The preparation process of the concrete crack self-healing repair agent according to claim 5, characterized in that: In S2, modified calcium sulfoaluminate powder, nano-silica, sodium gluconate, and calcium lactate are uniformly mixed in a mass ratio of (30-40): (10-15): (5-8): (10-15) to obtain a core material, which is wrapped in the composite wall material, and capsules with two particle sizes of 20-50 μm and 50-100 μm are prepared by microfluidic technology to obtain a second component.
7. The preparation process of the concrete crack self-healing repair agent according to claim 6, characterized in that: The preparation method of the modified calcium sulfoaluminate powder is as follows: mixing the calcium sulfoaluminate powder and magnesium stearate in a mass ratio of 100:5, and stirring at 80° C. for 30 minutes.
8. A concrete material comprising a repairing agent obtained by the preparation process according to any one of claims 1 to 7, characterized in that: The mixture comprises the following components in mass ratio: 50-80 parts of Portland cement, 30-60 parts of medium sand, 50-80 parts of crushed stone with a particle size of 5-25 mm, 20-40 parts of water, and 5-15 parts of a repair agent.
9. The concrete material according to claim 8, characterized in that: The silicate cement is selected to have a strength grade of 42.5 or above.
10. The concrete material according to claim 8, characterized in that: The medium sand has a controlled fineness modulus of 2.3-3.0, and the crushed stone has a controlled needle-like particle content of no more than 10%.