Self-repairing composite concrete and preparation method thereof

Abstract

The application relates to a self-repairing composite concrete and a preparation method thereof, and belongs to the technical field of concrete. The components of the concrete are as follows: 380-410 parts of ordinary Portland cement, 1000-1200 parts of gravel, 720-760 parts of sand, 25-35 parts of mineral powder, 8.2-10.5 parts of a self-repairing agent, 3.5-4.3 parts of a water reducing agent and 190-210 parts of water; the self-repairing agent takes sodium silicate and calcium acetate as a core, takes a high-crosslinking acrylate with a quaternary ammonium structure as a shell, is highly hydrophilic on the surface, migrates to a cement paste-capillary pore interface in the concrete in a directional manner, balances evaporation and bleeding rates of water, reduces generation of shrinkage cracks, analyzes water out of a water analysis channel, repairs inherent defects of the water analysis channel when deformation breaks, and improves the self-repairing function from 'crack remediation' to 'pore prevention-targeted repair' of an active protection level.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of concrete, and particularly relates to a self-repairing composite concrete and a preparation method thereof. BACKGROUND

[0002] Concrete, as the most common building material, is widely used, but due to its insufficient tensile strength and inherent brittleness, cracks are inevitably generated under the action of load, freeze-thaw and other factors, thereby reducing the stability of the concrete structure, especially in wall materials, these cracks lead to cracking of the decorative layer, and even water seepage of the wall surface.

[0003] Self-repairing concrete, also known as self-healing concrete, mainly refers to a concrete composite material having the ability to automatically repair micro cracks, in the prior art, mainly by adding self-repairing materials such as organic resins, inorganic hydration-promoting materials and their biological-based materials, and in order to avoid direct reaction of the self-repairing materials with the components of the concrete and failure, currently, microcapsule technology is used to encapsulate them, thereby giving the traditional concrete material good self-repairing performance; however, the self-repairing ability of this type of concrete has a significant bottleneck: in long-term research, it is found that these repair materials play a repairing role by being dispersed in the concrete, excessive addition forms internal defects, breaks the continuity of the hydration of the concrete, affects the initial strength, and the conventional self-repairing materials cannot effectively repair the micro cracks, especially water evaporation forms a large number of micro water separation voids in the concrete, which are easily induced to expand to form micro cracks under the action of freeze-thaw cycles and external forces, and the traditional self-repairing materials cannot effectively repair them, and there is a significant limitation. SUMMARY

[0004] In order to solve the technical problems mentioned in the background, the purpose of the present application is to provide a self-repairing composite concrete and a preparation method thereof.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A self-repairing composite concrete, the specific weight parts of the components are as follows: ordinary Portland cement 380-410 parts, crushed stone 1000-1200 parts, sand 720-760 parts, mineral powder 25-35 parts, self-repairing agent 8.2-10.5 parts, water reducing agent 3.5-4.3 parts and water 190-210 parts.

[0007] The self-repairing agent is prepared by the following method:

[0008] Step A1: N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran are mixed, dry nitrogen is introduced for protection, an ice water bath is used to control the temperature of the reaction system to be not higher than 10℃, diethylenedichlorosilane is slowly added and stirred for 2.5-3h, after the reaction is completed, the salt is removed by filtration, and tetrahydrofuran is removed by rotary evaporation to obtain intermediate 1;

[0009] Further, the amount ratio of divinyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 10-14 mL: 220-300 mL, N, N-dimethylpropanolamine is substituted with divinyl dichlorosilane, and the reaction route is as follows:

[0010]

[0011] Step A2: intermediate 1, mercaptoethanol, photoinitiator and acetone are mixed, 365 nm ultraviolet light is applied at room temperature, the intensity is controlled to be 40-50 mW / cm 2 , stirring for 3-4 h, removing acetone by rotary evaporation after the reaction is completed, to obtain intermediate 2;

[0012] Further, the amount ratio of intermediate 1, mercaptoethanol, photoinitiator and acetone is 0.1 mol: 0.2 mol: 0.15-0.2 g: 180-240 mL, and mercaptoethanol is subjected to click addition reaction with intermediate 1, and the reaction route is as follows:

[0013]

[0014] Step A3: intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane are mixed, dry nitrogen is introduced for protection, methyl acryloyl chloride is slowly added at room temperature, stirring for 2-3 h, then the temperature is increased to 60-80 °C, and the reaction is continued for 1-1.5 h, after the reaction is completed, water is added for washing after cooling, the aqueous phase is separated, and vacuum drying is performed, to obtain intermediate 3;

[0015] Further, the amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane is 0.1 mol: 0.2 mol: 5.5-7 g: 350-420 mL, and methyl acryloyl chloride is subjected to esterification reaction with intermediate 2, and the reaction route is as follows:

[0016]

[0017] Step A4: intermediate 3, 1-iodopropane and toluene are mixed, the temperature is increased to 70-85 °C, and stirring is performed under reflux for 10-15 h, after the reaction is completed, toluene is removed by rotary evaporation under reduced pressure, to obtain a modified embedding agent;

[0018] Further, the amount ratio of intermediate 3, 1-iodopropane and toluene is 0.1 mol: 0.5-0.62 mol: 120-160 mL, and 1-iodopropane is subjected to quaternary ammonium reaction with intermediate 3, and the reaction route is as follows:

[0019]

[0020] Step A5: sodium silicate, calcium acetate and deionized water are mixed, the modified embedding agent is sheared and dispersed, then pentaerythritol tetraacrylate is added and mixed, and the temperature is controlled at 60-70 DEG C in a water bath, ammonium persulfate solution is slowly added and stirred for 3-4h, and then spray drying is carried out to obtain the self-repairing agent;

[0021] Further, the amount ratio of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water is 50g: 15-25g: 8.5-10g: 3.7-4.5g: 0.8-1g: 550-650mL, the complex is formed by the complexation of the sulfur-oxygen structure of the modified embedding agent introduced by mercaptoethanol, the capture of sodium silicate and calcium acetate, and the amphiphilic property of the acrylate structure and the quaternary ammonium structure, and the microcapsule structure is formed by the copolymerization of pentaerythritol tetraacrylate under the initiation of ammonium persulfate.

[0022] Further, the crushed stone is a continuous grading granite mechanism material with a size of 5-20mm, and the granite is dense and has low water absorption and less cracks.

[0023] Further, the water reducing agent is a non-ionic preparation, which reduces the interaction with the surface quaternary ammonium structure of the self-repairing agent and maintains the stability of the self-repairing agent.

[0024] A preparation method of a self-repairing composite concrete, specifically comprising the following steps: premixing ordinary Portland cement, sand, mineral powder and a self-repairing agent, then adding crushed stones and uniformly mixing, dispersing a water reducing agent in water and mixing with the mixture to obtain the self-repairing composite concrete.

[0025] The beneficial effects of the present application are as follows:

[0026] The present application is based on the existing microencapsulation technology, and introduces a self-repairing aid into the concrete, the microcapsule shell layer of which is rich in quaternary ammonium salt groups, so that it is highly hydrophilic and fully dispersed in the water phase of the concrete, and in the water bleeding stage, it is oriented to the cement paste-capillary pore interface, increases the tortuosity of the water analysis channel, slows down the water evaporation and bleeding rate, makes the concrete fully hydrated, and reduces the generation of shrinkage cracks; in addition, with the slow evaporation of water, the self-repairing aid remains in the water analysis channel, when the pore is deformed due to freezing and thawing or external force, the high cross-linked acrylate shell layer of the self-repairing aid preferentially breaks, the released sodium silicate and calcium acetate react in the pore to form a secondary gel to block the channel and repair the cracks; the present application effectively repairs the inherent defects of the water analysis channel, and improves the self-repairing function from "crack repair" to "pore prevention-targeted repair" of the active protection level. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0028] Embodiment 1, preparation of self-repairing composite concrete, the specific implementation process is as follows:

[0029] (1) Preparation of self-repairing agent

[0030] Step A1: N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced for protection, an ice water bath was used to control the temperature of the reaction system to be 2℃, and divinyl dichlorosilane was slowly added for stirring reaction for 3h, wherein the amount ratio of divinyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran was 0.1 mol: 0.2 mol: 10 mL: 220 mL, after the reaction was completed, the salt was removed by filtration, and tetrahydrofuran was removed by rotary evaporation to obtain intermediate 1.

[0031] Step A2: intermediate 1, mercaptoethanol, a photoinitiator and acetone were mixed, 365nm ultraviolet light was applied at room temperature, the intensity was controlled to be 40mW / cm 2 , and stirring reaction was performed for 4h, wherein the photoinitiator was PI-1173, and the amount ratio of intermediate 1, mercaptoethanol, the photoinitiator and acetone was 0.1mol: 0.2mol: 0.15g: 180mL, after the reaction was completed, acetone was removed by rotary evaporation to obtain intermediate 2.

[0032] Step A3: intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane were mixed, dry nitrogen was introduced for protection, methyl acryloyl chloride was slowly added at room temperature for stirring reaction for 3h, and then the temperature was increased to 60℃ for continuing reaction for 1.5h, wherein the amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane was 0.1mol: 0.2mol: 5.5g: 350mL, after the reaction was completed, water was added for washing after the water phase was separated, and vacuum drying was performed to obtain intermediate 3.

[0033] Step A4: intermediate 3, 1-iodopropane and toluene were mixed, the temperature was increased to 70℃ for stirring reflux for 15h, wherein the amount ratio of intermediate 3, 1-iodopropane and toluene was 0.1mol: 0.5mol: 120mL, after the reaction was completed, toluene was removed by rotary evaporation under reduced pressure to obtain the modified embedding agent.

[0034] Step A5: Take sodium silicate, calcium acetate and deionized water into a dissolvent, add modified embedding agent, shear dispersion for 4 min at 1200 rpm, then add pentaerythritol tetraacrylate and mix in a water bath to control the temperature at 60℃, prepare a 10% mass fraction of ammonium persulfate solution, slowly add ammonium persulfate solution and stir for 4 h, wherein the amount ratio of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water is 50 g: 15 g: 8.5 g: 4 g: 0.8 g: 550 mL, and finally spray drying to obtain a self-repairing agent.

[0035] (2) Preparation of self-repairing composite concrete

[0036] The following raw materials are proportioned by weight: ordinary Portland cement 400 parts, P.042.5 type cement is selected; gravel 1120 parts, 5-20 mm continuous graded granite machine-made material is selected; sand 750 parts, machine-made sand with a modulus of about 2.6 is selected; mineral powder 28 parts, S95 grade mineral powder is selected; self-repairing agent 9.5 parts, self-made by this embodiment; water reducing agent 4 parts, MPEG-500 type non-ionic agent is selected; water 200 parts.

[0037] The ordinary Portland cement, sand, mineral powder and self-repairing agent are added to the mixer for pre-mixing, then the gravel is added and mixed evenly, then the water reducing agent is dispersed in water and mixed with the mixture to obtain the self-repairing composite concrete.

[0038] Example 2, preparation of self-repairing composite concrete, the specific implementation process is as follows:

[0039] (1) Preparation of self-repairing agent

[0040] Step Al: Take N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran, and mix them, then pass dry nitrogen gas to protect them, control the temperature of the reaction system to be 10℃ by ice water bath, slowly add diethenyl dichlorosilane and stir for 2.5 h, wherein the amount ratio of diethenyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 14 mL: 300 mL, after the reaction is completed, filter out the salt, and remove tetrahydrofuran by rotary evaporation to obtain intermediate 1.

[0041] Step A2: Take intermediate 1, mercaptoethanol, photoinitiator and acetone, mix them, apply 365 nm ultraviolet light at room temperature, control the intensity to be 50 mW / cm 2 , stir for 3 h, wherein the photoinitiator is PI-1173, the amount ratio of intermediate 1, mercaptoethanol, photoinitiator and acetone is 0.1 mol: 0.2 mol: 0.2 g: 240 mL, after the reaction is completed, remove acetone by rotary evaporation to obtain intermediate 2.

[0042] Step A3: Intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane were mixed, and dry nitrogen was introduced for protection. Methyl acryloyl chloride was slowly added at room temperature and stirred for 2 h, and then the temperature was increased to 80°C and the reaction was continued for 1 h. The amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane was 0.1 mol: 0.2 mol: 7 g: 420 mL. After the reaction was completed and cooled, water was added and mixed, the aqueous phase was separated, and then vacuum dried to obtain intermediate 3.

[0043] Step A4: Intermediate 3, 1-iodopropane and toluene were mixed and heated to 85°C and stirred for 10 h. The amount ratio of intermediate 3, 1-iodopropane and toluene was 0.1 mol: 0.62 mol: 160 mL. After the reaction was completed, toluene was removed by rotary evaporation under reduced pressure to obtain a modified embedding agent.

[0044] Step A5: Sodium silicate, calcium acetate and deionized water were mixed, and the modified embedding agent was added. Shearing dispersion was carried out at 1500 rpm for 3 min, then pentaerythritol tetraacrylate was added and mixed in a water bath controlled at 70°C. A mass fraction of 10% ammonium persulfate solution was prepared, and ammonium persulfate solution was slowly added and stirred for 3 h. The amount ratio of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water was 50 g: 25 g: 10 g: 4.5 g: 1 g: 650 mL. Finally, spray drying was carried out to obtain a self-repairing agent.

[0045] (2) Preparation of self-repairing composite concrete

[0046] The following raw materials were mixed according to the weight ratio: ordinary Portland cement 410 parts, P.O 42.5 type cement was selected; gravel 1200 parts, 5-20 mm continuous graded granite machine-made material was selected; sand 760 parts, machine-made sand with a modulus of about 2.6 was selected; mineral powder 35 parts, S95 grade mineral powder was selected; self-repairing agent 10.5 parts, self-made according to the embodiment; water reducing agent 4.3 parts, MPEG-500 type non-ionic agent was selected; water 210 parts.

[0047] The ordinary Portland cement, sand, mineral powder and self-repairing agent were added to the mixer for pre-mixing, then the gravel was added and mixed evenly, then the water reducing agent was dispersed in the water and mixed with the mixture to obtain the self-repairing composite concrete.

[0048] Example 3, preparation of self-repairing composite concrete, the specific implementation process is as follows:

[0049] (1) Preparation of self-repairing agent

[0050] Step Al: N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran were mixed, dry nitrogen was introduced to protect the reaction system, and the reaction system was controlled at 5°C by ice water bath. Diethenyl dichlorosilane was slowly added and stirred for 2.8h. The amount ratio of diethenyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran was 0.1mol: 0.2mol: 12mL: 260mL. After the reaction was completed, the salt was removed by filtration, and the tetrahydrofuran was removed by rotary evaporation to obtain intermediate 1.

[0051] Step A2: Intermediate 1, mercaptoethanol, photoinitiator and acetone were mixed, and 365nm ultraviolet light was applied at room temperature to control the intensity at 45mW / cm 2 , and stirred for 3.5h. The amount ratio of intermediate 1, mercaptoethanol, photoinitiator and acetone was 0.1mol: 0.2mol: 0.17g: 210mL. After the reaction was completed, the acetone was removed by rotary evaporation to obtain intermediate 2.

[0052] Step A3: Intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane were mixed, dry nitrogen was introduced to protect the reaction system, and methyl acryloyl chloride was slowly added at room temperature and stirred for 2.5h. Then the temperature was increased to 70°C and the reaction was continued for 1.3h. The amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane was 0.1mol: 0.2mol: 6.2g: 390mL. After the reaction was completed, water was added after cooling to wash, the aqueous phase was separated and vacuum dried to obtain intermediate 3.

[0053] Step A4: Intermediate 3, 1-iodopropane and toluene were mixed, the temperature was increased to 80°C and stirred to reflux for 12h. The amount ratio of intermediate 3, 1-iodopropane and toluene was 0.1mol: 0.55mol: 140mL. After the reaction was completed, the toluene was removed by rotary evaporation under reduced pressure to obtain the modified embedding agent.

[0054] Step A5: Sodium silicate, calcium acetate and deionized water were mixed, the modified embedding agent was added, and sheared at 1400rpm for 4min. Then pentaerythritol tetraacrylate was mixed and the temperature was controlled at 65°C by water bath. A 10% ammonium persulfate solution was prepared, and ammonium persulfate solution was slowly added and stirred for 3.5h. The amount ratio of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water was 50g: 22g: 9.5g: 3.7g: 0.9g: 600mL. Finally, the self-repairing agent was obtained by spray drying.

[0055] (2) Preparation of self-repairing composite concrete

[0056] The following raw materials are mixed according to the weight ratio: 380 parts of ordinary Portland cement, P.042.5 type cement is selected; 1000 parts of crushed stone, 5-20 mm continuous graded granite machine material is selected; 720 parts of sand, machine-made sand with a modulus of about 2.6 is selected; 30 parts of mineral powder, S95 grade mineral powder is selected; 8.2 parts of self-repairing agent, self-made in this example; 3.8 parts of water reducing agent, MPEG-500 type non-ionic agent is selected; 190 parts of water.

[0057] The ordinary Portland cement, sand, mineral powder and self-repairing agent are pre-mixed in the mixer, then the crushed stone is mixed, and then the water reducing agent is dispersed in water and mixed with the mixture to obtain the self-repairing composite concrete.

[0058] In example 4, the self-repairing composite concrete is prepared, and the specific implementation process is as follows:

[0059] (1) Preparation of self-repairing agent

[0060] Step A1: N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran are mixed, dry nitrogen is introduced for protection, an ice water bath is used to control the temperature of the reaction system to 10℃, and diethenyl dichlorosilane is slowly added and stirred for 2.5h, wherein the amount ratio of diethenyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran is 0.1mol:0.2mol:12mL:280mL, after the reaction is completed, the salt is removed by filtration, and the tetrahydrofuran is removed by rotary evaporation to obtain intermediate 1.

[0061] Step A2: Intermediate 1, mercaptoethanol, photoinitiator and acetone are mixed, 365nm ultraviolet light is applied at room temperature, the intensity is controlled to be 50mW / cm 2 , and stirring reaction is carried out for 3.2h, wherein PI-1173 is used as the photoinitiator, and the amount ratio of intermediate 1, mercaptoethanol, photoinitiator and acetone is 0.1mol:0.2mol:0.18g:200mL, after the reaction is completed, the acetone is removed by rotary evaporation to obtain intermediate 2.

[0062] Step A3: Intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane are mixed, dry nitrogen is introduced for protection, methyl acryloyl chloride is slowly added at room temperature and stirred for 2.2h, and then the temperature is increased to 75℃ and the reaction is continued for 1.2h, wherein the amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane is 0.1mol:0.2mol:6g:380mL, after the reaction is completed, water is added for washing after cooling, the water phase is separated, and then vacuum drying is carried out to obtain intermediate 3.

[0063] Step A4: Intermediate 3, 1-iodopropane and toluene were mixed, and the mixture was stirred at 75℃ under reflux for 13h. The amount of Intermediate 3, 1-iodopropane and toluene was 0.1 mol: 0.58 mol: 130 mL. After the reaction was completed, toluene was removed by rotary evaporation under reduced pressure to obtain the modified embedding agent.

[0064] Step A5: Sodium silicate, calcium acetate and deionized water were mixed, and the modified embedding agent was added. The mixture was sheared at 1500 rpm for 4 min, then pentaerythritol tetraacrylate was added and mixed. The temperature was controlled at 65℃ by water bath. A 10% ammonium persulfate solution was prepared, and ammonium persulfate solution was slowly added. The mixture was stirred for 3.8h. The amount of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water was 50g: 20g: 9.2g: 4.1g: 1g: 620mL. Finally, spray drying was performed to obtain the self-repairing agent.

[0065] (2) Preparation of self-repairing composite concrete

[0066] The following raw materials were mixed according to the weight ratio: Portland cement 390 parts, P.O 42.5 type cement was selected; gravel 1080 parts, 5-20 mm continuous graded granite machine-made material was selected; sand 735 parts, machine-made sand with a modulus of about 2.6 was selected; mineral powder 25 parts, S95 grade mineral powder was selected; self-repairing agent 9.8 parts, self-made according to the embodiment; water reducing agent 3.5 parts, MPEG-500 type non-ionic agent was selected; water 195 parts.

[0067] The Portland cement, sand, mineral powder and self-repairing agent were added to the mixer for pre-mixing, then the gravel was added and mixed evenly. The water reducing agent was dispersed in water and mixed with the mixture to obtain the self-repairing composite concrete.

[0068] Comparative Example 1, according to Example 4, the self-repairing agent was replaced by 5.8 parts of sodium silicate, 2.4 parts of calcium acetate and 1.6 parts of KRQ-S2415 (pre-mixed with water when preparing concrete) type quaternary ammonium concrete additive, and the rest of the implementation process was the same.

[0069] Comparative Example 2, according to the prior art, a microcapsule self-repairing agent with sodium silicate and calcium acetate as the core was prepared. The specific preparation method was as follows:

[0070] Sodium dodecyl sulfate, polyvinylpyrrolidone and water were pre-mixed, sodium silicate and calcium acetate were mixed and high-speed sheared at 2000 rpm for 5 min, then methyl methacrylate and pentaerythritol tetraacrylate were mixed, the water bath was warmed to 60°C, 10wt% ammonium persulfate solution was slowly added and stirred for 6h, wherein the amount ratio of sodium silicate, calcium acetate, methyl methacrylate, pentaerythritol tetraacrylate, ammonium persulfate, sodium dodecyl sulfate, polyvinylpyrrolidone and water was 50g:20g:12g:5.5g:1.5g:2.2g:0.9g:600mL, and the self-repairing agent was obtained after spray drying.

[0071] Referring to Example 4, the self-repairing agent prepared above was used to replace the same amount of Example 4, and 1.2 parts of KRQ-S2415 type quaternary ammonium concrete additive was additionally added, and the rest of the process was the same as Example 4.

[0072] The concrete prepared above was poured into a mold, cured at room temperature for 24h, demolded, and standard cured for 28 days to obtain a test sample; the strength test was performed according to the GB / T 50081-2019 standard, and the permeability test was performed according to the BS EN 12390-8:2019 standard;

[0073] Sample damage and self-repairing test: the sample was cured for 7 days after 100 freeze-thaw cycles according to the GB / T 50082-2024 standard; a stress level of 65% of the initial compressive strength was used for 20 times of repeated stress impact, and then cured for 7 days; the strength and permeability were tested again, and the strength loss rate and permeability change rate were calculated;

[0074] Wherein, σ0: initial compressive strength, σ1: compressive strength after freeze-thaw self-repairing, σ2: compressive strength after repeated stress impact self-repairing, k0: initial permeability coefficient, k1: permeability coefficient after freeze-thaw self-repairing, k2: permeability coefficient after repeated stress impact self-repairing; the freeze-thaw strength loss rate η1=(σ0-σ1) / σ0×100%, the freeze-thaw permeability change rate Δ1=(k1-k0) / k0×100%, the stress impact strength loss rate η2=(σ0-σ2) / σ0×100%, and the stress impact permeability change rate Δ2=(k2-k0) / k0×100%; the specific test results are shown in Table 1:

[0075] Table 1

[0076] [σ0 / MPa] [k0 / m·s -1 ]]> [eta]1 / % [eta]2 / % Δ1 / % Δ2 / % Example 1 38.8 1.49 x 10 -12 ]]> 16.7 21.9 24.3 50.7 Example 2 40.3 2.17 x 10 -12 ]] 18.6 22.8 27.1 53.9 Example 3 37.9 2.55 x 10 -12 ]] 15.2 27.3 20.8 44.6 Example 4 39.5 1.62 x 10 -12 ]]> 14.4 20.2 18.5 38.2 Comparative Example 1 41.1 1.14 x 10 -12 ]] 30.1 30.5 104.9 255.3 Comparative Example 2 34.6 5.38 x 10 -12 ]] 25.5 33.2 72.6 181.7

[0077] From the data in Table 1, it can be seen that the compressive strength of the concrete prepared in the examples is high and the permeability coefficient is low after curing, and the concrete has good anti-permeability performance. After self-repairing under the impact of freeze-thaw and external damage, the strength loss rate and the permeability change rate are significantly lower than those of the existing self-repairing system, which endows the concrete with excellent self-repairing ability.

[0078] In the description of the specification, the description of the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. The above is only an example and illustration of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A self-healing composite concrete, characterized in that, The components by weight are: ordinary Portland cement 380-410 parts, broken stone 1000-1200 parts, sand 720-760 parts, mineral powder 25-35 parts, self-repairing agent 8.2-10.5 parts, water reducing agent 3.5-4.3 parts, and water 190-210 parts; The self-repairing agent is prepared by the following method: Step A1: N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran are mixed, dry nitrogen is introduced for protection, the reaction system temperature is controlled to be not higher than 10 DEG C by ice water bath, and diethenyl dichlorosilane is slowly added for stirring reaction for 2.5-3h to prepare intermediate 1; Step A2: Intermediate 1, mercaptoethanol, photoinitiator and acetone were mixed at 40-50 mW / cm 2 The reaction was stirred under UV irradiation for 3-4 h to produce intermediate 2; Step A3: Intermediate 2, 4-dimethylaminopyridine and anhydrous dioxane are mixed, dry nitrogen is introduced for protection, methyl acryloyl chloride is slowly added at room temperature for stirring reaction for 2-3h, and then the temperature is increased to 60-80 DEG C for continuing reaction for 1-1.5h to prepare intermediate 3; Step A4: Intermediate 3, 1-iodopropane and toluene are mixed, the temperature is increased to 70-85 DEG C for stirring reflux for 10-15h to prepare modified embedding agent; Step A5: Sodium silicate, calcium acetate and deionized water are mixed, the modified embedding agent is added for shearing dispersion, then pentaerythritol tetraacrylate is added for mixing, the temperature is controlled to be 60-70 DEG C by water bath, ammonium persulfate solution is slowly added for stirring reaction for 3-4h, and then self-repairing agent is obtained by spray drying.

2. A self-healing composite concrete according to claim 1, characterized in that The amount ratio of diethenyl dichlorosilane, N, N-dimethylpropanolamine, triethylamine and anhydrous tetrahydrofuran is 0.1mol:0.2mol:10-14mL:220-300mL.

3. A self-healing composite concrete according to claim 2, wherein The amount ratio of intermediate 1, mercaptoethanol, photoinitiator and acetone is 0.1mol:0.2mol:0.15-0.2g:180-240mL.

4. A self-healing composite concrete according to claim 3, wherein The amount ratio of intermediate 2, methyl acryloyl chloride, 4-dimethylaminopyridine and anhydrous dioxane is 0.1mol:0.2mol:5.5-7g:350-420mL.

5. A self-healing composite concrete according to claim 4, wherein The amount ratio of intermediate 3, 1-iodopropane and toluene is 0.1mol:0.5-0.62mol:120-160mL.

6. A self-healing composite concrete according to claim 5, wherein The amount ratio of sodium silicate, calcium acetate, modified embedding agent, pentaerythritol tetraacrylate, ammonium persulfate and deionized water is 50g:15-25g:8.5-10g:3.7-4.5g:0.8-1g:550-650mL.

7. The self-healing composite concrete according to claim 1, wherein, The water reducing agent is a non-ionic preparation.

8. A method of producing a self-healing composite concrete according to any one of claims 1-7, characterized in that, Specifically, ordinary Portland cement, sand, mineral powder and self-repairing agent are premixed, then broken stone is added for mixing, then the water reducing agent is dispersed in water and mixed with the mixture to obtain self-repairing composite concrete.

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