Self-repairing channel lining concrete with added microbial capsule repair agent and preparation method thereof

Abstract

The present invention discloses a self-repairing channel lining concrete with added microbial capsule repair agent, the concrete being composed of the following components: cement, sand, crushed stone, fly ash, metakaolin, phosphorus slag powder, water reducer, air entraining agent, modified plant fiber, water, and microbial capsule repair agent. The present invention also provides a method for preparing the microbial capsule repair agent, which uses a physical-chemical method to treat waste rubber, prepares a modified porous rubber carrier with a three-dimensional network structure by melt blending and vulcanization, immobilizes spores in the carrier pores by negative pressure adsorption, and then sprays a germination agent and a protective layer. After curing, the microbial capsule repair agent is obtained. By adding the microbial capsule repair agent, the present invention activates microbial spores when cracks appear in the concrete, and generates mineralized deposits through metabolic reactions to automatically repair the cracks. The present invention also has the advantages of suitable strength, low elastic modulus, and excellent frost resistance, effectively extending the service life of the channel and reducing maintenance costs.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering composite materials, and particularly relates to a self-repairing channel lining concrete added with a microbial capsule repair agent and a preparation method thereof. Background Art

[0002] Water transfer channels in Northwest China primarily rely on channel lining for anti-seepage. This lining is currently the most widely used type of lining in my country, due to its readily available raw materials, good impact resistance, and mature construction techniques. However, due to climatic conditions and agricultural production and planting structures, channels in most parts of Xinjiang also operate in winter (for winter wheat irrigation). Under these operating conditions, the concrete linings of these channels experience significant damage annually. The primary causes of this damage are expansion and frost heave, leading to varying degrees of cracking in the anti-seepage projects. This accelerates the aging process of the anti-seepage projects, damages the anti-seepage structures, wastes water resources, and increases maintenance costs.

[0003] By modifying waste rubber through a combination of physical and chemical processes to create a homogeneous, three-dimensional, reticulated porous material, this material, used as a carrier for microbial remediation agents, can reduce the concrete's elastic modulus, increase its ultimate tensile deformation and frost resistance, and better adapt to the complex and changing working environment of the canal. This technology addresses the environmental pollution and resource waste caused by waste rubber, and has significant economic benefits and social significance.

[0004] Microbial self-healing technology for concrete involves introducing specific microorganisms into concrete and leveraging their metabolic activity to produce mineral compounds, thereby enabling the self-repair of microcracks on or within the concrete surface. This microbial self-healing process proactively identifies and fills cracks in concrete, effectively maintaining the integrity of the concrete structure. The development and application of this technology is of great significance for promoting innovation in building materials, improving the overall performance of building structures, and promoting environmental protection and sustainable development.

[0005] Therefore, it is necessary to combine modified rubber carriers with microbial self-repair technology to develop a self-repairing channel lining concrete incorporating a microbial capsule repair agent. Applying this technology to water channel lining projects in Northwest my country not only fully utilizes waste rubber resources, rationally utilizes resources, and reduces environmental pollution, but is expected to provide a more reliable, environmentally friendly, and economical solution for water channel projects in the region, further promoting the efficient use and rational allocation of water resources. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the shortcomings of the above-mentioned prior art and provide a self-repairing channel lining concrete with the addition of a microbial capsule repair agent. By adding the microbial capsule repair agent, when cracks develop during use after pouring the self-repairing channel lining concrete, the carrier ruptures, spores are activated, and microorganisms, through metabolic reactions such as denitrification and ureolysis, produce calcium carbonate mineral deposits, which fill the cracks and prevent external corrosion particles from further invading the concrete structure. This provides the advantages of timely repair without the need for external measures, effectively extending the service life of the channel and reducing maintenance costs.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a self-repairing channel lining concrete with added microbial capsule repair agent, characterized in that the concrete is composed of the following components in parts by mass: 205-220 parts of cement, 734-740 parts of sand, 1250-1260 parts of crushed stone, 56-66 parts of fly ash, 15-25 parts of metakaolin, 10-18 parts of phosphorus slag powder, 4.515-4.710 parts of water reducer, 0.205-0.225 parts of air entraining agent, 0.8-1.2 parts of modified plant fiber, and 117-122 parts of water; 0.2m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ~0.6m 3 .

[0008] The present invention controls the composition of concrete and adds a microbial capsule repair agent thereto, so that the self-repairing channel lining concrete with the added microbial capsule repair agent has the characteristics of suitable strength, low elastic modulus, large ultimate tensile deformation, excellent antifreeze performance, etc.; and when cracks are generated in the self-repairing channel lining concrete with the added microbial capsule repair agent after pouring during use, the carrier ruptures, the spores are activated, and the microorganisms generate calcium carbonate mineralization deposits through metabolic reactions such as denitrification and urealysis, filling the cracks and preventing external corrosion particles from continuing to invade the concrete components. The invention has the advantages of timely repair and the ability to repair cracks without the help of external measures, effectively extending the service life of the channel and reducing maintenance costs.

[0009] In the present invention, sisal fiber is processed into modified plant fiber with a length of 10 mm to 20 mm after being hydrolyzed by strong alkaline solution, ultrasonically heated, neutralized, washed, soaked in silane coupling agent and dried. The density of the modified plant fiber is 1.42 g / cm 3 , tensile strength is 512MPa, tensile modulus is 32GPa, and elongation at break is 6.7%.

[0010] The self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the preparation method of the microbial capsule repair agent comprises the following steps:

[0011] Step 1: Sorting and crushing of waste rubber: crushing and separating the waste rubber to obtain rubber powder with a particle size of less than 16 mesh;

[0012] Step 2: Cleaning: Soak the rubber powder obtained in step 1 in clean water and alkaline solution in turn, then wash it to neutrality and dry it;

[0013] Step 3: Ultrasonic desulfurization and activation treatment: The rubber powder dried in step 2 is activated using an ultrasonic energy-focusing transducer, and then aged in a dry environment to obtain desulfurized and activated rubber powder;

[0014] Step 4, melt blending and vulcanization treatment: The desulfurized activated rubber powder obtained in step 3, polylactic acid, polybutylene terephthalate-adipate and a crosslinking agent are placed in a high temperature, high shear mixer for melt blending and dynamic vulcanization to obtain dynamically vulcanized rubber powder;

[0015] Step 5: Cooling and grinding: placing the rubber powder obtained in step 4 after dynamic vulcanization treatment in a dry constant temperature chamber to cool, and then grinding to obtain micro rubber powder with a particle size of less than 100 mesh;

[0016] Step 6: preparing a dormant spore suspension: culturing dormant spores of urease-decomposing bacteria and denitrifying bacteria, respectively, to obtain a urease-decomposing bacteria dormant spore suspension and a denitrifying bacteria dormant spore suspension, respectively;

[0017] Step 7, Preparation of Bacteria-Loaded Microgel Powder: The microgel powder obtained in step 5 is placed in a vacuum chamber, which is then evacuated. The dormant spore suspension of the urease-degradable bacteria obtained in step 6 is then sucked into the vacuum chamber through a pipe using the negative pressure within the vacuum chamber to be adsorbed by the microgel powder. The vacuum chamber is then opened to dry the product to obtain bacteria-loaded microgel powder A. The above process is repeated with the dormant spore suspension of the denitrifying bacteria obtained in step 6 to obtain bacteria-loaded microgel powder B.

[0018] Step 8, preparing a spore nutrient germination agent: uniformly mixing the C source, the N source and the spore germination agent to obtain a spore nutrient germination agent;

[0019] Step 9, coating the bacteria-loaded microgel powder with a spore nutrient germination agent: placing the bacteria-loaded microgel powder A obtained in step 7 into a blender for stirring, adding the spore nutrient germination agent obtained in step 8 into a high-pressure spraying device, and then spraying the spore nutrient germination agent on the surface of the bacteria-loaded microgel powder A in a stirred state, and then aging and drying to obtain germinated bacteria-loaded microgel powder A, repeating the above process with the bacteria-loaded microgel powder B obtained in step 7 to obtain germinated bacteria-loaded microgel powder B;

[0020] Step 10, preparation of a protective shell of bacteria-carrying microgel powder: cement, calcium-based bentonite, CaCl2 and water are mixed to obtain a slurry, and then the slurry is mixed with sodium silicate to obtain a protective liquid, and then the protective liquid is added to a high-pressure spraying device, and the germinated bacteria-carrying microgel powder A obtained in step 9 is placed in a mixer for stirring, and the protective liquid is sprayed on the surface of the germinated bacteria-carrying microgel powder A in a stirring state, and then cured and dried to obtain a protective shell of bacteria-carrying microgel powder A, and the above process is repeated with the bacteria-carrying microgel powder B obtained in step 9 to obtain a protective shell of bacteria-carrying microgel powder B;

[0021] Step 11, microbial capsule repair agent: grind the protective shell-loaded bacteria microgel powder A and the protective shell-loaded bacteria microgel powder B obtained in step 10 separately, pass through a 100-mesh sieve, and then mix them to obtain the microbial capsule repair agent.

[0022] The waste rubber in the invention adopts old rubber tires with seriously damaged tire bodies, and the steel wire bundles in the old rubber tires can also be separated and recycled.

[0023] The present invention removes impurities such as oil, dust, and organic matter from the rubber surface, thereby increasing the roughness and hydrophilicity of the rubber surface and improving the interfacial bonding between the rubber aggregate and the cement matrix. Furthermore, ultrasonic desulfurization and activation treatment is performed, in which the acoustic energy directly acts on the waste rubber powder to cavitate it, destroying the CS bonds and SS bonds in the vulcanized rubber, which have lower energy than the CC bonds, and selectively destroying the three-dimensional network structure to achieve desulfurization and regeneration. The physical and mechanical properties of the vulcanized regenerated rubber are similar to those of the original rubber material, and the product has the advantages of high product quality, no pollution, and low energy consumption. Through melt blending and vulcanization treatment, the dynamically vulcanized rubber powder prepared has a uniform and continuous honeycomb network structure, a homogeneous three-dimensional spatial network structure, high specific surface area, multiple cavities, and excellent adsorption effect. Furthermore, during the melt blending process of the desulfurized activated rubber powder with organic materials such as polylactic acid and polybutylene terephthalate-adipate, the secondary components undergo decomposition and transform into a dispersed phase with a smaller particle size, which reduces the spacing between the dispersed phase particles and thus improves its toughness.

[0024] The aforementioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the sequential soaking in clean water and alkaline solution in step 2 comprises soaking in clean water for 6 to 8 hours, with mechanical stirring for 10 minutes every 2 to 3 hours, followed by removal and soaking in a 1.0 to 2.0 mol / L NaOH solution for 24 hours, with mechanical stirring for 10 minutes every 4 to 6 hours. By controlling the soaking and cleaning parameters, the present invention fully removes impurities such as oil, dust, and organic matter from the rubber surface, increases the roughness and hydrophilicity of the rubber surface, and improves the interfacial bonding between the rubber aggregate and the cement matrix.

[0025] The above-mentioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the frequency of the ultrasonic energy-focusing transducer in the activation treatment in step 3 is 20KHz to 50KHz, the activation treatment time is 10min to 20min, and the aging time is 6h to 10h. The present invention controls the parameters of the activation treatment so that the ultrasonic wave generated by the ultrasonic energy-focusing transducer can directly act on the dried rubber powder, causing cavitation, destroying the CS bonds and SS bonds in the vulcanized rubber, which have lower energy than the CC bonds, selectively destroying the three-dimensional network structure, and achieving desulfurization and regeneration. The physical and mechanical properties of the desulfurized activated rubber powder are similar to those of the original rubber material, and it has the advantages of high product quality, no pollution, and low energy consumption.

[0026] The above-mentioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the mass ratio of the desulfurized activated micro-gel powder, polylactic acid and polybutylene terephthalate-adipate in step 4 is 5-7:2-3:1-2, the cross-linking agent is one or more of dicumyl peroxide, benzoyl peroxide and diethylenetriamine, the dosage of the cross-linking agent is 2% to 5% of the mass of the desulfurized activated rubber powder, the temperature of the high temperature and high shear mixer in the melt blending is 150°C to 190°C, and the pressure is 10kg / cm 2 ~20kg / cm 2 , the rotation speed is 150rpm to 300rpm, and the melt blending time is 20min to 40min. In the present invention, by controlling the ratio of each raw material and the melt blending parameters, the secondary components undergo decomposition in the melt blending process of the desulfurized activated micro-gel powder and the organic matter, and are transformed into a dispersed phase with a smaller particle size, so that the spacing between the dispersed phase particles is also reduced accordingly, thereby improving its toughness. The prepared rubber powder after dynamic vulcanization treatment has a uniform and continuous honeycomb network structure, which is a homogeneous three-dimensional spatial network structure with the characteristics of high specific surface area, multiple cavities, etc., and exhibits excellent adsorption effect. Using the rubber powder after dynamic vulcanization treatment as a bacterial carrier has the advantages of simple procedure, saving bacterial spores, low cost and better crack resistance.

[0027] The self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the urease-decomposing bacteria in step 6 are Bacillus clausii and Saccharomyces cerevisiae, or Bacillus subtilis and Saccharomyces cerevisiae, and the denitrifying bacteria are Pseudomonas aeruginosa and Lysinibacillus sphaericus, or Alishewanella and Lysinibacillus sphaericus; the culturing process is as follows: dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria are inoculated into spore-forming culture medium respectively, placed in a constant temperature shaking incubator, the internal environment has an internal pH value of 9-11, a temperature of 30°C-40°C, a liquid volume of 100mL, a shaker speed of 150rpm-180rpm, and cultured for 4d, then the cultured liquid is divided into 100mL-200mL centrifuge tubes, centrifuged at 4000rpm-6000rpm, 0°C-4°C for 3min-5min, and repeatedly centrifuged and washed three or more times, resuspended in deionized water, and placed in a refrigerator at 0°C-4°C for standby use; the vacuuming in step seven is to vacuumize to -0.04MPa--0.08MPa, the adsorption time is 5min-10min, and the drying adopts a blast drying oven, the drying temperature is 30°C-40°C, and the time is 24h.The core strain of the urease-decomposing strain in the present invention is Bacillus clausii (Bacillus clausii) or Bacillus subtilis (Bacillus subtilis), and the auxiliary strain is Saccharomyces cerevisiae (Saccharomyces cerevisiae), which can generate NH3 through metabolism; the core strain of the denitrifying strain is Pseudomonas aeruginosa (Pseudomonas aeruginosa) or Alishewanella (Alternative Ximei bacteria), and the auxiliary strain is Lysinibacillus sphaericus (spherical lysine Bacillus), which can generate NO2 / NH3 through metabolism; the present invention adopts urease-decomposing bacteria and denitrifying bacteria as core mineralizing bacteria to form a multi-remediation bacteria, which satisfies the requirement that there are bacteria that can metabolize under aerobic and anaerobic conditions, overcomes the defect of a small scope of use of a single bacteria, and adopts bacteria of the type adapted to it as auxiliary bacteria. The two bacteria can not only jointly cope with the impact of the outside world through synergistic action, but also solve the problem of insufficient yeast extract in the later mineralization due to early consumption; for a single repair system, the multi-remediation system can not only coordinate the joint action of multiple metabolic mechanisms in the system, but also undertake more tasks and be more in line with the actual environment of coexistence of multiple bacteria outside, thereby maintaining the stability of microbial mineralization. In addition, in the present invention, the culture medium and culture dish are sterilized during the culture process, and all materials such as the reagents are sterilized in a high-pressure sterilizer at 121°C to 130°C for more than 30 minutes, thereby ensuring the quality of the bacteria.

[0028] It should be noted that Bacillus clausii (Bacillus clausii) strain number: ATCC 700160, storage number: No. SDSJ-JZ2024001; Saccharomyces cerevisiae (beer yeast) strain number: BMZ071744, storage number: No. SDSJ-JZ2024002; Bacillus subtilis (Bacillus subtilis) strain number: CICC 25023, storage number: No. SDSJ-JZ2024003; Pseudomonas aeruginosa (Pseudomonas aeruginosa) strain number: BNCC360090, storage number: No. SDSJ-JZ2024004; Lysinibacillus sphaericus (Lysinibacillus sphaericus) strain number: NCIB 8216, storage number: No.SDSJ-JZ2024005; Alishewanella (alternative Shewanella) strain number: SDUM 163001, storage number: No.SDSJ-JZ2024006; the above strains are all preserved in the strain collection. The strains that are not used for a long time are preserved at a deep low temperature. The 4℃ refrigerator is often used for short-term strain preservation in daily work.

[0029] The self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the C source in step eight is glucose, the N source is trypsin and urea, and the spore germination agent is prepared from pyridine-2,6-dicarboxylic acid, L-calcium lactate, L-alanine, carboxymethyl cellulose, NaH2PO4, Na2MoO4, MgCO3, Cu(NO3)2 and CaCl2. In the present invention, L-alanine, as a specific amino acid, provides a nitrogen source and plays an important catalytic role in the bacterial spore germination process; Ca 2+ 、Na + 、Cu 2+ As a cofactor of certain enzymes, it can promote the binding of amino acid growth-promoting factor DPA to germination receptors and enter the spore body in the form of coordinated transport, thereby promoting the earlier binding of germination factors to germination receptors, with a significant stimulation effect; L-calcium lactate is an important nutrient and calcium source for bacteria. When cracks appear in concrete, water will penetrate into the cracks and come into contact with capsules containing microorganisms and calcium lactate, causing the capsules to melt and activate microorganisms to feed on calcium lactate and produce limestone, thereby repairing the cracks; Mo 6+ etc. participate in the composition of nitrate reductase and play an important role in nitrogen metabolism; NaH2PO4, Mg 2+ It has a significant stimulating effect on microbial urease and can significantly increase the activity of urease; carboxymethyl cellulose can not only increase the adhesiveness of the spore nutrient germination agent, making it more adherent, but also provide a certain carbon source.

[0030] The above-mentioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the stirring speed in step nine is 400r / min~600r / min, the time is 8min~12min, the spraying flow rate is 0.5mL / s~2mL / s, the time is 3min~4min, the aging time is 24h, and the drying is carried out in a blast drying oven, the drying temperature is 30℃~40℃, and the time is 24h.

[0031] The above-mentioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the mass ratio of cement, calcium-based bentonite and CaCl2 in step ten is 20-40:50-65:5-10, the solid-liquid ratio of the slurry is 0.6-1:1, the volume ratio of the slurry to sodium silicate is 1-2:1, the stirring speed is 400r / min-600r / min, the time is 3min-5min, the spraying flow rate is 0.5mL / s-2mL / s, the time is 2min-3min, the curing time is 48h, and the drying adopts a blast drying oven, the drying temperature is 30℃-40℃, and the time is 24h. Since the bacteria-carrying micro-gel powder is easily destroyed and damaged by the mutual collision and friction between aggregates during the concrete mixing process, the present invention uses sodium silicate, which is a readily available and inexpensive raw material and will not cause adverse effects on cement-based materials, to react with cement, calcium-based bentonite and CaCl2 to generate silica gel and calcium silicate gel, which plays a role in cementation and pore sealing, thereby improving the strength and carrying capacity of the micro-gel powder. A large number of microbial spores are immobilized inside the porous micro-gel powder carrier, and the spore nutrient germination agent effectively promotes microbial germination. The protective layer material formed by the reaction of sodium silicate and calcium chloride can form a protective layer structure on the carrier surface, which has the effects of moderate strength, brittle texture and good wrapping properties, and can effectively solve the fatal defect of poor interface stability with cement-based materials. At the same time, it reduces and reduces the effect of rubber particles on attracting large-pore gas, thereby improving the strength of concrete.

[0032] In addition, the present invention also provides a method for preparing self-repairing channel lining concrete with added microbial capsule repair agent, characterized in that the method comprises the following steps:

[0033] Step 101: Put sand and gravel into a mixer and stir for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates;

[0034] Step 102: uniformly adding the modified plant fiber to the mixer containing coarse and fine aggregates obtained in step 101 by a shaker or disperser and stirring for more than 30 seconds to obtain a mixer containing coarse and fine aggregates and fibers;

[0035] Step 103: Evenly mix cement, fly ash, metakaolin, phosphorus slag powder, and air-entraining agent, and then divide the mixture into three equal parts to obtain three parts of cementitious materials;

[0036] Step 104: adding the two portions of cementitious materials obtained in step 103 to the mixer containing coarse and fine aggregates and fibers obtained in step 102 and stirring for more than 30 seconds, then adding two-thirds of the total water and a water reducer and stirring for more than 60 seconds to obtain a mixer containing a mixture;

[0037] Step 105: Evenly mix the remaining portion of the cementitious material in step 103 with the microbial capsule repair agent, and then add it together with the remaining one-third of water into the mixer containing the mixture obtained in step 104 and stir for more than 60 seconds to obtain a self-repairing channel lining concrete with the addition of the microbial capsule repair agent.

[0038] The present invention adds different materials in batches, which can protect the microbial capsule repair agent to the greatest extent and reduce damage, and make it more evenly dispersed in the overall structure of the concrete. First, during the concrete preparation process, the early stirring operation may cause certain damage to the microbial capsule repair agent. Mixing the microbial capsule repair agent with the remaining portion of cementitious material and then adding it for the second time can reduce the adverse effects such as mechanical damage it suffers during the early stirring process; secondly, after the first addition of two portions of cementitious material and most of the water for stirring, a certain structural framework has been formed inside the concrete. At this time, adding the cementitious material containing the microbial capsule repair agent and the remaining water can make the microbial capsule repair agent more evenly dispersed in this relatively stable structural framework. Compared with mixing all at the beginning, due to the complex interaction between materials such as aggregate and cement during the early stirring process, the microbial capsule repair agent may be locally aggregated, affecting its uniformity in the concrete, and thus affecting the repair effect.

[0039] The invention uniformly adds the modified plant fiber into a mixer filled with coarse and fine aggregates through a shaking screen or a disperser, thereby ensuring that the modified plant fiber is uniformly dispersed in the coarse and fine aggregates and avoiding agglomeration.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. The present invention controls the composition of concrete and adds microbial capsule repair agents thereto. When cracks occur in the self-repairing channel lining concrete added with the microbial capsule repair agent after pouring during use, the carrier ruptures, the spores are activated, and the microorganisms generate calcium carbonate mineral deposits through metabolic reactions such as denitrification and urealysis, filling the cracks and preventing external corrosion particles from further invading the concrete components. This has the advantages of timely repair and the ability to repair cracks without the need for external measures, effectively extending the service life of the channel and reducing maintenance costs.

[0042] 2. The self-repairing channel lining concrete with added microbial capsule repair agent used in the present invention has a lower elastic modulus, better ductility, frost resistance and ability to resist deformation in the surrounding environment compared to conventional concrete lining. Waste rubber is prepared into a porous microbial carrier with a homogeneous three-dimensional spatial network structure, realizing resource recycling and reducing resource and environmental pollution.

[0043] 3. The microbial capsule repair agent of the present invention adopts a multi-microbial repair system with two bacteria with different repair mechanisms as the core repair colonies, and adds different auxiliary colonies to assist the metabolism of the core colonies with mineralization and deposition functions, so as to achieve the synergistic effect of multiple core colonies to achieve the purpose of repair, so that it can be repaired under both aerobic and anaerobic conditions, and can adapt to the complex environment in which concrete components actually serve, thereby improving the repair efficiency and scope of application of microbial concrete.

[0044] 4. The protective layer of the microbial capsule repair agent in the present invention has moderate strength, brittle texture, and good wrapping properties, which prevents the loss of microorganisms and nutrients, ensures that it breaks in time when cracks occur, and has good bonding with the concrete interface, effectively ensuring the workability and mechanical properties of the concrete.

[0045] 5. When microcracks form in the self-repairing channel lining concrete to which the microbial capsule repair agent is added in the present invention, the shell of the repair agent ruptures, the spores are activated, and the microorganisms react with CO2 in the air to generate calcium carbonate mineral deposits, thereby filling the cracks. After the cracks are repaired, the spores will enter a dormant state. Compared with traditional crack repair technology, the present invention is more environmentally friendly, timely, and intelligent, and is a new trend in the development of concrete repair technology.

[0046] The technical solution of the present invention is further described in detail below through examples. DETAILED DESCRIPTION

[0047] Example 1

[0048] This embodiment includes the following steps:

[0049] Step 1: Sorting and crushing of waste rubber: crushing and separating the waste rubber to obtain rubber powder with a particle size of less than 16 mesh;

[0050] Step 2: Cleaning: Soak the rubber powder obtained in step 1 in clean water for 7 hours, and mechanically stir for 10 minutes every 2.5 hours, then remove it and soak it in 1.25 mol / L NaOH solution for 24 hours, and mechanically stir for 10 minutes every 5 hours, then wash it until it is neutral and dry it;

[0051] Step 3: Ultrasonic desulfurization and activation treatment: The rubber powder dried in step 2 is activated using an ultrasonic energy-focusing transducer at a frequency of 50 kHz for 15 minutes, and then aged in a dry environment for 8 hours to obtain desulfurized and activated rubber powder;

[0052] Step 4, melt blending and vulcanization treatment: the desulfurized activated rubber powder obtained in step 3, polylactic acid and polybutylene terephthalate-adipate are mixed in a mass ratio of 7:2:1 and a cross-linking agent is added in an amount of 3% of the mass of the desulfurized activated rubber powder, and then placed in a high temperature, high shear mixer at a temperature of 180 ° C and a pressure of 20 kg / cm 2 , melt blending at a rotation speed of 200 rpm for 30 minutes, and dynamically vulcanizing to obtain rubber powder after dynamic vulcanization treatment; the crosslinking agent is dicumyl peroxide;

[0053] Step 5: Cooling and grinding: placing the rubber powder obtained in step 4 after dynamic vulcanization treatment in a dry constant temperature chamber to cool, and then grinding to obtain micro rubber powder with a particle size of less than 100 mesh;

[0054] Step 6: Preparation of dormant spore suspension: culturing dormant bacterial spores of urease-degrading bacteria and denitrifying bacteria respectively to obtain urease-degrading bacterial dormant spore suspension and denitrifying bacterial dormant spore suspension; the urease-degrading bacterial species are Bacillus clausii and Saccharomyces cerevisiae, and the denitrifying bacterial species are Pseudomonas aeruginosa and Lysinibacillus sphaericus; the culture process is as follows: dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria are inoculated into spore-forming culture medium respectively, placed in a constant temperature shaking incubator, the internal environment has an internal pH value of 10, a temperature of 35°C, a liquid volume of 100 mL, a shaker speed of 180 rpm, and cultured for 4 days, then the cultured liquid is divided into 100 mL centrifuge tubes, centrifuged at 5000 rpm, 0°C to 4°C for 5 minutes, and repeatedly centrifuged and washed three or more times, resuspended in deionized water, and placed in a refrigerator at 0°C to 4°C for use;

[0055] Step 7, Preparation of Bacteria-Loaded Microgel Powder: The microgel powder obtained in step 5 is placed in a vacuum chamber, which is then evacuated to -0.06 MPa. The dormant spore suspension of the urease-degradable bacteria obtained in step 6 is then sucked into the vacuum chamber through a pipe using the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 8 minutes. The vacuum chamber is then opened and the product is dried in a forced air drying oven at 35° C. for 24 hours to obtain bacteria-loaded microgel powder A. The above process is repeated with the dormant spore suspension of the denitrifying bacteria obtained in step 6 to obtain bacteria-loaded microgel powder B.

[0056] Step eight, preparation of spore nutrient germination agent: mixing the C source, N source and spore germination agent uniformly to obtain a spore nutrient germination agent; the C source is 3.0 g / L glucose, the N source is 20 g / L tryptone and 40 g / L urea, and the spore germination agent is prepared by 10 mmol / L pyridine-2,6-dicarboxylic acid, 3.0 g / L L-calcium lactate, 1.0 g / L L-alanine, 2.0 g / L carboxymethyl cellulose, 0.30 g / L NaH2PO4, 0.07 g / L Na2MoO4, 0.3 g / L MgCO3, 5.0 g / L Cu(NO3)2 and 0.4 g / L CaCl2;

[0057] Step nine, coating the bacteria-loaded microgel powder with a spore nutrient germination agent: placing the bacteria-loaded microgel powder A obtained in step seven into a blender at a speed of 500 r / min and stirring for 10 minutes, adding the spore nutrient germination agent obtained in step eight into a high-pressure spraying device, and then spraying the spore nutrient germination agent on the surface of the bacteria-loaded microgel powder A in the stirring state at a flow rate of 1 mL / s for 3 minutes, then aging for 24 hours and drying in a blast drying oven at 35° C. for 24 hours to obtain germinated bacteria-loaded microgel powder A, and repeating the above process with the bacteria-loaded microgel powder B obtained in step seven to obtain germinated bacteria-loaded microgel powder B;

[0058] Step 10. Preparation of protective shell of bacteria-loaded microgel powder: Cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 30:65:7 are mixed to obtain a slurry with a solid-liquid ratio of 0.6:1, and then the slurry with a volume ratio of 2:1 is mixed with sodium silicate to obtain a protective liquid, and the protective liquid is added to a high-pressure spraying device. The germinated bacteria-loaded microgel powder A obtained in step 9 is placed in a mixer and stirred at a speed of 500r / min for 5 minutes. The protective liquid is sprayed on the surface of the germinated bacteria-loaded microgel powder A in the stirring state at a flow rate of 2mL / s for 2 minutes, and then cured for 48 hours and dried in a blast drying oven at 35°C for 24 hours to obtain a protective shell of bacteria-loaded microgel powder A. The above process is repeated for the bacteria-loaded microgel powder B obtained in step 9 to obtain a protective shell of bacteria-loaded microgel powder B;

[0059] Step 11, microbial capsule repair agent: grind the protective shell-loaded bacteria microgel powder A and the protective shell-loaded bacteria microgel powder B obtained in step 10 separately, pass through a 100-mesh sieve, and then mix them to obtain the microbial capsule repair agent.

[0060] Comparative Example 1

[0061] The difference between this comparative example and Example 1 is that in step nine, no spore nutrient germination agent is sprayed.

[0062] Comparative Example 1 Compared with Example 1, no spore nutrient germination agent was added. After 4 days of fermentation, the OD600 of the bacteria cultured in Comparative Example 1 was 1.0, and the number of viable bacteria was 0.79×10 9 CFU / mL, the spore production rate was 23.4%, while after culture in Example 1, OD600 = 1.0, the number of viable bacteria was 4.92×10 9 CFU / mL, the spore production rate reached 91.8%, and the spore production rate increased by 292.3%.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that step ten is not performed, and the germinated bacteria-loaded microgel powder A and the germinated bacteria-loaded microgel powder B obtained in step nine are directly ground and passed through a 100-mesh sieve, and then mixed to obtain a microbial capsule repair agent.

[0065] Compared with Example 1, Comparative Example 2 did not spray a protective layer on the repair agent. Example 1 used bentonite-cement-sodium silicate slurry as the coating protective material of the carrier, effectively ensuring the long-term survival of the carried microorganisms. The survival rate of the bacterial community of the microbial capsule repair agent of Comparative Example 2 in concrete after 180 days was only 29.84%, while the survival rate of the microbial capsule repair agent of Example 1 reached 83.97% after 180 days of concrete curing, and the microbial survival rate could be increased by 181.4%.

[0066] After testing, the bulk density of the microbial capsule repair agent prepared in this embodiment is 209kg / m 3 The bulk density of the rubber powder obtained in step 1 is only 105 kg / m 3 , increased by 99.0%. The bulk density of the microbial capsule repair agent prepared in Comparative Example 2 was only 155 kg / m 3 , which is reduced by 34.8% compared with Example 2, the water absorption rate of Example 1 is 15.8%, the water absorption rate of Comparative Example 2 is 69.8%, and the water absorption rate is reduced by 77.4%; the cylinder pressure strength of Comparative Example 2 is 289.6kPa, and the cylinder pressure strength of the microbial capsule repair agent of Example 1 is 585.1kPa, which is increased by 102.0% compared with the micro-gelatin powder without protective layer spraying. The surface of the microbial capsule repair agent of Example 1 is wrapped with nutrients and protective layers with high strength and dense structure, and the wrapping material has good interface bonding with the micro-gelatin powder, thereby improving strength and reducing water absorption.

[0067] Example 2

[0068] This embodiment includes the following steps:

[0069] Step 1: Sorting and crushing of waste rubber: crushing and separating the waste rubber to obtain rubber powder with a particle size of less than 16 mesh;

[0070] Step 2: Cleaning: Soak the rubber powder obtained in step 1 in clean water for 8 hours, and mechanically stir for 10 minutes every 2 hours, then remove it and soak it in 1.0 mol / L NaOH solution for 24 hours, and mechanically stir for 10 minutes every 4 hours, then wash it until it is neutral and dry it;

[0071] Step 3: Ultrasonic desulfurization and activation treatment: The rubber powder dried in step 2 is activated using an ultrasonic energy-focusing transducer at a frequency of 40 kHz for 10 minutes, and then aged in a dry environment for 6 hours to obtain desulfurized and activated rubber powder;

[0072] Step 4, melt blending and vulcanization treatment: the desulfurized activated rubber powder obtained in step 3, polylactic acid and polybutylene terephthalate-adipate are mixed in a mass ratio of 6:2.5:1.5 and a cross-linking agent is added in an amount of 5% of the mass of the desulfurized activated rubber powder. Then, the mixture is placed in a high temperature, high shear mixer at a temperature of 190°C and a pressure of 10 kg / cm 2 , melt blending at a rotation speed of 300 rpm for 20 minutes, and dynamically vulcanizing to obtain rubber powder after dynamic vulcanization treatment; the crosslinking agent is benzoyl peroxide;

[0073] Step 5: Cooling and grinding: placing the rubber powder obtained in step 4 after dynamic vulcanization treatment in a dry constant temperature chamber to cool, and then grinding to obtain micro rubber powder with a particle size of less than 100 mesh;

[0074] Step 6: Preparation of dormant spore suspension: culturing dormant bacterial spores of urease-degrading bacteria and denitrifying bacteria to obtain urease-degrading bacterial dormant spore suspension and denitrifying bacterial dormant spore suspension, respectively; the urease-degrading bacterial species are Bacillus subtilis and Saccharomyces cerevisiae, and the denitrifying bacterial species are Alishewanella and Lysinibacillus sphaericus; the culture process is as follows: dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria are inoculated into spore-forming culture medium respectively, placed in a constant temperature shaking incubator, the internal environment has an internal pH value of 9, a temperature of 40°C, a liquid volume of 100 mL, a shaker speed of 150 rpm, and cultured for 4 days, then the cultured liquid is divided into 200 mL centrifuge tubes, centrifuged at 6000 rpm, 0°C to 4°C for 3 minutes, and repeatedly centrifuged and washed three or more times, resuspended in deionized water, and placed in a refrigerator at 0°C to 4°C for use;

[0075] Step 7, Preparation of Bacteria-Loaded Microgel Powder: The microgel powder obtained in step 5 is placed in a vacuum chamber, which is then evacuated to -0.08 MPa. The dormant spore suspension of the urease-degradable bacteria obtained in step 6 is then sucked into the vacuum chamber through a pipe using the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 5 minutes. The vacuum chamber is then opened and the product is dried in a forced air drying oven at 30° C. for 24 hours to obtain bacteria-loaded microgel powder A. The above process is repeated with the dormant spore suspension of the denitrifying bacteria obtained in step 6 to obtain bacteria-loaded microgel powder B.

[0076] Step eight, preparation of spore nutrient germination agent: mixing the C source, N source and spore germination agent uniformly to obtain a spore nutrient germination agent; the C source is 3.0 g / L glucose, the N source is 20 g / L tryptone and 40 g / L urea, and the spore germination agent is prepared by 10 mmol / L pyridine-2,6-dicarboxylic acid, 3.0 g / L L-calcium lactate, 1.0 g / L L-alanine, 2.0 g / L carboxymethyl cellulose, 0.30 g / L NaH2PO4, 0.07 g / L Na2MoO4, 0.3 g / L MgCO3, 5.0 g / L Cu(NO3)2 and 0.4 g / L CaCl2;

[0077] Step nine, coating the bacteria-loaded microgel powder with a spore nutrient germination agent: placing the bacteria-loaded microgel powder A obtained in step seven into a blender at a speed of 400 r / min and stirring for 12 minutes, adding the spore nutrient germination agent obtained in step eight into a high-pressure spraying device, and then spraying the spore nutrient germination agent on the surface of the bacteria-loaded microgel powder A in the stirring state at a flow rate of 0.5 mL / s for 4 minutes, then aging for 24 hours and drying in a blast drying oven at 30° C. for 24 hours to obtain germinated bacteria-loaded microgel powder A, and repeating the above process with the bacteria-loaded microgel powder B obtained in step seven to obtain germinated bacteria-loaded microgel powder B;

[0078] Step 10. Preparation of protective shell of bacteria-loaded microgel powder: Cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 20:65:5 are mixed to obtain a slurry with a solid-liquid ratio of 0.8:1, and then the slurry with a volume ratio of 1.5:1 is mixed with sodium silicate to obtain a protective liquid, and the protective liquid is added to a high-pressure spraying device. The germinated bacteria-loaded microgel powder A obtained in step 9 is placed in a mixer and stirred at a speed of 600 r / min for 3 minutes. The protective liquid is sprayed on the surface of the germinated bacteria-loaded microgel powder A in the stirring state at a flow rate of 0.5 mL / s for 3 minutes, and then cured for 48 hours and dried in a blast drying oven at 30°C for 24 hours to obtain a protective shell of bacteria-loaded microgel powder A. The above process is repeated for the bacteria-loaded microgel powder B obtained in step 9 to obtain a protective shell of bacteria-loaded microgel powder B;

[0079] Step 11, microbial capsule repair agent: grind the protective shell-loaded bacteria microgel powder A and the protective shell-loaded bacteria microgel powder B obtained in step 10 separately, pass through a 100-mesh sieve, and then mix them to obtain the microbial capsule repair agent.

[0080] Example 3

[0081] This embodiment includes the following steps:

[0082] Step 1: Sorting and crushing of waste rubber: crushing and separating the waste rubber to obtain rubber powder with a particle size of less than 16 mesh;

[0083] Step 2: Cleaning: Soak the rubber powder obtained in step 1 in clean water for 6 hours, and mechanically stir for 10 minutes every 3 hours, then remove it and soak it in 2.0 mol / L NaOH solution for 24 hours, and mechanically stir for 10 minutes every 6 hours, then wash it until it is neutral and dry it;

[0084] Step 3: Ultrasonic desulfurization and activation treatment: The rubber powder dried in step 2 is activated by an ultrasonic energy-focusing transducer at a frequency of 20 kHz for 20 minutes, and then aged in a dry environment for 10 hours to obtain desulfurized and activated rubber powder;

[0085] Step 4, melt blending and vulcanization treatment: the desulfurized activated rubber powder obtained in step 3, polylactic acid and polybutylene terephthalate-adipate are mixed in a mass ratio of 5:3:2 and a cross-linking agent is added in an amount of 2% of the mass of the desulfurized activated rubber powder. Then, the mixture is placed in a high temperature, high shear mixer at a temperature of 150°C and a pressure of 15 kg / cm 2 , melt blending at a rotation speed of 150 rpm for 40 minutes, and dynamically vulcanizing to obtain rubber powder after dynamic vulcanization treatment; the crosslinking agent is benzoyl peroxide and diethylenetriamine;

[0086] Step 5: Cooling and grinding: placing the rubber powder obtained in step 4 after dynamic vulcanization treatment in a dry constant temperature chamber to cool, and then grinding to obtain micro rubber powder with a particle size of less than 100 mesh;

[0087] Step 6, preparation of dormant spore suspension: culturing dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria respectively to obtain urease-decomposing bacteria dormant spore suspension and denitrifying bacteria dormant spore suspension, respectively; the urease-decomposing bacteria are Bacillus clausii and Saccharomyces cerevisiae, or Bacillus subtilis and Saccharomyces cerevisiae, and the denitrifying bacteria are Pseudomonas aeruginosa and Lysinibacillus sphaericus, or Alishewanella and Lysinibacillus sphaericus; the culture process is as follows: dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria are inoculated into spore-forming culture medium respectively, placed in a constant temperature shaking incubator, the internal environment has an internal pH value of 11, a temperature of 30°C, a liquid volume of 100 mL, a shaker speed of 160 rpm, and cultured for 4 days, then the cultured liquid is divided into 150 mL centrifuge tubes, centrifuged at 4000 rpm, 0°C to 4°C for 4 minutes, and repeatedly centrifuged and washed three or more times, resuspended in deionized water, and placed in a refrigerator at 0°C to 4°C for use;

[0088] Step 7, Preparation of Bacteria-Loaded Microgel Powder: The microgel powder obtained in step 5 is placed in a vacuum chamber, which is then evacuated to -0.04 MPa. The dormant spore suspension of the urease-degradable bacteria obtained in step 6 is then sucked into the vacuum chamber through a pipe using the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 10 minutes. The vacuum chamber is then opened and the product is dried in a forced air drying oven at 40° C. for 24 hours to obtain bacteria-loaded microgel powder A. The above process is repeated with the dormant spore suspension of the denitrifying bacteria obtained in step 6 to obtain bacteria-loaded microgel powder B.

[0089] Step eight, preparation of spore nutrient germination agent: mixing the C source, N source and spore germination agent uniformly to obtain a spore nutrient germination agent; the C source is 3.0 g / L glucose, the N source is 20 g / L tryptone and 40 g / L urea, and the spore germination agent is prepared by 10 mmol / L pyridine-2,6-dicarboxylic acid, 3.0 g / L L-calcium lactate, 1.0 g / L L-alanine, 2.0 g / L carboxymethyl cellulose, 0.30 g / L NaH2PO4, 0.07 g / L Na2MoO4, 0.3 g / L MgCO3, 5.0 g / L Cu(NO3)2 and 0.4 g / L CaCl2;

[0090] Step nine, coating the bacteria-loaded microgel powder with a spore nutrient germination agent: placing the bacteria-loaded microgel powder A obtained in step seven into a blender at a speed of 600 r / min and stirring for 8 minutes, adding the spore nutrient germination agent obtained in step eight into a high-pressure spraying device, and then spraying the spore nutrient germination agent on the surface of the bacteria-loaded microgel powder A in the stirring state at a flow rate of 2 mL / s for 3 minutes, then aging for 24 hours and drying in a blast drying oven at 40° C. for 24 hours to obtain germinated bacteria-loaded microgel powder A, and repeating the above process with the bacteria-loaded microgel powder B obtained in step seven to obtain germinated bacteria-loaded microgel powder B;

[0091] Step 10. Preparation of protective shell of bacteria-loaded microgel powder: Cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 40:50:10 are mixed to obtain a slurry with a solid-liquid ratio of 1:1, and then the slurry with a volume ratio of 1:1 is mixed with sodium silicate to obtain a protective liquid, and the protective liquid is added to a high-pressure spraying device. The germinated bacteria-loaded microgel powder A obtained in step 9 is placed in a mixer and stirred at a speed of 400r / min for 4 minutes. The protective liquid is sprayed on the surface of the germinated bacteria-loaded microgel powder A in the stirring state at a flow rate of 1mL / s for 2.5 minutes, and then cured for 48 hours and dried in a blast drying oven at 40°C for 24 hours to obtain a protective shell of bacteria-loaded microgel powder A. The above process is repeated for the bacteria-loaded microgel powder B obtained in step 9 to obtain a protective shell of bacteria-loaded microgel powder B;

[0092] Step 11, microbial capsule repair agent: grind the protective shell-loaded bacteria microgel powder A and the protective shell-loaded bacteria microgel powder B obtained in step 10 separately, pass through a 100-mesh sieve, and then mix them to obtain the microbial capsule repair agent.

[0093] Example 4

[0094] The concrete in this embodiment is composed of the following components by mass: 210 parts of cement, 737 parts of sand, 1255 parts of crushed stone, 61 parts of fly ash, 20 parts of metakaolin, 14 parts of phosphorus slag powder, 4.575 parts of water reducer, 0.218 parts of air entraining agent, 1.0 parts of modified plant fiber, and 119 parts of water; 0.2m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 .

[0095] This embodiment includes the following steps:

[0096] Step 101: Put sand and gravel into a mixer and stir for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates;

[0097] Step 102: uniformly adding the modified plant fiber to the mixer containing coarse and fine aggregates obtained in step 101 by a shaker or disperser and stirring for more than 30 seconds to obtain a mixer containing coarse and fine aggregates and fibers;

[0098] Step 103: Evenly mix cement, fly ash, metakaolin, phosphorus slag powder, and air-entraining agent, and then divide the mixture into three equal parts to obtain three parts of cementitious materials;

[0099] Step 104: adding the two portions of cementitious materials obtained in step 103 to the mixer containing coarse and fine aggregates and fibers obtained in step 102 and stirring for more than 30 seconds, then adding two-thirds of the total water and a water reducer and stirring for more than 60 seconds to obtain a mixer containing a mixture;

[0100] Step 105: Evenly mix the remaining portion of the cementitious material in step 103 with the microbial capsule repair agent prepared in Example 1, and then add the remaining one-third of the water into the mixer containing the mixture obtained in step 104 and stir for more than 60 seconds to obtain a self-repairing channel lining concrete with the addition of the microbial capsule repair agent.

[0101] Comparative Example 3

[0102] The difference between this comparative example and Example 4 is that no modified plant fiber is added.

[0103] Comparative Example 4

[0104] The difference between this comparative example and Example 4 is that modified plant fiber and microbial capsule repairing agent are not added.

[0105] Example 5

[0106] The concrete in this embodiment is composed of the following components by mass: 210 parts of cement, 737 parts of sand, 1255 parts of crushed stone, 61 parts of fly ash, 20 parts of metakaolin, 14 parts of phosphorus slag powder, 4.575 parts of water reducer, 0.218 parts of air entraining agent, 1.0 parts of modified plant fiber, and 119 parts of water; 0.4m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as that in Example 4.

[0107] Example 6

[0108] The concrete in this embodiment is composed of the following components by mass: 210 parts of cement, 737 parts of sand, 1255 parts of crushed stone, 61 parts of fly ash, 20 parts of metakaolin, 14 parts of phosphorus slag powder, 4.575 parts of water reducer, 0.218 parts of air entraining agent, 1.0 parts of modified plant fiber, and 119 parts of water; 0.6m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as that in Example 4.

[0109] According to the standards such as GB / T 50081, GB / T50082, and DL / T5144, the concrete of Examples 4 to 6 was cast into test pieces and then cured for 28 days to perform performance tests such as workability, mechanical properties, impermeability grade, relative dynamic modulus after 300 freeze-thaw cycles, mass loss, and evaluation of concrete crack self-repair effect. The results are shown in Table 1. The test piece preparation process is as follows: the mixed concrete was placed in a homemade 150 mm long × width × height 150 mm × 15 In the 0mm×50mm test mold, after demolding, it was placed in a standard curing room for curing to 28 days; the process of evaluating the self-repair effect of concrete cracks was as follows: the specimens cured to the specified age were taken out, and the upper and lower surfaces of the specimens were pressurized with upper and lower semicircular top pieces to create cracks, which were marked with a marker. The image processing method was used to count the width and number of cracks in each group of specimens, and the concrete with cracks was fixed with an external fixer to prevent the specimens from being damaged by excessive cracks. The fixed specimens were cured for another 28 days, and the width and number of cracks after repair were recorded.

[0110] Table 1

[0111]

[0112] The difference between Examples 4, 5 and 6 is that the dosage of microbial capsule repair agent is different, which is 0.2m 3 / m 3 , 0.4m 3 / m 3 and 0.6m 3 / m 3 ; The difference between Comparative Example 3 and Examples 4, 5, and 6 is that no modified plant fiber is added; Comparative Example 4 does not add microbial capsule repair agent and modified plant fiber, and is the benchmark group.

[0113] As can be seen from Table 1, the slump results of Examples 4, 5, 6 and Comparative Examples 3 and 4 are between 64 mm and 70 mm, with the maximum and minimum values ​​differing by only 6 mm, all within the concrete design range. Therefore, it can be seen that the addition of microbial capsule repair agents and modified plant fibers has almost no effect on the workability and air entrainment properties of concrete.

[0114] Compared with Comparative Example 4, the compressive strength of Examples 4, 5, 6 and Comparative Example 3 decreased by 3.01%, 3.87%, 8.84% and 6.35%, and the flexural strength decreased by 0.00%, 3.13%, 9.38% and 15.63%. It can be seen that with the increase in the dosage of the microbial capsule repair agent, the compressive strength and flexural strength of the concrete both showed a decreasing trend. Although the microbial capsule repair agent improved the defects of the rubber-cement matrix interface through the encapsulation technology, the mechanical properties of the concrete were reduced due to the low density and compressive strength of the rubber itself. However, they all met the design requirements. The modified plant fiber can improve the mechanical properties of concrete.

[0115] Compared with Comparative Example 4, the elastic moduli of Examples 4, 5, 6 and Comparative Example 3 were all less than 30.4 GPa, which were reduced by 3.29%, 7.24%, 10.20% and 3.62% respectively. This shows that the microbial capsule repair agent can enhance the toughness and ductility of concrete and improve the deformation resistance of the concrete channel lining structure to a certain extent.

[0116] After 300 freeze-thaw cycles, the relative dynamic moduli of Examples 4, 5, 6 and Comparative Example 3 were 81.9%, 86.1%, 80.4% and 78.7%, respectively, and the relative dynamic modulus of Comparative Example 4 was 75.4%, with the relative dynamic moduli increasing by 8.62%, 14.19%, 6.63% and 4.38%, respectively; the mass loss rates of Examples 4, 5, 6 and Comparative Example 3 were 1.99%, 1.43%, 2.23% and 2.77%, respectively, and the mass loss rate of Comparative Example 4 was 2. 89%, and the mass loss rate decreased by 31.14%, 50.52%, 22.84% and 4.15% respectively. From the above test data, it can be seen that the frost resistance of modified rubber microbial self-repairing concrete is greatly improved. This is because the addition of microbial capsule repair agent improves the pore structure of concrete, and its main rubber differential has excellent toughness and ductility of rubber. When frost heave occurs, the micro-gel powder can deform and absorb part of the stress, playing a buffering role and reducing the damage of ice crystal formation to concrete during freeze-thaw cycles.

[0117] Evaluation of crack self-repair effect: When the crack width is not greater than 0.3mm, all cracks in Examples 4, 5, 6 and Comparative Example 3 are repaired after 28d, and the repair rate can reach 100%; Comparative Example 4 has no repair effect; When the crack width is 0.3mm-0.6mm, all cracks in Examples 5 and 6 are repaired after 28d, and the repair rate is 100%; the repair rate of Example 4 is 71.43%; the repair rate of Comparative Example 3 is 60.00%; Comparative Example 4 has no repair effect; When the crack width is greater than 0.6mm, the repair rate of Example 4 is 40.00%, the repair rate of Example 5 is 66.67%, the repair rate of Example 6 is 33.33%, and the repair rate of Comparative Example 3 is 0. It is 14.29%, and comparative example 4 has no repair effect. It can be seen from the above data that the microbial capsule repair agent has the best repair effect on cracks with a width of no more than 0.3 mm. As the crack width increases, the repair rate of the microbial capsule repair agent tends to decrease. After the concrete specimen cracks, the CaCO3 produced by the organisms will adhere to the modified fibers in the cracks for deposition and growth. The fibers provide nucleation sites for the deposition and growth of CaCO3, and at the same time provide a bridging effect for the repair of the cracks. With the increase of the repair and maintenance age, calcium carbonate crystals gather and grow here, and gradually fill the three-dimensional network structure composed of fibers. Finally, the cracks are completely filled under the coupling action of fibers and microorganisms.

[0118] Taking into account the performance and economic factors of concrete, Example 5 is the optimal mix ratio.

[0119] Example 7

[0120] The concrete in this embodiment is composed of the following components by mass: 205 parts of cement, 740 parts of sand, 1260 parts of crushed stone, 66 parts of fly ash, 25 parts of metakaolin, 18 parts of phosphorus slag powder, 4.710 parts of water reducer, 0.225 parts of air entraining agent, 0.8 parts of modified plant fiber, and 122 parts of water; 0.4 m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as that in Example 4.

[0121] Example 8

[0122] The concrete in this embodiment is composed of the following components by mass: 220 parts of cement, 734 parts of sand, 1250 parts of crushed stone, 56 parts of fly ash, 15 parts of metakaolin, 10 parts of phosphorus slag powder, 4.515 parts of water reducer, 0.205 parts of air entraining agent, 1.2 parts of modified plant fiber, and 117 parts of water; 0.4m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as that in Example 4.

[0123] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A self-repairing channel lining concrete with added microbial capsule repair agent, characterized in that: The concrete is composed of the following components by mass: 205-220 parts of cement, 734-740 parts of sand, 1250-1260 parts of crushed stone, 56-66 parts of fly ash, 15-25 parts of metakaolin, 10-18 parts of phosphorus slag powder, 4.515-4.710 parts of water reducer, 0.205-0.225 parts of air entraining agent, 0.8-1.2 parts of modified plant fiber, and 117-122 parts of water; 0.2m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ~0.6m 3 ; The preparation method of the microbial capsule repair agent comprises the following steps: Step 1: Sorting and crushing of waste rubber: crushing and separating the waste rubber to obtain rubber powder with a particle size of less than 16 mesh; Step 2: Cleaning: Soak the rubber powder obtained in step 1 in clean water and alkaline solution in turn, then wash it to neutrality and dry it; Step 3: Ultrasonic desulfurization and activation treatment: The rubber powder dried in step 2 is activated using an ultrasonic energy-focusing transducer, and then aged in a dry environment to obtain desulfurized and activated rubber powder; Step 4, melt blending and vulcanization treatment: The desulfurized activated rubber powder obtained in step 3, polylactic acid, polybutylene terephthalate-adipate and a crosslinking agent are placed in a high temperature, high shear mixer for melt blending and dynamic vulcanization to obtain dynamically vulcanized rubber powder; Step 5: Cooling and grinding: placing the rubber powder obtained in step 4 after dynamic vulcanization treatment in a dry constant temperature chamber to cool, and then grinding to obtain micro rubber powder with a particle size of less than 100 mesh; Step 6: preparing a dormant spore suspension: culturing dormant spores of urease-decomposing bacteria and denitrifying bacteria, respectively, to obtain a urease-decomposing bacteria dormant spore suspension and a denitrifying bacteria dormant spore suspension, respectively; Step 7, Preparation of Bacteria-Loaded Microgel Powder: The microgel powder obtained in step 5 is placed in a vacuum chamber, which is then evacuated. The dormant spore suspension of the urease-degradable bacteria obtained in step 6 is then sucked into the vacuum chamber through a pipe using the negative pressure within the vacuum chamber to be adsorbed by the microgel powder. The vacuum chamber is then opened to dry the product to obtain bacteria-loaded microgel powder A. The above process is repeated with the dormant spore suspension of the denitrifying bacteria obtained in step 6 to obtain bacteria-loaded microgel powder B. Step 8, preparing a spore nutrient germination agent: uniformly mixing the C source, the N source and the spore germination agent to obtain a spore nutrient germination agent; Step 9, coating the bacteria-loaded microgel powder with a spore nutrient germination agent: placing the bacteria-loaded microgel powder A obtained in step 7 into a blender for stirring, adding the spore nutrient germination agent obtained in step 8 into a high-pressure spraying device, and then spraying the spore nutrient germination agent on the surface of the bacteria-loaded microgel powder A in a stirred state, and then aging and drying to obtain germinated bacteria-loaded microgel powder A, repeating the above process with the bacteria-loaded microgel powder B obtained in step 7 to obtain germinated bacteria-loaded microgel powder B; Step 10, preparation of a protective shell of bacteria-carrying microgel powder: cement, calcium-based bentonite, CaCl2 and water are mixed to obtain a slurry, and then the slurry is mixed with sodium silicate to obtain a protective liquid, and then the protective liquid is added to a high-pressure spraying device, and the germinated bacteria-carrying microgel powder A obtained in step 9 is placed in a mixer for stirring, and the protective liquid is sprayed on the surface of the germinated bacteria-carrying microgel powder A in a stirring state, and then cured and dried to obtain a protective shell of bacteria-carrying microgel powder A, and the above process is repeated with the bacteria-carrying microgel powder B obtained in step 9 to obtain a protective shell of bacteria-carrying microgel powder B; Step 11, microbial capsule repair agent: grind the protective shell-loaded bacteria microgel powder A and the protective shell-loaded bacteria microgel powder B obtained in step 10 separately, pass through a 100-mesh sieve, and then mix them to obtain the microbial capsule repair agent.

2. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The soaking process in clean water and alkaline solution in step 2 is as follows: soaking in clean water for 6h~8h, and mechanically stirring for 10min every 2h~3h, then taking it out and soaking it in 1.0mol / L~2.0mol / L NaOH solution for 24h, and mechanically stirring it for 10min every 4h~6h.

3. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The frequency of the ultrasonic energy-focusing transducer in the activation treatment in step 3 is 20KHz~50KHz, the activation treatment time is 10min~20min, and the aging time is 6h~10h.

4. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: In step 4, the mass ratio of the desulfurized activated rubber powder, polylactic acid and polybutylene terephthalate-adipate is 5-7:2-3:1-2, the crosslinking agent is one or more of dicumyl peroxide, benzoyl peroxide and diethylenetriamine, and the amount of the crosslinking agent is 2%-5% of the mass of the desulfurized activated rubber powder. The temperature of the high temperature and high shear mixer in the melt blending is 150°C-190°C and the pressure is 10kg / cm 2 ~20kg / cm 2 , the rotation speed is 150rpm~300rpm, and the melt blending time is 20min~40min.

5. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The urease-decomposing bacteria described in step 6 are Bacillus clausii and Saccharomyces cerevisiae ,or Bacillus subtilis and Saccharomyces cerevisiae The denitrifying bacteria are Pseudomonas aeruginosa and Lysinibacillus sphaericus ,or Alishewanella and Lysinibacillus sphaericus ; The culture process is as follows: dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria are inoculated into spore-forming culture medium respectively, placed in a constant temperature shaking incubator, the internal environment has an pH value of 9-11, a temperature of 30°C-40°C, a liquid volume of 100mL, a shaker speed of 150rpm-180rpm, and cultured for 4d, and then the cultured liquid is divided into 100mL-200mL centrifuge tubes, centrifuged at 4000rpm-6000rpm, 0°C-4°C for 3min-5min, and repeatedly centrifuged and washed three or more times, resuspended in deionized water, and placed in a refrigerator at 0°C-4°C for standby use; the vacuuming in step seven is to be vacuumed to -0.04MPa-0.08MPa, the adsorption time is 5min-10min, and the drying adopts a blast drying oven, the drying temperature is 30°C-40°C, and the time is 24h.

6. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: In step eight, the C source is glucose, the N source is trypsin and urea, and the spore germination agent is prepared from pyridine-2,6-dicarboxylic acid, L-calcium lactate, L-alanine, carboxymethyl cellulose, NaH2PO4, Na2MoO4, MgCO3, Cu(NO3)2 and CaCl2.

7. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The stirring speed in step nine is 400r / min~600r / min, the time is 8min~12min, the spraying flow rate is 0.5mL / s~2mL / s, the time is 3min~4min, the aging time is 24h, and the drying adopts a blast drying oven, the drying temperature is 30℃~40℃, and the time is 24h.

8. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The mass ratio of cement, calcium bentonite and CaCl2 in step 10 is 20~40:50~65:5~10, the solid-liquid ratio of the slurry is 0.6~1:1, the volume ratio of the slurry to sodium silicate is 1~2:1, the stirring speed is 400r / min~600r / min, the time is 3min~5min, the spraying flow rate is 0.5mL / s~2mL / s, the time is 2min~3min, the curing time is 48h, and the drying adopts a blast drying oven, the drying temperature is 30℃~40℃, and the time is 24h.

9. A method for preparing the self-repairing channel lining concrete with added microbial capsule repair agent according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Step 101: Put sand and gravel into a mixer and stir for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates; Step 102: uniformly adding the modified plant fiber to the mixer containing coarse and fine aggregates obtained in step 101 by a shaker or disperser and stirring for more than 30 seconds to obtain a mixer containing coarse and fine aggregates and fibers; Step 103: Evenly mix cement, fly ash, metakaolin, phosphorus slag powder, and air-entraining agent, and then divide the mixture into three equal parts to obtain three parts of cementitious materials; Step 104: adding the two portions of cementitious materials obtained in step 103 to the mixer containing coarse and fine aggregates and fibers obtained in step 102 and stirring for more than 30 seconds, then adding two-thirds of the total water and a water reducer and stirring for more than 60 seconds to obtain a mixer containing a mixture; Step 105: Evenly mix the remaining portion of the cementitious material in step 103 with the microbial capsule repair agent, and then add it together with the remaining one-third of water into the mixer containing the mixture obtained in step 104 and stir for more than 60 seconds to obtain a self-repairing channel lining concrete with the addition of the microbial capsule repair agent.

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