Self-repairing canal lining concrete added with microbial capsule repairing agent and preparation method of self-repairing canal lining concrete

Abstract

The invention discloses self-repairing canal lining concrete added with a microbial capsule repairing agent. The concrete is prepared from the following components: cement, sand, gravel, fly ash, metakaolin, phosphorus slag powder, a water reducing agent, an air entraining agent, modified plant fibers, water and the microbial capsule repairing agent. The invention also provides a preparation method of the microbial capsule repairing agent, which comprises the following steps: treating waste rubber by adopting a physical-chemical method, preparing a modified porous rubber carrier with a three-dimensional network structure through melt blending and vulcanization, immobilizing spores in carrier pores through negative pressure adsorption, and then spraying a germinating agent and a protective layer to obtain the microbial capsule repairing agent. And curing to obtain the microbial capsule repairing agent. By adding the microbial capsule repairing agent, when the concrete generates cracks, microbial spores are activated, mineralized deposition is generated through metabolic reaction to automatically repair the cracks, meanwhile, the concrete has the advantages of being appropriate in strength, low in elasticity modulus, excellent in frost resistance and the like, the service life of a channel is effectively prolonged, and the maintenance cost is reduced.

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 delivery channels in the northwest region mainly use channel lining for anti-seepage, which has the advantages of easy availability of raw materials, good anti-impact performance, and mature construction technology. It is currently the most widely used lining form in my country. Due to factors such as climatic conditions and agricultural production and planting structures, channels in most areas of Xinjiang also need to operate in winter (winter wheat winter irrigation water). Under such operating conditions, a large number of channel concrete linings will be damaged every year. The main reasons for the damage are expansion and frost heave. Cracks appear in the anti-seepage project to varying degrees, which accelerates the aging process of the anti-seepage project, causing damage to the anti-seepage structure, resulting in waste of water resources and increased maintenance costs.

[0003] Waste rubber is modified by physical and chemical methods to be prepared into a homogeneous three-dimensional mesh porous material. As a carrier of microbial repair agents, it can also reduce the elastic modulus of concrete, increase the ultimate tensile deformation and antifreeze performance, and better adapt to the complex and changeable channel working environment. This technology solves the problem of waste rubber polluting the environment and wasting resources, and has high economic benefits and social significance.

[0004] The microbial self-repair technology of concrete introduces specific microorganisms into concrete and uses the metabolic activities of these microorganisms to produce mineral compounds, thereby achieving self-repair of microcracks on the surface or inside of concrete. The microbial self-repair process can actively identify and fill cracks in concrete, effectively maintaining the integrity of the concrete structure. The research and development and application of this technology are of great significance for promoting innovation in the field of building materials, improving the overall performance of building structures, and promoting environmental protection and sustainable development.

[0005] Therefore, it is necessary to combine the modified rubber carrier with the microbial self-repairing technology to form a self-repairing channel lining concrete with added microbial capsule repair agent. Applying this technology to the lining project of water conveyance channels in Northwest my country not only makes full use of waste rubber resources, rationally utilizes resources and reduces environmental pollution, but is also expected to provide a more reliable, environmentally friendly and economical solution for water conveyance channel projects in Northwest China, and further promote 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 provide a self-repairing channel lining concrete with added microbial capsule repair agent in view of the deficiencies of the above-mentioned prior art. The concrete is added with microbial capsule repair agent. When cracks are generated in the self-repairing channel lining concrete with added microbial capsule repair agent after pouring, the carrier is broken, the spores are activated, and the microorganisms generate calcium carbonate mineralization deposits through metabolic reactions such as denitrification and urealysis, which fill the cracks and prevent external corrosion particles from continuing to invade concrete components. It has the advantages of timely repair and can repair cracks without 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 during use after pouring, the carrier ruptures, the spores are activated, and the microorganisms generate calcium carbonate mineralization deposits through metabolic reactions such as denitrification and urealysis to fill the cracks, thereby preventing external corrosion particles from continuing to invade concrete components. The present invention has the advantages of timely repair and the ability to repair cracks without the aid of external measures, etc., effectively extending the service life of the channel and reducing maintenance costs.

[0009] In the present invention, the sisal fiber is processed into a modified plant fiber with a length of 10 mm to 20 mm after being hydrolyzed by a strong alkaline solution, ultrasonically heated, neutralized, washed, soaked in a 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 above-mentioned 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 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 by 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: placing the desulfurized activated rubber powder obtained in step 3, polylactic acid, polybutylene terephthalate-adipate and a crosslinking agent in a high temperature, high shear mixer for melt blending, and performing dynamic vulcanization to obtain a rubber powder after dynamic vulcanization treatment;

[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, preparation of dormant spore suspension: culturing dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria, respectively, to obtain dormant spore suspension of urease-decomposing bacteria and dormant spore suspension of denitrifying bacteria, respectively;

[0017] Step 7, preparation of bacteria-carrying microgel powder: the microgel powder obtained in step 5 is placed in a vacuum chamber, and then the vacuum chamber is evacuated, and then the urease-decomposing bacteria dormant spore suspension obtained in step 6 is sucked into the vacuum chamber through a pipeline by using the negative pressure in the vacuum chamber to allow the microgel powder to adsorb, and then the vacuum chamber is opened to dry the product to obtain bacteria-carrying microgel powder A, and the above process is repeated with the denitrifying bacteria dormant spore suspension obtained in step 6 to obtain bacteria-carrying microgel powder B;

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

[0019] Step nine, coating the bacteria-carrying micro-gel powder with a spore nutrient germination agent: putting the bacteria-carrying micro-gel powder A obtained in step seven into a mixer for stirring, 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-carrying micro-gel powder A in a stirring state, and then aging and drying to obtain germinated bacteria-carrying micro-gel powder A, and repeating the above process with the bacteria-carrying micro-gel powder B obtained in step seven to obtain germinated bacteria-carrying micro-gel powder B;

[0020] Step 10, preparation of protective shell of bacteria-carrying micro-gel powder: cement, calcium-based bentonite, CaCl2 and water are mixed to obtain slurry, and then the slurry is mixed with sodium silicate to obtain protective liquid, and then the protective liquid is added into high-pressure spraying equipment, the germinated bacteria-carrying micro-gel powder A obtained in step 9 is put into a mixer for stirring, and the protective liquid is sprayed on the surface of the germinated bacteria-carrying micro-gel powder A in a stirring state, and then cured and dried to obtain protective shell bacteria-carrying micro-gel powder A, and the above process is repeated for the bacteria-carrying micro-gel powder B obtained in step 9 to obtain protective shell bacteria-carrying micro-gel 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 respectively, pass through a 100-mesh sieve, and then mix them to obtain a microbial capsule repair agent.

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

[0023] In the present invention, impurities such as oil, dust, and organic matter on the rubber surface are cleaned and removed, so as to improve the roughness and hydrophilicity of the rubber surface and improve the interfacial bonding performance between the rubber aggregate and the cement matrix; ultrasonic desulfurization and activation treatment is performed, in which the acoustic energy directly acts on the waste rubber powder to cavitate it, destroy the CS bond and SS bond in the vulcanized rubber whose energy is lower than that of the CC bond, selectively destroy the three-dimensional network structure, and realize 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 prepared rubber powder after dynamic vulcanization treatment has a uniform and continuous honeycomb network structure, which is a homogeneous three-dimensional spatial network structure, has the characteristics of high specific surface area, multiple cavities, etc., and shows excellent adsorption effect; and in the melt blending process of the desulfurized activated rubber powder with organic substances such as polylactic acid, polybutylene terephthalate-adipate, etc., the secondary components are decomposed and transformed into a dispersed phase with a smaller particle size, so that the spacing between the dispersed phase particles is correspondingly reduced, thereby improving its toughness.

[0024] The above-mentioned self-repairing channel lining concrete with added microbial capsule repair agent is characterized in that the process of soaking in clean water and alkaline solution in sequence in step 2 is: soaking in clean water for 6h to 8h, and mechanically stirring for 10min every 2h to 3h, then taking it out and soaking it in 1.0mol / L to 2.0mol / L NaOH solution for 24h, and mechanically stirring it for 10min every 4h to 6h. The present invention fully removes impurities such as oil, dust, and organic matter on the rubber surface by controlling the parameters of soaking and cleaning, improves the roughness and hydrophilicity of the rubber surface, and improves the interfacial bonding performance 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 to cavitate it, destroy the CS bond and SS bond in the vulcanized rubber with lower energy than the CC bond, selectively destroy the three-dimensional network structure, realize desulfurization regeneration, and the physical and mechanical properties of the desulfurized activated rubber powder are similar to those of the original rubber material, with 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 diisopropylbenzene 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~300rpm, and the melt blending time is 20min~40min. In the present invention, by controlling the ratio of each raw material and the parameters of melt blending, the secondary components undergo decomposition and are transformed into a dispersed phase with a smaller particle size in the melt blending process of the desulfurized activated micro-gel powder and the organic matter, 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 space network structure with the characteristics of high specific surface area, multiple cavities, etc., and exhibits excellent adsorption effect. The rubber powder after dynamic vulcanization treatment is used as a bacterial carrier, which has the advantages of simple procedure, saving bacterial spores, low cost and better crack resistance.

[0027] The above-mentioned 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: inoculating dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria into spore-producing culture medium respectively, placing in a constant temperature shaking incubator, the internal environment pH value is 9-11, the temperature is 30℃-40℃, the liquid volume is 100mL, the shaking speed is 150rpm-180rpm, culturing for 4d, and then the cultured liquid is divided into 100mL-200mL centrifuge tubes, centrifuged at 4000rpm-6000rpm, 0℃-4℃ for 3min-5min, and repeatedly centrifuged and washed for more than three times, re-suspended in deionized water, and placed in a refrigerator at 0℃-4℃ for standby; the vacuuming in step seven is vacuuming to -0.04MPa--0.08MPa, the adsorption time is 5min-10min, the drying adopts a blast drying oven, the drying temperature is 30℃-40℃, and the time is 24h.The core strain of the urease-decomposing strain in the present invention is Bacillus clausii or Bacillus subtilis, and the auxiliary strain is Saccharomyces cerevisiae, which can generate NH3 through metabolism; the core strain of the denitrifying strain is Pseudomonas aeruginosa or Alishewanella, 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 can meet the requirement that there are bacteria that can metabolize under aerobic and anaerobic conditions, overcome the defect of a small application range of a single bacteria, and adopt bacteria of a type that is compatible with it as an 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-component repair system, the multi-component repair 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 agent 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 the strain number of Bacillus clausii is ATCC 700160, and the storage number is No. SDSJ-JZ2024001; the strain number of Saccharomyces cerevisiae is BMZ071744, and the storage number is No. SDSJ-JZ2024002; the strain number of Bacillus subtilis is CICC 25023, and the storage number is No. SDSJ-JZ2024003; the strain number of Pseudomonas aeruginosa is BNCC360090, and the storage number is No. SDSJ-JZ2024004; and the strain number of Lysinibacillus sphaericus is 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. In daily work, a 4°C refrigerator is often used for short-term strain preservation.

[0029] The above-mentioned 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 some enzymes, it can promote the binding of amino acid growth-promoting factor DPA to germination receptors and enter the spores in the form of coordinated transport, thereby promoting the earlier binding of germination factors to germination receptors, and the stimulation effect is significant; L-calcium lactate is an important nutrient and calcium source for the flora. When cracks appear in concrete, water will penetrate into the cracks and 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 adhesion 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 adopts 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, 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 mutual collision and friction between aggregates during the concrete mixing process, the present invention adopts sodium silicate, which is easy to obtain, cheap and will not cause adverse effects on cement-based materials, and cement, calcium-based bentonite and CaCl2 to react to generate silica gel and calcium silicate gel, which play 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 the germination of microorganisms. The protective layer material formed by the reaction of sodium silicate and calcium chloride can form a protective layer structure on the surface of the carrier, which has the effects of moderate strength, brittle texture and good wrapping, and can effectively solve the fatal defect of poor interface stability with cement-based materials, while reducing and reducing the effect of rubber particles on introducing large-pore gas, thereby improving the strength of concrete.

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

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

[0034] Step 102, uniformly adding the modified plant fiber into the mixer filled with coarse and fine aggregates obtained in step 101 by a shaking screen or a disperser and stirring for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates and fibers;

[0035] Step 103, mixing cement, fly ash, metakaolin, phosphorus slag powder and air entraining agent uniformly, and then dividing 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 reducing agent 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 different materials of the present invention are added 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, in the process of concrete preparation, the initial stirring operation may cause certain damage to the microbial capsule repair agent. The microbial capsule repair agent is mixed with the remaining portion of cementitious material and then added for the second time, which can reduce the adverse effects such as mechanical damage to it during the initial 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, the addition of 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 of them at the beginning, due to the complex interaction between materials such as aggregates and cement during the initial 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 a microbial capsule repair agent thereto. When cracks are generated 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 mineralization deposits through metabolic reactions such as denitrification and urealysis to fill the cracks and prevent external corrosion particles from continuing to invade concrete components. It 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.

[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 the ability to resist deformation in the surrounding environment compared to conventional concrete linings. Waste rubber is prepared into a porous microbial carrier with a homogeneous three-dimensional spatial network structure, thereby realizing resource recycling and reducing resource and environmental pollution.

[0043] 3. The microbial capsule repair agent in 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 are formed 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 mineralization 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 green, 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 embodiments. 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 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 take it out 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 to neutrality and dry it;

[0051] 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 50 KHz for 15 minutes, and then aged in a dry environment for 8 hours to obtain desulfurized 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 20kg / 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-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, and the denitrifying bacteria are Pseudomonas aeruginosa and Lysinibacillus sphaericus; the culture process is: inoculating dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria into spore-producing culture medium respectively, placing in a constant temperature shaking incubator, the internal environment pH value is 10, the temperature is 35°C, the liquid volume is 100mL, the shaker speed is 180rpm, and the culture is 4d, and then the cultured liquid is divided into 100mL centrifuge tubes, centrifuged at 5000rpm, 0℃~4℃ for 5min, and repeatedly centrifuged and washed for more than three times, re-suspended in deionized water, and placed in a refrigerator at 0℃~4℃ for standby;

[0055] Step 7, preparation of bacteria-loaded microgel powder: the microgel powder obtained in step 5 is placed in a vacuum chamber, and then the vacuum chamber is evacuated to -0.06MPa, and then the urease-decomposing bacteria dormant spore suspension obtained in step 6 is sucked into the vacuum chamber through a pipeline by the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 8 minutes, and then the vacuum chamber is opened to dry the product in a forced air drying oven at 35° C. for 24 hours to obtain bacteria-loaded microgel powder A, and the above process is repeated with the denitrifying bacteria dormant spore suspension obtained in step 6 to obtain bacteria-loaded microgel powder B;

[0056] Step eight, preparation of spore nutrient germination agent: uniformly mix the C source, N source and spore germination agent to obtain the 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-carrying micro-gel powder with a spore nutrient germination agent: placing the bacteria-carrying micro-gel powder A obtained in step seven into a mixer and stirring at a speed of 500 r / min for 10 min, 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-carrying micro-gel powder A in a stirring state at a flow rate of 1 mL / s for 3 min, then aging for 24 h and drying in a blast drying oven at 35° C. for 24 h to obtain germinated bacteria-carrying micro-gel powder A, and repeating the above process with the bacteria-carrying micro-gel powder B obtained in step seven to obtain germinated bacteria-carrying micro-gel powder B;

[0058] Step 10, preparation of protective shell of bacteria-carrying micro-gel powder: mix cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 30:65:7 to obtain a slurry with a solid-liquid ratio of 0.6:1, and then mix the slurry with a volume ratio of 2:1 with sodium silicate to obtain a protective liquid, and then add the protective liquid into a high-pressure spraying device, put the germinated bacteria-carrying micro-gel powder A obtained in step 9 into a mixer and stir at a speed of 500r / min for 5min, spray the protective liquid on the surface of the germinated bacteria-carrying micro-gel powder A in a stirring state at a flow rate of 2mL / s for 2min, and then cure for 48h and dry in a blast drying oven at 35°C for 24h to obtain a protective shell of bacteria-carrying micro-gel powder A, repeat the above process with the bacteria-carrying micro-gel powder B obtained in step 9 to obtain a protective shell of bacteria-carrying micro-gel 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 respectively, pass through a 100-mesh sieve, and then mix them to obtain a 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 the OD600 after culture in Example 1 was 1.0, and 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, respectively, 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, which effectively ensured the long-term survival of the carried microorganisms. The survival rate of the bacterial flora 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 could reach 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 , which was 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 34.8% lower than that of Example 2, the water absorption rate of Example 1 is 15.8%, and 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 102.0% higher than that of the micro-gel 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-gel powder, thereby improving the strength and reducing the water absorption rate.

[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 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 take it out 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 to neutrality and dry it;

[0071] Step 3, ultrasonic desulfurization activation treatment: the rubber powder dried in step 2 is activated by 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 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, and then placed in a high temperature, high shear mixer at a temperature of 190°C and a pressure of 10kg / cm 2 , melting and 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-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 subtilis and Saccharomyces cerevisiae, and the denitrifying bacteria are Alishewanella and Lysinibacillus sphaericus; the culture process is: inoculating dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria into spore-producing culture medium respectively, placing in a constant temperature shaking incubator, the internal environment pH value is 9, the temperature is 40°C, the liquid volume is 100mL, the shaker speed is 150rpm, and the culture is 4d, and then the cultured liquid is divided into 200mL centrifuge tubes, centrifuged at 6000rpm, 0℃~4℃ for 3min, and repeatedly centrifuged and washed for more than three times, re-suspended in deionized water, and placed in a refrigerator at 0℃~4℃ for standby;

[0075] Step 7, preparation of bacteria-loaded microgel powder: the microgel powder obtained in step 5 is placed in a vacuum chamber, and then the vacuum chamber is evacuated to -0.08MPa, and then the urease-decomposing bacteria dormant spore suspension obtained in step 6 is sucked into the vacuum chamber through a pipeline by the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 5 minutes, and then the vacuum chamber is opened to dry the product in a forced air drying oven at 30° C. for 24 hours to obtain bacteria-loaded microgel powder A, and the above process is repeated with the denitrifying bacteria dormant spore suspension obtained in step 6 to obtain bacteria-loaded microgel powder B;

[0076] Step eight, preparation of spore nutrient germination agent: uniformly mix the C source, N source and spore germination agent to obtain the 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-carrying micro-gel powder with a spore nutrient germination agent: placing the bacteria-carrying micro-gel powder A obtained in step seven into a mixer and stirring at a speed of 400 r / min for 12 min, 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-carrying micro-gel powder A in a stirring state at a flow rate of 0.5 mL / s for 4 min, then aging for 24 h and drying in a forced air drying oven at 30° C. for 24 h to obtain germinated bacteria-carrying micro-gel powder A, and repeating the above process with the bacteria-carrying micro-gel powder B obtained in step seven to obtain germinated bacteria-carrying micro-gel powder B;

[0078] Step 10, preparation of protective shell of bacteria-carrying micro-gel powder: mix cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 20:65:5 to obtain a slurry with a solid-liquid ratio of 0.8:1, and then mix the slurry with a volume ratio of 1.5:1 with sodium silicate to obtain a protective liquid, and then add the protective liquid into a high-pressure spraying device, put the germinated bacteria-carrying micro-gel powder A obtained in step 9 into a mixer and stir at a speed of 600r / min for 3min, spray the protective liquid on the surface of the germinated bacteria-carrying micro-gel powder A in a stirring state at a flow rate of 0.5mL / s for 3min, and then cure for 48h and dry in a blast drying oven at 30°C for 24h to obtain a protective shell of bacteria-carrying micro-gel powder A, repeat the above process with the bacteria-carrying micro-gel powder B obtained in step 9 to obtain a protective shell of bacteria-carrying micro-gel 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 respectively, pass through a 100-mesh sieve, and then mix them to obtain a 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 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 take it out 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 to neutrality and dry it;

[0084] Step 3, ultrasonic desulfurization 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 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, and then placed in a high temperature, high shear mixer at a temperature of 150°C and a pressure of 15kg / cm 2 , melting and 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: inoculating dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria into spore-producing culture medium respectively, placing in a constant temperature shaking incubator, the internal environment pH value is 11, the temperature is 30°C, the liquid volume is 100mL, the shaker speed is 160rpm, and the culture is 4d, and then the cultured liquid is divided into 150mL centrifuge tubes, centrifuged at 4000rpm, 0℃~4℃ for 4min, and repeatedly centrifuged and washed for more than three times, re-suspended in deionized water, and placed in a refrigerator at 0℃~4℃ for standby;

[0088] Step 7, preparation of bacteria-loaded microgel powder: the microgel powder obtained in step 5 is placed in a vacuum chamber, and then the vacuum chamber is evacuated to -0.04 MPa, and then the urease-decomposing bacteria dormant spore suspension obtained in step 6 is sucked into the vacuum chamber through a pipeline by the negative pressure in the vacuum chamber to allow the microgel powder to adsorb for 10 minutes, and then the vacuum chamber is opened to dry the product in a forced air drying oven at 40° C. for 24 hours to obtain bacteria-loaded microgel powder A, and the above process is repeated with the denitrifying bacteria dormant spore suspension obtained in step 6 to obtain bacteria-loaded microgel powder B;

[0089] Step eight, preparation of spore nutrient germination agent: uniformly mix the C source, N source and spore germination agent to obtain the 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-carrying micro-gel powder with a spore nutrient germination agent: placing the bacteria-carrying micro-gel powder A obtained in step seven into a mixer and stirring at a speed of 600 r / min for 8 min, 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-carrying micro-gel powder A in a stirring state at a flow rate of 2 mL / s for 3 min, then aging for 24 h and drying in a blast drying oven at 40° C. for 24 h to obtain germinated bacteria-carrying micro-gel powder A, and repeating the above process with the bacteria-carrying micro-gel powder B obtained in step seven to obtain germinated bacteria-carrying micro-gel powder B;

[0091] Step 10, preparation of protective shell of bacteria-carrying micro-gel powder: mix cement, calcium-based bentonite and CaCl2 solution in a mass ratio of 40:50:10 to obtain a slurry with a solid-liquid ratio of 1:1, then mix the slurry with a volume ratio of 1:1 with sodium silicate to obtain a protective liquid, and then add the protective liquid into a high-pressure spraying device, put the germinated bacteria-carrying micro-gel powder A obtained in step 9 into a mixer and stir at a speed of 400r / min for 4min, spray the protective liquid on the surface of the germinated bacteria-carrying micro-gel powder A in a stirring state at a flow rate of 1mL / s for 2.5min, and then cure for 48h and dry in a blast drying oven at 40°C for 24h to obtain a protective shell of bacteria-carrying micro-gel powder A, repeat the above process with the bacteria-carrying micro-gel powder B obtained in step 9 to obtain a protective shell of bacteria-carrying micro-gel 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 respectively, pass through a 100-mesh sieve, and then mix them to obtain a microbial capsule repair agent.

[0093] Example 4

[0094] In this embodiment, the concrete 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, putting sand and gravel into a mixer and stirring for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates;

[0097] Step 102, uniformly adding the modified plant fiber into the mixer filled with coarse and fine aggregates obtained in step 101 by a shaking screen or a disperser and stirring for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates and fibers;

[0098] Step 103, mixing cement, fly ash, metakaolin, phosphorus slag powder and air entraining agent uniformly, and then dividing 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 reducing agent 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 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.

[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] In this embodiment, the concrete 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; 0.4 m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as Example 4.

[0107] Example 6

[0108] In this embodiment, the concrete 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; 0.6 m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as Example 4.

[0109] According to the standards such as "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" GB / T 50081, "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete" GB / T50082, and "Specification for Construction of Hydraulic Concrete" 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 preparation process of the test piece is as follows: the mixed concrete is placed in a homemade 150 mm × 150 mm long × 150 mm wide × 150 mm high In the test mold of 0mm×50mm, after demolding, it was placed in the standard curing room for curing to 28d; 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 semicircular top pieces were used to pressurize the upper and lower surfaces of the specimens to create cracks, which were marked with a marker, and the image processing method was used to count the crack width and number of each group of specimens, and the concrete with cracks created was fixed with an external fixer to prevent the specimens from being damaged by excessive cracks, and the fixed specimens were cured for another 28d, 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 the microbial capsule repair agent is different, which is 0.2 m 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] It can be seen from Table 1 that the slump results of Examples 4, 5, 6 and Comparative Examples 3 and 4 are between 64 mm and 70 mm, and the difference between the maximum and minimum values ​​is only 6 mm, which are all within the concrete design range. Therefore, it can be seen that the addition of microbial capsule repair agent and modified plant fiber has almost no effect on the workability and air entrainment performance 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 amount of microbial capsule repair agent, the compressive strength and flexural strength of concrete both tend to decrease. Although the microbial capsule repair agent improves the defects of the rubber-cement matrix interface through the encapsulation technology, the mechanical properties of the concrete are reduced due to the low density and compressive strength of the rubber itself, but they all meet 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, indicating 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 are 81.9%, 86.1%, 80.4%, 78.7%, and the relative dynamic modulus of Comparative Example 4 is 75.4%, and the relative dynamic moduli are increased by 8.62%, 14.19%, 6.63%, and 4.38%, respectively; the mass loss rates of Examples 4, 5, 6 and Comparative Example 3 are 1.99%, 1.43%, 2.23%, and 2.77%, and the mass loss rate of Comparative Example 4 is 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 antifreeze performance 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 be deformed to absorb part of the stress, which plays a buffering role and reduces the damage of ice crystal formation to concrete in the freeze-thaw cycle.

[0117] Evaluation of crack self-repair effect: When the crack width is not more 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 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] In this embodiment, the concrete 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 Example 4.

[0121] Example 8

[0122] In this embodiment, the concrete 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; 0.4 m3 of microbial capsule repair agent is added to each cubic meter of the concrete. 3 ; The preparation method is the same as Example 4.

[0123] The above 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 change made to the above embodiment according to the technical essence of the present invention still falls within the protection scope 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 .

2. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 1, characterized in that: The preparation method of the microbial capsule repairing 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 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 by 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: placing the desulfurized activated rubber powder obtained in step 3, polylactic acid, polybutylene terephthalate-adipate and a crosslinking agent in a high temperature, high shear mixer for melt blending, and performing dynamic vulcanization to obtain a rubber powder after dynamic vulcanization treatment; 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, preparation of dormant spore suspension: culturing dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria, respectively, to obtain dormant spore suspension of urease-decomposing bacteria and dormant spore suspension of denitrifying bacteria, respectively; Step 7, preparation of bacteria-carrying microgel powder: the microgel powder obtained in step 5 is placed in a vacuum chamber, and then the vacuum chamber is evacuated, and then the urease-decomposing bacteria dormant spore suspension obtained in step 6 is sucked into the vacuum chamber through a pipeline by using the negative pressure in the vacuum chamber to allow the microgel powder to adsorb, and then the vacuum chamber is opened to dry the product to obtain bacteria-carrying microgel powder A, and the above process is repeated with the denitrifying bacteria dormant spore suspension obtained in step 6 to obtain bacteria-carrying microgel powder B; Step 8, preparing a spore nutrient germination agent: uniformly mixing a C source, a N source and a spore germination agent to obtain a spore nutrient germination agent; Step nine, coating the bacteria-carrying micro-gel powder with a spore nutrient germination agent: putting the bacteria-carrying micro-gel powder A obtained in step seven into a mixer for stirring, 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-carrying micro-gel powder A in a stirring state, and then aging and drying to obtain germinated bacteria-carrying micro-gel powder A, and repeating the above process with the bacteria-carrying micro-gel powder B obtained in step seven to obtain germinated bacteria-carrying micro-gel powder B; Step 10, preparation of protective shell of bacteria-carrying micro-gel powder: cement, calcium-based bentonite, CaCl2 and water are mixed to obtain slurry, and then the slurry is mixed with sodium silicate to obtain protective liquid, and then the protective liquid is added into high-pressure spraying equipment, the germinated bacteria-carrying micro-gel powder A obtained in step 9 is put into a mixer for stirring, and the protective liquid is sprayed on the surface of the germinated bacteria-carrying micro-gel powder A in a stirring state, and then cured and dried to obtain protective shell bacteria-carrying micro-gel powder A, and the above process is repeated for the bacteria-carrying micro-gel powder B obtained in step 9 to obtain protective shell bacteria-carrying micro-gel 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 respectively, pass through a 100-mesh sieve, and then mix them to obtain a microbial capsule repair agent.

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

4. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, characterized in that: In the activation treatment in step 3, the frequency of the ultrasonic energy-focusing transducer is 20KHz to 50KHz, the activation treatment time is 10min to 20min, and the aging time is 6h to 10h.

5. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, characterized in that: The mass ratio of the desulfurized activated micro-rubber 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 amount of the cross-linking 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.

6. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, characterized in that: In step 6, 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 culturing process is: inoculating dormant bacterial spores of urease-decomposing bacteria and denitrifying bacteria into spore-producing culture medium respectively, placing in a constant temperature shaking incubator, the internal environment pH value is 9-11, the temperature is 30℃-40℃, the liquid volume is 100mL, the shaking speed is 150rpm-180rpm, culturing for 4d, and then the cultured liquid is divided into 100mL-200mL centrifuge tubes, centrifuged at 4000rpm-6000rpm, 0℃-4℃ for 3min-5min, and repeatedly centrifuged and washed for more than three times, re-suspended in deionized water, and placed in a refrigerator at 0℃-4℃ for standby; the vacuuming in step seven is vacuuming to -0.04MPa--0.08MPa, the adsorption time is 5min-10min, the drying adopts a blast drying oven, the drying temperature is 30℃-40℃, and the time is 24h.

7. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, 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.

8. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, 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.

9. The self-repairing channel lining concrete with added microbial capsule repair agent according to claim 2, characterized in that: In step ten, the mass ratio of cement, calcium-based bentonite and CaCl2 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.

10. A method for preparing the self-repairing channel lining concrete with added microbial capsule repair agent as claimed in any one of claims 1 to 9, characterized in that: The method comprises the following steps: Step 101, putting sand and gravel into a mixer and stirring for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates; Step 102, uniformly adding the modified plant fiber into the mixer filled with coarse and fine aggregates obtained in step 101 by a shaking screen or a disperser and stirring for more than 30 seconds to obtain a mixer filled with coarse and fine aggregates and fibers; Step 103, mixing cement, fly ash, metakaolin, phosphorus slag powder and air entraining agent uniformly, and then dividing 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 reducing agent 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.

Images