A biological repair method and application of micro cracks in concrete structures in hidden and restricted working areas of port workers

Abstract

The present invention discloses a biological repair method for micro cracks in concrete structures in hidden restricted operation areas of port workers, wherein the method comprises the following steps: fermenting and culturing urease-producing bacterial fermentation broth, and collecting and fermenting spore suspensions rich in spores of carbonic anhydrase-producing bacteria; dissolving urea in the urease-producing bacterial fermentation broth; then preparing a calcium salt solution, adding the spore suspension of carbonic anhydrase-producing bacteria to the calcium salt solution for mixing; and preparing a germination nutrient solution; and using a pressure injection method to independently inject the repair solution and the nutrient solution into the hidden crack area of ​​concrete to be repaired in the hidden crack area of ​​concrete to be repaired. The method of the present invention significantly reduces the construction procedures, and while improving the repair efficiency of the microbial method in concrete structures, the selected injection repair method can obviously solve the construction difficulty of hidden restricted areas such as the side and bottom of the concrete structure in the port area, and has very important application value in the repair of concrete cracks in the port area, especially in the hidden restricted operation area.

Description

Technical Field

[0001] The invention belongs to the technical field of repairing cracks in cracked concrete, and in particular to a biological repair method and application of micro-cracks in concrete structures in hidden and restricted working areas of port workers. Background Art

[0002] Reinforced concrete is the most widely used material in construction projects. However, as the service time goes by, millimeter-level microcracks will appear inside the concrete. Under long-term load, these microcracks will further extend to form through cracks connecting the concrete surface and the internal steel bar surface. In the marine environment, water vapor and other corrosive elements (such as Cl - ) will penetrate into the concrete through the through cracks and reach the surface of the steel bars, causing the passive film on the steel bar surface to be destroyed and producing rust products, which in turn reduces the bond strength between the concrete and the steel bars and the bearing capacity of the components, causing potential safety hazards to the building and endangering the service life of the structure. The safety of concrete structure buildings is particularly important, especially in the restricted operation areas of ports and docks. The hidden restricted operation areas of port workers refer specifically to those structural areas located on the side and bottom of the dock that are not easy to construct and maintain on a daily basis.

[0003] According to relevant data, the main repair methods for concrete structures in port areas include structural reinforcement, crack sealing and repair, and grouting. Among them, the structural reinforcement method refers to the use of increased cross-section reinforcement, external steel reinforcement, steel plate reinforcement, carbon fiber composite reinforcement and other means to maintain the bearing capacity of the concrete structure in damaged and cracked port terminals. Although a certain maintenance purpose has been achieved, the concrete damage area has not been fundamentally repaired, and the durability of the structure is still problematic. Crack sealing repair means that a groove that meets the construction requirements must be excavated along the crack direction, and the sealing material is filled and leveled. Crack grouting repair refers to injecting grouting liquid from the grouting nozzle into the crack according to the construction, and repairing the concrete surface. For sealing repair and grouting repair, the commonly used repair materials in the construction process include resins and amides, etc. Although they have their own advantages, their disadvantages are also significant, such as toxicity, environmental pollution, can only be used under specific conditions, or too high viscosity is not conducive to construction, etc.; there are also some mortars or polymer mortars, most of which are also organic materials, pollute the environment, and have poor durability. Therefore, a green and environmentally friendly simple repair method is urgently needed for concrete cracks in hidden and restricted working areas under port environmental conditions.

[0004] Through searching, no patent publication documents related to the patent application of the present invention have been found. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing methods for repairing concrete cracks in different directions in hidden and restricted operating areas of ports, and to provide a biological repair method and application for micro-cracks in concrete structures in hidden and restricted operating areas of port workers.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A biological repair method for micro cracks in concrete structures in hidden restricted working areas of port workers comprises the following steps: fermenting and culturing urease-producing bacterial fermentation liquid, and collecting spore suspensions rich in carbonic anhydrase-producing bacterial spores through fermentation and cultivation; dissolving urea in the urease-producing bacterial fermentation liquid to produce a large amount of carbonate ions; then preparing a calcium salt solution, adding the carbonic anhydrase-producing bacterial spore suspension into the calcium salt solution for mixing; and preparing a germination nutrient solution for self-healing mineralization of carbonic anhydrase bacterial spores; in a hidden crack area of ​​concrete to be repaired, using a pressure injection method, installing grouting equipment according to the size of the cracks, and independently injecting a repair liquid and a nutrient solution into the hidden crack area of ​​concrete for repair.

[0008] Furthermore, the urease-producing bacteria is Sporosarcina pasteurii ATCC11859;

[0009] The carbonic anhydrase-producing bacteria is Bacillushalodurans ATCC27557;

[0010] Alternatively, the urease-producing bacterial fermentation broth is measured by a spectrophotometer to determine its absorbance value OD 600 The conductivity of the bacterial solution was between 8.0-9.0, and the urease activity of the bacterial solution was measured by conductivity and was between 14.0-16.0 mM / min.

[0011] Further, the following steps are included:

[0012] (1) Preparation of urease-producing bacterial fermentation broth: prepare a fermentation medium, sterilize it at 121°C for 20 min, inoculate urease-producing bacteria into the sterile fermentation medium at a 1% inoculation rate, and culture it in a constant temperature shaking incubator at 30°C and 200 rpm for 30-40 h. Collect the bacterial broth and store it at 4°C for later use;

[0013] (2) Preparation of spore suspension: prepare fermentation medium, sterilize at 115°C for 30 min, cool to room temperature, add sterile Na2CO3 solution with a mass concentration of 10%, inoculate the carbonic anhydrase-producing bacteria into the sterile fermentation medium at a 1% inoculum amount, culture in a constant temperature shaking incubator at 37°C and 200 r / min for 48-72 h, centrifuge at 4°C and discard the supernatant, wash with distilled water to prepare a suspension, and store at 4°C for later use;

[0014] (3) Before repair, the urease-producing bacterial fermentation liquid was placed in a 30°C water bath for 1 hour, urea was added, and the mixture was reacted in a water bath for 1-2 hours to obtain repair liquid A;

[0015] (4) preparing a calcium salt solution, and mixing the spore suspension into the calcium salt solution to prepare a repair solution B;

[0016] (5) preparing a germination nutrient solution C for germination of the spore suspension;

[0017] (6) After flushing the hidden crack area of ​​the concrete to be repaired with water, repair liquid A and repair liquid B are injected into the hidden crack area of ​​the concrete to be repaired at the same time through different pipes through a pressure grouting device. The two components are arranged at intervals to prevent the calcium carbonate precipitate produced by the mixing of the two components from clogging the outlet of the grouting equipment. After 1 hour of adding repair liquids A and B, nutrient solution C is injected. Repeat this step until the hidden crack area of ​​the concrete to be repaired is completely filled and the repair is completed.

[0018] Furthermore, the fermentation medium of the urease-producing bacteria in step (1) includes 30 g / L yeast extract, 5 g / L peptone, 0.1 mol / L urea, 10 g / L (NH4)2SO4, pH=9, 1L 0.13 mol / L Tris-HCl;

[0019] The formula of the fermentation medium for producing carbonic anhydrase bacteria in step (2) is: 10g of peptone, 5g of yeast extract, 10g of glucose, 1g of K2HPO4, and 0.02g of MnSO4·H2O per 900mL of distilled water; and 100mL of 10% Na2CO3 solution is added to every 900mL of distilled water.

[0020] Furthermore, the final concentration of urea added in step (3) is 3 mol / L. When used, urea is added to the bacterial solution in advance so that it can be fully decomposed to produce a large amount of carbonate ions to make the repair solution A.

[0021] Furthermore, in step (4), the calcium salt is calcium acetate, and the concentration of the calcium salt in the calcium salt solution is 2 mol / L, which has the same mineralization deposition effect as calcium chloride and avoids the problem of Cl - The reintroduction of potential corrosion effects on reinforced concrete;

[0022] The mixing volume ratio of spore suspension and calcium salt solution is 1:3, which is used as repair solution B. Carbonic anhydrase spores can act as nucleation sites for mineralization reaction in repair solution B. Then, in the rapid mineralization reaction, the spores are embedded in calcium carbonate precipitation and exist in the concrete as dormant bodies. To prevent the area from cracking again due to other reasons after repair, carbonic anhydrase spores can germinate and carry out self-healing mineralization reaction in the presence of nutrients such as mineralized nutrient solution added in advance due to the entry of air and moisture after cracking, and repair the cracked microcracks.

[0023] Furthermore, in step (6), the volume ratio of the repair liquid A to the repair liquid B is 1:2, and the volume ratio of the repair liquid A to the germination nutrient solution C is 1-2:1.

[0024] Furthermore, in step (6), the germination nutrient solution C is: 10 g of peptone, 5 g of yeast extract, 10 g of glucose, 1 g of K2HPO4, and 17 g of calcium acetate are added to every 1000 mL of distilled water.

[0025] Furthermore, in step (6), for micro-cracks with a width of 0.3-1 mm, since the cracks are too small, in order to allow the two repair liquids to fully mix and react, the spacing between the grouting nozzles of the pressure grouting device is set between 15-25 cm; for micro-cracks with a width of 1-2 mm, since the cracks are wider, the spacing between the grouting nozzles is set between 25-35 cm.

[0026] The bioremediation method as described above is applied in the repair of micro cracks in concrete structures in hidden and restricted working areas of port workers.

[0027] The advantages and positive effects achieved by the present invention are:

[0028] 1. Compared with the traditional concrete crack repair method, the method of the present invention utilizes the induced mineralization technology of microorganisms to make it green and environmentally friendly; and the calcium carbonate produced by the method has high compatibility with the concrete matrix, reducing the use of organic compounds; dissolving urea in the bacterial solution and then reacting with the calcium salt solution improves the efficiency of the mineralization reaction; at the same time, carbonic anhydrase bacteria is used as a self-healing mineralizing strain to solve the problem of cracking in the area again due to other reasons after the cracks are repaired; and the use of pressure grouting equipment simplifies the repair process, solves the limitation problem of microbial method on the side and bottom of the port concrete due to fluidity, improves the efficiency of repairing concrete microcracks in hidden areas of the port, can achieve the purpose of repairing microcracks in hidden areas of concrete structures under port environments, and has good anti-seepage performance.

[0029] 2. In the method of the present invention, the microorganism is cultured at a constant temperature for 30-40 hours, and then its absorbance value OD is measured by a spectrophotometer. 600The conductivity of the solution is between 8.0-9.0. The urease activity of the bacterial solution is measured by the conductivity method. When it is between 14.0-16.0 mM / min, the urease activity is relatively high. Urease hydrolyzes urea to generate a large amount of carbonate ions and ammonium ions, which will increase the conductivity of the solution. The amount of urea hydrolysis is proportional to the change in solution conductivity, so the change in solution conductivity can be used to characterize the urease activity of microorganisms.

[0030] 3. In the method of the present invention, the carbonic anhydrase bacteria ATCC27557 is fermented to 48-72 hours (fermentation decay period), at which time the bacteria are in the growth decay period, the nutrients have been basically consumed, and the bacteria gradually transform from a reproductive body to a spore dormant body, so that a large number of carbonic anhydrase bacteria spores can be collected at this stage.

[0031] 4. In the method of the present invention, a carbonic anhydrase spore suspension is mixed with a calcium salt solution in a volume ratio of 1:3 to prepare a repair solution B. The carbonic anhydrase spores can act as nucleation sites for the mineralization reaction in the repair solution B. Subsequently, in a rapid mineralization reaction, the spores are embedded in the calcium carbonate precipitate. After the crack is completely repaired, in order to prevent the area from cracking again due to other reasons, the carbonic anhydrase spores come into contact with air and moisture after cracking, and then germinate to carry out a self-healing mineralization reaction to repair the microcracks.

[0032] 5. The method of the present invention combines urease bacteria liquid with high mineralization efficiency and carbonic anhydrase bacteria spores based on self-healing mineralization repair, and uses pressure injection method to inject the repair liquid into the cracks in the hidden restricted operation area of ​​the port, and uses the efficient mineralization ability of urease bacteria to realize the rapid filling of the cracks with the mineralized product calcium carbonate. In order to prevent the repair area from cracking again due to other reasons, the carbonic anhydrase spores can germinate after cracking, and mineralization reaction occurs in the presence of oxygen, water and calcium ions, and the damaged parts are self-healed and mineralized. Repair. At the same time, the pressure grouting method as a repair method can avoid the problem of fluidity of the repair liquid in other hidden restricted areas except the horizontal plane. The repair liquid can be pumped into the cracks through a pressure device to achieve the purpose of mineralization repair filling. This method significantly reduces the construction procedures relative to the traditional method. While improving the repair efficiency of the microbial method in the concrete structure, the selected injection repair method can obviously solve the construction difficulty of hidden restricted areas such as the side and bottom of the concrete structure in the port area, and has very important application value in the repair of concrete cracks in the port area, especially in the hidden restricted operation area. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flow chart of the bioremediation method of the present invention;

[0034] Figure 2This is a graph showing the results of the anti-seepage test of concrete specimens repaired by urease-producing bacteria in the present invention; after a 2-3 day repair period, compared with the anti-seepage conditions of unrepaired specimens and intact specimens, it was found that the water absorption rate of the repaired specimens was basically the same as that of the intact specimens after 7 hours of the experiment, indicating that under this experimental method, the anti-seepage performance of the specimens after microbial mineralization repair of cracks has been significantly improved;

[0035] Figure 3 The surface condition diagram of the test piece at different stages of the self-healing mineralization reaction of carbonic anhydrase-producing bacteria in the present invention; after the micro-cracks with a width of 0.3-0.5 are generated, nutrient solution C is sprayed twice a day in the morning and evening to allow it to penetrate into the cracks, and the carbonic anhydrase bacteria spores can germinate and recover with the participation of oxygen and nutrients. After 7 days of self-healing mineralization reaction, it can be seen that the cracks have been filled with white precipitates, indicating the effectiveness and feasibility of carbonic anhydrase bacteria spores in the self-healing mineralization reaction process of concrete micro-cracks. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the embodiments. The following embodiments are descriptive rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0037] The various experimental operations involved in the specific embodiments are all routine techniques in the art. For parts not specially annotated in this document, ordinary technicians in the art can implement them by referring to various commonly used reference books, scientific and technological literature or related instructions, manuals, etc. before the filing date of this invention.

[0038] A method for biological repair of micro cracks in concrete structures in hidden restricted working areas of port workers, comprising: fermenting and culturing urease-producing bacterial fermentation broth, and collecting spore suspensions rich in carbonic anhydrase-producing bacteria spores through fermentation and culture; dissolving urea in the urease-producing bacterial fermentation broth to produce a large amount of carbonate ions; then preparing a calcium salt solution, adding the carbonic anhydrase-producing bacteria spore suspension to the calcium salt solution and mixing; and preparing a germination nutrient solution for self-healing mineralization of carbonic anhydrase bacteria spores; using a pressure injection method in the hidden crack area of ​​concrete to be repaired, installing grouting equipment according to the size of the cracks, and independently injecting the repair fluid and nutrient solution into the hidden crack area of ​​concrete for repair. It can be as follows Figure 1 shown.

[0039] Preferably, the urease-producing bacteria is Sporosarcina pasteurii ATCC11859;

[0040] The carbonic anhydrase-producing bacteria is Bacillushalodurans ATCC27557;

[0041] Alternatively, the urease-producing bacterial fermentation broth is measured by a spectrophotometer to determine its absorbance value OD600 The conductivity of the bacterial solution was between 8.0-9.0, and the urease activity of the bacterial solution was measured by conductivity and was between 14.0-16.0 mM / min.

[0042] Preferably, the method comprises the following steps:

[0043] (1) Preparation of urease-producing bacterial fermentation broth: prepare a fermentation medium, sterilize it at 121°C for 20 min, inoculate urease-producing bacteria into the sterile fermentation medium at a 1% inoculation rate, and culture it in a constant temperature shaking incubator at 30°C and 200 rpm for 30-40 h. Collect the bacterial broth and store it at 4°C for later use;

[0044] (2) Preparation of spore suspension: prepare fermentation medium, sterilize at 115°C for 30 min, cool to room temperature, add sterile Na2CO3 solution with a mass concentration of 10%, inoculate the carbonic anhydrase-producing bacteria into the sterile fermentation medium at a 1% inoculum amount, culture in a constant temperature shaking incubator at 37°C and 200 r / min for 48-72 h, centrifuge at 4°C and discard the supernatant, wash with distilled water to prepare a suspension, and store at 4°C for later use;

[0045] (3) Before repair, the urease-producing bacterial fermentation liquid was placed in a 30°C water bath for 1 hour, urea was added, and the mixture was reacted in a water bath for 1-2 hours to obtain repair liquid A;

[0046] (4) preparing a calcium salt solution, and mixing the spore suspension into the calcium salt solution to prepare a repair solution B;

[0047] (5) preparing a germination nutrient solution C for germination of the spore suspension;

[0048] (6) After flushing the hidden crack area of ​​the concrete to be repaired with water, repair liquid A and repair liquid B are injected into the hidden crack area of ​​the concrete to be repaired at the same time through different pipes through a pressure grouting device. The two components are arranged at intervals to prevent the calcium carbonate precipitate produced by the mixing of the two components from clogging the outlet of the grouting equipment. After 1 hour of adding repair liquids A and B, nutrient solution C is injected. Repeat this step until the hidden crack area of ​​the concrete to be repaired is completely filled and the repair is completed.

[0049] Preferably, the fermentation medium of the urease-producing bacteria in step (1) comprises 30 g / L yeast extract, 5 g / L peptone, 0.1 mol / L urea, 10 g / L (NH4)2SO4, pH=9, 1L 0.13 mol / L Tris-HCl;

[0050] The formula of the fermentation medium for producing carbonic anhydrase bacteria in step (2) is: 10g of peptone, 5g of yeast extract, 10g of glucose, 1g of K2HPO4, and 0.02g of MnSO4·H2O per 900mL of distilled water; and 100mL of Na2CO3 solution is added to every 900mL of distilled water.

[0051] Preferably, the final concentration of urea added in step (3) is 3 mol / L, and it is added to the bacterial solution in advance to allow it to be fully decomposed to produce a large amount of carbonate ions to serve as repair solution A.

[0052] Preferably, the calcium salt in step (4) is calcium acetate, and the concentration of calcium salt in the calcium salt solution is 2 mol / L, which has the same mineralization deposition effect as calcium chloride and avoids Cl - The reintroduction of potential corrosion effects on reinforced concrete;

[0053] The mixing volume ratio of spore suspension and calcium salt solution is 1:3, which is used as repair solution B. Carbonic anhydrase spores can act as nucleation sites for the first mineralization reaction in repair solution B, and then in the rapid mineralization reaction, the spores are embedded in calcium carbonate precipitation. When the crack is completely repaired, in order to prevent other reasons from causing cracking in the area, the carbonic anhydrase spores germinate due to the entry of air and moisture, and then undergo a self-healing mineralization reaction to repair the microcracks.

[0054] Preferably, in step (6), the volume ratio of the repair solution A to the repair solution B is 1:2, and the volume ratio of the repair solution A to the germination nutrient solution C is 1-2:1.

[0055] Preferably, the germination nutrient solution C in step (6) is: 10 g of peptone, 5 g of yeast extract, 10 g of glucose, 1 g of K2HPO4, and 17 g of calcium acetate are added to every 1000 mL of distilled water.

[0056] Preferably, in step (6), for micro cracks with a width of 0.3-1 mm, since the cracks are too small, in order to allow the two repair solutions to fully mix and react, the distance between the grouting nozzles of the pressure grouting device is set between 15-25 cm; for micro cracks with a width of 1-2 mm, since the cracks are relatively wide, the distance between the grouting nozzles is set between 25-35 cm.

[0057] The bioremediation method as described above is applied in the repair of micro cracks in concrete structures in hidden and restricted working areas of port workers.

[0058] Specifically, the relevant preparation and detection are as follows:

[0059] Example 1

[0060] A bioremediation method for micro-cracks in concrete structures in hidden and restricted working areas of port workers, comprising the following steps:

[0061] Preparation of fermentation broth: Prepare urease bacteria ATCC11859 fermentation medium, the main components of which are: yeast extract 30g / L, peptone 5g / L, urea 0.1mol / L, (NH4)2SO4 10g / L, 0.13mol / LTris-HCl (pH=9) 1L. Then sterilize at 121℃ for 20min, cool to room temperature, inoculate the bacteria into the sterile fermentation medium at 1% inoculation amount, and culture in a constant temperature shaking incubator at 30℃, 180r / min for 36h. Put the fermentation broth in a sterile container and store it in a 4℃ refrigerator for later use. At the same time, prepare the carbonic anhydrase fermentation medium, whose main components are: peptone 10g, yeast extract 5g, glucose 10g, K2HPO41g, MnSO4·H2O0.02g, 900mL distilled water, autoclave at 115℃ for 30min, cool to room temperature, add 10% Na2CO3100mL aseptically, inoculate at 1% inoculation amount, culture in a constant temperature shaking incubator at 37℃, 200r / min for 72h, centrifuge at 4℃ to discard the supernatant, wash with distilled water and store the resuspension at 4℃ for standby use. Before repair, place the urease bacterial solution in a 30℃ water bath for 1h, add 3mol / L urea, react in a water bath for 2h, and obtain repair solution A. Prepare 2mol / L calcium acetate solution, mix the two according to the volume ratio of spore suspension and calcium salt solution of 1:3, and make repair solution B. Then prepare repair solution C. For cracks in hidden areas of concrete structures, after cleaning the inside of the cracks to be repaired, for micro cracks with a width of 0.3-1mm, because the crack width is too small, in order to allow the two repair liquids to fully mix and react, the interval between the grouting nozzles should be set between 15-25cm. Bury the grouting nozzles, seal the upper layer of the cracks between the grouting nozzles with sealing glue, and then install the grouting device for grouting. The added volume ratio of repair liquid A to repair liquid B is: 1:2. Repair liquid A and repair liquid B are injected through independent grouting equipment respectively, and the two components are injected in an interval arrangement to prevent the calcium carbonate precipitate produced by the mixing of the two components from clogging the outlet of the grouting equipment. After 1 hour, inject repair liquid C. This step can be repeated until the inside of the concrete crack is completely filled and repaired.

[0062] Example 2

[0063] A bioremediation method for micro-cracks in concrete structures in hidden and restricted working areas of port workers, comprising the following steps:

[0064] Preparation of fermentation broth: Prepare urease bacteria ATCC11859 fermentation medium, the main components of which are: yeast extract 30g / L, peptone 5g / L, urea 0.1mol / L, (NH4)2SO4 10g / L, 0.13mol / LTris-HCl (pH=9) 1L. Then sterilize at 121℃ for 20min, cool to room temperature, inoculate the bacteria into the sterile fermentation medium at 1% inoculation amount, and culture in a constant temperature shaking incubator at 30℃, 200r / min for 36h. Put the fermentation broth in a sterile container and store it in a 4℃ refrigerator for later use. At the same time, prepare the carbonic anhydrase fermentation medium, whose main components are: peptone 10g, yeast extract 5g, glucose 10g, K2HPO41g, MnSO4·H2O0.02g, 900mL distilled water, autoclave at 115℃ for 30min, cool to room temperature, add 10% Na2CO3100mL aseptically, inoculate at 1% inoculation amount, culture in a constant temperature shaking incubator at 37℃, 200r / min for 72h, centrifuge at 4℃ to discard the supernatant, wash with distilled water and store the resuspension at 4℃ for standby use. Before repair, place the urease bacterial solution in a 30℃ water bath for 1h, add 3mol / L urea, react in a water bath for 2h to obtain repair solution A. And prepare 2mol / L calcium acetate solution, mix the two at a volume ratio of 1:3 between the bacterial suspension and the calcium salt solution to make repair solution B. Then prepare repair solution C. For micro cracks in hidden areas of concrete structures, after cleaning the inside of the cracks to be repaired, for micro cracks with a width of 1-2mm, the interval between the grouting nozzles should be set between 25-35cm because the cracks are relatively wide. After burying the grouting nozzles, seal the upper layer of the cracks between the grouting nozzles with sealing glue, and then install the grouting device for grouting. The added volume ratio of repair liquid A to repair liquid B is 1:2. Repair liquid A and repair liquid B are injected through independent grouting equipment respectively, and the two components are injected in an interval arrangement to prevent the calcium carbonate precipitate produced by the mixing of the two components from clogging the outlet of the grouting equipment. After 1 hour, inject repair liquid C. This step can be repeated until the inside of the concrete crack is completely filled and repaired.

[0065] The relevant detection of the present invention is as follows:

[0066] Figure 2Test method for test specimen impermeability: The water absorption of concrete refers to the amount of water absorbed by the specimen within a certain period of time. When cracks appear in concrete, water can quickly pass through the specimen through the cracks. If the cracks are repaired, it will take more time for water to penetrate into the specimen. Therefore, water absorption can be used to characterize the change in the impermeability of concrete specimens before and after repair. After wax sealing the surrounding areas of the test specimen and the unrepaired experimental area, record its mass as M1, then turn the repaired surface upside down and fully immerse it in water, take it out at different time periods, quickly absorb the surface moisture with a wet towel and immediately weigh it, record it as M2, then its water absorption rate E = (M2-M1) / M1, at the same time, use the unrepaired cracked specimens as the blank group and the intact specimens as the control group.

[0067] Figure 3 Visual observation diagrams of the concrete specimens at different stages of the self-healing process.

[0068] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A bioremediation method for micro-cracks in concrete structures in hidden and restricted working areas of port workers, characterized by: Fermenting and culturing a urease-producing bacterial fermentation broth, and at the same time, collecting a spore suspension rich in spores of carbonic anhydrase-producing bacteria; dissolving urea in the urease-producing bacterial fermentation broth to produce a large amount of carbonate ions; Then, a calcium salt solution is prepared, and a spore suspension of carbonic anhydrase-producing bacteria is added to the calcium salt solution and mixed; and a germination nutrient solution for self-healing and mineralization of carbonic anhydrase bacteria spores is prepared; in the hidden crack area of ​​concrete to be repaired, a pressure injection method is used, and grouting equipment is installed according to the size of the crack, and the repair liquid and the nutrient solution are independently injected into the hidden crack area of ​​concrete to perform repair; The urease-producing bacteria is Sporosarcina pasteurii ATCC 11859; The carbonic anhydrase-producing bacteria is Bacillus halodurans ATCC 27557; The urease-producing bacterial fermentation broth is measured by a spectrophotometer to determine its absorbance value OD 600 The urease activity of the bacterial solution measured by the conductivity method was between 14.0 and 16.0 mM / min; The steps include: (1) Preparation of urease-producing bacterial fermentation broth: prepare a fermentation medium, sterilize it at 121°C for 20 min, inoculate urease-producing bacteria into the sterile fermentation medium at a 1% inoculation rate, and culture it in a constant temperature shaking incubator at 30°C and 200 rpm for 30-40 h. Collect the bacterial broth and store it at 4°C for later use; (2) Preparation of spore suspension: prepare fermentation medium, sterilize at 115°C for 30 min, cool to room temperature, add sterile Na2CO3 solution with a mass concentration of 10%, inoculate the carbonic anhydrase-producing bacteria into the sterile fermentation medium at a 1% inoculum amount, culture in a constant temperature shaking incubator at 37°C and 200 r / min for 48-72 h, centrifuge at 4°C and discard the supernatant, wash with distilled water to prepare a suspension, and store at 4°C for later use; (3) Before repair, the urease-producing bacterial fermentation liquid was placed in a 30°C water bath for 1 hour, urea was added, and the mixture was reacted in a water bath for 1-2 hours to obtain repair liquid A; (4) preparing a calcium salt solution, and mixing the spore suspension into the calcium salt solution to prepare a repair solution B; (5) preparing a germination nutrient solution C for germination of the spore suspension; (6) After flushing the hidden crack area of ​​the concrete to be repaired with water, the repair liquid A and the repair liquid B are injected into the hidden crack area of ​​the concrete to be repaired at the same time through different pipes through the pressure grouting device. After the repair liquids A and B are added for 1 hour, the nutrient solution C is injected. This step is repeated until the hidden crack area of ​​the concrete to be repaired is completely filled and the repair is completed; The fermentation medium of the urease-producing bacteria in step (1) comprises 30 g / L yeast extract, 5 g / L peptone, 0.1 mol / L urea, 10 g / L (NH4)2SO4, pH=9, 1L 0.13 mol / L Tris-HCl; The formula of the fermentation medium for producing carbonic anhydrase bacteria in step (2) is: 10 g of peptone, 5 g of yeast extract, 10 g of glucose, 1 g of K2HPO4, and 0.02 g of MnSO4·H2O per 900 mL of distilled water; 100 mL of Na2CO3 solution is added to each 900 mL of distilled water; The final concentration of urea added in step (3) is 3 mol / L; In step (4), the calcium salt is calcium acetate, and the concentration of the calcium salt in the calcium salt solution is 2 mol / L; The spore suspension and calcium salt solution were mixed in a volume ratio of 1:3 to make repair solution B; In the step (6), the volume ratio of the repair solution A to the repair solution B is 1:2, and the volume ratio of the repair solution A to the germination nutrient solution C is 1-2:1; The germination nutrient solution C in step (6) is: 10 g of peptone, 5 g of yeast extract, 10 g of glucose, 1 g of K2HPO4, and 17 g of calcium acetate are added to every 1000 mL of distilled water; In the step (6), for micro cracks with a width of 0.3-1 mm, since the cracks are too small, in order to allow the two repair liquids to fully mix and react, the spacing between the grouting nozzles of the pressure grouting device is set between 15-25 cm; for micro cracks with a width of 1-2 mm, since the cracks are wider, the spacing between the grouting nozzles is set between 25-35 cm.

2. Application of the bioremediation method as claimed in claim 1 in the repair of micro cracks in concrete structures in hidden and restricted working areas of port workers.

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