Algal-fungal microbial micp concrete crack repair dynamic monitoring system and monitoring method thereof

Abstract

The present application provides an algal bacterial microbial MICP concrete crack repair dynamic monitoring system and a monitoring method thereof, and belongs to the field of concrete crack and monitoring. The present application solves the problems in the prior art, such as difficulty in controlling the gas boundary condition, difficulty in synchronously monitoring the gas concentration change and crack repair morphology, reduction of measurement accuracy caused by the influence of the transparent cavity wall on the external visual measurement, and the problems of easy disturbance of the test piece and reaction environment caused by the subsequent installation of sensors or optical components during the repair process. The present application comprises a nitrogen gas source, a carbon dioxide gas cylinder, a mass flow control and gas mixing unit, a reaction cavity, a pre-embedded optical fiber, a programmable light source unit, an optical oxygen probe, an oxygen sensor, a carbon dioxide sensor, a binocular visual measurement module and a data acquisition and coupling analysis unit. The present application realizes the synchronous monitoring and quantitative analysis of the carbon dioxide transport process, the microbial mineralization behavior and the crack healing process, and improves the accuracy and reliability of the MICP repair mechanism research and repair effect evaluation.

Description

Technical Field

[0001] This invention belongs to the field of concrete crack and monitoring technology, specifically involving microbial induced calcium carbonate deposition (MICP) repair technology, gas mass transfer monitoring technology, optical oxygen detection technology, binocular vision three-dimensional measurement technology, and durability evaluation technology for civil engineering materials. In particular, it relates to a dynamic monitoring system and method for algae-bacterial microbial MIP concrete crack repair. Background Technology

[0002] Microbially Induced Calcium Carbonate Precipitation (MICP) is a bioremediation technology that utilizes the metabolic activity of microorganisms to induce the formation and deposition of calcium carbonate. This technology enables calcium carbonate to deposit inside cracks or pores, thereby filling concrete cracks, reducing material permeability, and improving the durability of structures.

[0003] In the microbial-algal microbial (MICP) remediation system, carbon dioxide, as a crucial factor in cyanobacterial photosynthesis, affects the oxygen concentration released during photosynthesis. This, in turn, influences bacterial urea hydrolysis, carbonate ion formation, calcium ion deposition, and the formation of calcium carbonate mineralization products within the cracks. Therefore, the carbon dioxide environment is one of the key factors affecting the effectiveness of microbial-algal microbial microbial crack remediation.

[0004] Currently, MICP crack repair tests typically involve culturing concrete cracked specimens in an open environment, a constant-temperature incubator, or a conventional reaction vessel. The crack healing effect is evaluated through methods such as periodic photography, manual observation, permeability testing, ultrasonic testing, mass change measurement, specimen cross-section analysis, and before-and-after comparisons. While these methods provide information on the repair results, they struggle to continuously monitor changes in carbon dioxide concentration near the crack area during the repair process. Furthermore, they are difficult to simultaneously analyze and correlate changes in carbon dioxide concentration, microbial metabolic behavior, calcium carbonate deposition processes, and crack healing morphology.

[0005] Furthermore, existing visual monitoring methods typically mount cameras on the outside of transparent containers, acquiring images of cracks through the transparent walls. When using binocular vision technology for 3D measurement, the transparent walls are prone to light refraction, reflection, wall thickness errors, and surface distortion. Additionally, external mounting can introduce camera attitude deviations, thus reducing the accuracy of binocular parallax calculations and 3D reconstruction. When the monitored object is a micro-crack, crack edge sediment, or a locally mineralized area, these errors further affect the accuracy of measurements of parameters such as crack width, crack area, crack depth, and sediment coverage.

[0006] On the other hand, temporarily installing oxygen probes, fiber optic sensors, or lighting devices during the repair process can easily interfere with the geometry of the crack, the distribution of bacterial solution, the flow of the reaction liquid, and the gas diffusion path. It may even change the gas transmission state inside the reaction chamber, thereby affecting the authenticity of the repair process and the reliability of the monitoring results.

[0007] Therefore, it is necessary to develop a dynamic monitoring system that can operate under controlled carbon dioxide boundary conditions, without opening the reaction chamber and without disturbing the repair environment, so as to realize the synchronous acquisition and continuous monitoring of changes in oxygen concentration in the crack area and changes in the three-dimensional healing morphology of the crack during the MICP crack repair process. Summary of the Invention

[0008] In view of this, the present invention aims to solve the problems existing in the prior art, such as the difficulty in controlling gas boundary conditions, the inability to simultaneously monitor changes in oxygen concentration in the crack area and crack repair morphology, the reduced measurement accuracy of external visual measurements due to the influence of the transparent cavity wall, and the easy disturbance of the specimen and reaction environment by subsequent installation of sensors or optical components during the repair process. The present invention proposes a dynamic monitoring system and monitoring method for microbial MICP concrete crack repair, which realizes simultaneous monitoring and quantitative analysis of gas transport process, microbial mineralization behavior and crack healing process, thereby improving the accuracy and reliability of MCP repair mechanism research and repair effect evaluation.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a dynamic monitoring system for the repair of concrete cracks by algae and bacteria microorganisms (MICP), comprising a nitrogen source, a carbon dioxide source, a mass flow control and gas mixing unit, an air inlet, a reaction chamber, a pre-embedded optical fiber, a programmable light source unit, an optical oxygen sensor probe, a carbon dioxide sensor, an oxygen sensor, a binocular vision measurement module, an air outlet, and a data acquisition and coupling analysis unit. The concrete crack specimen is placed inside the reaction chamber. The nitrogen gas source and the carbon dioxide gas source are respectively connected to the mass flow control and gas mixing unit. The mass flow control and gas mixing unit delivers a mixed gas with a preset carbon dioxide concentration into the reaction chamber through the gas inlet. The gas outlet of the reaction chamber is used for exhaust gas emission or collection. The pre-embedded optical fiber is pre-embedded inside the concrete crack specimen or near the crack sidewall, with its light-emitting end facing the crack repair area, and the other end of the pre-embedded optical fiber is connected to the programmable light source unit. An optical oxygen sensor probe and a built-in sealed binocular vision measurement module are installed at the sensor interface of the reaction chamber. The optical oxygen sensor probe extends into the interior of the chamber near the crack area to monitor the change of oxygen concentration in the crack area over time during the repair process in real time. The data acquisition and coupling analysis unit is electrically connected to the mass flow control and gas mixing unit, the programmable light source unit, the optical oxygen sensor probe, the carbon dioxide sensor, the oxygen sensor, and the built-in sealed binocular vision measurement module, respectively. It is used to synchronously acquire and store gas flow parameters, oxygen concentration data in the crack area, carbon dioxide and oxygen concentration data in the cavity, optical input parameters, binocular image data, and crack morphology information.

[0010] Preferably, the reaction chamber is made of transparent acrylic material.

[0011] Preferably, the binocular vision measurement module includes two cameras and an airtight electrical connector. The two cameras are installed at a preset baseline distance and directly face the crack area to collect image data. The binocular vision measurement module is connected to the data acquisition and coupling analysis unit through the airtight electrical connector.

[0012] Preferably, the binocular vision measurement module further includes a transparent protective window, which is made of transparent corrosion-resistant sheet material; the sealing method is O-ring, sealing ring, potting or compression sealing.

[0013] Preferably, the pre-embedded optical fiber is a multimode optical fiber with a core diameter of 200-600 μm and a numerical aperture of 0.22-0.39; the working wavelength range covers 300-1200 nm or 400-2200 nm, and it is used for local light input, supplementary light or optical signal introduction to avoid post-insertion disturbance.

[0014] Preferably, the pre-embedded optical fiber is arranged in single or multiple strands, with the light-emitting end facing the sidewall of the crack, the bottom of the crack, or the bacterial active area, and is provided with a protective sleeve or alkali-resistant coating on the outside.

[0015] Preferably, a low-power supplementary lighting unit is provided outside the binocular vision measurement module, or a pre-embedded optical fiber or an independent light source inside the cavity is used to supplement the lighting in the crack area.

[0016] A dynamic monitoring method for the repair of concrete cracks using algae and bacteria microbial MICP, utilizing the aforementioned monitoring system, includes the following steps: Step 1: Prepare concrete crack specimens with cracks, and pre-embed optical fibers during the specimen forming stage, so that the light-emitting end faces the crack repair area. Step 2: Inoculate the crack area with cyanobacterial aerobic bacteria and add the nutrient solution, urea and calcium source solution required for the MIP reaction to construct a biomineralization remediation system. Step 3: Place the concrete crack specimen into the reaction chamber, install the optical oxygen sensor probe and binocular vision measurement module, and complete the system sealing check; Step 4: Calibrate the binocular vision measurement module to ensure the accuracy of crack morphology measurement; Step 5: A mixed gas with a preset carbon dioxide concentration is introduced into the reaction chamber through mass flow control and gas mixing unit to form controllable carbon dioxide boundary conditions. Step 6: During the MIP repair process, continuously collect oxygen concentration, gas flow rate, optical parameters and binocular image data in the area near the crack, and identify and reconstruct the crack images in three dimensions. Step 7: Obtain parameters such as crack width, crack area, crack depth, three-dimensional contour, and calcium carbonate deposition coverage based on the reconstruction results, and perform synchronous analysis with oxygen concentration data. Step 8: Compare the characteristics of cyanobacterial photosynthesis, crack healing, and calcium carbonate deposition under different carbon dioxide conditions, and evaluate the effect of carbon dioxide concentration changes on the repair effect of MIP cracks.

[0017] Preferably, the crack width healing rate is calculated according to η. w(t) =[w0-w t The calculation is performed using ] / w0×100%, where w0 is the initial crack width, and w t Let be the crack width at time t; the crack area healing rate is calculated according to η. A(t) =[A0-A t ] / A0×100% calculation, where A0 is the initial crack area, A t Let be the crack area at time t; calcium carbonate deposition coverage is calculated according to P. c(t) =S c(t) / S crack(t) Calculated by multiplying by 100%, where S c(t) S represents the area covered by sediment in the fracture region. crack(t) This represents the area of ​​the initial or currently identifiable region of the crack.

[0018] Preferably, under closed operating conditions, the apparent carbon dioxide consumption rate is calculated based on the relationship between carbon dioxide concentration and time; under flowing operating conditions, it is corrected by combining the inlet carbon dioxide concentration, outlet carbon dioxide concentration, gas flow rate, and effective volume of the reaction chamber.

[0019] Compared with existing technologies, the beneficial effects of the dynamic monitoring system and monitoring method for the repair of concrete cracks using algae and bacteria microbial MICP as described in this invention are: 1. This invention addresses the problems of uncontrollable carbon dioxide boundaries and difficulty in recording oxygen changes. It forms a controllable oxygen boundary through a nitrogen gas source, a carbon dioxide gas source, and a mass flow control and gas mixing unit. An optical oxygen sensor probe continuously records the oxygen concentration in the crack area. The carbon dioxide operating conditions can cover setpoints such as 0.5%-1%, 5%, 10%, 21%, and 30% CO2. The preferred oxygen sampling frequency is 1-10 Hz.

[0020] 2. This invention addresses the issue of external vision being affected by the transparent cavity wall by placing the binocular vision measurement module inside the cavity, directly facing the crack area, thereby reducing acrylic wall refraction, reflection, wall thickness error, and external installation angle error.

[0021] 3. This invention addresses the problem of cracks caused by the insertion of optical fibers or sensors. By pre-embedding optical fibers inside the specimen or near the crack, the repair process does not require subsequent insertion into the crack area, which can reduce the disturbance to the crack geometry, bacterial liquid distribution and gas diffusion path.

[0022] 4. This invention addresses the problem of asynchronous oxygen data and healing morphology. Through a data acquisition and coupling analysis unit, it simultaneously acquires oxygen concentration, flow rate, illumination, binocular images, and three-dimensional morphology data, enabling simultaneous acquisition of w (t) A (t) Crack depth, three-dimensional profile, η w(t) η A(t) and P c(t) .

[0023] 5. This invention addresses the issue of insufficient equipment feasibility by setting key component parameters based on existing commercially available finished equipment, without relying on specific trademarks or models. The oxygen probe can achieve gas-phase t 90 Less than 0.5 s level; binocular camera can achieve close-range measurement of 70-500 mm; flow control response can reach 30 ms level.

[0024] 6. This invention can be used to study the MICP crack repair process of algae and bacteria under different carbon dioxide concentrations, and realize the dynamic monitoring and quantitative analysis of carbon dioxide transport, microbial metabolic activity, calcium carbonate deposition behavior and crack healing process. It is particularly suitable for the study and evaluation of the coupling relationship between carbon dioxide environment and biomineralization repair effect in concrete, mortar, cementitious materials and other porous materials, and provides technical support for improving material durability and developing intelligent crack repair technology. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in this invention; Figure 2 A schematic diagram of the built-in sealed binocular vision measurement module; Figure 3 for Figure 2 The left view; Figure 4 for Figure 2 Top view; Figure 5 This is a structural diagram of the camera location; Figure 6 A schematic diagram showing the relative arrangement of the pre-embedded optical fiber, oxygen probe, and crack repair area; Figure 7 Flowchart for coupled analysis of carbon dioxide concentration regulation, cyanobacterial photosynthesis, and aerobic bacterial MIP-crack repair performance.

[0026] In the diagram: 1. Nitrogen source; 2. Carbon dioxide source; 3. Mass flow control and gas mixing unit; 4. Inlet; 5. Reaction chamber; 6. Concrete crack specimen; 7. Embedded optical fiber; 8. Programmable light source unit; 9. Optical oxygen sensor probe; 10. Binocular vision measurement module; 11. Outlet; 12. Data acquisition and coupling analysis unit; 13. Oxygen value meter; 14. Oxygen sensor; 15. Carbon dioxide sensor; 16. Computer; 17. Flow controller; 18. Double-ended bolt; 19. Epoxy resin; 20. Sealing gasket; 21. Piston sealing ring; 22. Moving piston; 23. Gas delivery valve; 24. Gas delivery conduit; 25. Crack area; 26. Crack repair area; 27. Algae and bacteria repair area; 28. Oxygen concentration detection area; 29. Protective housing 10-1, camera 10-2, first camera 10-2-1, second camera 10-2-2, transparent protective window 10-3, airtight electrical connector 10-4, rigid mounting bracket 10-5, first infrared projector 10-6-1, second infrared projector 10-6-2. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the drawings, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the invention.

[0028] See Figure 1-7 This embodiment describes a dynamic monitoring system for the repair of concrete cracks using algae and bacteria microbial MICP, comprising a nitrogen source 1, a carbon dioxide source 2, a mass flow control and gas mixing unit 3, an air inlet 4, a reaction chamber 5, a concrete crack specimen 6, a pre-embedded optical fiber 7, a programmable light source unit 8, an optical oxygen sensor probe 9, a binocular vision measurement module 10, an air outlet 11, and a data acquisition and coupling analysis unit 12. The reaction chamber 5 is used to construct a closed reaction environment with adjustable carbon dioxide concentration. The concrete crack specimen 6 is placed inside the reaction chamber 5. The crack repair area 26 of the specimen is inoculated with algae and bacteria, and nutrient solution, urea and calcium source solution required for the MICP reaction are added to form a biomineralization repair system.

[0029] The reaction chamber 5 is preferably made of transparent acrylic, and is a rectangular or cylindrical transparent chamber. It is equipped with a removable sealing cover, an air inlet 4, an air outlet 11, a sensor interface, an airtight electrical connection interface, and an internal mounting bracket. The chamber wall thickness and effective volume are determined based on the dimensions of the concrete crack specimen 6.

[0030] Nitrogen source 1 and carbon dioxide source 2 are respectively connected to mass flow control and gas mixing unit 3. Mass flow control and gas mixing unit 3 delivers a mixed gas with a preset carbon dioxide concentration into reaction chamber 5 through inlet 4. By adjusting the ratio of nitrogen to carbon dioxide / air, the oxygen concentration in reaction chamber 5 is controlled to form a controllable oxygen boundary condition, thereby achieving regulation of the carbon dioxide boundary condition of the reaction environment. Outlet 11 is used for exhaust or collection of exhaust gas from reaction chamber 5, and together with inlet 4, maintains a stable gas exchange environment inside the reaction chamber.

[0031] The pre-embedded optical fiber 7 is embedded inside the concrete crack specimen 6 or near the crack sidewall, with its light-emitting end facing the crack repair area 26. This avoids interference with the crack structure and gas transmission process caused by subsequent optical fiber installation. One end of the pre-embedded optical fiber 7 is connected to the programmable light source unit 8, used to transmit optical signals to the crack area 25, provide local illumination, or assist in optical detection. Due to the pre-embedded structure, there is no need to insert additional detection devices into the crack area 25 during the repair process, thereby reducing the impact on crack geometry, microbial distribution, reaction liquid distribution, and gas diffusion path.

[0032] The pre-embedded optical fiber 7 can be arranged as a single or multiple fibers, with the light-emitting end facing the sidewall of the crack, the bottom of the crack, or the bacterial active area. A protective sleeve or alkali-resistant coating can be installed on the outside.

[0033] An optical oxygen sensor probe 9 is installed at the sensor interface of the reaction chamber 5 and extends into the chamber near the crack area. It is used to monitor the change in oxygen concentration in the crack area over time during crack repair. By continuously acquiring oxygen concentration data, the intensity of cyanobacterial photosynthesis and microbial metabolic activity can be reflected. A controllable carbon dioxide boundary condition is constructed through mass flow control and the gas mixing unit 3, and continuous in-situ monitoring of oxygen concentration in the crack area is achieved in conjunction with the optical oxygen sensor probe 9. The optical oxygen sensor probe 9 can be used for gas phase detection, and can also be inserted into the liquid film or near the reaction liquid for liquid phase dissolved oxygen detection as needed.

[0034] The binocular vision measurement module 10 is fixedly installed inside the reaction chamber 5. It includes a first camera 10-2-1 and a second camera 10-2-2. The two cameras are installed at a preset baseline distance and directly face the crack area 25 to collect image data. Compared with the traditional external vision measurement method, this structure directly faces the concrete crack area to collect images, avoiding light refraction, reflection and imaging distortion caused by the transparent cavity wall, and improving the accuracy of crack three-dimensional reconstruction and morphology measurement.

[0035] The binocular vision measurement module 10 can be equipped with a low-power supplementary lighting unit; it can also use the pre-embedded optical fiber 7 or an independent light source inside the cavity to supplement lighting in the crack area.

[0036] When the accuracy requirements are low or the cavity space is insufficient, an external binocular camera can be used as an alternative, but the refraction and reflection of the acrylic wall should be calibrated and compensated.

[0037] Preferably, the binocular vision measurement module 10 is provided with a sealed protective housing 10-1, a transparent protective window 10-3, and an airtight electrical connector 10-4. The front end of the sealed protective housing 10-1 is provided with a planar transparent protective window 10-3. The transparent protective window 10-3 can be made of planar acrylic sheet, glass sheet, or other transparent corrosion-resistant sheet material. The sealing method can be O-ring, sealing rubber ring, potting, or compression sealing. The cable is led out through the airtight electrical connector 10-4, which ensures the airtightness of the cavity while ensuring its stable operation in high humidity, biological reaction liquid, and calcium carbonate deposition environment.

[0038] Infrared projectors are mounted on the outer sides of the two cameras. The two cameras measure distance using left-right parallax, while the infrared projectors are responsible for projecting "invisible textures" onto the target surface, making it easier for the cameras to calculate depth. The infrared projectors enhance texture features, improve depth measurement accuracy, enhance recognition capabilities in low-light environments, and assist in close-range 3D perception.

[0039] The data acquisition and coupling analysis unit 12 is electrically connected to the mass flow control and gas mixing unit 3, the programmable light source unit 8, the optical oxygen sensor probe 9, the oxygen sensor 14, the carbon dioxide sensor 15, and the built-in sealed binocular vision measurement module 10. The data acquisition and coupling analysis unit 12 can send control commands to the mass flow control and gas mixing unit 3 and the programmable light source unit 8, and can also receive oxygen and carbon dioxide concentrations in the cavity, oxygen concentrations in the crack area, flow rates, light intensity, and binocular image data to achieve time synchronization.

[0040] The data acquisition and coupling analysis unit 12 simultaneously acquires oxygen concentration data, optical parameters, gas flow data, and three-dimensional morphology data of the cracks. Based on the acquired data, the data acquisition and coupling analysis unit 12 further calculates evaluation indicators such as cyanobacterial oxygen production rate, crack width healing rate, crack area healing rate, and calcium carbonate deposition coverage, so as to realize the coupling analysis and dynamic evaluation between the carbon dioxide transport process, the microbial mineralization process, and the crack healing process.

[0041] This system has no traditional mechanical transmission mechanism and mainly achieves dynamic monitoring through gas flow control, light input control, optical oxygen detection, and binocular vision imaging.

[0042] Key component parameters: The mass flow control and gas mixing unit 3 can be selected from 0.5 SCCM-20 SLPM or other ranges depending on the chamber volume; the control range can cover 0.01%-100% of the full scale; the response time can reach the 30 ms level; the accuracy can be selected as approximately ±0.5% of the reading or ±0.05% of the full scale, realizing low carbon dioxide, normal carbon dioxide, rich carbon dioxide, step and periodic carbon dioxide boundaries.

[0043] The pre-embedded optical fiber 7 can be a multimode optical fiber with a core diameter of 200-600 μm; the numerical aperture can be selected from 0.22-0.39; the working wavelength can cover 300-1200 nm or 400-2200 nm, and it is used for local light input, supplementary light or optical signal introduction to avoid post-insertion disturbance.

[0044] Programmable light source unit 8 uses PAR to characterize illumination, and the measurement range can cover 0-4000 μmol·m -2 ·s -1 The response time can be less than 1 ms, and the calibration band can cover about 400-700 nm, which is used to calibrate the output of optical fibers or the intensity of intracavity supplementary light.

[0045] The optical oxygen sensor probe 9 is a fluorescence quenching optical oxygen sensor; it can be used in both gas and liquid phases; it does not consume oxygen; the probe can adopt a rigid probe structure with a diameter of about 3 mm and a length of about 100 mm, for continuous collection of O2(t) near the crack, which is suitable for monitoring rapid oxygen changes during the MCP process of algae and bacteria.

[0046] The optical oxygen sensor probe 9 preferably has a resolution of no more than 0.01% O2 in the low oxygen range and no more than 0.05% O2 in the normal oxygen range; the gas phase t90 is preferably less than 0.5 s and the aqueous phase t90 is preferably less than 3 s.

[0047] The oxygen measurement range for the gas phase is preferably 0-50% O2, and can be extended to a maximum of 0-100% O2; the liquid phase can be converted according to dissolved oxygen or air saturation, covering near-oxygen, low-oxygen, normal-oxygen and oxygen-rich working conditions.

[0048] The carbon dioxide operating conditions can be set to 0.5%-1% CO2, 5% CO2, 10% CO2, 21% CO2, 30% CO2, etc.; step, periodic or gradient changes can also be performed to study the effects of carbon dioxide concentration changes on cyanobacterial photosynthesis, bacterial metabolism and MIP remediation.

[0049] The binocular vision measurement module 10 is a near-range binocular depth camera or a dual-camera module; the working distance is preferably 70-500 mm, and the intracavity distance is preferably 70-200 mm; the resolution is not less than 720p, the frame rate can reach 30 fps or higher, and the fast process can be selected at 90 fps level, directly facing the crack area to reduce the refraction and reflection error of the transparent cavity wall.

[0050] The preferred sampling frequency for oxygen concentration in the data acquisition and coupling analysis unit 12 is 1-10 Hz. Binocular images can be acquired at 1-30 fps. Long-term experiments can be saved at intervals of 10 s-10 min. All data are accompanied by a unified timestamp to ensure that O2(t), w(t), A(t), three-dimensional morphology and sediment coverage can be analyzed synchronously.

[0051] The working principle of the dynamic monitoring system for the repair of concrete cracks using algae and bacteria microbial MICP described in this invention is as follows: During operation, the carbon dioxide concentration in the reaction chamber 5 is first set by the gas mixing unit 3, placing the concrete crack specimen 6 in a near-low carbon dioxide, normal carbon dioxide, carbon dioxide-rich, or dynamically changing carbon dioxide environment. Subsequently, cyanobacteria release oxygen through photosynthesis, promoting metabolic reactions in the crack repair area 26 and inducing calcium carbonate deposition. The optical oxygen sensor probe 9 continuously collects O2(t) near the crack. The binocular vision measurement module 10 simultaneously acquires crack images and reconstructs the three-dimensional morphology of the crack. The data acquisition and coupling analysis unit 12 correlates O2(t) with crack width, crack area, crack depth, three-dimensional contour, and deposition coverage over time, thereby evaluating the impact of carbon dioxide concentration changes on the crack repair performance of algae-bacteria-MICP.

[0052] The method for monitoring the dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in this invention includes the following steps: Step 1: Prepare a concrete crack specimen 6 with cracks, and pre-embed an optical fiber 7 during the specimen forming stage, so that its light-emitting end faces the crack repair area 26. Step 2: Inoculate the crack area with cyanobacteria and aerobic microorganisms, and add the nutrient solution, urea and calcium source solution required for the MIP reaction to construct a biomineralization remediation system; Step 3: Place the concrete crack specimen 6 into the reaction chamber 5, install the optical oxygen sensor probe 9 and the binocular vision measurement module 10, and complete the system sealing check. Step 4: Calibrate the binocular vision measurement module 10 to ensure the accuracy of crack morphology measurement; Step 5: A mixed gas with a preset carbon dioxide concentration is introduced into the reaction chamber 5 through the mass flow control and gas mixing unit 3 to form a controllable carbon dioxide boundary condition. Step 6: During the MIP repair process, continuously collect oxygen and carbon dioxide concentrations in the cavity, oxygen concentration in the crack area, gas flow rate, optical parameters, and binocular image data, and identify and reconstruct the crack images in three dimensions. Step 7: Based on the reconstruction results, obtain parameters such as crack width, crack area, crack depth, three-dimensional contour, and calcium carbonate deposition coverage, and perform synchronous analysis with oxygen concentration data. Step 8: Compare the oxygen consumption characteristics, crack healing characteristics, and calcium carbonate deposition characteristics under different carbon dioxide conditions to evaluate the effect of carbon dioxide concentration changes on the repair effect of MICP cracks.

[0053] Crack width healing rate can be calculated according to η w(t) =[w0-w (t) The calculation is performed using ] / w0×100%, where w0 is the initial crack width, and w (t) Let t be the crack width at time t.

[0054] The crack area healing rate can be calculated according to η. A(t) =[A0-A (t) ] / A0×100% calculation, where A0 is the initial crack area, A (t) Let be the crack area at time t.

[0055] Calcium carbonate deposition coverage can be calculated as P c(t) =S c(t) / S crack(t) Calculated by multiplying by 100%, where S c(t) S represents the area covered by sediment in the fracture region. crack(t) This represents the area of ​​the initial or currently identifiable region of the crack.

[0056] Implementation Method 1: Microcrystalline Carbon Dioxide Concentration (MICP) Crack Repair Monitoring with Built-in Binocular Vision A concrete crack specimen 6 with artificial cracks is prepared, the crack width preferably being 0.2–1.0 mm, and the specimen size is determined according to the specifications of the reaction chamber 5. During the specimen molding stage, pre-embedded optical fibers 7 are placed near the crack sidewall, with the distance between their light-emitting end and the crack repair area 26 preferably being 2–10 mm. To improve durability and sealing, a transparent protective sleeve, an alkali-resistant coating, or a flexible sealing layer can be installed on the outside of the optical fiber.

[0057] Cyanobacteria and aerobic microorganisms were inoculated into the crack area, and nutrient solution, urea, and calcium source solution required for the MICP reaction were added. Subsequently, the specimen 6 was fixed in the transparent and airtight reaction chamber 5, and a closed reaction environment was formed through the sealing structure, sensor interface, and airtight electrical connection interface.

[0058] An optical oxygen sensor probe 9 is installed inside the cavity 5 and close to the crack repair area 26 to monitor changes in oxygen concentration in the crack area in real time. A built-in sealed binocular vision measurement module 10 is fixed to a bracket inside the cavity, with the distance between the camera and the crack area preferably between 70 and 200 mm. After installation, the binocular vision measurement module 10 is calibrated using a calibration plate, and the calibration parameters are imported into the data acquisition and coupling analysis unit 12.

[0059] The built-in sealed binocular vision measurement module 10 is installed on the internal support of the reaction chamber 5, with the camera facing the crack area. The camera is set inside the sealed protective housing 10-1, and the transparent protective window 10-3 faces the area to be measured. After installation, the binocular vision measurement module 10 is calibrated using a calibration plate, and the calibration parameters are imported into the data acquisition and coupling analysis unit 12.

[0060] During the experiment, a mixed gas with a preset oxygen concentration was introduced into the reaction chamber 5 through mass flow control and gas mixing unit 3 to create different oxygen boundary conditions. During the repair process, the optical oxygen sensor probe 9 continuously collected oxygen concentration data O2(t), and the built-in sealed binocular vision measurement module 10 simultaneously collected crack images.

[0061] The data acquisition and coupling analysis unit 12 performs crack identification, three-dimensional reconstruction, and deposition area analysis on the image data to obtain the crack width w. (t) Crack area A (t) Crack depth, three-dimensional morphology and calcium carbonate deposition coverage P c(t) The parameters were analyzed in tandem with oxygen concentration data to evaluate the impact of oxygen concentration changes on the repair effect of MIP cracks.

[0062] Implementation Method 2: Experiment on Step Change in Carbon Dioxide Concentration Based on implementation method 1, the carbon dioxide concentration in the reaction chamber 5 is adjusted stepwise by mass flow control and gas mixing unit 3. For example, low carbon dioxide, normal carbon dioxide and high carbon dioxide conditions are set sequentially, and oxygen concentration data O2(t) and binocular images of the crack area are continuously collected during the carbon dioxide concentration switching process.

[0063] Data acquisition and coupled analysis unit 12 studies the oxygen production rate of cyanobacteria photosynthesis and the crack width healing rate η under different carbon dioxide conditions. w(t) Crack area healing rate η A(t) and calcium carbonate deposition coverage P c(t) Comparative analysis was conducted to evaluate the impact of changes in carbon dioxide concentration on microbial metabolic activity and the repair effect of MICP cracks.

[0064] Implementation Method 3: Comparative Verification of Built-in Binocular Vision and External Vision To verify the measurement performance of the binocular vision measurement module 10, an external binocular vision system was installed outside the reaction cavity 5 as a control group. The external binocular vision system acquired crack images through the transparent cavity wall, while the built-in binocular vision measurement module 10 acquired crack images directly inside the cavity.

[0065] Using standard crack samples, calibration plates, or reference objects of known dimensions, parameters such as crack width, crack area, three-dimensional morphology, and deposition coverage obtained by two visual measurement methods were compared and analyzed. By comparing measurement errors, the effectiveness of the built-in binocular vision structure in reducing light refraction, reflection, and wall thickness errors caused by the transparent cavity wall, as well as its role in improving the accuracy of crack three-dimensional reconstruction, were verified.

[0066] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A dynamic monitoring system for the repair of concrete cracks using algae and bacteria microbial (MICP) technology, characterized in that: It includes a nitrogen gas source (1), a carbon dioxide gas source (2), a mass flow control and gas mixing unit (3), a reaction chamber (5), a pre-embedded optical fiber (7), a programmable light source unit (8), an optical oxygen sensor probe (9), a binocular vision measurement module (10), an outlet (11), and a data acquisition and coupling analysis unit (12). The concrete crack specimen (6) is placed inside the reaction chamber (5). The nitrogen gas source (1) and the carbon dioxide gas source (2) are respectively connected to the mass flow control and gas mixing unit (3). The mass flow control and gas mixing unit (3) controls the oxygen concentration in the reaction chamber (5) by adjusting the ratio of nitrogen to carbon dioxide / air, so as to form a controllable oxygen boundary condition. The gas outlet (11) of the reaction chamber (5) is used for exhaust gas emission or collection. The pre-embedded optical fiber (7) is pre-embedded inside the concrete crack specimen (6) or near the crack sidewall, with its light-emitting end facing the crack repair area (26), and the other end of the pre-embedded optical fiber (7) is connected to the programmable light source unit (8). An optical oxygen sensor probe (9) and a built-in sealed binocular vision measurement module (10) are installed at the sensor interface of the reaction chamber (5). The optical oxygen sensor probe (9) extends into the interior of the chamber near the crack area (27) to monitor the change of oxygen concentration in the crack area over time during the repair process in real time. The data acquisition and coupling analysis unit (12) is electrically connected to the mass flow control and gas mixing unit (3), the programmable light source unit (8), the optical oxygen sensor probe (9), and the built-in sealed binocular vision measurement module (10) to synchronously acquire and store gas flow parameters, oxygen concentration data, optical input parameters, binocular image data, and crack morphology information.

2. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 1, characterized in that: The reaction chamber (5) is made of transparent acrylic material.

3. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 1, characterized in that: The binocular vision measurement module (10) includes two cameras (10-2) and an airtight electrical connector (10-4). The two cameras (10-2) are installed at a preset baseline distance and directly face the crack area (27) to collect image data. The binocular vision measurement module (10) is connected to the data acquisition and coupling analysis unit (12) through the airtight electrical connector (10-4).

4. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 3, characterized in that: The binocular vision measurement module (10) also includes a transparent protective window (10-3), which is made of transparent corrosion-resistant sheet material; the sealing method is O-ring, sealing ring, potting or compression sealing.

5. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 1, characterized in that: The pre-embedded optical fiber (7) is a multimode optical fiber with a core diameter of 200-600 μm and a numerical aperture of 0.22-0.

39. The working wavelength range covers 300-1200 nm or 400-2200 nm. It is used for local light input, supplementary light or optical signal introduction to avoid post-insertion disturbance.

6. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 1, characterized in that: The pre-embedded optical fiber (7) is arranged in single or multiple strands, with the light-emitting end facing the sidewall of the crack, the bottom of the crack, or the active area of ​​algae and bacteria, and is provided with a protective sleeve or alkali-resistant coating on the outside.

7. The dynamic monitoring system for concrete crack repair using algae and bacteria microbial MICP as described in claim 1, characterized in that: The binocular vision measurement module (10) is equipped with a low-power supplementary light unit, or a pre-embedded optical fiber (7) or an independent light source inside the cavity is used to supplement the light in the crack area.

8. A method for dynamic monitoring of microbial microbial (MICP) concrete crack repair, characterized in that: The monitoring system according to any one of claims 1-7 includes the following steps: Step 1: Prepare a concrete crack specimen (6) with cracks, and pre-embed optical fiber (7) during the specimen forming stage, so that its light-emitting end faces the crack repair area (26). Step 2: Inoculate aerobic microorganisms and cyanobacteria in the area (27) where the crack is located, and add the nutrient solution, urea and calcium source solution required for the MIP reaction to construct a biomineralization remediation system; Step 3: Place the concrete crack specimen (6) in the reaction chamber (5), install the optical oxygen sensor probe (9) and the binocular vision measurement module (10), and complete the system sealing check; Step 4: Calibrate the binocular vision measurement module (10) to ensure the accuracy of crack morphology measurement; Step 5: Through mass flow control and gas mixing unit (3), a mixed gas with a preset carbon dioxide concentration is introduced into the reaction chamber (5) to form a controllable carbon dioxide boundary condition; Step 6: During the MIP repair process, continuously collect oxygen concentration, gas flow rate, optical parameters and binocular image data of the crack repair area, and identify and reconstruct the crack images in three dimensions. Step 7: Obtain parameters such as crack width, crack area, crack depth, three-dimensional contour, and calcium carbonate deposition coverage based on the reconstruction results, and perform synchronous analysis with oxygen concentration data. Step 8: Compare the characteristics of cyanobacterial photosynthesis, crack healing, and calcium carbonate deposition under different carbon dioxide conditions, and evaluate the effect of carbon dioxide concentration changes on the repair effect of algal-bacterial MIP cracks.

9. The method for dynamic monitoring of concrete crack repair using algae-bacterial microbial MICP as described in claim 8, characterized in that: Crack width healing rate as η w(t) =[w0-w t The calculation is performed using ] / w0×100%, where w0 is the initial crack width, and w t Let be the crack width at time t; the crack area healing rate is calculated according to η. A(t) =[A0-A t ] / A0×100% calculation, where A0 is the initial crack area, A t Let be the crack area at time t; calcium carbonate deposition coverage is calculated according to P. c(t) =S c(t) / S crack(t) Calculated by multiplying by 100%, where S c(t) S represents the area covered by sediment in the fracture region. crack(t) This represents the area of ​​the initial or currently identifiable region of the crack.

10. The method for dynamic monitoring of concrete crack repair using algae-bacterial microbial MICP as described in claim 8, characterized in that: Under closed operating conditions, the apparent carbon dioxide consumption rate is calculated based on the relationship between carbon dioxide concentration and time; under flowing operating conditions, it is corrected by combining the inlet carbon dioxide concentration, outlet carbon dioxide concentration, gas flow rate, and effective volume of the reaction chamber.

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