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CN-121976199-A - Bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system and method

CN121976199ACN 121976199 ACN121976199 ACN 121976199ACN-121976199-A

Abstract

The invention discloses a bridge reinforced concrete pulse inversion-electroosmosis cooperative chlorine removal system and method, relates to the technical field of reinforced concrete structure corrosion prevention, and aims to solve the problems that in the conventional constant direct current electric field chlorine removal technology, anode polarization is large, the risk of secondary corrosion of a steel bar is high, the chlorine removal efficiency is difficult to quantify, the rigidity of the anode is large, a complex structure cannot be attached, the regeneration efficiency is free from quantification standard, the anode cost is high, the replacement is difficult, and the service life is free from deduction basis. The method establishes a chloride ion migration volume formula through optimizing pulse inversion parameters and electroosmosis collaborative design, realizes efficient migration of chloride ions, ensures stability of reinforcing steel bars, quantitatively evaluates resource circulation value, reduces cost and environmental burden, designs a soluble chitosan frame, derives an anode life formula, realizes automatic disintegration and integral replacement within 24 hours after anode exhaustion, constructs a generalized and quantifiable chlorine removal system, and covers the full requirements from efficient chlorine removal to low-cost maintenance through multi-technology collaborative and formulated evaluation.

Inventors

  • GONG YAFENG
  • Shang Liliang
  • SONG JIAXIANG
  • Zhai Yiyuan
  • SUN YI

Assignees

  • 吉林大学

Dates

Publication Date
20260505
Application Date
20260204

Claims (10)

  1. 1. A bridge reinforced concrete pulse inversion-electroosmosis co-chlorine removal system, the system comprising: The system is adaptive to the selection and foundation detection module and is used for preparing a chlorine removal scheme in the bridge environment, detecting the conductivity of the reinforcing mesh and marking the cathode connection point; The material pretreatment and anode prefabrication module is used for cleaning and repairing the concrete surface and prefabricating a corresponding anode according to the prepared chlorine removal scheme; The electrode layout and circuit connection module is used for laying electrodes according to the prepared chlorine removal scheme, connecting a circuit and detecting conductivity and polarization potential; the parameter setting and running module is used for setting parameters according to the prepared dechlorination scheme, injecting electroosmosis liquid and starting dechlorination; the chlorine removal process real-time monitoring module is used for detecting chloride ions, the potential of the steel bars and the anode state, and adjusting parameters when abnormal; and the shutdown recovery module is used for shutting down according to conditions, dismantling and cleaning the anode, and recovering the reusable anode.
  2. 2. The bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 1, wherein the anode in the material pretreatment and anode prefabrication module is a flexible carbon nanofiber anode, a sacrificial bismuth-carbon composite anode or a Ti/IrO 2 ×Ta 2 O 5 anode grid.
  3. 3. The bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 1, wherein the set parameters are pulse parameters and electroosmosis liquid injection parameters of a Ti/IrO 2 ×Ta 2 O 5 anode grid, flexible anode system parameters or sacrificial anode system parameters; The pulse parameters and electroosmosis liquid injection parameters of the Ti/IrO 2 ×Ta 2 O 5 anode grid are as follows: Pulse parameter, setting the duty cycle of square wave pulse Wherein t + is the forward pulse time, t - is the reverse pulse time, frequency f=0.5 Hz, forward current density I + =1.2-1.8A/m 2 , reverse current density I - =0.1-0.5A/m 2 ; Average current density is calculated according to the formula Calculating, substituting parameters to obtain Iavg=0.5-0.9A/m 2 ; Electroosmosis liquid injection, namely injecting 0.5 mol/L LiOH electroosmosis liquid, maintaining the pH value of the electroosmosis liquid to be 12.5+/-0.2, setting injection interval to be 0.3s, and setting single injection amount to be 0.2-0.8mL/cm 2 ; Electroosmosis flow monitoring according to the formula , wherein, Represents the electroosmotic flow rate, Represents the electroosmotic coefficient of the concrete, Representing the thickness of the protective layer of concrete, Representing the porosity of the concrete by 0.15 to 0.25; U is the actual effective electric field strength, where, Representing the average current density of the current in the current collector, Representing the electrical resistance of the concrete, For anodic polarization correction factor, the electroosmosis solution is fed in every hour and the pH value of the electroosmosis solution is maintained to be 12.5+/-0.2; setting parameters of a flexible anode system, namely setting current density to be 1-3A/m 2 ; the sacrificial anode system parameters are that the current density is set to 0.5-1A/m 2 .
  4. 4. The bridge reinforced concrete pulse inversion-electroosmosis cooperative chlorine removal system according to claim 1, wherein the electrode is arranged according to the prepared chlorine removal scheme, the chlorine removal scheme is determined according to the characteristics of bridge scenes, and the electrode is arranged as follows: when the concrete protective layer is more than or equal to 80mm, the initial chlorine content is more than or equal to 0.8 percent and the concrete protective layer is in a marine high-salt-fog environment, a pulse inversion-electroosmosis chlorine removal scheme is selected, and the electrode is a Ti/IrO 2 ×Ta 2 O 5 novel anode grid system; when the curvature radius of the bridge pier is less than or equal to 5m and the bridge pier is positioned in an ice salt removing use area, a pulse inversion chlorine removing scheme is selected, and the electrode is a novel anode system of the foldable flexible carbon nanofiber; when project budget is less than or equal to 50 yuan/m 2 and the bridge is in a rural low-traffic scene, a pulse chlorine removal scheme is selected, and the electrode is a sacrificial bismuth-carbon composite anode.
  5. 5. A method for removing chlorine by adopting the pulse inversion-electroosmosis cooperative chlorine removal system of the bridge reinforced concrete according to any one of claims 1 to 4, which is characterized in that the method comprises the following steps: Step S1, system adaptation selection and basic detection Determining the bridge type, the thickness of a concrete protective layer, the initial chlorine content and the erosion environment through on-site investigation, determining a chlorine removal system scheme, and finishing the detection of the concrete foundation state and the steel bar cathode conductivity; S2, material pretreatment and anode prefabrication After cleaning and repairing the concrete surface, selecting a flexible carbon nanofiber anode, a sacrificial bismuth-carbon composite anode or a Ti/IrO 2 ×Ta 2 O 5 anode grid; the matrix material carbon nanofiber-polyvinylidene fluoride composite film of the flexible carbon nanofiber anode has the following tensile fracture strain which needs to satisfy the formula: wherein L 1 represents the actual length of the anode substrate when stretched to break, and L 1 ≥115mm,L 0 represents the initial length of the anode substrate; The catalytic layer is formed by growing Bi 2 O 3 nm flowers in situ, and the load is 5-15wt%; The sacrificial bismuth-carbon composite anode has the density of 3-4 g/cm 3 , and comprises 50-70wt% of nano Bi 2 O 3 , 20-40wt% of crystalline flake graphite and 5-15wt% of modified phenolic resin, wherein the periphery of the sacrificial bismuth-carbon composite anode is coated with a temperature-sensitive chitosan frame; The Ti/IrO 2 ×Ta 2 O 5 anode grid is characterized in that the thickness of a functional layer formed by IrO 2 and Ta 2 O 5 is 5-8 mu m; Step S3, electrode layout and circuit connection The flexible carbon nanofiber anode, the sacrificial bismuth-carbon composite anode or the Ti/IrO 2 ×Ta 2 O 5 anode grid is used as an electrode to be laid out and built with a circuit; Step S4, setting and running of pulse inversion-electroosmosis cooperative parameters Setting pulse parameters and electroosmosis liquid injection parameters, flexible anode system parameters or sacrificial anode system parameters according to selected flexible carbon nanofiber anode, sacrificial bismuth-carbon composite anode or Ti/IrO 2 ×Ta 2 O 5 anode grid, starting dechlorination operation, Step S5, real-time monitoring of chlorine removal process Monitoring the content of chloride ions, the potential of the reinforcing steel bars and the anode state, and ensuring the chlorine removal effect and the system stability; S6, judging system shutdown and recycling resources When the chlorine removal effect reaches the standard or the anode is exhausted, stopping operation is carried out, and recycling treatment is carried out on the reusable anode and equipment.
  6. 6. The method for removing chlorine in a reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system for a bridge according to claim 5, wherein the cathode conductivity of the reinforced concrete in the step S1 is detected as follows: bridge detection using multimeter the conductivity of the reinforcing steel bar net exists, the judgment standard is as follows: Conductivity of the reinforcing steel bar mesh is qualified when the Conductivity of the reinforcing steel bar mesh is equal to 1, and is unqualified when the Conductivity is equal to 0, and novel conductive paste is required to be coated at the unqualified part.
  7. 7. The method for removing chlorine of the bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 5, which is characterized in that in the step S2, the material pretreatment and the cleaning and repairing of the concrete surface in the anode prefabrication are carried out by adopting differential treatment flows aiming at different surface types: General cleaning, namely flushing dust and greasy dirt on the surface by a high-pressure water gun, and wiping by alcohol to ensure that the cleanliness is more than or equal to 195%; repairing cracks, namely repairing cracks with the width of more than 0.2mm by adopting epoxy-basalt fiber mortar until the surface flatness error is less than or equal to 2mm; The curved surface treatment, namely polishing the slurry by sand paper for the curved bridge pier, and spraying 10wt% of silane coupling agent; plane marking: the plane area marks the anode grid mounting datum line, and the datum line deviation is less than or equal to 1mm.
  8. 8. The method for removing chlorine of the bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 5, wherein the step S3 is characterized in that the electrode layout and the circuit connection are specifically as follows: 1) Anode arrangement of pulse inversion-electroosmosis cooperative system Fixing Ti/IrO 2 ×Ta 2 O 5 anode grids according to plum blossom-shaped intervals of 20cm multiplied by 20 cm; coating agar-salt composite gel between the anode and the concrete; Compacting and exhausting to ensure that the contact resistance between the anode and the concrete interface is reduced to 50-80 omega; 2) Flexible anode system layout Attaching the flexible carbon nanofiber anode patch to the concrete according to the radian of the curved surface, compacting, and ensuring that the bubble area of the interface between the anode and the concrete is less than or equal to 1%, and dissolving NaCl crystals after the anode and the concrete are in contact with water for 10min, wherein the on-resistance is less than or equal to 50Ω; 3) Sacrificial anode system layout The four corners of the sacrificial bismuth-carbon composite anode module are aligned with fixing pins with positioning grooves and clamped in, and a clearance between the module and concrete is detected by using a feeler gauge, so that the clearance is less than or equal to 0.5mm.
  9. 9. The method for removing chlorine of the bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 5, wherein the pulse parameters and the electroosmosis liquid injection parameters are as follows: Pulse parameter, setting the duty cycle of square wave pulse Wherein t + is the forward pulse time and t - is the reverse pulse time; Average current density is calculated according to the formula Calculating, wherein I + is forward current density, and I - is reverse current density; Electroosmosis liquid injection, namely, injecting 0.5mol/L LiOH novel electroosmosis, and setting an injection interval of 0.3s and a single injection amount of 0.2-0.8 mL/cm 2 ; Electroosmosis flow monitoring according to the formula , wherein, In order for the actual effective electric field strength to be, Is the osmotic coefficient of electroosmosis, For anodic polarization correction factor, electroosmotic solution is applied per hour and maintained at ph=12.5±0.2; setting parameters of a flexible anode system, namely setting current density to be 1-3A/m 2 ; the sacrificial anode system parameters are that the current density is set to 0.5-1A/m 2 .
  10. 10. The method for removing chlorine by the bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system according to claim 5, wherein the step S5 is a chlorine removal process real-time monitoring method which is characterized by comprising the following steps: s5.1 real-time monitoring of sacrificial bismuth-carbon composite anode dechlorination process 1) Chloride ion content monitoring ① The monitoring frequency is that coring is carried out at 3 point positions with the distance of more than or equal to 1m every 2h, and the chlorine content is detected by an ion chromatograph; ② Calculating the migration quantity of chloride ions according to a formula And (3) calculating, wherein, In order to achieve an average current density, Is a function of the faraday constant, In order to remove the chlorine from the water during the operation, For the purpose of the migration efficiency of chloride ions, Is a novel anode catalytic efficiency coefficient, N=1 for anode coverage area; ③ Judging the chlorine removal effect, namely the chloride ion discharge rate And is qualified, wherein, the method comprises the steps of, For the total amount of chloride ion migration, The total amount of initial chloride ions in the concrete; 2) Reinforcing steel bar potential monitoring A saturated copper sulfate reference electrode is tightly attached to concrete, the potential of the steel bar is recorded in real time, and a judgment standard is that the potential deviation is controlled to be less than or equal to 80mV, and pulse parameter adjustment is automatically triggered when the potential is abnormal; 3) Anode status special monitoring Sacrificial anode for detecting weight of module every 50h, judging that weight is reduced by more than or equal to 10% to be exhausted, and according to the formula The life of the device is pre-judged, For the quality of the BI 2 O 3 , Is that Is used for the reaction of the reaction rate of the reaction product, Is a function of the faraday constant, For the activity coefficient of BI 2 O 3 , In order for the intensity of the current to be high, Is the module area; S5.2 flexible carbon nanofiber anode real-time monitoring Monitoring the thickness of the catalytic layer by using an eddy current thickness gauge in operation, and judging the standard that the thickness is more than or equal to 10 mu m, supplementing deposition when the thickness is insufficient, and avoiding anode wrinkles; s5.3 Ti/IrO 2 ×Ta 2 O 5 anode grid real-time monitoring Detecting polarization state every 12h by using an oscilloscope, and judging that the polarization degree is less than or equal to 20%.

Description

Bridge reinforced concrete pulse inversion-electroosmosis collaborative chlorine removal system and method Technical Field The invention belongs to the technical field of reinforced concrete structure corrosion prevention, and particularly relates to a bridge reinforced concrete pulse inversion-electroosmosis cooperative chlorine removal system and method. Background In modern infrastructure construction, reinforced concrete structures are widely applied to various important engineering fields such as bridges, ports and docks, tunnels, high-rise buildings and the like due to the obvious advantages of relatively low cost, high strength, good durability and the like. However, such structures are commonly faced with corrosion of the internal reinforcing steel caused by chloride ion attack during long-term service, severely threatening the safety performance and long-term durability of the overall structure. Especially in marine environment, road and bridge area using deicing salt in winter and industrial pollution influence range, chloride ions can gradually permeate and concentrate on the surface of the steel bar through capillary pores and microcracks in the concrete, and when the concentration exceeds a critical threshold value, the passivation film on the surface of the steel bar can be damaged to induce and accelerate the electrochemical corrosion process. The volume expansion of the steel bar corrosion products can cause cracking and peeling of surrounding concrete protective layers, so that the bonding performance between the steel bars and the concrete is obviously weakened, the integral bearing capacity of the structure is reduced, and the service life of engineering is greatly shortened. Taking a large-scale underground garage of Hainan sea island as an example, the chlorine ion corrosion of the environment is serious, the chlorine ion content of a part of areas is up to 1.488%, and the limit value of the chlorine ion content is far beyond the limit value of 0.3% in the national standard, so that the engineering quality problems of bearing upright column cracking, internal reinforcing steel bar exposure, serious corrosion and the like occur within four years after completion of the structure, and the actual harm of the chlorine ion corrosion is fully reflected. Currently, in the practice of protecting reinforced concrete structures such as bridges, comprehensive protection systems integrating electrochemical desalination technology, material performance optimization and systematic management and control strategy have been developed gradually for the treatment of chloride ions. Although the system can delay the erosion of chloride ions and prolong the service period of the structure to a certain extent, a plurality of obvious technical bottlenecks and application limitations still exist. For example, at present, most of the technical schemes adopt a constant direct current electric field for electrochemical chlorine removal, in practical application, the electrode reactivity is easily reduced due to overlarge anodic polarization, the chlorine removal efficiency is difficult to continuously stabilize, and meanwhile, the risk of secondary corrosion of the reinforcing steel bars is also accompanied. Taking the technology described in CN118702238a as an example, it still operates based on a constant dc electric field, and fails to introduce the self-cleaning effect of the electrode caused by the "pulse inversion" electric field mode, so that the problems of fouling and corrosion on the electrode surface cannot be effectively alleviated, and the defects of the existing method in long-term maintenance are further exposed. In addition, although researches related to the same university Ma Jie subject group and patent CN116514238a propose material innovation of adopting flexible carbon nanofiber anodes, the conductivity is improved to a certain extent, the defects of large rigidity of materials, difficulty in tightly fitting complex geometric shapes such as curved bridge piers and the like still exist, and the specific implementation scheme of the anode which is stripped and recovered after use is lacking, so that the recycling of resources and environmental protection are not facilitated, and meanwhile, the total cost of practical application is increased. On the other hand, although the patent CN112080764A of the northwest mining and metallurgy institute provides a new thought of using bismuth-based materials to assist in chlorine removal, the prior art such as CN118702238A still depends on high-cost titanium iridium (Ti/Ir) anode materials, which restricts the popularization of the materials in large-scale engineering, and meanwhile, the technologies also fail to design a modularized structural scheme of 'the whole anode can be replaced after being exhausted', so that the replacement and maintenance process is complex, and the feasibility and the operation efficiency of the engineering are reduced. In summ