Electrolyte solution for electrochemical deposition repair of underground structure concrete crack and preparation method thereof

Abstract

The invention relates to the technical field of underground structure concrete crack repair, in particular to an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks and a preparation method of the electrolyte solution. The preparation method comprises the following steps: taking a zinc acetate solution as an electrolyte, taking a sodium citrate solution as a complexing agent, adding a calcium acetate solution and a sodium bicarbonate solution, and mixing to prepare a target solution. The invention provides and prepares an optimized electrolyte solution for concrete water seepage crack electro-deposition repair by combining an electrochemical deposition repair principle aiming at the current situation that most electrolyte solutions adopted in underground structure concrete repair at present have certain damage to a concrete matrix. The method not only avoids the damage of strong electrolyte cations and strong acid radical ions (magnesium salt, sulfate, chlorine salt and the like) to concrete and steel bars, but also effectively solves the problem that the electrolyte is gradually acidified along with the deposition time, and has the advantages of good deposition effect, small damage to concrete, stable deposition PH and the like.

Description

Technical Field

[0001] The invention relates to the technical field of underground structure concrete crack repair, and in particular to an electrolyte solution used for electrochemical deposition repair of underground structure concrete cracks and a preparation method thereof. Background Art

[0002] In the prior art, reinforced concrete is widely used in tunnels, bridges, highways, water conservancy and many other infrastructures. However, concrete has the characteristics of brittleness, heterogeneity, and porosity, which makes it easy to crack when subjected to load, thermal stress, and chemical erosion, significantly reducing the material performance and the safety of the project. In particular, concrete located in underground structures is affected by groundwater for a long time, and microcracks are very likely to occur, which brings great hidden dangers to underground projects. In addition, the maintenance costs and renovation costs of concrete structures used in underground projects are also very large. Therefore, in order to extend the service life of concrete infrastructure and ensure the healthy service of underground structures, it is urgent to implement efficient, durable and sustainable repair technology for microcracks in concrete of underground structures.

[0003] Electrochemical deposition repair technology is an emerging concrete crack repair technology that has emerged in recent years. It is used in marine and land engineering and has unique potential for repairing concrete structures. Compared with traditional concrete repair and reinforcement methods, electrodeposition is one of the effective means to repair existing microcracks in a water-filled environment. The structural steel bars in the concrete are used as deposition cathodes, and an external electrode is set as a deposition anode. Under the action of the electric field, the cations in the electrolyte migrate to the cathode and combine with the hydroxide generated by electrolysis near the cathode to form a precipitate to repair the cracks. This method is not only simple to operate, but also avoids damage to the concrete matrix caused by drilling and pressurization.

[0004] Domestic and foreign research on electrochemical deposition mostly uses strong acid salts or magnesium salts as electrolyte solutions. Magnesium salts, chloride salts and sulfates are easy to damage the concrete matrix. Magnesium salts can cause magnesium salt corrosion of concrete, sulfates can cause expansion damage to concrete, and chloride salts can easily cause corrosion of steel bars in concrete (Zhao G, Shi M, Fan H, et al. The influence of multiple combined chemical attack on cast-in-situ concrete: Deformation, mechanical development and mechanisms [J]. Construction and Building Materials, 2020, 251: 118988.). And as the reaction proceeds, a large number of generated hydrogen ions will combine with strong acid radicals to form a strong acid solution, dissolving alkaline substances in concrete and destroying the concrete matrix. Therefore, the current electrodeposition electrolyte solution still has limitations and deficiencies in the application process. It is necessary to further optimize the electrodeposition electrolyte solution to achieve the best repair effect. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an electrolyte solution for electrochemical deposition repair of cracks in underground structure concrete and a preparation method thereof, so as to avoid the negative effects of strong acid ions such as chloride and sulfate in traditional electrolyte solutions on the concrete matrix and steel bars. A chelating agent is added to improve the deposition quality and deposition rate at the seepage cracks, so as to achieve the effect of sealing pores and repairing cracks, so that the durability and safety of the micro-cracks in the underground structure concrete after electrochemical deposition repair are greatly improved compared with the structure using the traditional electrolyte method.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] A method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks is provided, which comprises the following steps:

[0008] The target solution is prepared by using zinc acetate solution as electrolyte, sodium citrate solution as complexing agent, adding calcium acetate solution and sodium bicarbonate solution.

[0009] The beneficial effects of the present invention are:

[0010] (1) The repair electrolytes currently used for electrodeposition of underground structural concrete contain harmful ions such as magnesium salts, chloride salts, and sulfates in the solution system, which can easily damage the steel bars and concrete matrix. Weak acid ions (CH3COO -) avoids the influence of strong acid that may be produced in the solution on the concrete matrix and steel bars, and solves the problem of gradual acidification of the electrolyte with sedimentation time.

[0011] (2) Sodium citrate complexing agent is introduced into the electrolyte solution, sodium citrate and Zn 2+ After combining, it exists in the electrolyte solution in the form of a complex, thereby improving the deposition quality and deposition rate. The complexing agent can not only control the reduction of zinc, but also promote the deposition of Zn(OH) 2 The formation of organic complexing agents can improve the quality of the precipitate, making it finer and more compact. In addition, the organic complexing agent can improve the cathode activity, provide more activation energy for electrochemistry, and accelerate the deposition reaction.

[0012] (3) Introducing an appropriate amount of calcium acetate and sodium bicarbonate into the original electrolyte solution, in conjunction with sodium citrate, can achieve a better repair effect on the concrete matrix. Using the optimized electrolyte solution in the electrodeposition repair process not only avoids the harm of harmful ions such as magnesium salts and sulfates to concrete, but also improves the quality of sediments in deep-water cracks, so that the durability and safety of the micro-cracks in the concrete of the underground structure after electrodeposition repair are greatly improved compared with the structure using the traditional electrolyte method. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The photos of the deposited products under different mass ratios of zinc and sodium citrate in the examples are shown;

[0014] Figure 2 The XRD patterns of the deposited products at a mass ratio of 3:0 and 3:2 sodium zinc citrate in the embodiment;

[0015] Figure 3 The XRD spectrum of the deposited product at a mass ratio of 3:4 zinc citrate to sodium in the embodiment;

[0016] Figure 4 This is the XRD spectrum of the deposited product at a mass ratio of 3:8 zinc citrate to sodium in the embodiment;

[0017] Figure 5 Schematic diagram of the change of electrolyte pH over time at different zinc-sodium citrate mass ratios in the embodiment;

[0018] Figure 6 For different Ca 2+ Schematic diagram of deposition quality at different concentrations. DETAILED DESCRIPTION

[0019] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0020] Embodiment 1:

[0021] The optimized electrolyte solution for electrochemical deposition repair of underground structure concrete cracks is a composite electrolyte solution, which is prepared by mixing two solutions A and B in a certain proportion, and adding appropriate amounts of calcium acetate and calcium bicarbonate solution to the system, wherein solution A is 0.05 mol / L zinc acetate solution, solution B is 0.10 mol / L sodium citrate solution, as well as 0.025 mol / L calcium acetate solution and 0.005 mol / L sodium bicarbonate solution. The preparation method of the electrolyte solution includes the following steps:

[0022] (1) Prepare 0.05 mol / L zinc acetate solution, 0.10 mol / L sodium citrate solution, 0.025 mol / L calcium acetate solution, and 0.005 mol / L sodium bicarbonate solution, respectively.

[0023] (2) Solutions A and B are prepared in a mass ratio of 3:0 between zinc citrate and sodium, and mixed with calcium acetate and calcium bicarbonate solutions with a mass fraction of about 1%, and stirred evenly to obtain the target solution.

[0024] Embodiment 2:

[0025] In Example 2, the same points as Example 1 are not described here, and only the differences from Example 1 are described. The difference between Example 2 and Example 1 is that the mass ratio of zinc citrate sodium is 3:2, and the rest is the same as described in Example 1.

[0026] Embodiment 3:

[0027] In Example 3, the same points as Example 1 are not described here, and only the differences from Example 1 are described. The difference between Example 3 and Example 1 is that the mass ratio of zinc citrate sodium is 3:4, and the rest is the same as described in Example 1.

[0028] Embodiment 4:

[0029] In Example 4, the same points as Example 1 are not described here, and only the differences from Example 1 are described. The difference between Example 4 and Example 1 is that the mass ratio of zinc citrate sodium is 3:6, and the rest is the same as described in Example 1.

[0030] Embodiment 5:

[0031] In Example 5, the same points as Example 1 are not described here, and only the differences from Example 1 are described. The difference between Example 5 and Example 1 is that the mass ratio of zinc citrate sodium is 3:8, and the rest is the same as described in Example 1.

[0032] Embodiment 6:

[0033] In Example 6, the same points as Example 1 are not described here, and only the differences from Example 1 are described. The difference between Example 6 and Example 1 is that the mass ratio of zinc citrate sodium is 3:10, and the rest is the same as described in Example 1.

[0034] The mechanism of repairing concrete cracks by the electrolyte solution of the present invention is mainly divided into three stages:

[0035] Stage 1: Zn 2+ It reacts with citrate ions to form a stable zinc citrate complex, and the reaction formula is as follows. Under the action of the electric field and the concentration difference, it moves to the cathode. At this time, water electrolysis occurs at the anode to generate hydrogen ions; water electrolysis occurs at the cathode to generate hydroxide.

Claims

1. A method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks, characterized in that: The following steps are involved: The target solution is prepared by using zinc acetate solution as electrolyte, sodium citrate solution as complexing agent, adding calcium acetate solution and sodium bicarbonate solution.

2. The method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks according to claim 1, characterized in that: The concentration of the zinc acetate solution is 0.05 mol / L.

3. The method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks according to claim 1, characterized in that: The concentration of the sodium citrate solution is 0.10 mol / L.

4. The method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks according to claim 1, characterized in that: The concentration of the calcium acetate solution is 0.025 mol / L.

5. The method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks according to claim 1, characterized in that: The concentration of the sodium bicarbonate solution is 0.005 mol / L.

6. The method for preparing an electrolyte solution for electrochemical deposition repair of underground structure concrete cracks according to claim 1, characterized in that: The mass ratio of the zinc acetate to the sodium citrate is 3:

6.

7. An electrolyte solution for electrochemical deposition repair of concrete cracks in underground structures obtained by the preparation method according to any one of claims 1 to 6.

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