An alkaline-activated gel material for anode coating and a preparation method thereof

Abstract

The application discloses an alkali-activated gel material for anode coating and a preparation method thereof, and belongs to the technical field of building engineering. The alkali-activated agent solvent is prepared by using lithium hydroxide or a mixture of lithium hydroxide and sodium hydroxide, and by adding specific zinc powder material, the alkali-activated gel material for anode coating has the characteristics of moderate setting time, good electrical conductivity, stable strength, high anode current efficiency after coating and the like, can serve as a conductive medium, and can meet the demand of the market for the sacrificial anode protection of building steel bars.

Description

Technical Field

[0001] This invention belongs to the field of building engineering technology, and in particular relates to an alkaline-activated gel material for anode coating and its preparation method. Background Technology

[0002] In construction engineering, reinforced concrete structures are the primary method of building construction, and the corrosion of reinforcing steel has a significant impact on the service life and safety of roads, bridges, and other building projects. For such projects, aluminum or zinc anodes are typically used for sacrificial anode protection of the reinforcing steel structure. During the protection process, it is required that the connection between the anode and the reinforcing steel structure be good, and that the anode structure possess a certain degree of resistance to deformation.

[0003] Currently, alkali-activated gels on the market are generally used as environmentally friendly alternatives to cement. However, their strength is unstable, their conductivity is poor (generally above 10kΩ·cm), and their anodic current efficiency is low after coating with zinc anodes (generally around 65%).

[0004] Therefore, there is an urgent need to provide an alkaline-activated gel material for coating anode materials that has both good mechanical and electrochemical properties. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a method for preparing an alkali-activated gel material for anodic coating, comprising the following steps:

[0006] 1) Preparation of activator solution: The content of hydrated lithium hydroxide in the activator solution is 1% to 10% by mass fraction, and it is left to stand for 20 to 30 hours for later use;

[0007] 2) Pour and stir the solid materials evenly; the solid materials include mineral powder, fly ash and aggregate;

[0008] 3) Add zinc powder to the activator solution before use, and then slowly add the activator solution to the solid material while stirring to obtain a gel material.

[0009] In some preferred embodiments, in step 3), the amount of zinc powder added is 5 wt% to 10 wt% of the activator solution.

[0010] In some preferred embodiments, in step 3), the particle size of the zinc powder ranges from 10 to 40 mesh.

[0011] In some preferred embodiments, in step 3), the content of the activator solution in the gel material is 5 wt% to 10 wt%.

[0012] In some preferred embodiments, the activator solution further contains sodium hydroxide, wherein the mass content of sodium hydroxide in the activator solution is 0.1% to 5%.

[0013] In some preferred embodiments, in step 3), the content of mineral powder in the gel material is 35-40 wt%, the content of fly ash is 30-35 wt%, and the content of aggregate is 15-20 wt%.

[0014] The present invention also provides an alkali-activated gel material prepared by the preparation method described above.

[0015] Furthermore, the present invention also provides an application of the aforementioned alkali-activated gel material in anode coating.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention provides a stable and conductive dielectric gel for anode materials, which can be used to coat anode materials, especially for the protection of sacrificial anodes in reinforced steel structures in engineering construction.

[0018] 2. This invention uses lithium hydroxide or a mixture of lithium hydroxide and sodium hydroxide to prepare an alkaline activator solvent. By adding specific zinc powder materials, the strength, stability, mechanical properties, and conductivity of the gel can be improved, thus providing stable protection for the structural components that need to be protected.

[0019] 3. The alkaline-activated gel described in this invention is used for coating anode materials. Its compressive strength is as high as 75-90 MPa, and its resistivity is as low as about 100 Ω·cm. The current efficiency of the coated zinc anode can reach more than 85%. It can act as a conductive medium to ensure the protection of the steel structure by the anode, and can also provide coating protection for the anode to avoid the anode self-corrosion rate being too fast and reducing the service life.

[0020] 4. The alkali-activated gel material for anode coating involved in this invention has the characteristics of moderate solidification time, good conductivity, stable strength, and high anode current efficiency after coating. It can act as a conductive medium and meet the market demand for sacrificial anode protection of building steel bars. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments:

[0022] Example 1:

[0023] 1) Preparation of activator solution: The activator solution contains 5% lithium hydroxide hydrate and 3% sodium hydroxide by mass fraction, and is left to stand for 24 hours before use;

[0024] 2) Pour and mix the solid materials thoroughly; the solid materials include mineral powder, fly ash, and aggregates;

[0025] 3) Before use, add high-purity zinc powder with a particle size range of 10-40 mesh to the activator solution, and the amount added is 5 wt% of the activator solution; then slowly add the activator solution to the solid material and stir thoroughly to obtain the gel material;

[0026] By mass percentage, the gel material comprises 35% mineral powder, 35% fly ash, 20% aggregate, and 10% activator solution.

[0027] Pour the gel material into the anode mold, fill it, and allow it to solidify; then demold and cure.

[0028] Table 1 Material composition of alkaline-activated gel material in Example 1

[0029]

[0030]

[0031] After curing, the anode products were tested for their electrochemical performance under soil conditions according to GB17848 standard, and their current efficiency was tested to be 85%.

[0032] Example 2:

[0033] The preparation was carried out using the same method and process as in Example 1, with the following component parameters, and other steps were consistent with those in Example 1.

[0034] Table 2 Material composition of alkaline-activated gel material in Example 2

[0035]

[0036] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard, and its current efficiency was found to be 87%.

[0037] Example 3:

[0038] The preparation was carried out using the same method and process as in Example 1, with the following component parameters, and other steps were consistent with those in Example 1.

[0039] Table 3 Material composition of alkaline-activated gel material in Example 3

[0040]

[0041]

[0042] After curing, the anode products were tested for their electrochemical performance under soil conditions according to GB17848 standard, and their current efficiency was 91%.

[0043] Comparative Example 1:

[0044] Based on Example 3, the process of "adding high-purity zinc powder with a particle size range of 10-40 mesh to the activator solution before use, with the amount added being 5 wt% of the activator solution" in step 3) is omitted. Instead, the activator solution is slowly added directly to the solid material and stirred thoroughly to obtain a gel material.

[0045] The other components and processes remain consistent with those in Example 3.

[0046] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard. The current efficiency showed a significant downward trend compared to Example 3, with a current efficiency of only 71%, proving that adding specific zinc powder to the activator solution before use can significantly improve the electrochemical performance of the electrode product.

[0047] Comparative Example 2:

[0048] Based on Example 3, replace "high-purity zinc powder" in step 3) with "high-purity copper powder".

[0049] The other components and processes remain consistent with those in Example 3.

[0050] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard. The current efficiency was 46%. Due to the negative electrode potential of copper, the addition of copper powder will accelerate the corrosion of the anode and affect the protection of the steel structure by the anode, resulting in low current efficiency and failure to achieve the expected effect.

[0051] Comparative Example 3:

[0052] Based on Example 2, the process of "adding high-purity zinc powder with a particle size range of 10-40 mesh to the activator solution before use, with the amount added being 5 wt% of the activator solution" in step 3) is omitted. Instead, the activator solution is slowly added directly to the solid material and stirred thoroughly to obtain a gel material.

[0053] The other components and processes remain consistent with those in Example 2.

[0054] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard. The current efficiency of the test showed a significant downward trend compared with Example 2, proving that adding specific zinc powder to the activator solution before use can significantly improve the electrochemical performance of the electrode product.

[0055] Example 4:

[0056] The preparation method and process of Example 3 were followed, and the following component parameters were used for preparation. Other steps were the same as in Example 3.

[0057] Table 4 Material composition of alkaline-activated gel material in Example 4

[0058]

[0059] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard. The current efficiency was similar to that of Example 3, with no significant difference, and the electrical performance was excellent.

[0060] Example 5:

[0061] The preparation was carried out using the same method and process as in Example 1, with the following component parameters, and other steps were consistent with those in Example 1.

[0062] Table 5. Material composition of the alkaline-activated gel material in Example 5

[0063]

[0064] After curing, the anode product was tested for its electrochemical performance under soil conditions according to GB17848 standard. The current efficiency was consistent with that of Example 1, with no significant difference, and the electrochemical performance was excellent.

[0065] The mechanical properties and resistivity of the above embodiments and comparative examples are shown in Table 6 below.

[0066] Table 6. Material mechanical and electrochemical properties of the alkaline activated gel materials of the examples and comparative examples.

[0067]

[0068]

[0069] The alkali-activated gel material prepared in the above embodiments significantly improves the strength stability, mechanical properties, and conductivity of the gel, providing stable protection for the structural components requiring protection. When used for coating anode materials, its compressive strength reaches over 75-90 MPa, its resistivity is controlled at approximately 100-500 Ω·cm, and as low as around 100 Ω·cm. The current efficiency of the coated zinc anode can reach over 75-90%. It can act as a conductive medium to ensure the protection of the reinforcing steel structure by the anode, and also provide coating protection for the anode, preventing excessively rapid self-corrosion of the anode and reducing its service life. The alkali-activated gel material for anode coating prepared in the above embodiments has the characteristics of moderate solidification time, good conductivity, stable strength, and high anode current efficiency after coating. It can act as a conductive medium and can meet the market demand for sacrificial anode protection for building reinforcing steel.

Claims

1. A method for preparing an alkali-activated gel material for anodic coating, comprising the following steps: 1) Preparation of activator solution: The content of hydrated lithium hydroxide in the activator solution is 1%~10% by mass fraction, and it is left to stand for 20~30 hours for later use; 2) Stir the solid materials evenly; the solid materials include mineral powder, fly ash, and aggregates; 3) Before use, zinc powder is added to the activator solution, and then the activator solution is slowly added to the solid material while stirring to obtain a gel material; in step 3), the amount of zinc powder added is 5wt%~10wt% of the activator solution; The particle size range of zinc powder is 10~40 mesh.

2. The preparation method according to claim 1, wherein, In step 3), the content of the activator solution in the gel material is 5wt%~10wt%.

3. The preparation method according to claim 1 or 2, wherein, The activator solution also contains sodium hydroxide, wherein the content of sodium hydroxide in the activator solution is 0.1wt%~5wt%.

4. The preparation method according to claim 1, wherein, In step 3), the content of mineral powder in the gel material is 35wt%~40wt%, the content of fly ash is 30wt%~35wt%, and the content of aggregate is 15wt%~20wt%.

5. An alkali-activated gel material prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the alkali-activated gel material of claim 5 in anode coating.

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