A method for repairing concrete using electrochemically compatible repair geopolymer

Abstract

The present invention provides a repair method using electrochemically compatible repair geopolymer concrete, which relates to the technical field of reinforced concrete. The method comprises the following steps: dry-mixing fly ash, slag powder, and silica powder to obtain a first mixture; adding a mixed liquid to the first mixture, wherein the mixed liquid includes potassium silicate water glass, water, and an admixture, and stirring after adding the mixed liquid to obtain a second mixture; adding aggregate and PVA fiber to the second mixture and stirring to obtain electrochemically compatible repair geopolymer concrete; connecting the exposed old steel bars at the site to be repaired with the new steel bars for repair using stirrups to form a pre-buried steel bar structure; casting the site to be repaired using electrochemically compatible repair geopolymer concrete, covering the pre-buried steel bar structure, and curing to complete the repair. The present invention utilizes geopolymer concrete to repair corroded structures, which can reduce the macroscopic corrosion effect of steel bars in the new and old concretes, and improve the electrochemical incompatibility and corrosion resistance of the new and old concretes.

Description

Technical Field

[0001] The present invention relates to the technical field of reinforced concrete, and in particular to a repair method using electrochemically compatible repair geopolymer concrete. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Reinforced concrete components will develop various defects over time. The manifestations of these defects include pulverization, cracking, peeling, and strength loss of the concrete matrix. Steel bar corrosion is also one of the important causes of deterioration of reinforced concrete structures. Corrosive media will invade along existing defective areas, accelerating steel bar corrosion and volume expansion, thereby reducing component strength. Repairing defective reinforced concrete components is an important means of increasing their service life. Repair methods include: chiseling out the loose concrete matrix of the repaired area, then cleaning the chiseled area with a brush to remove dust and debris, then rinsing and moistening it with water, and finally filling and compacting it with repair mortar. During the process, new steel bars will be used to replace the removed corroded steel bars, and the new steel bars will be connected to the original old steel bars exposed in the defective area with stirrups to repair the original steel cage and other structures to ensure the integrity of the reinforced concrete components.

[0004] Existing reinforced concrete repair materials mainly focus on improving the bonding properties of the interface between new and old concrete and the synergistic mechanical properties after repair. However, due to the large potential difference between the steel bars in the new and old concrete, the macroscopic corrosion current generated between the new and old steel bars after repair is large, resulting in serious electrochemical incompatibility. The steel bars in the old concrete have a lower potential, which will cause anodic polarization and accelerate the dissolution rate of the steel bars. The steel bars in the newly repaired concrete have a higher potential, which inhibits the dissolution rate of the steel bars. Therefore, although the mechanical properties and durability of the newly repaired concrete are better, the corrosion of the steel bars in the old concrete will be aggravated, and the overall mechanical properties of the structure will be greatly reduced. It is often necessary to repair again shortly after repair, which not only threatens the safety of the structure but is also uneconomical. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a repair method using electrochemically compatible repair geopolymer concrete, which can not only improve the strain hardening performance and bearing capacity of the repaired concrete structure, but also improve the bonding strength, impermeability and electrochemical compatibility of the interface between the new and old concrete.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a repair method using electrochemically compatible repair geopolymer concrete, comprising the following steps:

[0008] S1. Mix 45-55 parts by mass of fly ash, 35-45 parts by mass of slag powder, and 10-20 parts by mass of silicon fume, wherein the fly ash, the slag powder, and the silicon fume total 100 parts by mass, and dry-mix for 3-7 minutes to obtain a first mixture;

[0009] S2. Adding a mixed solution to the first mixture, the mixed solution comprising 10 to 15 parts by mass of potassium silicate water glass, 25 to 35 parts by mass of water, and 1 to 2 parts by mass of an admixture, stirring for 2 to 6 minutes after adding the mixed solution to obtain a second mixture;

[0010] S3, adding 120-150 parts by mass of aggregate and 0.3-1.0 parts by mass of PVA fiber to the second mixture, stirring for 2-6 minutes to obtain an electrochemically compatible repair geopolymer concrete;

[0011] S4. Use stirrups to connect the old steel bars exposed in the repaired area with the new steel bars for repair to form a pre-buried steel bar structure;

[0012] S5. Use the electrochemically compatible repair geopolymer concrete obtained in S3 to cast the part to be repaired, cover the embedded steel structure, and perform curing to complete the repair.

[0013] Optionally, in S1, the particle size of the silicon powder is 4 to 100 microns.

[0014] Optionally, in S1, the dry mixing method is a mixer speed of 45~50r / min.

[0015] Optionally, in S2, the modulus of the potassium silicate water glass is 1.1~1.4.

[0016] Optionally, in S2, the admixture is a polycarboxylate water reducer.

[0017] Optionally, in S2, the mixer speed during stirring is 90-100 r / min.

[0018] Optionally, in S3, the PVA fiber has a length of 8 to 15 mm, a radius of 0.012 mm to 0.015 mm, an aspect ratio ≥ 800, and a tensile strength ≥ 1600 MPa.

[0019] Optionally, in S3, the length of the PVA fiber is 12 mm.

[0020] Optionally, in S3, the stirring method is a stirring machine speed of 90-100 r / min.

[0021] Optionally, in S4, the new steel bars used for repair are made of the same material and strength grade as the old steel bars.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The present invention provides a repair method for electrochemically compatible geopolymer concrete using fly ash (FA), ground slag (GGBS), and silica fume (SF) as cementitious raw materials. Calcium silicate hydrate (CSH) gel, calcium aluminate hydrate (CAH) gel, and calcium aluminosilicate hydrate (CASH) gel produced by the polymerization of slag, fly ash, silica fume, and other materials are denser in structure, have lower ion concentration, and higher resistivity than the hydration products of Portland cement, thus helping to reduce macro-corrosion current. On the other hand, the active components SiO2 and Al2O3 in the slag powder are also stimulated by water glass alkali to react and generate cementitious materials such as CSH and CAH, while releasing hydroxide ions (OH). - , thereby increasing the pH value of the pore fluid. The pore fluid, through contact with the steel surface, passivates the steel, further inhibiting steel corrosion. By adding PVA fibers to reduce shrinkage and improve its strain hardening properties, an electrochemically compatible PVA fiber-reinforced geopolymer concrete for repairing steel corrosion is formed, achieving the purpose of improving the tensile bond strength, chloride ion permeability and electrochemical compatibility between new and old concrete.

[0024] 2. This invention uses geopolymer concrete to repair corroded reinforced concrete structures, reducing the macroscopic corrosion of steel bars in both new and old concrete, improving the electrochemical incompatibility and corrosion resistance of both, extending the service life of the structure, reducing the frequency of repairs, and saving costs. Furthermore, replacing traditional cement with industrial waste materials such as fly ash and slag powder reduces carbon emissions from the cement production process, contributing to ecological benefits and energy conservation and emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] In order to show the positions of various parts, the distances or sizes between them are exaggerated in the figure, and the schematic diagram is for reference only.

[0027] Figure 1 This is a schematic diagram of the structure before repair in Example 1.

[0028] Figure 2 This is a schematic diagram of the repaired structure in Example 1.

[0029] Figure 3 Schematic diagram of a macro current detection device in a specific implementation manner.

[0030] Among them, 1. Old steel bars; 2. Stirrups; 3. New steel bars for repair; 4. Repair layer; 5. Base layer; 6. Conductor; A1, A2 and A3 are the connection positions of the ammeter respectively. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] A method for repairing concrete using an electrochemically compatible repair geopolymer comprises the following steps:

[0035] S1. Mix 45-55 parts by mass of fly ash, 35-45 parts by mass of slag powder, and 10-20 parts by mass of silicon fume, wherein the fly ash, the slag powder, and the silicon fume total 100 parts by mass, and dry-mix for 3-7 minutes to obtain a first mixture;

[0036] S2. Adding a mixed solution to the first mixture, the mixed solution comprising 10 to 15 parts by mass of potassium silicate water glass, 25 to 35 parts by mass of water, and 1 to 2 parts by mass of an admixture, stirring for 2 to 6 minutes after adding the mixed solution to obtain a second mixture;

[0037] S3, adding 120-150 parts by mass of aggregate and 0.3-1.0 parts by mass of PVA fiber to the second mixture, stirring for 2-6 minutes to obtain an electrochemically compatible repair geopolymer concrete;

[0038] S4. Use stirrups to connect the old steel bars exposed in the repaired area with the new steel bars for repair to form a pre-buried steel bar structure. S5. Use the electrochemically compatible repair geopolymer concrete obtained in S3 to cast the repaired area, cover the pre-buried steel bar structure, and perform maintenance to complete the repair.

[0039] Optionally, in S1, typical main components (mass percentage) of the fly ash include: SiO2 (59%), Al2O3 (23%), Fe2O3 (23%), CaO (3%), etc.

[0040] Optionally, in S1, the typical main components (mass percentage) of the slag powder include: SiO2 (32%), CaO (40%), Al2O3 (15%) and MgO (10%), etc.

[0041] Optionally, in S1, the silicon powder is also called microsilica powder, scientifically known as silica fume, which is silicon oxide collected and processed by a special capture device during the high-temperature smelting of industrial silicon and ferrosilicon in an industrial electric furnace, with a particle size of 4 to 100 microns.

[0042] Optionally, in S2, the admixture is a polycarboxylic acid high-efficiency water reducer, which can reduce the amount of water used.

[0043] Optionally, in S2, the modulus of the potassium silicate water glass is 1.1-1.4; it is used to stimulate the activity of the geopolymer and produce a gel.

[0044] Among the components used in the above repair methods, fly ash (FA), ground slag (GGBS), and silica fume (SF) improve the interface and pore structure of new and old concrete, enhance the interfacial bonding strength between the repair layer prepared by electrochemically compatible repair geopolymer concrete and the base layer of the original concrete, and also improve the impermeability of the concrete, thus avoiding the formation of new cracks and thus preventing the corrosive medium from continuing to corrode the steel bars along the new cracks. In terms of electrochemical compatibility, the calcium silicate hydrate (CSH) gel, calcium aluminate hydrate (CAH) gel, and calcium aluminosilicate hydrate (CASH) gel produced by the polymerization of slag, fly ash, silica fume and other materials have a denser structure, lower ion concentration, and higher resistivity than the hydration products of silicate cement, thus helping to reduce the macro-corrosion current (hereinafter referred to as macro-current, the larger the macro-current, the more severe the corrosion caused). On the other hand, the active components SiO2 and Al2O3 in the slag powder are also stimulated by water glass alkali to react to form cementitious materials such as CSH and CAH, while releasing hydroxide OH. - , thereby increasing the pH value of the pore fluid. The pore fluid passivates the steel bar by contacting with the steel bar surface, thereby further inhibiting the corrosion of the steel bar.

[0045] Optionally, in S3, the PVA fiber is a polyvinyl alcohol fiber with a length of 8 to 15 mm, a radius of 0.012 mm to 0.015 mm, an aspect ratio ≥ 800, and a tensile strength ≥ 1600 MPa; preferably, the PVA fiber length is 12 mm; using PVA fibers of this specification, the surface active groups of the PVA fibers can form chemical bonds with hydration products (such as CSH gel) in the cement matrix and form physical intercalation in the cement matrix, thereby improving the interfacial bonding strength; the PVA fibers improve the strain hardening properties of the repaired concrete and the overall bearing capacity of the repaired structure. When the geopolymer concrete shrinks, the PVA fibers are evenly distributed inside the concrete and can connect local concrete within the length range of the PVA fibers, playing a pulling role, thereby reducing the shrinkage stress in the concrete and reducing cracks. At the same time, the PVA fibers can span the microcracks inside the concrete, forming a bridging effect to prevent crack expansion, thereby making the electrochemically compatible repair geopolymer concrete also have higher impermeability and durability than ordinary concrete.

[0046] Optionally, in S3, the aggregate is siliceous sand with a fineness modulus of 2.4 to 2.8, which is used to improve strength.

[0047] Optionally, in S1, the mixer speed is 45~50r / min during dry mixing.

[0048] Optionally, in S2, the mixer speed is 90~100r / min.

[0049] Optionally, in S3, the mixer speed is 90~100r / min.

[0050] Optionally, in S4, the new steel bars used for repair are made of the same material and strength grade as the old steel bars.

[0051] Optionally, in the repaired reinforced concrete, the strength of the concrete matrix is ​​C20~C60.

[0052] Example 1

[0053] A method for repairing concrete using an electrochemically compatible repair geopolymer comprises the following steps:

[0054] S1. Mix 50 parts by mass of fly ash, 40 parts by mass of slag powder, and 10 parts by mass of silicon powder, and dry-mix at a low speed (45 rpm) for 5 minutes to obtain a first mixture;

[0055] S2. Add a mixture of 12 parts by mass of potassium silicate water glass, 29 parts by mass of water, and 2 parts by mass of a polycarboxylate superplasticizer to the first mixture, and stir at a medium speed (90 rpm) for 4 minutes to obtain a second mixture;

[0056] S3. Add 136 parts by mass of aggregate and 0.5 parts by mass of PVA fiber to the second mixture, and stir for 4 minutes to obtain electrochemically compatible repair geopolymer concrete.

[0057] The modulus of potassium silicate water glass added to S2 is 1.25.

[0058] The aggregate added in S3 is siliceous sand with a fineness modulus of 26.

[0059] The specifications of the PVA fiber added in S3 are: length 12 mm, aspect ratio ≥ 800, and tensile strength ≥ 1600 MPa.

[0060] like Figure 1 As shown, the old steel bars 1 in the base layer 5 of ordinary concrete have been corroded. After the loose concrete matrix of the repaired part is removed, the old steel bars 1 are still buried in the existing concrete structure and are difficult to remove. The repair method for this position is:

[0061] S4, using uncorroded stirrups 2 to connect the corroded old steel bars 1 in the repaired area and the uncorroded new repair steel bars 3 to form a three-dimensional embedded steel bar structure;

[0062] S5, using the electrochemically compatible repair geopolymer concrete obtained in S3 to cast the part to be repaired, covering the embedded steel bars to form a repair layer 4, and curing to complete the repair, to obtain Figure 2 The structure shown.

[0063] The new steel bars 3 used for repair are made of the same material and strength grade as the old steel bars 1 .

[0064] In the repaired reinforced concrete, the strength grade of the concrete matrix of the base layer 5 is C30.

[0065] Example 2

[0066] A repair method using electrochemically compatible repair geopolymer concrete differs from Example 1 in that:

[0067] In S1, 45 parts by mass of fly ash, 40 parts by mass of slag powder, and 15 parts by mass of silicon powder were added.

[0068] In S2, the amount of potassium silicate water glass added was 10 parts by mass, the amount of water added was 25 parts by mass, and the amount of polycarboxylate high-efficiency water reducer added was 1 part by mass.

[0069] In S3, 120 parts by mass of aggregate and 0.3 parts by mass of PVA fiber were added.

[0070] The specifications of each component are the same as those in Example 1.

[0071] The repair steps are the same as S4-S5 in Example 1.

[0072] Example 3

[0073] A repair method using electrochemically compatible repair geopolymer concrete differs from Example 1 in that:

[0074] In S1, 55 parts by mass of fly ash, 35 parts by mass of slag powder, and 10 parts by mass of silicon powder were added.

[0075] In S2, the amount of potassium silicate water glass added was 15 parts by mass, the amount of water added was 35 parts by mass, and the amount of polycarboxylate high-efficiency water reducer added was 1.5 parts by mass.

[0076] In S3, 150 parts by mass of aggregate and 1.0 part by mass of PVA fiber were added.

[0077] In each step, the specifications of each component are the same as those in Example 1.

[0078] The repair steps are the same as S4-S5 in Example 1.

[0079] Comparative Example 1

[0080] Commercially available PO 42.5 ordinary concrete was used to replace the electrochemically compatible repair geopolymer concrete obtained in S3 of Example 1, and repair was carried out according to steps S4 to S5 of Example 1 to obtain a test piece of Comparative Example 1.

[0081] Comparative Example 2

[0082] A repair method using electrochemically compatible repair geopolymer concrete is different from Example 1 in that fly ash is not added, but the ratio of slag and silica fume is the same as that in Example 1.

[0083] Specifically, in S1, no fly ash was added, 80 parts by mass of slag powder was added, and 20 parts by mass of silicon powder was added.

[0084] In other steps, the specifications of each component are the same as those in Example 1, and the repair steps are the same as those in Example 1, to obtain the test piece of Comparative Example 2.

[0085] Comparative Example 3

[0086] A repair method using electrochemically compatible repair geopolymer concrete is different from Example 1 in that no slag powder is added, and the ratio of fly ash and silica fume is the same as that in Example 1.

[0087] Specifically, in S1, no slag powder was added, 83 parts by mass of fly ash was added, and 17 parts by mass of silica fume was added.

[0088] In other steps, the specifications of each component are the same as those in Example 1, and the repair steps are the same as those in Example 1, to obtain the test piece of Comparative Example 3.

[0089] Performance testing

[0090] Macrocurrent detection between steel bars

[0091] like Figure 3 As shown, a zero-resistance multimeter was used as an ammeter. A wire 6 was used to connect the old rebar 1 and the new repair rebar 3 to measure the current reading A1. Then, a wire 6 was used to connect the old rebar 1 and the stirrup 2 to obtain the current reading A2. Finally, a wire 6 was used to connect the new repair rebar 3 and the stirrup 2 to obtain the current reading A3. The macrocurrents of Example 1 and Comparative Examples 1, 2, and 3 were measured. The test results are shown in Table 1.

[0092] Table 1 Current detection results

[0093]

[0094] The results are as follows: after the electrochemically compatible repair geopolymer concrete in Example 1 was used for repair, the macrocurrent between the old steel bar 1 and the repaired new steel bar 3 was 11 μA, the macrocurrent between the old steel bar 1 and the stirrup 2 was 40.9 μA, and the macrocurrent between the repaired new steel bar 3 and the stirrup 2 was 5.6 μA; 42.5 configuration ordinary concrete was repaired, the macrocurrent between the old steel bar 1 and the new steel bar 3 for repair was 59μA, the macrocurrent between the old steel bar 1 and the stirrup 2 was 68.4μA, and the macrocurrent between the new steel bar 3 for repair and the stirrup 2 was 69.3μA; comparing Example 1 and Comparative Example 1, it was found that: the macrocurrent A1 between the old steel bar 1 and the new steel bar 3 for repair in Example 1 decreased by 80% compared with the ordinary concrete repair, and the macrocurrent between the new steel bar 3 for repair and the stirrup 2 decreased by 91%; correspondingly, compared with Comparative Example 1, the macrocurrent A1 of Comparative Example 2 decreased by 44%, the macrocurrent A3 decreased by 70%, but the macrocurrent A2 basically did not decrease; compared with Comparative Example 1, the macrocurrent A1 of Comparative Example 3 decreased by 24%, the macrocurrent A3 decreased by 47%, and the macrocurrent A2 increased by 17%.

[0095] Compared with Example 1, Comparative Example 2 has more slag. Although the polymerization reaction is fast and good early strength can be obtained, shrinkage strain and microcracks are easily generated, which affect the bonding performance and impermeability.

[0096] Compared with Example 1, Comparative Example 3 does not contain slag, and the activity of fly ash is low, so the flexural strength is not high, and the density and impermeability are also reduced.

[0097] The potassium silicate water glass in Example 1 is an alkaline activator and is also a necessary component. Without potassium silicate water glass, fly ash and slag cannot undergo polymerization reaction, cannot produce cementitious material, and cannot achieve repair effect.

[0098] The corrosion current density was measured according to the test results and was positively correlated with the corrosion rate, which could reflect the changing trend of the corrosion rate: after ordinary cement concrete was used for repair in Comparative Example 1, compared with the corrosion state of the old steel bars before repair, the corrosion current density of the old steel bar 1 decreased from 11.6μA / cm² to 9.06μA / cm², and the corrosion current density of the stirrup 2 decreased from 12μA / cm² to 8.95μA / cm²; after electrochemically compatible repair geopolymer concrete was used for repair in Example 1, compared with the corrosion state of the old steel bars before repair, the corrosion current density of the old steel bar 1 decreased from 8.56μA / cm² to 3.91μA / cm², and the corrosion current density of the stirrup 2 decreased from 10.4μA / cm² to 6.35μA / cm².

[0099] A comparison revealed that the corrosion rate of the old steel bar 1 decreased by 54%, indicating that the repair method provided by the present invention using electrochemically compatible repair geopolymer concrete can effectively reduce the potential difference between the steel bars in the new and old concrete, avoid the problem of aggravated corrosion of the steel bars in the old concrete, and extend the repair period.

[0100] Chloride ion permeability test

[0101] According to the test method of "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete" (GB / T 50081), the chloride ion permeability coefficients of PO 42.5 ordinary concrete, the electrochemically compatible repair geopolymer concrete prepared by S1 to S3 in Example 1, and the concrete prepared by the comparative example formula were tested respectively. The results showed that the chloride ion permeability coefficient of PO 42.5 ordinary concrete was 1.82×10 -12 m 2 / s, the chloride ion permeability coefficient of the electrochemically compatible repair geopolymer concrete in Example 1 is 7×10 -13 m 2 / s, the chloride ion permeability coefficient of comparative example 2 is 1.2×10 -12 m 2 / s, the chloride ion permeability coefficient of comparative example 3 is 2.7×10 -12 m 2 / s, Example 1 is significantly lower than Comparative Examples 2 and 3.

[0102] This indicates that the electrochemically compatible repair geopolymer concrete prepared in Example 1 of the present invention can effectively reduce the corrosion of new steel bars by chloride ions at the repair location.

[0103] Tensile bond strength test

[0104] According to the testing method of "Standard for Test Methods for Basic Properties of Building Mortar" JGJ / T 70-2009, the tensile bond strengths of PO 42.5 ordinary concrete, the electrochemically compatible repair geopolymer concrete prepared from S1 to S3 in Example 1, and the concrete prepared from the comparative example formulation were tested. The results showed that the tensile bond strength of the PO 42.5 ordinary concrete was 0.19 MPa, the tensile bond strength of the electrochemically compatible repair geopolymer concrete prepared in Example 1 was 0.32 MPa, but the tensile bond strength of Comparative Example 2 was only 0.16 MPa.

[0105] It is shown that the electrochemically compatible repair geopolymer concrete prepared in Example 1 of the present invention has high tensile bonding strength, and can form a unified whole with the original structure after repair, thereby improving durability and extending the repair period.

[0106] Flexural strength

[0107] According to the test method of "Test Method for Strength of Cement Mortar (ISO Method)" GB / T 17671-2021, the flexural strength of PO 42.5 ordinary concrete, the electrochemically compatible repair geopolymer concrete prepared by S1 to S3 in Example 1, and the concrete prepared by the comparative example formula were tested respectively. The results were: the flexural strength of PO 42.5 ordinary concrete was 2.3 MPa, the flexural strength of the electrochemically compatible repair geopolymer concrete in Example 1 was 4.0 MPa, but the flexural strength of Comparative Example 3 was only 1.4 MPa.

[0108] This indicates that the electrochemically compatible repair geopolymer concrete prepared in Example 1 of the present invention has a high mechanical level, the flexural strength of the material at the repaired part is high, and no obvious mechanically weak area is formed.

[0109] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for repairing geopolymer concrete using electrochemically compatible repair materials, characterized in that: By using hydrated calcium silicate gel, hydrated calcium aluminate gel and hydrated calcium silicate aluminate gel, which have a denser structure, lower ion concentration and higher resistivity than the hydration products of Portland cement, the macroscopic corrosion effect of steel bars in new and old concrete is reduced, the electrochemical incompatibility and corrosion resistance of new and old concrete are improved, and the service life of the structure is extended; The following steps are involved: S1. Mix 45-55 parts by mass of fly ash, 35-45 parts by mass of slag powder, and 10-20 parts by mass of silicon fume, wherein the fly ash, the slag powder, and the silicon fume total 100 parts by mass, and dry-mix for 3-7 minutes to obtain a first mixture; The particle size of the silicon powder is 4 to 100 microns; S2. Adding a mixed solution to the first mixture, the mixed solution comprising 10 to 15 parts by mass of potassium silicate water glass, 25 to 35 parts by mass of water, and 1 to 2 parts by mass of an admixture, stirring for 2 to 6 minutes after adding the mixed solution to obtain a second mixture; S3, adding 120-150 parts by mass of aggregate and 0.3-1.0 parts by mass of PVA fiber to the second mixture, stirring for 2-6 minutes to obtain an electrochemically compatible repair geopolymer concrete; S4. Use stirrups to connect the old steel bars exposed in the repaired area with the new steel bars for repair to form a pre-buried steel bar structure; The new steel bars used for repair are of the same material and strength grade as the old steel bars; S5. Casting the repaired area with the electrochemically compatible repair geopolymer concrete obtained in S3, covering the embedded steel structure, and curing to complete the repair; In S2, the modulus of the potassium silicate water glass is 1.1-1.4, and the admixture is a polycarboxylate water reducer.

2. The repair method using electrochemically compatible repair geopolymer concrete according to claim 1, characterized in that: In S1, the mixer speed is 45~50r / min during dry mixing.

3. The repair method using electrochemically compatible repair geopolymer concrete according to claim 1, characterized in that: In S2, the mixer speed is 90~100r / min during stirring.

4. The repair method using electrochemically compatible repair geopolymer concrete according to claim 1, characterized in that: In S3, the PVA fiber has a length of 8 to 15 mm, a radius of 0.012 mm to 0.015 mm, an aspect ratio of ≥800, and a tensile strength of ≥1600 MPa.

5. The repair method using electrochemically compatible repair geopolymer concrete according to claim 4, characterized in that: In S3, the length of the PVA fiber is 12 mm.

6. The repair method using electrochemically compatible repair geopolymer concrete according to claim 1, characterized in that: In S3, the mixer speed is 90~100r / min during stirring.

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