Preparation method and application of crack repairing mortar for seepage-resistant marine concrete structure

Abstract

The invention discloses a preparation method and application of crack repairing mortar for a seepage-resistant marine concrete structure, and the preparation method comprises the following steps: (1) mixing paraffin, hydroxyapatite powder, iron powder and sodium silicate and / or potassium silicate powder, then continuously stirring and heating until the paraffin is molten, stopping heating, continuously stirring and cooling until the paraffin is solidified; and grinding the obtained mixture to obtain the modifier powder. And (2) uniformly mixing the raw materials such as a cement binding material, gravel fine aggregate, a mineral admixture, modifier powder, glass fiber and a water reducing agent, adding mixing water, and uniformly stirring to obtain the repair mortar. The crack repairing mortar disclosed by the invention not only can form good mechanical strength, but also can construct a waterproof impervious system and a chloride ion erosion prevention system, so that the crack repairing effect is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of crack repair material preparation, and in particular to a method for preparing crack repair mortar for a permeability-resistant marine concrete structure and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the 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 a person skilled in the art.

[0003] A large amount of concrete materials are consumed in the construction of marine engineering, such as dams, cross-sea bridges, docks, and offshore platforms. These concrete structures are in the harsh environment of the ocean during construction and service. When the volume shrinkage stress caused by changes in temperature and humidity exceeds the tensile strength of the concrete structure, cracking will inevitably occur, which will not only reduce the safety of the concrete structure, but also the salt in the seawater will penetrate through the cracks and accelerate chemical erosion, steel corrosion, freeze-thaw damage, carbonization and other processes, reducing the durability of the concrete structure.

[0004] One of the commonly used methods at present is to fill and repair cracks in concrete structures with repair materials. Cement-based repair mortar is widely used to repair cracks in concrete structures due to its advantages such as good mechanical strength, adhesion, durability and affordability. However, for concrete structures serving in marine environments, they are exposed to salt and water erosion when immersed in seawater, especially in the repaired parts, which are prone to water seepage again. Therefore, for materials used to repair such concrete structures, they also need to have good waterproof and anti-seepage properties to improve the repair effect of cracks. Summary of the invention

[0005] The present invention provides a method for preparing crack repair mortar for a permeability-resistant marine concrete structure and its application, wherein the repair mortar can not only form good mechanical strength, but also construct a waterproof and anti-seepage system and a chloride ion corrosion prevention system, thereby ensuring the repair effect of cracks. Specifically, the technical solution of the present invention is as follows.

[0006] First, the present invention provides a process for preparing crack repair mortar for a permeability-resistant marine concrete structure, comprising the following steps: (1) Paraffin wax, hydroxyapatite powder, iron powder, sodium silicate and / or potassium silicate powder are mixed, and then the mixture is continuously stirred and heated until the paraffin wax melts, and then the heating is stopped and the mixture is continuously stirred and cooled until the paraffin wax solidifies. The obtained mixture is then ground to obtain a modifier powder.

[0007] (2) Cement binder, sand and gravel fine aggregate, mineral admixture, the modifier powder, glass fiber, water reducing agent and the like are mixed as raw materials, and then mixing water is added and stirred evenly to obtain the repair mortar.

[0008] Furthermore, in step (1), the ratio of the paraffin wax, hydroxyapatite powder, iron powder, sodium silicate and / or potassium silicate powder is 10-15 parts by weight: 7-9 parts by weight: 3-6 parts by weight: 1-1.4 parts by weight. Optionally, the melting temperature of the paraffin wax is not higher than 70°C.

[0009] Furthermore, in step (1), the fineness of the hydroxyapatite powder is 100-200 mesh; the fineness of the iron powder is 300-500 mesh; and the fineness of the modifier powder is 30-70 mesh.

[0010] Furthermore, in step (2), the ratio of the cementitious material, sand and gravel fine aggregate, mineral admixture, modifier powder, glass fiber and water reducing agent is 100-115 parts by weight: 220-260 parts by weight: 15-30 parts by weight: 18-24 parts by weight: 4-7 parts by weight: 1.6-2 parts by weight.

[0011] Furthermore, in step (2), the mixing water is added according to a water-cement ratio of 0.38 to 0.45. The "ash" includes the cementitious material and mineral admixtures.

[0012] Furthermore, in step (2), the mineral admixture includes at least one of fly ash, silica fume, slag powder, steel slag powder, etc.

[0013] Furthermore, in step (2), the mineral admixture is treated by the following method: the mineral admixture is placed in an alkali solution for heating. After the treatment, the mineral admixture is separated, washed, placed in saturated lime water for heating and insulation, and after the reaction is completed, the solid product is separated and dried to obtain the product.

[0014] Furthermore, the ratio of the mineral admixture to the alkali solution is 1 g: 5-20 ml. Optionally, the concentration of the alkali solution is 1-3 mol / L. The alkali solution includes at least one of a sodium hydroxide solution, a potassium hydroxide solution, and the like.

[0015] Furthermore, the heating treatment time is 2 to 4 hours, and the heating temperature is 40 to 60°C.

[0016] Furthermore, the ratio of the separated mineral admixture to saturated lime water is 1 g: 25-50 ml.

[0017] Furthermore, the heating and heat preservation temperature is 180-230° C., and the heat preservation time is 5-7 hours.

[0018] Furthermore, in step (2), the water reducer includes any one of a polycarboxylate water reducer, a naphthalene-based water reducer, a lignin sulfonate water reducer, and the like.

[0019] Furthermore, in step (2), the length of the glass fiber is 0.5-2 mm, and the glass fiber can effectively improve the crack resistance of the repair mortar of the present invention.

[0020] Secondly, the present invention provides an application of the crack repair mortar in repairing cracks in a concrete structure, comprising the following steps: (I) Filling the crack repair mortar into the cracks of the concrete structure and then curing until the repair mortar hardens.

[0021] (II) The hardened repair mortar in the crack is subjected to microwave heating treatment to melt and diffuse the paraffin in the modifier powder to construct an anti-seepage system, and then cooled to room temperature.

[0022] Furthermore, in step (I), the curing time is 7 to 10 days, so that the repair mortar undergoes hydration reaction to form early strength.

[0023] Furthermore, in step (II), the microwave heating power is 600-1200 W, the heating frequency is 10-20 GHz, and the heating time is 5-8 min.

[0024] Compared with the prior art, the present invention has at least the following beneficial technical effects: The crack repair mortar of the present invention is added with a modifier formed by paraffin, hydroxyapatite powder, iron powder, sodium silicate and / or potassium silicate powder, and then assisted by microwave heating function, so that it can not only form good mechanical strength, but also construct a waterproof and anti-seepage system and a chloride ion corrosion prevention system, thereby improving the repair effect of cracks generated in marine concrete structures. This is because before the modifier is heated by microwave, it does not play a role in the repair material. At this time, the cement gelling material in the repair material undergoes a hydration reaction under the action of mixing water to form a gelling component, ensuring that the repair material can form good mechanical strength. When microwave heating treatment is subsequently performed, the iron powder in the modifier first absorbs microwaves and generates heat to melt the paraffin into a liquid state, and then gradually diffuses to the surroundings to infiltrate the matrix of the repair material to construct a waterproof and anti-seepage system, which helps to reduce and delay the penetration of water carrying chloride ions into the concrete structure, and prevents the accelerated corrosion of steel bars in the concrete structure. Secondly, if water penetrates into the repair material, on the one hand, the hydroxyapatite uses its ion exchange capacity to exchange with chloride ions through the hydroxyl groups it contains, thereby solidifying the chloride ions and reducing the chloride ion content entering the repair material. On the other hand, the iron powder particles are corroded by chloride ions to form iron ions, which further react with the silicate ions released by the sodium silicate and / or potassium silicate to form iron silicate precipitates, which can fill and block the water seepage pores and channels in the repair material, helping to reduce the further infiltration of water. The system formed by the hydroxyapatite, iron powder, sodium silicate and / or potassium silicate in the repair material where water has not penetrated will not be activated, so that it can remain effective for a long time. In addition, the repair material of the present invention also adds specially treated mineral admixtures, which are first activated in alkali solution by the present invention to depolymerize the silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron on its surface to form active ion monomers, and after further reacting with saturated lime water, these active ion monomers react with calcium ions to form nano-hydrated calcium silicate and nano-hydrated calcium aluminate loaded on the surface of the mineral admixture. After this mineral admixture enters into the repair material, the nano-hydrated calcium silicate and nano-hydrated alumina on its surface can act as crystal nuclei to induce the cement cementitious material to accelerate hydration, thereby increasing the completeness of the hydration reaction before microwave heating treatment and forming more cementitious products, ensuring that the repair material has good mechanical strength. This is because the paraffin will infiltrate and coat the cement particles after melting, which will lead to further hydration reaction of the cement particles and development of strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention, and do not constitute an improper limitation of the present invention.

[0026] Figure 1 is a sample picture of the modifier powder prepared in the following Example 1.

[0027] Figure 2 1 is a compressive strength test diagram of the following Example 1.

[0028] Figure 3 This is a sample picture of the modifier powder prepared in the following Example 2.

[0029] Figure 4 2 is a compressive strength test diagram of the following Example 2.

[0030] Figure 5 This is a sample picture of the modifier powder prepared in the following Example 3.

[0031] Figure 6 is a sample picture of the modifier powder prepared in the following Example 4. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific examples, which are only used to illustrate the present invention and are not used to limit the scope of the present invention. The preferred implementation methods and materials described in the text are only for demonstration purposes. It should be noted that all professional and scientific terms used in the text have the same meanings as those familiar to those skilled in the art, unless otherwise defined.

[0033] In addition, the reagents or raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in a conventional manner in the art or in accordance with the product instructions.

[0034] Example 1 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) Mix the above components in a ratio of 12 parts by weight of paraffin wax, 8 parts by weight of 100-mesh hydroxyapatite powder, 5 parts by weight of 300-mesh iron powder, and 1.3 parts by weight of sodium silicate powder, and then heat to 70°C under stirring to melt the paraffin wax into a liquid state, then stop heating, and continue stirring and cooling until the paraffin wax solidifies. Then grind the obtained mixture and sieve it through 50 mesh (the sieve residue is less than 3%) to obtain a modifier powder (such as Figure 1 as shown), for standby use.

[0035] (2) Take the following components in the following proportions: 110 parts by weight of cement (PO42.5), 245 parts by weight of medium sand, 25 parts by weight of slag powder, 22 parts by weight of the modifier powder, 5 parts by weight of glass fiber with a length of 1 mm, and 1.8 parts by weight of polycarboxylate water reducer. Mix the above components and stir them evenly, then add mixing water according to a water-cement ratio of 0.4 and stir for 2 minutes to obtain the repair mortar.

[0036] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 7 days. Then, microwave heating treatment is performed (power is 800W, heating frequency is 15GHz, and heating time is 5min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019) (such as Figure 2 (2) According to the "Standard for Test Methods of Long-term Performance and Durability of Concrete" (GBT 50082-2024), the chloride ion migration coefficient of the test piece is tested. (3) The test piece is split in the middle and the contact angle of the cross section is tested. The larger the contact angle, the better the hydrophobic and impermeable performance of the test piece. The test results are: compressive strength = 30.18MPa, chloride ion migration coefficient = 5.42×10 -13 m 2 / s, contact angle = 116.4°.

[0037] Example 2 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) Mix the above components in a ratio of 10 parts by weight of paraffin wax, 7 parts by weight of 200-mesh hydroxyapatite powder, 3 parts by weight of 400-mesh iron powder, and 1.0 parts by weight of sodium silicate powder, and then heat to 65°C under stirring to melt the paraffin wax into a liquid state, then stop heating, and continue stirring and cooling until the paraffin wax solidifies. Then grind the obtained mixture and sieve it through 70 mesh (the sieve residue is less than 3%) to obtain a modifier powder (such as Figure 3 as shown), for standby use.

[0038] (2) Take the following components in the following proportions: 115 parts by weight of cement (PO42.5), 260 parts by weight of medium sand, 20 parts by weight of silica fume, 20 parts by weight of the modifier powder, 7 parts by weight of glass fiber with a length of 0.5 mm, and 2 parts by weight of polycarboxylate water reducer. Mix the above components and stir them evenly, then add mixing water at a water-cement ratio of 0.45 and stir for 2 minutes to obtain the repair mortar.

[0039] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 7 days. Then, microwave heating treatment is performed (power is 600W, heating frequency is 20GHz, and heating time is 8min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GBT 50081-2019) (such as Figure 4(2) According to the "Standard for Test Methods of Long-term Performance and Durability of Concrete" (GBT 50082-2024), the chloride ion migration coefficient of the test piece is tested. (3) The test piece is split in the middle and the contact angle of the cross section is tested. The larger the contact angle, the better the hydrophobic and impermeable performance of the test piece. The test results are: compressive strength = 32.67MPa, chloride ion migration coefficient = 6.83×10 -13 m 2 / s, contact angle = 107.1°.

[0040] Example 3 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) Mix the above components in a ratio of 15 parts by weight of paraffin wax, 9 parts by weight of 200-mesh hydroxyapatite powder, 4 parts by weight of 500-mesh iron powder, and 1.2 parts by weight of sodium silicate powder, and then heat to 60°C under stirring to melt the paraffin wax into a liquid state, then stop heating, and continue stirring and cooling until the paraffin wax solidifies. Then grind the obtained mixture and sieve it through 70 mesh (the sieve residue is less than 3%) to obtain a modifier powder (such as Figure 5 as shown), for standby use.

[0041] (2) Mix fly ash and 3 mol / L sodium hydroxide solution in a ratio of 1g:5ml, stir evenly, and then heat to 60°C for 2 hours. After completion, filter out the mineral admixture, wash with clean water to remove residual alkali solution, put the mineral admixture and saturated lime water in a reactor in a ratio of 1g:25ml, mix and stir evenly, then seal the reactor and heat to 180°C for 7 hours. After completion, filter out the solid product, dry at 120°C to constant weight, and obtain pretreated fly ash for later use.

[0042] (3) Take the following components in the following proportions: 100 parts by weight of cement (PO42.5), 220 parts by weight of medium sand, 30 parts by weight of the pretreated fly ash, 18 parts by weight of the modifier powder, 4 parts by weight of glass fiber with a length of 2 mm, and 1.6 parts by weight of sodium lignin sulfonate water reducer. Mix the above ingredients and stir them evenly, then add mixing water according to a water-cement ratio of 0.42 and stir for 2 minutes to obtain the repair mortar.

[0043] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 10 days. Then, microwave heating treatment is carried out (power is 1200W, heating frequency is 10GHz, and heating time is 5min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split in the middle. The larger the contact angle, the better the hydrophobic and impermeability performance of the test piece. The test results are: compressive strength = 36.41MPa, chloride ion migration coefficient = 6.22×10 -13 m 2 / s, contact angle = 104.6°.

[0044] Example 4 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) Mix the above components in a ratio of 13 parts by weight of paraffin wax, 8 parts by weight of 200-mesh hydroxyapatite powder, 6 parts by weight of 300-mesh iron powder, and 1.4 parts by weight of potassium silicate powder, and then heat to 60°C under stirring to melt the paraffin wax into a liquid state, then stop heating, and continue stirring and cooling until the paraffin wax solidifies. Then grind the obtained mixture and sieve it through 30 mesh (the sieve residue is less than 3%) to obtain a modifier powder (such as Figure 6 as shown), for standby use.

[0045] (2) Mix 300-mesh steel slag powder and 1 mol / L potassium hydroxide solution in a ratio of 1 g: 20 ml, stir evenly, and then heat to 40°C for 4 hours. After completion, filter out the mineral admixture, wash with clean water to remove residual alkali solution, place the mineral admixture and saturated lime water in a reactor in a ratio of 1 g: 50 ml, mix and stir evenly, then seal the reactor and heat to 230°C for 5 hours. After completion, filter out the solid product, dry at 120°C to constant weight, and obtain the pretreated steel slag powder for later use.

[0046] (3) Take the following components in the following proportions: 100 parts by weight of cement (PO42.5), 240 parts by weight of medium sand, 15 parts by weight of the pretreated steel slag powder, 24 parts by weight of the modifier powder, 6 parts by weight of glass fiber with a length of 1 mm, and 2 parts by weight of sodium lignin sulfonate water reducer. Mix the above ingredients and stir evenly, then add mixing water according to a water-cement ratio of 0.38 and stir for 2 minutes to obtain the repair mortar.

[0047] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 8 days. Then, microwave heating treatment is carried out (power is 1000W, heating frequency is 15GHz, and heating time is 6min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split from the middle. The larger the contact angle, the better the hydrophobic and impermeability performance of the test piece. The test results are: compressive strength = 35.52MPa, chloride ion migration coefficient = 5.17×10 -13 m 2 / s, contact angle = 120.3°.

[0048] Example 5 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: Take the following components in the following proportions: 110 parts by weight of cement (PO42.5), 245 parts by weight of medium sand, 25 parts by weight of slag powder, 5 parts by weight of glass fiber with a length of 1 mm, and 1.8 parts by weight of polycarboxylate water reducer. Mix the above components and stir them evenly, then add mixing water according to a water-cement ratio of 0.4 and stir for 2 minutes to obtain the repair mortar.

[0049] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 7 days. Then microwave heating treatment is carried out (power is 800W, heating frequency is 15GHz, and heating time is 5min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split in the middle. The larger the contact angle, the better the hydrophobic and impermeability performance of the test piece. The test results are: compressive strength = 30.86MPa, chloride ion migration coefficient = 2.91×10 -12 m 2 / s, contact angle = 54.2°.

[0050] Example 6 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) The above components are mixed in a ratio of 10 parts by weight of paraffin wax, 3 parts by weight of 400-mesh iron powder, and 1.0 parts by weight of sodium silicate powder, and then heated to 65°C under stirring conditions to melt the paraffin wax into a liquid state, and then the heating is stopped, and the mixture is cooled with stirring until the paraffin wax solidifies. The obtained mixture is then ground and sieved through 70 mesh (the sieve residue is less than 3%) to obtain a modifier powder for standby use.

[0051] (2) Take the following components in the following proportions: 115 parts by weight of cement (PO42.5), 260 parts by weight of medium sand, 20 parts by weight of silica fume, 20 parts by weight of the modifier powder, 7 parts by weight of glass fiber with a length of 0.5 mm, and 2 parts by weight of polycarboxylate water reducer. Mix the above components and stir them evenly, then add mixing water at a water-cement ratio of 0.45 and stir for 2 minutes to obtain the repair mortar.

[0052] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 7 days. Then microwave heating treatment is carried out (power is 600W, heating frequency is 20GHz, and heating time is 8min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split in the middle. The larger the contact angle, the better the hydrophobic and impermeability resistance of the test piece. The test results are: compressive strength = 32.04MPa, chloride ion migration coefficient = 1.13×10 -12 m 2 / s, contact angle = 109.7°.

[0053] Example 7 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) The above components are mixed in a ratio of 12 parts by weight of paraffin wax, 8 parts by weight of 100-mesh hydroxyapatite powder, and 5 parts by weight of 300-mesh iron powder, and then heated to 70°C under stirring conditions to melt the paraffin wax into a liquid state, and then the heating is stopped, and the mixture is cooled with stirring until the paraffin wax solidifies. The obtained mixture is then ground and sieved through 50 mesh (the sieve residue is less than 3%) to obtain a modifier powder for standby use.

[0054] (2) Take the following components in the following proportions: 110 parts by weight of cement (PO42.5), 245 parts by weight of medium sand, 25 parts by weight of slag powder, 22 parts by weight of the modifier powder, 5 parts by weight of glass fiber with a length of 1 mm, and 1.8 parts by weight of polycarboxylate water reducer. Mix the above components and stir them evenly, then add mixing water according to a water-cement ratio of 0.4 and stir for 2 minutes to obtain the repair mortar.

[0055] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 7 days. Then, microwave heating treatment is carried out (power is 800W, heating frequency is 15GHz, and heating time is 5min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split in the middle. The larger the contact angle, the better the hydrophobic and impermeability performance of the test piece. The test results are: compressive strength = 29.26MPa, chloride ion migration coefficient = 9.14×10 -13 m 2 / s, contact angle = 113.8°.

[0056] Example 8 A method for preparing crack repair mortar for a permeability-resistant marine concrete structure comprises the following steps: (1) Fly ash and 3 mol / L sodium hydroxide solution are mixed in a ratio of 1 g: 5 ml and stirred evenly, and then heated to 60° C. and kept warm for 2 hours. After completion, the mineral admixture is filtered out, washed with clean water to remove the residual alkali solution, and then dried at 120° C. to constant weight to obtain pretreated fly ash for later use.

[0057] (2) Take the following components in the following proportions: 100 parts by weight of cement (PO42.5), 220 parts by weight of medium sand, 30 parts by weight of the pretreated fly ash of this embodiment, 18 parts by weight of the modifier powder of the above-mentioned embodiment 3, 4 parts by weight of glass fiber with a length of 2 mm, and 1.6 parts by weight of sodium lignin sulfonate water reducer. Mix the above components and stir them evenly, then add mixing water according to a water-cement ratio of 0.42 and stir for 2 minutes to obtain the repair mortar.

[0058] Performance test: The repair mortar prepared in this embodiment is poured into a mold, and after hardening and demoulding, it is naturally cured at room temperature until the age of 10 days. Then, microwave heating treatment is carried out (power is 1200W, heating frequency is 10GHz, and heating time is 5min). After completion, it is naturally cooled to room temperature to obtain the test piece. (1) The compressive strength of the test piece is tested in accordance with the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GBT 50081-2019). (2) The chloride ion migration coefficient of the test piece is tested in accordance with the "Standard for Test Methods for Long-term Performance and Durability of Concrete" (GBT 50082-2024). (3) The contact angle of the cross section is tested after the test piece is split in the middle. The larger the contact angle, the better the hydrophobic and impermeability resistance of the test piece. The test results are: compressive strength = 34.09MPa, chloride ion migration coefficient = 6.57×10 -13 m 2 / s, contact angle = 101.5°.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing crack repair mortar for permeability-resistant marine concrete structure, characterized in that: The steps include: (1) paraffin wax, hydroxyapatite powder, iron powder, sodium silicate and / or potassium silicate powder are mixed, and then the mixture is continuously stirred and heated until the paraffin wax is melted, and then the heating is stopped and the mixture is continuously stirred and cooled until the paraffin wax is solidified; and then the obtained mixture is ground to obtain a modifier powder; (2) Cement binder, sand and gravel fine aggregate, mineral admixture, modifier powder, glass fiber and water reducing agent are used as raw materials, mixed evenly, and then mixing water is added and stirred evenly to obtain the repair mortar.

2. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 1, characterized in that: In step (1), the ratio of the paraffin wax, hydroxyapatite powder, iron powder, sodium silicate and / or potassium silicate powder is 10-15 parts by weight: 7-9 parts by weight: 3-6 parts by weight: 1-1.4 parts by weight.

3. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 1, characterized in that: In step (1), the melting temperature of the paraffin wax is not higher than 70°C; Optionally, in step (1), the fineness of the hydroxyapatite powder is 100-200 mesh; Optionally, in step (1), the fineness of the iron powder is 300-500 mesh; Optionally, in step (1), the fineness of the modifier powder is 30-70 mesh.

4. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 1, characterized in that: In step (2), the ratio of the cementitious material, sand and gravel fine aggregate, mineral admixture, modifier powder, glass fiber, and water reducing agent is 100-115 parts by weight: 220-260 parts by weight: 15-30 parts by weight: 18-24 parts by weight: 4-7 parts by weight: 1.6-2 parts by weight; Optionally, in step (2), the mixing water is added according to a water-cement ratio of 0.38-0.45, and the "cement" includes the cementitious material and mineral admixtures.

5. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 1, characterized in that: In step (2), the mineral admixture includes at least one of fly ash, silica fume, slag powder and steel slag powder.

6. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 5, characterized in that: In step (2), the mineral admixture is treated by the following method: the mineral admixture is placed in an alkaline solution for heating treatment; after the completion, the mineral admixture is separated, washed, placed in saturated lime water for heating and insulation, and after the reaction is completed, the solid product is separated and dried to obtain the product.

7. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to claim 6, characterized in that: The ratio of the mineral admixture to the alkali solution is 1g:5-20ml; optionally, the concentration of the alkali solution is 1-3mol / L; the alkali solution includes at least one of a sodium hydroxide solution and a potassium hydroxide solution; Optionally, the heating treatment time is 2 to 4 hours, and the heating temperature is 40 to 60° C.; Optionally, the ratio of the separated mineral admixture to saturated lime water is 1 g: 25-50 ml; Optionally, the heating and insulation temperature is 180-230° C., and the insulation time is 5-7 hours.

8. The process for preparing crack repair mortar for permeability-resistant marine concrete structure according to any one of claims 1 to 7, characterized in that: In step (2), the water reducer includes any one of a polycarboxylate water reducer, a naphthalene water reducer, and a lignin sulfonate water reducer; Optionally, in step (2), the length of the glass fiber is 0.5-2 mm.

9. Application of the crack repair mortar obtained by the preparation process according to any one of claims 1 to 8 in repairing cracks in concrete structures, characterized in that: The steps include: (I) filling the crack repair mortar into the cracks of the concrete structure and curing until the repair mortar hardens; (II) The hardened repair mortar in the crack is subjected to microwave heating treatment to melt and diffuse the paraffin in the modifier powder to construct an anti-seepage system, and then cooled to room temperature.

10. The use according to claim 9, characterized in that: In step (I), the curing time is 7 to 10 days; optionally, in step (II), the microwave heating power is 600 to 1200 W, the heating frequency is 10 to 20 GHz, and the heating time is 5 to 8 min.

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