Polymer repair mortar for marine concrete and method for preparing the same

Abstract

The application discloses a polymer repair mortar for marine concrete and a preparation method thereof. The polymer repair mortar comprises dry powder mortar and a composite modified polymer. The dry powder mortar comprises 525 cement, an expanding agent, high-activity metakaolin, sand, a water reducing agent, a defoaming agent, latex powder and modified polypropylene fibers. The composite modified polymer comprises water-based epoxy resin, graphene, sodium hydroxymethyl cellulose and amide modified hydrogenated castor oil. The dry powder mortar and the composite modified polymer are mixed uniformly to obtain the polymer repair mortar. The polymer repair mortar improves the impermeability and impact resistance of the repaired marine concrete. The composite modified polymer can form a dense waterproof protective film on the surface of the mortar, effectively reducing the influence of the dry-wet cycle of the sea, chloride ion corrosion and the impact of sea waves. In addition, the adhesion between the repair mortar and the marine concrete matrix is further improved.

Description

Technical Field

[0001] This invention belongs to the field of repair mortar, and particularly relates to a polymer repair mortar for marine concrete and its preparation method. Background Technology

[0002] The booming development of my country's construction industry has led to the widespread application of concrete in various fields, making it an extremely important building material. This has resulted in higher quality requirements for concrete. However, numerous cases of concrete structures being damaged by erosion within their designated service life are emerging, with particularly prominent issues involving concrete in damp conditions. Marine concrete, in particular, is affected by chloride ion penetration, salt corrosion, freeze-thaw cycles, and wave impacts. These factors pose a significant challenge to marine engineering. Over time, the need to resist these attacks has led to surface cracks and peeling in concrete, shortening its service life and creating a new challenge: the repair of marine concrete.

[0003] Repair mortar refers to a type of mortar used for repairing or reinforcing surface defects in concrete structures. It possesses high compressive strength, adhesion, crack resistance, and waterproofing. However, while existing repair mortars for marine concrete meet the required compressive strength, they suffer from poor corrosion resistance and weak adhesion, resulting in low bond strength. For example, the exposed reinforcement concrete repair mortar disclosed in CN202110107749.6 and the high-strength frost-resistant concrete repair mortar disclosed in CN201910005082.1 both exhibit poor adhesion. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide a polymer repair mortar that is not only highly corrosion-resistant, impermeable, and impact-resistant, but also has strong adhesion to marine concrete substrates, and its preparation method.

[0005] Technical solution: The polymer repair mortar for marine concrete of the present invention comprises dry powder mortar and composite modified polymer in a weight ratio of 1:0.20-0.24;

[0006] The dry powder mortar, by weight, comprises: 400-450 parts of 525 cement, 24-28 parts of expanding agent, 45-50 parts of highly active metakaolin, 470-474 parts of sand, 1.5-2.3 parts of water-reducing agent, 0.5-0.8 parts of defoamer, 2.6-3.4 parts of latex powder, and 1.1-1.5 parts of modified polypropylene fiber;

[0007] The composite modified polymer comprises, by weight, 45-49 parts of waterborne epoxy resin, 5.8-7.8 parts of graphene, 3.8-4.4 parts of sodium hydroxymethyl cellulose, and 1.6-2.8 parts of amide-modified hydrogenated castor oil.

[0008] This invention employs a repair mortar composed of dry-mixed mortar and a composite modified polymer in a weight ratio of 1:0.20-0.24. The dry-mixed mortar, based on cement, sand, and other additives, incorporates polypropylene fibers modified with silane coupling agents and acrylic acid surface treatment. This not only transforms the fibers into a rough and tough type but also improves their dispersibility, enabling them to form a mesh structure within the mortar. This mesh structure improves the internal porosity of the polymer mortar, increases its density, enhances its bonding strength with the concrete surface, and improves the performance of marine engineering concrete. The invention improves the impermeability and impact resistance of concrete. Furthermore, the highly active metakaolin of this invention, modified with calcium phosphate, undergoes ion exchange and polymerization with calcium phosphate under alkaline conditions inside the concrete, enhancing the strength of the polymer repair mortar. The addition of phosphate also improves resistance to seawater erosion. Secondly, the composite modified polymer of this invention uses sodium hydroxymethyl cellulose as a dispersant and amide-modified hydrogenated castor oil as an anti-settling agent to disperse graphene into epoxy resin, thereby forming a "film" that acts as a barrier, effectively inhibiting the erosion of chemical elements in seawater.

[0009] Most importantly, this repair mortar is based on modified polypropylene fibers with a mesh structure. When the acrylic acid loaded on the polypropylene fibers is compounded with the composite modified polymer liquid material, it undergoes a grafting reaction with the amide-modified hydrogenated castor oil in the composite modified polymer under the action of a silane coupling agent. This generates a large number of carboxyl ions and other active groups, increasing the chemical bonding points on the surface of the modified epoxy resin film and further improving the adhesion performance between the polymer repair mortar and the marine concrete matrix.

[0010] Furthermore, the modified polypropylene fiber used in this invention is prepared by the following steps: 0.1-0.5 parts of silane coupling agent are dissolved in 80-100 parts of an acrylic acid aqueous solution with a concentration of 2.3-2.5%, 20-25 parts of polypropylene fiber are weighed and soaked in the solution for 6-8 hours, then washed with clean water and dried at 70-90°C.

[0011] Furthermore, the highly active metakaolin used in this invention is prepared by the following steps: kaolin is calcined at 650-900℃ for 6-16 hours to obtain metakaolin; 60-65 parts of this metakaolin, 30-35 parts of S95 grade mineral powder, and 3-5 parts of calcium phosphate are weighed and mixed and ground in an air classifier, with the airflow rate adjusted to 100-120 m / s. 3The process involves grinding at a rate of 1 / min for 1-2 hours to obtain highly active metakaolin with a particle size ≤3μm (submicron grade).

[0012] Furthermore, the sand used in this invention is lake sand, which is a mixture of three graded sands with fineness moduli of 0.8-1.0, 1.4-1.6, and 2.3-2.5 in a ratio of 1:1.5:1.5, with a mud content of <3.0%.

[0013] Furthermore, the expanding agent used in this invention is HME-Ⅳ expanding agent; the water reducing agent is polycarboxylate high-performance water reducing agent; the defoamer is organosilicon defoamer; the latex powder is dispersible latex powder with a pH value of 5-8, a bulk density of 450-600 g / L, and an ash content of 8-10%.

[0014] Furthermore, the composite modified polymer used in this invention is prepared by the following steps:

[0015] (1) Preparation of amide-modified hydrogenated castor oil: Hydrogenated castor oil with a molar ratio of 1:2.3-2.5 is mixed with triethanolamine, heated to 110-120℃, and stirred until the hydrogenated castor oil is completely melted. The reaction is carried out for 2.5-3h to obtain the compound. The compound is poured out, cooled to 40-45℃, the pH is adjusted to 7.0-7.5, and the reaction is kept at this temperature for 1-1.5h. The solid content is adjusted to 40-45% by adding warm water to obtain amide-modified hydrogenated castor oil.

[0016] (2) Preparation of composite modified polymer: Waterborne epoxy resin is placed in a reaction vessel, and sodium hydroxymethyl cellulose and amide-modified hydrogenated castor oil are added under stirring at 35-40℃. Then graphene is added, and the reaction is carried out at 800-1200 rpm and 35-40℃ for 1.3-1.5 h. The mixture is then cooled to room temperature to obtain the composite modified polymer.

[0017] The method for preparing the above-mentioned polymer repair mortar for marine concrete according to the present invention includes the following steps:

[0018] (1) Preparation of dry powder mortar: Mix 525 cement, expansion agent, high-activity metakaolin, sand, water-reducing agent, defoamer, latex powder and modified polypropylene fiber evenly according to the weight parts.

[0019] (2) Preparation of polymer repair mortar: The dry powder mortar and the composite modified polymer are mixed evenly according to the weight ratio to obtain the polymer repair mortar.

[0020] Beneficial effects: Compared with the prior art, the significant advantages of this invention are as follows: This polymer repair mortar, based on the compounding of dry powder mortar and composite modified polymer, is applied to the repair of marine concrete. It not only improves the impermeability and impact resistance of the repaired marine concrete, but also allows the composite modified polymer to form a dense and waterproof protective film on the mortar surface, effectively reducing the impact of marine wet-dry cycles, chloride ion corrosion, and wave impact. In addition, the combination of dry powder mortar and composite modified polymer further improves the bonding performance between the repair mortar and the marine concrete matrix, increasing the bond strength between the two. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0022] It should be noted that all raw materials used in this invention are commercially available.

[0023] The sand is lake sand, which is a mixture of three graded sands with fineness moduli of 0.8-1.0, 1.4-1.6, and 2.3-2.5 in a ratio of 1:1.5:1.5, with a mud content of <3.0%. The expanding agent is HME-Ⅳ expanding agent.

[0024] The water-reducing agent is selected from polycarboxylate high-performance water-reducing agent; the defoamer is selected from silicone defoamer; the latex powder is selected from dispersible latex powder with a pH value of 5-8, a bulk density of 450-600 g / L, and an ash content of 8-10%.

[0025] The waterborne epoxy resin is an aqueous solution with a solid content of 40%; the graphene is industrial-grade graphene; the amide-modified hydrogenated castor oil is a liquid; and the sodium hydroxymethyl cellulose solution is a white flocculent powder with a viscosity of 400-1200.

[0026] The method of using the polymer repair mortar for marine concrete of the present invention is to directly apply the prepared polymer repair mortar for marine concrete to the marine concrete structure that needs to be repaired.

[0027] Example 1

[0028] The repair mortar of this embodiment 1 includes a dry powder mortar and a composite modified polymer with a weight ratio of 1:0.20; wherein, the raw material composition of the dry powder mortar is shown in Table 1 below, and the raw material composition of the composite modified polymer is shown in Table 2 below.

[0029] Table 1 Raw material composition of dry powder mortar

[0030] Serial Number raw material Content / serving 1 525 cement 450 2 Expanding agent 24 3 Highly active metakaolin 48 4 sand 470 5 Water reducing agent 1.5 6 Defoamer 0.6 7 Latex powder 2.6 8 Modified polypropylene fiber 1.1

[0031] Table 2 Raw material composition of composite modified polymers

[0032] Serial Number raw material Content / serving 1 Waterborne epoxy resin 45 2 graphene 5.8 3 Sodium hydroxymethylcellulose 3.8 4 Amide-modified hydrogenated castor oil 1.6

[0033] The preparation method of this polymer repair mortar includes the following steps:

[0034] (1) Preparation of highly active metakaolin: Metakaolin was obtained by calcining kaolin at 650℃ for 16h. 60 parts of the metakaolin, 30 parts of S95 grade mineral powder and 3 parts of calcium phosphate were weighed and mixed and ground in an air classifier. The airflow rate was adjusted to 100-120m. 3 The process involves grinding at a rate of 1 / min for 1-2 hours to obtain highly active metakaolin with a particle size ≤3μm (submicron grade).

[0035] (2) Preparation of modified polypropylene fiber: Dissolve 0.1 parts of silane coupling agent in 80 parts of 2.3% acrylic acid aqueous solution, weigh 20 parts of polypropylene fiber and soak it in the solution for 6-8 hours, then wash it with water and dry it at 70°C.

[0036] (3) Preparation of amide-modified hydrogenated castor oil: Hydrogenated castor oil with a molar ratio of 1:2.5 was mixed with triethanolamine and added to a reactor equipped with a heating device and a reflux condenser. The mixture was heated to 120°C and stirred continuously until the hydrogenated castor oil was completely melted. The reaction was carried out for 2.5 hours. The synthesized product was quickly poured out and cooled to 40°C. The pH of the reaction was adjusted to 7.0-7.5 with ammonia water. The reaction was kept at this temperature for 1 hour. The solid content was adjusted to 40% with warm water to obtain the amide-modified hydrogenated castor oil.

[0037] (4) Preparation of composite modified polymer: Place waterborne epoxy resin in a reaction vessel, adjust the stirring speed to 800 rpm-1200 rpm, the reaction temperature to 40℃, add sodium hydroxymethyl cellulose as a dispersant, add amide-modified hydrogenated castor oil as an anti-precipitant using a peristaltic pump with a rate of 8.500 mL / min, then disperse graphene in the waterborne epoxy resin, maintain the reaction at 40℃ for 1.5 h, and cool to room temperature to obtain the composite modified polymer.

[0038] (5) Preparation of dry powder mortar: Mix cement, expansion agent, high-activity metakaolin, sand, water-reducing agent, defoamer, latex powder and modified polypropylene fiber evenly according to the weight parts and set aside.

[0039] (6) Preparation of polymer repair mortar: The dry powder mortar and the composite modified polymer are mixed evenly according to the weight ratio to obtain the polymer repair mortar.

[0040] Example 2

[0041] The repair mortar of this embodiment 2 includes dry powder mortar and composite modified polymer in a weight ratio of 1:0.22; wherein, the raw material composition of the dry powder mortar is shown in Table 3 below, and the raw material composition of the composite modified polymer is shown in Table 4 below.

[0042] Table 3 Raw material composition of dry powder mortar

[0043] Serial Number raw material Content / serving 1 525 cement 450 2 Expanding agent 25 3 Highly active metakaolin 46 4 sand 470 5 Water reducing agent 1.8 6 Defoamer 0.7 7 Latex powder 2.9 8 Modified polypropylene fiber 1.3

[0044] Table 4 Raw material composition of composite modified polymers

[0045] Serial Number raw material Content / serving 1 Waterborne epoxy resin 47 2 graphene 6.4 3 Sodium hydroxymethylcellulose 4.0 4 Amide-modified hydrogenated castor oil 1.7

[0046] The preparation method of this polymer repair mortar is the same as that in Example 1.

[0047] Example 3

[0048] The repair mortar of this embodiment 3 includes a dry powder mortar and a composite modified polymer in a weight ratio of 1:0.22; wherein, the raw material composition of the dry powder mortar is shown in Table 5 below, and the raw material composition of the composite modified polymer is shown in Table 6 below.

[0049] Table 5 Raw material composition of dry powder mortar

[0050] Serial Number raw material Content / serving 1 525 cement 450 2 Expanding agent 27 3 Highly active metakaolin 47 3 sand 470 4 Water reducing agent 1.9 5 Defoamer 0.7 6 Latex powder 2.9 7 Modified polypropylene fiber 1.4

[0051] Table 6 Raw material composition of composite modified polymers

[0052] Serial Number raw material Content / serving 1 Waterborne epoxy resin 48 2 graphene 6.4 3 Sodium hydroxymethylcellulose 4.1 4 Amide-modified hydrogenated castor oil 2.1

[0053] The preparation method of this polymer repair mortar is the same as that in Example 1.

[0054] Example 4

[0055] The repair mortar of Example 4 includes a dry powder mortar and a composite modified polymer in a weight ratio of 1:0.22; wherein, the raw material composition of the dry powder mortar is shown in Table 7 below, and the raw material composition of the composite modified polymer is shown in Table 8 below.

[0056] Table 7 Raw material composition of dry powder mortar

[0057] Serial Number raw material Content / serving 1 525 cement 420 2 Expanding agent 28 3 Highly active metakaolin 50 4 sand 470 5 Water reducing agent 2.3 6 Defoamer 0.8 7 Latex powder 3.4 8 Modified polypropylene fiber 1.5

[0058] Table 8 Raw material composition of composite modified polymers

[0059] Serial Number raw material Content / serving 1 Waterborne epoxy resin 49 2 graphene 7.8 3 Sodium hydroxymethylcellulose 4.4 4 Amide-modified hydrogenated castor oil 2.8

[0060] The preparation method of this polymer repair mortar is the same as that in Example 1.

[0061] Example 5

[0062] The repair mortar of Example 5 includes a dry powder mortar and a composite modified polymer in a weight ratio of 1:0.24; wherein, the raw material composition of the dry powder mortar is shown in Table 9 below, and the raw material composition of the composite modified polymer is shown in Table 10 below.

[0063] Table 9 Raw material composition of dry powder mortar

[0064]

[0065]

[0066] Table 10 Raw material composition of composite modified polymers

[0067] Serial Number raw material Content / serving 1 Waterborne epoxy resin 47 2 graphene 7.4 3 Sodium hydroxymethylcellulose 3.8 4 Amide-modified hydrogenated castor oil 2.1

[0068] The preparation method of this polymer repair mortar includes the following steps:

[0069] (1) Preparation of highly active metakaolin: Metakaolin was obtained by calcining kaolin at 900℃ for 6 hours. 65 parts of the metakaolin, 35 parts of S95 grade mineral powder and 5 parts of calcium phosphate were weighed and mixed and ground in an air classifier. The airflow rate was adjusted to 100-120 m / s. 3 The process involves grinding at a rate of 1 / min for 1-2 hours to obtain highly active metakaolin with a particle size ≤3μm (submicron grade).

[0070] (2) Preparation of modified polypropylene fiber: Dissolve 0.5 parts of silane coupling agent in 100 parts of 2.5% acrylic acid aqueous solution, weigh 25 parts of polypropylene fiber and soak it in the solution for 6-8 hours, then wash it with water and dry it at 90℃.

[0071] (3) Preparation of amide-modified hydrogenated castor oil: Hydrogenated castor oil with a molar ratio of 1:2.3 was mixed with triethanolamine and added to a reactor equipped with a heating device and a reflux condenser. The mixture was heated to 110°C and stirred continuously until the hydrogenated castor oil was completely melted. The reaction was carried out for 3 hours. The synthesized product was quickly poured out and cooled to 45°C. The pH of the reaction was adjusted to 7.0-7.5 with ammonia water. The reaction was kept at this temperature for 1.5 hours. The solid content was adjusted to 45% with warm water to obtain the amide-modified hydrogenated castor oil.

[0072] (4) Preparation of composite modified polymer: Place waterborne epoxy resin in a reaction vessel, adjust the stirring speed to 800 rpm-1200 rpm, the reaction temperature to 35℃, add sodium hydroxymethyl cellulose as a dispersant, add amide-modified hydrogenated castor oil as an anti-precipitant using a peristaltic pump with a rate of 8.500 mL / min, then disperse graphene in the waterborne epoxy resin, maintain the reaction at 35℃ for 1.3 h, and cool to room temperature to obtain the modified polymer.

[0073] (5) Preparation of dry powder mortar: Mix 525 cement, expansion agent, high-activity metakaolin, sand, water-reducing agent, defoamer, latex powder and modified polypropylene fiber evenly according to the weight parts.

[0074] (6) Preparation of polymer repair mortar: The dry powder mortar and the composite modified polymer are mixed evenly according to the weight ratio to obtain the polymer repair mortar.

[0075] Comparative Example 1

[0076] Comparative Example 1 is essentially the same as Example 5, except that modified polypropylene fibers are not added. Specifically, the raw material composition of the dry powder mortar is shown in Table 11 below, and the raw material composition of the composite modified polymer is shown in Table 12 below.

[0077] Table 11 Raw material composition of dry powder mortar

[0078] Serial Number raw material Content / serving 1 525 cement 400 2 Expanding agent 24 3 Highly active metakaolin 45 4 sand 474 5 Water reducing agent 1.8 6 Defoamer 0.5 7 Latex powder 2.8

[0079] Table 12 Raw material composition of composite modified polymers

[0080] Serial Number raw material Content / serving 1 Waterborne epoxy resin 47 2 graphene 7.4 3 Sodium hydroxymethylcellulose 3.8 4 Amide-modified hydrogenated castor oil 2.1

[0081] The preparation method of this polymer repair mortar is basically the same as that in Example 1.

[0082] Comparative Example 2

[0083] Comparative Example 2 is basically the same as Example 5, except that the polymer used in this polymer repair mortar is 47 parts of water-based epoxy resin, as shown in Tables 13 and 14 below.

[0084] Table 13 Raw material composition of dry powder mortar

[0085] Serial Number raw material Content / serving 1 525 cement 400 2 Expanding agent 24 3 Highly active metakaolin 45 4 sand 474 5 Water reducing agent 1.8 6 Defoamer 0.5 7 Latex powder 2.8 8 Modified polypropylene fiber 1.2

[0086] Table 14 Raw material composition of composite modified polymers

[0087] Serial Number raw material Content / serving 1 Waterborne epoxy resin 47

[0088] The preparation method of this polymer repair mortar is the same as that in Example 1.

[0089] Comparative Example 3

[0090] The basic steps are the same as in Example 5, except that the modified polypropylene fiber is prepared only by modifying polypropylene fiber and silane coupling agent. The steps are as follows: 0.5 parts of silane coupling agent are dissolved in 100 parts of aqueous solution, 25 parts of polypropylene fiber are weighed and soaked in the solution for 6-8 hours, then washed with clean water and dried at 90°C to obtain the product.

[0091] Performance testing

[0092] The performance of the polymer repair mortars for marine concrete prepared in Examples 1-5 was compared with that of the polymer repair mortars for marine concrete prepared in Comparative Examples 1-3. The results are shown in Table 15 below.

[0093] Table 15 Comparison of the performance of the repair mortars prepared in Examples 1-5 and Comparative Examples 1-3

[0094]

[0095]

[0096] As shown in Table 15, compared with Comparative Examples 1 and 2, the repair mortar of the present invention not only improves the impermeability and impact resistance of the repaired marine concrete, but also the composite modified polymer can form a dense and waterproof protective film on the mortar surface, effectively reducing the impact of marine wet-dry cycles, chloride ion corrosion, and wave impact. In addition, compared with Comparative Example 3, the combination of the dry powder mortar and the composite modified polymer of the present invention further improves the bonding performance between the repair mortar and the marine concrete matrix, and increases the bonding strength between the two.

Claims

1. A polymer repair mortar for marine concrete, characterized in that: The polymer repair mortar comprises dry powder mortar and composite modified polymer in a weight ratio of 1:0.20-0.24; The dry powder mortar, by weight, comprises: 400-450 parts of 525 cement, 24-28 parts of expanding agent, 45-50 parts of highly active metakaolin, 470-474 parts of sand, 1.5-2.3 parts of water-reducing agent, 0.5-0.8 parts of defoamer, 2.6-3.4 parts of latex powder, and 1.1-1.5 parts of modified polypropylene fiber; The composite modified polymer comprises, by weight, 45-49 parts of waterborne epoxy resin, 5.8-7.8 parts of graphene, 3.8-4.4 parts of sodium carboxymethyl cellulose, and 1.6-2.8 parts of amide-modified hydrogenated castor oil; it is prepared by the following steps: waterborne epoxy resin is placed in a reaction vessel, and sodium carboxymethyl cellulose and amide-modified hydrogenated castor oil are added while stirring at 35-40°C, followed by the addition of graphene. The reaction is maintained at 800-1200 rpm and 35-40°C for 1.3-1.5 hours, and then cooled to room temperature to obtain the composite modified polymer. The modified polypropylene fiber is prepared by the following steps: 0.1-0.5 parts of silane coupling agent are dissolved in 80-100 parts of an acrylic acid aqueous solution with a concentration of 2.3-2.5%, 20-25 parts of polypropylene fiber are weighed and soaked in the solution for 6-8 hours, then washed with water and dried at 70-90 ℃. The highly active metakaolin is prepared by the following steps: kaolin is calcined at 650-900℃ for 6-16 hours to obtain metakaolin; 60-65 parts of the metakaolin, 30-35 parts of S95 grade mineral powder, and 3-5 parts of calcium phosphate are weighed and mixed and ground in an air classifier, with the airflow rate adjusted to 100-120 m / s². 3 The process involves grinding at a rate of 1 / min for 1-2 hours to obtain highly active metakaolin with a particle size ≤3μm (submicron grade).

2. The polymer repair mortar for marine concrete according to claim 1, characterized in that: The sand is lake sand, which is a mixture of three graded sands with fineness moduli of 0.8-1.0, 1.4-1.6 and 2.3-2.5 in a ratio of 1:1.5:1.5, with a mud content of <3.0%.

3. The polymer repair mortar for marine concrete according to claim 1, characterized in that: The expanding agent is HME-Ⅳ expanding agent; the water reducing agent is polycarboxylate high-performance water reducing agent; the defoamer is organosilicon defoamer; the latex powder is dispersible latex powder with a pH value of 5-8, a bulk density of 450-600 g / L, and an ash content of 8-10%.

4. The polymer repair mortar for marine concrete according to claim 1, characterized in that: The amide-modified hydrogenated castor oil in the composite modified polymer is obtained by the following steps: Hydrogenated castor oil and triethanolamine were mixed in a molar ratio of 1:2.3-2.5 and heated to 110-120 °C. The mixture was stirred until the hydrogenated castor oil was completely melted, and the reaction was allowed to proceed for 2.5-3 h to obtain the synthesized product. The synthesized product was poured out, cooled to 40-45 °C, and the pH was adjusted to 7.0-7.

5. The reaction was maintained at this temperature for 1-1.5 h, and the solid content was adjusted to 40-45% by adding warm water to obtain amide-modified hydrogenated castor oil.

5. A method for preparing the polymer repair mortar for marine concrete as described in claim 1, characterized in that... Includes the following steps: (1) Preparation of dry powder mortar: Mix 525 cement, expansion agent, high-activity metakaolin, sand, water-reducing agent, defoamer, latex powder and modified polypropylene fiber evenly according to the weight parts; (2) Preparation of polymer repair mortar: The dry powder mortar and the composite modified polymer are mixed evenly according to the weight ratio to obtain the polymer repair mortar.

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