A polymer mortar repair material and its preparation method and application

Abstract

The invention discloses a polymer mortar repair material, comprising the following raw materials: cement, sand material, water, fiber, white carbon black, expansion agent, water reducing agent, styrene-butadiene rubber, epoxy acrylate and silica sol modified acrylate. The invention prepares a polymer mortar repair material with high mechanical properties and good freeze-thaw resistance by reasonably mixing styrene-butadiene rubber, epoxy acrylate and silica sol modified acrylate with cement mortar, and is suitable for repairing concrete cracks in cold areas.

Description

Technical Field

[0001] The invention belongs to the field of concrete component repair mortar, and in particular relates to a polymer mortar repair material and a preparation method and application thereof. Background Art

[0002] In recent years, in order to achieve water-saving irrigation and save water resources, many large irrigation areas in many provinces and regions across the country have carried out water-saving renovation projects. Most channels are lined with concrete slabs, which have good anti-seepage effects and are easy to construct. However, due to the influence of low temperature weather during operation, the frost heave damage of the channel foundation soil caused cracks in the concrete slab, which is very ineffective in the operation and management of the project. Measures should be taken in time to deal with it.

[0003] The method for dealing with concrete cracks is to use repair materials to repair the concrete structure. At present, concrete structure repair materials are divided into: cement-based repair materials, polymer repair materials, and cement-based polymer repair materials (polymer repair mortar) according to the material type. Among them, cement-based repair materials are only used in non-important engineering parts due to their shortcomings such as drying shrinkage and poor durability. Although polymer repair materials have high strength, good toughness, short maintenance period, convenient construction, and strong targeting, they cannot become mainstream repair materials because of a series of shortcomings such as easy aging, high cost, and high requirements for interface treatment with concrete.

[0004] Polymer repair mortar is a high-performance repair mortar that is prepared by adding polymers to cement mortar according to performance requirements, and has the characteristics of anti-seepage and anti-cracking, high toughness, and good adhesion. However, the current polymer repair mortar generally has low compressive strength and is prone to freeze-thaw degradation and failure under the climatic conditions of cold regions. Therefore, it is very necessary to develop a polymer repair mortar with good mechanical properties and antifreeze properties under the climatic conditions of cold regions. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a polymer mortar repair material and a preparation method and application thereof. The polymer mortar repair material provided by the present invention not only has good mechanical properties, but also has good freeze-thaw resistance and high bonding strength.

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

[0007] The invention provides a polymer mortar repair material, which comprises the following raw materials: cement, sand material, water, fiber, white carbon black, expansion agent, water reducing agent, styrene-butadiene rubber, epoxy acrylate and silica sol modified acrylate.

[0008] Preferably, the cement is fly ash cement.

[0009] Preferably, the sand material is quartz sand.

[0010] Preferably, the fiber is polypropylene fiber, polyvinyl alcohol fiber or carbon fiber.

[0011] Preferably, the expansion agent is a U-type expansion agent or an AEA expansion agent; and the water reducer is a polycarboxylic acid high-efficiency water reducer.

[0012] Preferably, the silica sol-modified acrylate comprises the following raw materials: silica sol, emulsifier, initiator, shell monomer, and core monomer.

[0013] Preferably, the silica sol is prepared by catalytic hydrolysis of tetraethyl orthosilicate, the emulsifier includes sodium dodecyl sulfonate and polyoxyethylene octylphenyl ether, the initiator is ammonium persulfate, the core monomer includes butyl acrylate and methyl methacrylate, and the shell monomer is acrylic acid.

[0014] Preferably, the polymer mortar repair material provided by the present invention includes, by weight, 100 parts of fly ash cement, 200-250 parts of sand, 20-30 parts of water, 0.02-0.15 parts of fiber, 0.5-2 parts of white carbon black, 5-8 parts of expansion agent, 0.5-1.2 parts of water reducer, 5-20 parts of styrene-butadiene rubber, 5-20 parts of epoxy acrylate, and 10-30 parts of silica sol-modified acrylate.

[0015] The present invention also provides a method for preparing the above polymer mortar repair material, comprising the following steps:

[0016] S1. Prepare epoxy acrylate and silica sol-modified acrylate for standby use;

[0017] S2. Mix cement, sand, fiber, white carbon, expansion agent and water reducing agent, stir evenly to obtain a mixture;

[0018] S3. Add water and styrene-butadiene rubber to the mixture and mix thoroughly, then add epoxy acrylate and silica sol-modified acrylate, continue to stir evenly, and obtain a polymer mortar repair material.

[0019] The present invention also provides an application of the polymer mortar repair material in treating cracks in concrete slabs in a channel lining project.

[0020] The beneficial effects of the present invention are:

[0021] The present invention adds styrene-butadiene rubber, epoxy acrylate and silica sol-modified acrylate into cement mortar to prepare a polymer mortar repair material with high compressive strength and flexural strength, good freeze-thaw resistance and high bonding strength, and can be used to repair concrete cracks in cold regions. DETAILED DESCRIPTION

[0022] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The emulsifier solution used in the preparation of silica sol modified acrylate in the embodiment of the present invention is sodium dodecyl sulfonate and polyoxyethylene octyl phenyl ether in a mass ratio of 1:1, the initiator is ammonium persulfate, the core monomer is butyl acrylate and methyl methacrylate in a mass ratio of 2:3, the shell monomer is acrylic acid, and the pH buffer is sodium bicarbonate. The weight ratio of silica sol, emulsifier, initiator, shell monomer, and core monomer is 10:6:0.2:20:15.

[0024] Example 1

[0025] The polymer mortar repair material of this embodiment includes, by weight, 100 parts of fly ash cement, 200 parts of quartz sand, 20 parts of water, 0.15 parts of polypropylene fiber, 2 parts of white carbon black, 8 parts of U-type expansion agent, 1.2 parts of polycarboxylic acid high-efficiency water reducing agent, 5 parts of styrene-butadiene rubber, 20 parts of epoxy acrylate, and 10 parts of silica sol-modified acrylate.

[0026] A method for preparing a polymer mortar repair material comprises the following steps:

[0027] (1) Preparation of epoxy acrylate and silica sol-modified acrylate

[0028] Epoxy acrylate is prepared according to the method disclosed in patent number CN 111574912 A.

[0029] The preparation method of silica sol modified acrylate is as follows:

[0030] Add 1 mol of tetraethyl orthosilicate (TEOS) and 6 mol of anhydrous ethanol into a three-necked flask, stir rapidly at 45°C, drop 0.1 mol of aqueous ammonia and 2 mol of distilled water into the flask, stir vigorously for 4 h, and leave it at room temperature for a certain period of time to age to obtain silica sol for use.

[0031] Take silica sol and emulsifier solution and disperse them at high speed in a magnetic stirrer for 15 minutes. Add the dispersed mixed solution into a four-necked flask at 45°C, add the buffer under medium-speed stirring, and heat to 82°C with nitrogen protection. Then add 1 / 3 of the core monomer and 1 / 3 of the initiator solution into the flask. After the reaction shows a uniform blue phase, slowly add the remaining 2 / 3 of the core monomer and 1 / 3 of the initiator solution, respectively, and control the dropping time to 1h. After the dropping is completed, heat to 86°C and keep warm for 1h, then cool to 82°C to obtain the seed emulsion. Add the shell monomer and the remaining 1 / 3 of the initiator solution to the seed emulsion, the dropping time is 3h, continue to keep warm at 82°C for 1h, cool to below 40°C, pass through a 60-mesh sieve, and adjust the pH to 8-9 with ammonia water to obtain a silica sol-modified acrylate emulsion.

[0032] (2) Mix fly ash cement, quartz sand, polypropylene fiber, white carbon black, expansion agent and water reducing agent, stir evenly to obtain a mixture.

[0033] (3) After adding water and styrene-butadiene rubber to the mixture and mixing thoroughly, epoxy acrylate and silica sol-modified acrylate are added, and stirring is continued to be uniform to obtain a polymer mortar repair material.

[0034] Example 2

[0035] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of styrene-butadiene rubber used was 20 parts by weight.

[0036] Example 3

[0037] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of epoxy acrylate used was 5 parts by weight.

[0038] Example 4

[0039] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of silica sol-modified acrylate was 30 parts by weight.

[0040] Comparative Example 1

[0041] A polymer mortar repair material was prepared in the same manner as in Example 1, except that no styrene-butadiene rubber was added to the raw materials.

[0042] Comparative Example 2

[0043] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of styrene-butadiene rubber used was 30 parts by weight.

[0044] Comparative Example 3

[0045] A polymer mortar repair material was prepared in the same manner as in Example 1, except that epoxy acrylate was not added to the raw materials.

[0046] Comparative Example 4

[0047] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of epoxy acrylate used was 50 parts by weight.

[0048] Comparative Example 5

[0049] The polymer mortar repair material was prepared in the same manner as in Example 1, except that no silica sol-modified acrylate was added to the raw materials.

[0050] Comparative Example 6

[0051] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the amount of silica sol-modified acrylate was 50 parts by weight.

[0052] Comparative Example 7

[0053] A polymer mortar repair material was prepared in the same manner as in Example 1, except that the cement was ordinary Portland cement.

[0054] Performance Testing

[0055] (1) Compressive strength, flexural strength and bonding strength: tested in accordance with DL / T5126-2001 “Test Procedure for Polymer Modified Cement Mortar”.

[0056] (2) Freeze-thaw resistance: Freeze-thaw test is carried out in accordance with GB / T 50082-2009 "Standard for test methods for long-term performance and durability of ordinary concrete".

[0057] The test results are shown in the following table:

[0058]

[0059]

[0060] It can be seen from the above table that the polymer mortar repair material prepared in the embodiment of the present invention has excellent mechanical properties and frost resistance.

[0061] Compared with Comparative Examples 1 and 2, the mechanical properties of Example 1 are improved, indicating the technical contribution made by styrene-butadiene rubber, and the larger the amount of styrene-butadiene rubber added, the better.

[0062] Compared with Comparative Examples 3 and 4, the mechanical properties of the repair material prepared in the embodiment of the present invention are significantly enhanced, and the antifreeze grade can reach F200, indicating the technical contribution made by epoxy acrylate, and excessive epoxy acrylate has an adverse effect on the comprehensive performance of the material.

[0063] It can be seen from Comparative Examples 5 and 6 that silica sol-modified acrylate has a great influence on material properties, and the amount of silica sol-modified acrylate also needs to be strictly controlled.

[0064] Comparison of Comparative Example 7 with Example 1 shows that fly ash cement improves material performance better than ordinary cement, especially the frost resistance grade and artificial weathering performance.

[0065] The invention prepares a polymer mortar repair material with high mechanical properties and good freeze-thaw resistance by reasonably mixing styrene-butadiene rubber, epoxy acrylate and silica sol-modified acrylate with cement mortar and controlling the ratio of each raw material. The polymer mortar repair material is suitable for repairing concrete cracks in cold areas.

[0066] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0067] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A polymer mortar repair material, characterized in that: The invention comprises, by weight, 100 parts of cement, 200-250 parts of sand, 20-30 parts of water, 0.02-0.15 parts of fiber, 0.5-2 parts of white carbon black, 5-8 parts of expansion agent, 0.5-1.2 parts of water reducer, 5-20 parts of styrene-butadiene rubber, 5-20 parts of epoxy acrylate and 10-30 parts of silica sol-modified acrylate; wherein the silica sol-modified acrylate comprises the following raw materials: silica sol, emulsifier, initiator, shell monomer and core monomer; the silica sol is prepared by catalytic hydrolysis of tetraethyl orthosilicate, the emulsifier comprises sodium dodecyl sulfate and polyoxyethylene octylphenyl ether, the initiator is ammonium persulfate, the core monomer comprises butyl acrylate and methyl methacrylate, and the shell monomer is acrylic acid.

2. The polymer mortar repair material according to claim 1, characterized in that: The cement is fly ash cement.

3. The polymer mortar repair material according to claim 1, characterized in that: The fiber is polypropylene fiber, polyvinyl alcohol fiber or carbon fiber.

4. The polymer mortar repair material according to claim 1, characterized in that: The expansion agent is a U-type expansion agent or an AEA expansion agent; the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent.

5. The method for preparing a polymer mortar repair material according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Preparation of epoxy acrylate and silica sol-modified acrylate for standby use; S2. Mix cement, sand, fiber, white carbon, expansion agent and water reducing agent, and stir evenly to obtain a mixture; S3. After adding water and styrene-butadiene rubber to the mixture and mixing thoroughly, epoxy acrylate and silica sol-modified acrylate are added, and stirring is continued to be uniform to obtain the polymer mortar repair material.

6. Use of the polymer mortar repair material according to any one of claims 1 to 4 in treating cracks in concrete slabs of channel lining projects.

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