Green and environment-friendly concrete and preparation method thereof

Abstract

The invention relates to the field of building materials, in particular to green and environment-friendly concrete and a preparation method thereof. The green and environment-friendly concrete is prepared from the following raw materials in parts by mass: 40 to 50 parts of matrix cement, 10 to 15 parts of fly ash, 10 to 15 parts of mineral powder residue soil, 8 to 15 parts of modified resin, 20 to 30 parts of fine aggregate, 30 to 40 parts of natural aggregate, 0.6 to 1 part of water reducing agent, 1 to 2 parts of expanding agent, 0.8 to 1.6 parts of cellulose ether, 10 to 18 parts of filler and 20 to 30 parts of water. The finally prepared green and environment-friendly concrete not only can maintain excellent mechanical properties, but also can maintain good waterproofness, corrosion resistance and durability, and effectively avoids performance fluctuation caused by addition of novel materials; further, the comprehensive performance requirements of the existing building material field on green and environment-friendly concrete are preferably met, and the concrete has very excellent application prospects.

Description

Technical Field

[0001] The present application relates to the field of building materials, and in particular to a green and environmentally friendly concrete and a preparation method thereof. Background Art

[0002] With the improvement of global awareness of environmental protection and the deepening of the concept of sustainable development, the construction industry has gradually transformed towards green and environmentally friendly directions. As one of the most widely used materials in construction projects, the high energy consumption and high carbon emissions in the production process of concrete have attracted increasing attention. Traditional concrete is mainly made of cement, aggregates (such as sand and gravel) and water. The production process of cement releases a large amount of carbon dioxide, which is one of the important reasons for the greenhouse effect. Therefore, the research and development of green and environmentally friendly concrete has become an important measure for the construction industry to reduce environmental impact.

[0003] Green concrete refers to concrete that uses new cementitious materials, adds industrial waste or natural mineral admixtures, uses high-efficiency water-reducing agents, and optimizes mix design, while ensuring basic properties such as strength and durability. This reduces cement usage, energy consumption, and CO 2 A new type of concrete material for the purpose of reducing emissions and improving resource utilization. It not only helps to alleviate the problem of resource shortage, but also effectively reduces environmental pollution during construction.

[0004] Although the research and development and application of green and environmentally friendly concrete have made certain progress, there are still some technical problems that need to be solved urgently. For example, some green and environmentally friendly concretes show large performance fluctuations in different environments, making it difficult to ensure long-term stable structural safety and durability; when new alternative materials are introduced, incompatibility with the original materials may occur, affecting the overall performance of the concrete, such as waterproofing and mechanical properties; performance verification is missing. Although some green and environmentally friendly concretes can show good performance in the initial stage, they lack performance verification in long-term use environments, such as corrosion resistance and weather resistance.

[0005] Therefore, in order to effectively solve the above problems, the present application provides a green and environmentally friendly concrete and a preparation method thereof. The green and environmentally friendly concrete finally obtained can not only maintain excellent mechanical properties, but also maintain good waterproofness, corrosion resistance and durability at the same time, effectively avoiding the performance fluctuations caused by the addition of new materials, and thus giving priority to meeting the comprehensive performance requirements of green and environmentally friendly concrete in the existing building materials field, and has very excellent application prospects. Summary of the invention

[0006] In order to solve the above problems, the first aspect of the present application provides a green and environmentally friendly concrete. The raw materials, measured by mass, are: 40 to 50 parts of matrix cement, 10 to 15 parts of fly ash, 10 to 15 parts of mineral powder slag, 8 to 15 parts of modified resin, 20 to 30 parts of fine aggregate, 30 to 40 parts of natural aggregate, 0.6 to 1 part of water reducer, 1 to 2 parts of expansion agent, 0.8 to 1.6 parts of cellulose ether, 10 to 18 parts of filler, and 20 to 30 parts of water.

[0007] As a preferred solution, the mass ratio of the matrix cement, fly ash and mineral powder slag is (42-48): (11-14): (13-15).

[0008] As a preferred solution, the mass ratio of the matrix cement, fly ash and mineral powder slag is (43-46): (12-13): (13-14).

[0009] As a preferred solution, the mass ratio of the matrix cement, the modified resin and the filler is (42-48): (9-13): (12-16).

[0010] As a preferred solution, the mass ratio of the matrix cement, the modified resin and the filler is (43-46): (10-12): (13-15).

[0011] As a preferred solution, the matrix cement is ordinary Portland cement.

[0012] As a preferred solution, the strength grade of the ordinary Portland cement is 32.5, 42.5 or 42.5R.

[0013] As a preferred solution, the fly ash is Class F fly ash or Class C fly ash.

[0014] As a preferred solution, the fly ash is Class F fly ash.

[0015] As a preferred solution, the mineral powder slag is blast furnace slag powder.

[0016] As a preferred solution, the blast furnace slag powder is S95 grade granulated blast furnace slag powder or G grade granulated blast furnace slag powder.

[0017] As a preferred solution, the preparation method of the modified resin specifically includes the following steps: S1: adding maleic anhydride, vinyl cyclohexene glycol diglycidyl ether and isooctyl acrylate to an acryloyl chloride solution, introducing nitrogen and adding an initiator, heating to 80-90°C for reaction for 3-5h to obtain a prepolymer; S2: mixing the prepolymer, pentaerythritol triacrylate and N,N'-methylenebisacrylamide and adding them to deionized water, adding the initiator for a second time and mixing, reacting for 6-8h under nitrogen environment protection to obtain a modified product solution; S3: after the reaction is completed, adding sodium hydroxide to adjust the pH value to 7-7.5, then cooling to 45-50°C, adding triethanolamine and stirring at 60-80rpm for 30-40min, then naturally cooling to room temperature, sieving the product through 500-600 mesh to remove large particles, and sealing and storing for standby use.

[0018] As a preferred solution, the mass ratio of maleic anhydride, vinyl cyclohexene glycol diglycidyl ether and isooctyl acrylate is (4-5): (2-2.5): (6-8).

[0019] As a preferred solution, the mass ratio of the prepolymer, pentaerythritol triacrylate and N,N'-methylenebisacrylamide is (8-10):(1-1.5):(18-22).

[0020] As a preferred solution, the mass ratio of the prepolymer to triethanolamine is (8-10):(1.5-2).

[0021] In this application, the modified resin and filler added together can greatly improve the mechanical properties of concrete while protecting excellent weather resistance, waterproof and corrosion resistance, and avoid the incompatibility caused by the addition of too many particle raw materials, which in turn causes performance fluctuations. The dense cross-linked network of the added modified resin itself can serve as an excellent bonding medium in the concrete system, thereby enhancing the aggregation and mutual adhesion of the internal particles, thereby increasing the internal strength.

[0022] On the other hand, the presence of modified resin can play a good guiding and extending role on cement particles in the system through its long molecular chain and multiple segments, thereby avoiding premature and excessive aggregation of internal cement particles, increasing the comprehensive dispersion uniformity of the system, and thus providing a basis for improving the waterproof, weather-resistant and self-stability properties of cement. The softer segments can play a flexible connecting role in the concrete system, so that they can play a good sliding role when external forces act, avoiding mutual slippage caused by external forces, thereby greatly improving the mechanical properties of concrete and avoiding the formation of large cracks, thereby reducing the feasibility of water intrusion and penetration.

[0023] Finally, the combined effect of modified resin and modified fiber filler, through the grafting modification of the modified fiber surface, greatly improves the connection stability with the system, thereby avoiding the poor compatibility previously caused by the separate addition, which in turn greatly reduces the various properties of concrete.

[0024] As a preferred solution, the fine aggregate is river sand or quartz sand.

[0025] As a preferred solution, the fine aggregate is quartz sand.

[0026] As a preferred solution, the average particle size of the fine aggregate is 4.75-9.5 mm.

[0027] As a preferred solution, the natural aggregate is crushed stone or gravel.

[0028] As a preferred solution, the natural aggregate is crushed stone.

[0029] As a preferred solution, the average particle size of the recycled aggregate is 24 to 31.5 mm.

[0030] As a preferred solution, the water reducer is a naphthalene-based water reducer or a polycarboxylic acid water reducer.

[0031] As a preferred solution, the water reducer is a polycarboxylate water reducer.

[0032] As a preferred solution, the expansion agent is a combination of calcium sulphoaluminate and magnesium oxide.

[0033] As a preferred solution, the mass ratio of calcium sulfoaluminate to magnesium oxide is (3.5-5):(1.2-2).

[0034] As a preferred solution, the mass ratio of calcium sulfoaluminate to magnesium oxide is (4-4.5):(1.4-1.8).

[0035] As a preferred solution, the cellulose ether is a combination of hydroxypropyl methylcellulose and carboxymethyl cellulose.

[0036] As a preferred solution, the mass ratio of hydroxypropyl methylcellulose to carboxymethyl cellulose is (3.2-4): (1.2-1.5).

[0037] As a preferred solution, the filler is modified fiber.

[0038] As a preferred scheme, the preparation method of the modified fiber specifically includes the following steps: S1: After washing the chopped carbon fiber with ethanol, vacuum drying it at 120-125°C for 10-12h, and then adding DMF, dried chopped carbon fiber, glycidyl methacrylate, maleic anhydride and diisopropylbenzene peroxide to the reaction container in sequence under nitrogen protection; S2: heating to 80-90°C, maintaining a speed of 250-400rpm for insulation reaction for 3-4h, after the reaction is completed, filtering and washing the product, and washing the unreacted monomer with DMF; S3: washing the product with ethanol several times to remove residual DMF and other impurities, and finally vacuum drying it at 70-80°C for 16-20h, and the product is obtained after completion.

[0039] As a preferred solution, the mass ratio of the chopped carbon fibers, glycidyl methacrylate, maleic anhydride and dicumyl peroxide is (8-10): (1.5-2): (0.6-0.8): (0.1-0.15).

[0040] As a preferred solution, the average diameter of the chopped carbon fibers is 6 to 8 μm, and the average length is 5 to 8 mm.

[0041] The second aspect of the present application provides a method for preparing the above-mentioned green environmentally friendly concrete, which specifically includes the following steps: S1: adding matrix cement, fly ash, mineral powder slag and expansion agent into a mixer for dry mixing for 20 to 25 minutes to ensure that these powdered materials are evenly distributed; S2: slowly adding water and water reducer, stirring continuously at 60 to 80 rpm for 10 to 15 minutes, and then adding fine aggregate, natural aggregate, modified resin and filler in turn, and continuing to stir for 5 to 10 minutes each time; S3: adding the remaining raw materials and continuing to stir for 3 to 8 minutes until the entire mixture is in a uniform state, and finally quickly transporting the mixed concrete to the pouring site, and making it dense and formed by appropriate vibration methods, and immediately starting curing after the pouring is completed, using standard curing conditions, and the concrete is ready.

[0042] The beneficial effects of this application are:

[0043] 1. The green and environmentally friendly concrete provided in the present application not only maintains excellent mechanical properties, but also maintains good waterproofness, corrosion resistance and durability, effectively avoiding performance fluctuations caused by the addition of new materials, and thus giving priority to meeting the comprehensive performance requirements of green and environmentally friendly concrete in the existing building materials field, and has very excellent application prospects.

[0044] 2. The green environmentally friendly concrete provided in the present application, the modified resin and filler added thereto can significantly improve the mechanical properties of the concrete while protecting the excellent weather resistance, waterproof and corrosion resistance, and avoid the incompatibility caused by the addition of too many particle raw materials, which in turn causes performance fluctuations. The dense cross-linked network of the added modified resin itself can serve as an excellent bonding medium in the concrete system, thereby enhancing the aggregation and mutual adhesion of the internal particles, thereby increasing the internal strength.

[0045] 3. In the green and environmentally friendly concrete provided in the present application, the modified resin can play a good guiding and extending role on the cement particles in the system through its long molecular chain and multiple segments, thereby avoiding the premature and excessive aggregation of internal cement particles, increasing the comprehensive dispersion uniformity of the system, and further providing a basis for improving the waterproof, weather-resistant and self-stability properties of cement. The softer segments can play a flexible connecting role in the concrete system, so that they can play a good sliding role when external forces act, avoiding the mutual slippage caused by external forces, thereby greatly improving the mechanical properties of the concrete, and avoiding the formation of large cracks, thereby reducing the feasibility of water intrusion and penetration. DETAILED DESCRIPTION

[0046] The following will further explain and demonstrate the technical solutions in the above invention content of this application in the form of specific implementation schemes. The following embodiments are only practical examples used to illustrate and explain the contents of the technical solutions in the specification, and should not limit the scope of the claims to be protected by this application. All technical products based on the technical solutions described in the invention content of this application should be included in the scope to be protected by this application.

[0047] In the following examples, unless otherwise specified, the raw materials are all commercially available products, or can be prepared by methods well known to those skilled in the art.

[0048] Example 1

[0049] Example 1 The first aspect provides a green and environmentally friendly concrete, in which the raw materials are, by mass: 44.5 parts of matrix cement, 12.6 parts of fly ash, 13.8 parts of mineral powder slag, 11.8 parts of modified resin, 22 parts of fine aggregate, 35.5 parts of natural aggregate, 0.8 parts of water reducer, 1.6 parts of expansion agent, 1.2 parts of cellulose ether, 14.2 parts of filler, and 22.5 parts of water.

[0050] The matrix cement is ordinary Portland cement with a strength grade of 42.5.

[0051] The fly ash is Class F fly ash, purchased from Zhenjiang Power Generation Co., Ltd.

[0052] The slag powder is S95 grade granulated blast furnace slag powder.

[0053] The preparation method of the modified resin specifically includes the following steps, calculated by mass: S1: adding 4.6 parts of maleic anhydride, 2.2 parts of vinyl cyclohexene glycol diglycidyl ether and 6.8 parts of isooctyl acrylate to 40 parts of acryloyl chloride solution, introducing nitrogen and adding 0.11 parts of potassium persulfate, heating to 85°C for reaction for 4 hours to obtain a prepolymer; S2: adding 9.2 parts of prepolymer, 1.3 parts of pentaerythritol triacrylate and 22 parts of N,N'-methylenebisacrylamide to 250 parts of deionized water, adding 0.21 parts of potassium persulfate for a second time, reacting for 7 hours under nitrogen environment protection to obtain a modified product solution; S3: after the reaction is completed, adding sodium hydroxide to adjust the pH value to 7.5, then cooling to 50°C, adding 1.8 parts of triethanolamine and stirring at 80rpm for 30 minutes, then naturally cooling to room temperature, sieving the product through 550 mesh to remove large particles, and sealing and storing for standby use.

[0054] The fine aggregate is quartz sand with an average particle size of 5.5 mm.

[0055] The natural aggregate is crushed stone with an average particle size of 26.8 mm.

[0056] The water reducer was a polycarboxylate water reducer, purchased from the QSC product sold by Wuhan Runxingyuan Technology Co., Ltd., China.

[0057] The expansion agent is a composition of calcium sulphoaluminate and magnesium oxide, and the mass ratio of the two is 4.2:1.5.

[0058] The cellulose ether is a composition of hydroxypropyl methylcellulose and carboxymethyl cellulose, and the mass ratio of the two is 3.6:1.4.

[0059] The filler is modified fiber; the preparation method of the modified fiber specifically includes the following steps, calculated by mass: S1: After washing the chopped carbon fiber with ethanol, vacuum dry it at 120°C for 12 hours, and then add 120 parts of DMF, 8.8 parts of dried chopped carbon fiber, 1.8 parts of glycidyl methacrylate, 0.68 parts of maleic anhydride and 0.12 parts of diisopropylbenzene peroxide to the reaction container in sequence under nitrogen protection; S2: heat to 85°C, maintain a speed of 300rpm for insulation reaction for 3.5 hours, after the reaction is completed, filter and wash the product, and use DMF to wash away unreacted monomers; S3: wash the product with ethanol several times to remove residual DMF and other impurities, and finally vacuum dry it at 75°C for 18 hours, and it is obtained after completion.

[0060] The chopped carbon fibers had an average diameter of 7 μm and an average length of 6.5 mm, and were purchased from Shanghai Lishuo Composite Materials Technology Co., Ltd., China.

[0061] The second aspect of the present embodiment provides a method for preparing the above-mentioned green environmentally friendly concrete, which specifically includes the following steps: S1: adding matrix cement, fly ash, mineral powder slag and expansion agent into a mixer for dry mixing for 25 minutes to ensure that these powdered materials are evenly distributed; S2: slowly adding water and water reducer, stirring continuously at 80rpm for 12 minutes, and then adding fine aggregate, natural aggregate, modified resin and filler in turn, and stirring continuously for 8 minutes each time; S3: adding the remaining raw materials and continuing to stir for 6 minutes until the entire mixture is in a uniform state, and finally quickly transporting the mixed concrete to the pouring site, and making it dense and formed by appropriate vibration methods, and immediately starting curing after the pouring is completed, using standard curing conditions, and the concrete is completed.

[0062] Example 2

[0063] The specific implementation of this embodiment is basically the same as that of Example 1, except that: the raw materials of the green environmentally friendly concrete, by weight, are: 48 parts of matrix cement, 11.2 parts of fly ash, 14.8 parts of mineral powder slag, 9.2 parts of modified resin, 24 parts of fine aggregate, 32.6 parts of natural aggregate, 0.8 parts of water reducer, 1.6 parts of expansion agent, 1.2 parts of cellulose ether, 15.5 parts of filler, and 24.6 parts of water.

[0064] The expansion agent is a composition of calcium sulphoaluminate and magnesium oxide, and the mass ratio of the two is 5:1.2.

[0065] The cellulose ether is a composition of hydroxypropyl methylcellulose and carboxymethyl cellulose, and the mass ratio of the two is 3.2:1.5.

[0066] Example 3

[0067] The specific implementation of this embodiment is basically the same as that of Example 1, except that: the raw materials of the green environmentally friendly concrete, by weight, are: 42 parts of matrix cement, 13.8 parts of fly ash, 13.1 parts of mineral powder slag, 13 parts of modified resin, 26 parts of fine aggregate, 31.5 parts of natural aggregate, 0.9 parts of water reducer, 1.4 parts of expansion agent, 1.4 parts of cellulose ether, 12.2 parts of filler, and 21.4 parts of water.

[0068] The expansion agent is a composition of calcium sulphoaluminate and magnesium oxide, and the mass ratio of the two is 3.5:2.

[0069] The cellulose ether is a composition of hydroxypropyl methylcellulose and carboxymethyl cellulose, and the mass ratio of the two is 4:1.2.

[0070] Comparative Example 1

[0071] The specific implementation method of this comparative example is basically the same as that of Example 1, except that: the raw materials of the green environmentally friendly concrete, by weight, are: 44.5 parts of matrix cement, 12.6 parts of fly ash, 13.8 parts of mineral powder slag, 5.5 parts of modified resin, 22 parts of fine aggregate, 35.5 parts of natural aggregate, 0.8 parts of water reducer, 1.6 parts of expansion agent, 1.2 parts of cellulose ether, 18.8 parts of filler, and 22.5 parts of water.

[0072] Comparative Example 2

[0073] The specific implementation method of this comparative example is basically the same as that of Example 1, except that: the raw materials of the green environmentally friendly concrete, by weight, are: 55 parts of matrix cement, 12.6 parts of fly ash, 13.8 parts of mineral powder slag, 11.8 parts of modified resin, 22 parts of fine aggregate, 35.5 parts of natural aggregate, 0.8 parts of water reducer, 1.6 parts of expansion agent, 1.2 parts of cellulose ether, 4.2 parts of filler, and 22.5 parts of water.

[0074] Comparative Example 3

[0075] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified resin specifically includes the following steps, calculated by mass: S1: adding 3.5 parts of glycidyl methacrylate and 5.2 parts of butyl acrylate to 40 parts of acryloyl chloride solution, introducing nitrogen and adding 0.11 parts of potassium persulfate, heating to 85°C for reaction for 4 hours to obtain a prepolymer; S2: adding 9.2 parts of prepolymer and 32.5 parts of acrylamide to 250 parts of deionized water, adding 0.21 parts of potassium persulfate for a second time, reacting for 7 hours under nitrogen environment protection to obtain a modified product solution; S3: after the reaction is completed, adding sodium hydroxide to adjust the pH value to 7.5, then cooling to 50°C, adding 1.8 parts of triethanolamine and stirring at 80rpm for 30min, then naturally cooling to room temperature, sieving the product through 550 mesh to remove large particles, and sealing and storing for standby use.

[0076] Comparative Example 4

[0077] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified resin specifically includes the following steps, calculated by mass: S1: adding 10.5 parts of maleic anhydride, 0.5 parts of vinyl cyclohexene glycol diglycidyl ether and 2.5 parts of isooctyl acrylate to 40 parts of acryloyl chloride solution, introducing nitrogen and adding 0.11 parts of potassium persulfate, heating to 85°C and reacting for 4 hours to obtain a prepolymer; S2: adding 9.2 parts of the prepolymer, 1.3 parts of pentaerythritol tetrachloride and 1.5 parts of isooctyl acrylate to 40 parts of acryloyl chloride solution, introducing nitrogen and adding 0.11 parts of potassium persulfate, heating to 85°C and reacting for 4 hours to obtain a prepolymer; Alcohol triacrylate and 22 parts of N,N'-methylenebisacrylamide are mixed and added to 250 parts of deionized water, and 0.21 parts of potassium persulfate are added twice, and the mixture is reacted for 7 hours under nitrogen environment protection to obtain a modified product solution; S3: After the reaction is completed, sodium hydroxide is added to adjust the pH value to 7.5, and then the temperature is lowered to 50°C, 1.8 parts of triethanolamine are added, and the mixture is stirred at 80rpm for 30 minutes, and then the mixture is naturally cooled to room temperature. The product is sieved through 550 mesh to remove large particles, and sealed and stored for later use.

[0078] Comparative Example 5

[0079] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified resin specifically comprises the following steps, calculated by mass: S1: adding 4.6 parts of maleic anhydride, 2.2 parts of vinyl cyclohexene glycol diglycidyl ether and 6.8 parts of isooctyl acrylate to 40 parts of acryloyl chloride solution, introducing nitrogen and adding 0.11 parts of potassium persulfate, heating to 85°C and reacting for 4 hours to obtain a prepolymer; S2: adding 15.5 parts of the prepolymer, 0.4 parts of pentaerythritol Triacrylate and 10.5 parts of N,N'-methylenebisacrylamide were mixed and added to 250 parts of deionized water, and 0.21 parts of potassium persulfate were added for a second time, and the mixture was reacted for 7 hours under nitrogen environment protection to obtain a modified product solution; S3: After the reaction was completed, sodium hydroxide was added to adjust the pH value to 7.5, and then the temperature was lowered to 50°C, 1.8 parts of triethanolamine was added, and the mixture was stirred at 80 rpm for 30 minutes, and then the mixture was naturally cooled to room temperature. The product was sieved through 550 mesh to remove large particles, and sealed and stored for later use.

[0080] Comparative Example 6

[0081] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified fiber specifically includes the following steps, calculated by mass: S1: After washing the chopped carbon fiber with ethanol, vacuum drying it at 120°C for 12 hours, and then under nitrogen protection, 120 parts of DMF, 12.5 parts of dried chopped carbon fiber, 0.6 parts of glycidyl methacrylate, 0.4 parts of maleic anhydride and 0.11 parts of diisopropylbenzene peroxide are added to the reaction container in sequence; S2: heating to 85°C, maintaining a speed of 300rpm for insulation reaction for 3.5 hours, after the reaction is completed, filtering and washing the product, and washing away the unreacted monomer with DMF; S3: washing the product with ethanol several times to remove residual DMF and other impurities, and finally vacuum drying it at 75°C for 18 hours, and the product is obtained after completion.

[0082] Comparative Example 7

[0083] The specific implementation of this comparative example is basically the same as that of Example 1, except that: the preparation method of the modified fiber specifically includes the following steps, calculated by mass: S1: After washing the chopped carbon fiber with ethanol, vacuum drying it at 120°C for 12 hours, and then, under nitrogen protection, adding 120 parts of DMF, 5.5 parts of dried chopped carbon fiber, 2.6 parts of glycidyl methacrylate, 1.2 parts of maleic anhydride and 0.12 parts of diisopropylbenzene peroxide to the reaction container in sequence; S2: heating to 85°C, maintaining a speed of 300 rpm for insulation reaction for 3.5 hours, after the reaction is completed, filtering and washing the product, and washing the unreacted monomer with DMF; S3: washing the product with ethanol several times to remove residual DMF and other impurities, and finally vacuum drying it at 75°C for 18 hours, and obtaining the product after completion.

[0084] Performance Evaluation

[0085] Waterproof and anti-penetration pressure: The concrete of the embodiment and the comparative example was tested for anti-penetration pressure with reference to the standard GB / T 50082-2009. The results were expressed as the maximum no-seepage pressure at 28 days. The test value was the average of 10 tests and recorded in Table 1.

[0086] Mechanical strength: The mechanical strength of the concrete obtained in the embodiment and the comparative example after curing was tested with reference to the standard GB / T 50081-2019, and the test value was the average value of 10 tests and recorded in Table 1.

[0087] Salt spray corrosion resistance: The concrete prepared in the examples and comparative examples was made into samples of 10 cm × 5 cm × 2 cm, and the samples were sprayed with 10 wt% NaCl at a rate of 2 mL / h·cm 2The test environment is 65±3℃ and 80±2% relative humidity. The aging corrosion of the test samples after 3 months is tested. If the sample bricks have inward concave corrosion, cracks and damage after 3 months, they are recorded as unqualified, otherwise they are qualified. 50 samples are tested in each group, and the qualified rate results are recorded in Table 1.

[0088] Table 1 Performance test results

[0089]

[0090] It can be seen from the examples and comparative examples of the present application and the data results in Table 1 that examples 1 to 3 of the present application have obvious advantages over comparative examples 1 to 7 in terms of mechanical properties, waterproof properties, weather resistance and corrosion resistance. This is mainly due to the combined effect of the modified resin, modified fiber filler and other matching schemes specified in the present application, while comparative examples 1 to 7 do not use suitable modified resins or suitable modified resin preparation methods. Similarly, modified fibers will not be able to effectively guide cement particles, resulting in premature cement aggregation and agglomeration, and the modified fibers will not be able to form a strong mutual adhesion with the modified resin, thereby weakening its uniform dispersion effect in the system, and failing to assist the modified resin in achieving a stable construction of an internal cross-linked network system, thereby greatly reducing the various properties of the concrete.

Claims

1. A green and environmentally friendly concrete, characterized by: Green environmentally friendly concrete, calculated by weight, has the following raw materials: 40-50 parts of matrix cement, 10-15 parts of fly ash, 10-15 parts of mineral powder slag, 8-15 parts of modified resin, 20-30 parts of fine aggregate, 30-40 parts of natural aggregate, 0.6-1 part of water reducing agent, 1-2 parts of expansion agent, 0.8-1.6 parts of cellulose ether, 10-18 parts of filler, and 20-30 parts of water; The matrix cement is ordinary Portland cement; the strength grade of the ordinary Portland cement is 32.5, 42.5 or 42.5R; The fly ash is Class F fly ash or Class C fly ash; The preparation method of the modified resin specifically comprises the following steps: S1: adding maleic anhydride, vinyl cyclohexene glycol diglycidyl ether and isooctyl acrylate to an acryloyl chloride solution, introducing nitrogen and adding an initiator, heating to 80-90° C. for reaction for 3-5 hours to obtain a prepolymer; S2: mixing the prepolymer, pentaerythritol triacrylate and N,N'-methylenebisacrylamide and adding them to deionized water, adding the initiator for a second time, and reacting for 6-8 hours under nitrogen environment protection to obtain a modified product solution; S3: after the reaction is completed, adding sodium hydroxide to adjust the pH value to 7-7.5, then cooling to 45-50° C., adding triethanolamine and stirring at 60-80 rpm for 30-40 minutes, then naturally cooling to room temperature, sieving the product through 500-600 mesh to remove large particles, and sealing and storing for standby use; The mass ratio of maleic anhydride, vinyl cyclohexene glycol diglycidyl ether and isooctyl acrylate is (4-5): (2-2.5): (6-8); The mass ratio of the prepolymer, pentaerythritol triacrylate and N,N'-methylenebisacrylamide is (8-10): (1-1.5): (18-22); The mass ratio of the prepolymer to triethanolamine is (8-10):(1.5-2).

2. The green environmentally friendly concrete according to claim 1 is characterized in that: The mass ratio of the matrix cement, fly ash and mineral powder slag is (42-48): (11-14): (13-15).

3. The green environmentally friendly concrete according to claim 2 is characterized in that: The mass ratio of the matrix cement, the modified resin and the filler is (42-48): (9-13): (12-16).

4. The green environmentally friendly concrete according to claim 3 is characterized by: The fine aggregate is river sand or quartz sand; the average particle size of the fine aggregate is 4.75-9.5 mm.

5. The green environmentally friendly concrete according to claim 4 is characterized in that: The natural aggregate is crushed stone or gravel; the average particle size of the recycled aggregate is 24 to 31.5 mm.

6. The green environmentally friendly concrete according to claim 5 is characterized in that: The water reducer is a naphthalene-based water reducer or a polycarboxylic acid water reducer.

7. The green environmentally friendly concrete according to claim 6 is characterized in that: The expansion agent is a composition of calcium sulfoaluminate and magnesium oxide; the mass ratio of calcium sulfoaluminate to magnesium oxide is (3.5-5): (1.2-2).

8. The green environmentally friendly concrete according to claim 7 is characterized in that: The cellulose ether is a composition of hydroxypropyl methylcellulose and carboxymethyl cellulose; the mass ratio of the hydroxypropyl methylcellulose to the carboxymethyl cellulose is (3.2-4): (1.2-1.5).

9. The green environmentally friendly concrete according to claim 8, characterized in that: The filler is modified fiber; The preparation method of the modified fiber specifically comprises the following steps: S1: after washing the short carbon fiber with ethanol, vacuum drying it at 120-125° C. for 10-12 hours, then under nitrogen protection, sequentially adding DMF, the dried short carbon fiber, glycidyl methacrylate, maleic anhydride and diisopropylbenzene peroxide into the reaction container; S2: heating to 80-90° C., maintaining the speed of 250-400 rpm for insulation reaction for 3-4 hours, after the reaction is completed, filtering and washing the product, and washing the unreacted monomer with DMF; S3: washing the product with ethanol several times to remove the residual DMF and other impurities, and finally vacuum drying it at 70-80° C. for 16-20 hours, and obtaining the modified fiber after completion; The mass ratio of the chopped carbon fiber, glycidyl methacrylate, maleic anhydride and dicumyl peroxide is (8-10): (1.5-2): (0.6-0.8): (0.1-0.15); The average diameter of the chopped carbon fibers is 6 to 8 μm, and the average length is 5 to 8 mm.

10. A method for preparing green environmentally friendly concrete according to any one of claims 1 to 9, characterized in that: The specific steps include: S1: Add matrix cement, fly ash, mineral powder slag and expansion agent into a mixer for dry mixing for 20 to 25 minutes to ensure that these powdered materials are evenly distributed; S2: Slowly add water and water reducer, stir continuously at 60 to 80 rpm for 10 to 15 minutes, then add fine aggregate, natural aggregate, modified resin and filler in turn, stirring for 5 to 10 minutes each time; S3: Add the remaining raw materials and continue stirring for 3 to 8 minutes until the entire mixture is in a uniform state. Finally, quickly transport the mixed concrete to the pouring site and make it dense and formed by appropriate vibration methods. After pouring, start curing immediately, using standard curing conditions, and the concrete is ready.

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