Environmentally friendly adhesive reducing agent for concrete and preparation method thereof

Abstract

The invention discloses a preparation method of an environmentally friendly gel reducer for concrete, which comprises, by 100% by mass, 15-40% of a reinforcing component, 10-25% of a dispersing component, 5-15% of a cationic polymer, 1-5% of a modified carboxymethyl hydroxyethyl cellulose and the balance of water. The invention provides a gel reducer and a preparation method thereof, which are added to concrete, and compared with blank concrete, the initial expansion of the concrete is substantially not reduced, the slump loss has little effect, the workability of the concrete can be significantly improved, and the early and late strengths of the concrete are improved.

Description

Technical Field

[0001] The invention belongs to the field of concrete admixtures, and in particular relates to an environmentally friendly gel reducing agent for concrete and a preparation method thereof. Background Art

[0002] Cement, as the main binder in concrete, is one of the indispensable components for preparing concrete. However, the cement production process has problems of high energy consumption, high pollution and high carbon emissions. Therefore, on the premise of ensuring various performance indicators, the amount of cement should be reduced as much as possible, or measures should be taken to use more industrial waste slag to replace part of the cement.

[0003] Water reducers can destroy the flocs produced during the hydration process, releasing some of the water that cannot react with the cementitious materials. Under the condition that the concrete maintains its original strength, it can reduce the amount of water used, improve the workability, strength and construction speed of the concrete. However, water reducers have limitations in destroying the floc structure. Since commonly used water reducers are composed of macromolecular polymers, they can only adsorb larger cement particles and destroy them through electrostatic repulsion. For some smaller cement particle aggregates, macromolecular water reducers will adsorb the entire aggregate and cannot destroy its floc structure, resulting in more cement particles being unable to be effectively hydrated, which is not conducive to improving the strength and other properties of the concrete. If the amount of cementitious materials used is further reduced by increasing the amount of water reducers, problems such as water seepage and segregation will often occur, and even lead to engineering accidents.

[0004] Concrete glue reducer, also known as concrete enhancer / concrete strengthener, is a concrete admixture different from concrete water reducer. Its main function is to better improve the performance of concrete, increase the utilization rate of cement materials in concrete, thereby reducing the amount of cement, and ensure the later strength development of concrete. It is also beneficial to the long-term durability of concrete. On the basis of adding water reducer, concrete glue reducer can better exert its glue reducing performance.

[0005] However, the common glue reducer products on the market currently have the following main problems: on the one hand, the products are uneven, and the product performance often fails to achieve the expected purpose. There are problems such as poor concrete workability and low early or late compressive strength, which have a serious impact on the workability, longevity and durability of concrete; on the other hand, the glue reducer has poor adaptability to materials and has high requirements for cement varieties; in addition, some glue reducers have complex preparation processes, and the raw materials used are not environmentally friendly and have safety hazards. The above problems have led to great limitations in the use and promotion of existing glue reducer products. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing an environmentally friendly adhesive reducer for concrete.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing an environmentally friendly adhesive reducer for concrete, comprising:

[0010] The triisopropanolamine and maleic anhydride are mixed, and p-toluenesulfonic acid accounting for 2-4 wt% of the mixture is added, and the temperature is raised to 110-120° C. for reaction for 4-6 hours, and the modified triisopropanolamine is obtained after cooling.

[0011] Slowly add acrylic acid dropwise to N, N-dimethylisopropanolamine under stirring conditions, continue stirring and reacting for 30-40 minutes after the addition is completed, and dilute to a solution with a mass concentration of 50% after cooling to obtain modified N, N-dimethylisopropanolamine;

[0012] Sodium α-olefin sulfonate, 2-acrylamido-2-methylpropane sulfonic acid and deionized water were added to the reactor, and nitrogen was passed through to deoxygenate for 10-20 minutes, and then the temperature was raised to 60-90°C, and an aqueous ammonium persulfate solution and methacrylic acid were added, and the reaction was continued for 1-2 hours, and then the temperature was lowered to room temperature to obtain dispersant A;

[0013] N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine are mixed to obtain a reinforcing component;

[0014] Mixing ethylenediaminetetramethylenephosphonic acid and dispersant A uniformly to obtain a dispersed component;

[0015] The reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are mixed and stirred uniformly to obtain a gelling agent.

[0016] As a preferred embodiment of the preparation method of the present invention, wherein: triisopropanolamine and maleic anhydride are mixed, wherein the molar ratio of triisopropanolamine to maleic anhydride is 0.8-1:1.

[0017] As a preferred embodiment of the preparation method of the present invention, acrylic acid is slowly added dropwise to N,N-dimethylisopropanolamine under stirring, wherein the mass ratio of acrylic acid to N,N-dimethylisopropanol is 0.8-1:1-1.2.

[0018] As a preferred embodiment of the preparation method of the present invention, the molar ratio of methacrylic acid to sodium α-olefin sulfonate is 2:0.8-1;

[0019] 2-Acrylamido-2-methylpropanesulfonic acid accounts for 1-2% of the total mass of methacrylic acid and sodium α-olefin sulfonate;

[0020] Ammonium persulfate accounts for 2-3% of the total mass of methacrylic acid and sodium α-olefin sulfonate;

[0021] Deionized water accounts for 2 to 3 times the total mass of the reactants.

[0022] As a preferred embodiment of the preparation method of the present invention, in the reinforcing component, the mass ratio of N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine is 1:1~3:2~5:1.

[0023] As a preferred embodiment of the preparation method of the present invention, the mass ratio of the dispersed component, wherein ethylenediaminetetramethylenephosphonic acid and dispersant A is 1:3-8.

[0024] As a preferred embodiment of the preparation method of the present invention, the preparation method of the cationic polymer comprises:

[0025] 12% methacrylamide, 3% bis(trimethylsilyl) vinyl phosphate, 2% crotonic anhydride, 7% sodium hypophosphite monohydrate and 22% water were added to a reaction kettle and stirred to dissolve;

[0026] Measure the temperature in the kettle and control it at 12°C. After the temperature stabilizes, add 2.8% ammonium persulfate at one time.

[0027] 5 minutes after adding ammonium persulfate, 8% solution A and 10% solution B were added dropwise in sequence. After solution A was added, solution B was added dropwise within 10 minutes. The addition time of solution B was 1.7 hours and the addition time of solution A was 2.2 hours.

[0028] Wherein, solution A is composed of thioglycolic acid and water in a mass ratio of 1:14, and solution B is composed of methacryloyloxyethyl trimethylammonium chloride, hydroxyethyl dimethacrylate of phthalic anhydride and water in a mass ratio of 7:4:14;

[0029] After the addition is completed, 1.4% sodium metabisulfite is added at one time, and the mixture is aged for 1 hour. After aging, the mixture is cooled. When the temperature of the reaction solution is lower than 30°C, 10% of a 30% sodium hydroxide solution is slowly added. The mixture is filled with water to 100% by mass and stirred evenly to obtain a cationic polymer.

[0030] As a preferred embodiment of the preparation method of the present invention, the preparation method of the modified carboxymethyl hydroxyethyl cellulose comprises:

[0031] Dissolve carboxymethyl hydroxyethyl cellulose in ethanol, add 37% mass concentration hydrochloric acid under stirring, heat to 75°C, react for 4 hours, add hexane until no solid precipitates, filter and dry to obtain small molecule carboxymethyl hydroxyethyl cellulose with a number average molecular weight of 12000; wherein, the mass ratio of carboxymethyl hydroxyethyl cellulose, ethanol and 37% mass concentration hydrochloric acid aqueous solution is 1:5:0.5, the number average molecular weight of carboxymethyl hydroxyethyl cellulose is 100000, the degree of substitution of carboxymethyl is 0.7, and the degree of substitution of hydroxyethyl is 1.2;

[0032] By weight, 8 parts of small molecule carboxymethyl hydroxyethyl cellulose were dissolved in 60 parts of N, N-dimethylformamide, stirred evenly, heated to 110°C, and then 10 parts of hexamethyldisilazane, 10 parts of water and 0.2 parts of phosphoric acid were added dropwise, reacted for 8 hours, and filtered to obtain a crude product;

[0033] The crude product is dispersed in acetone, filtered, added with distilled water, filtered, and dried to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose;

[0034] By weight, 8 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose and 80 parts of xylene were mixed, heated to 80°C, stirred for reaction for 1.5 hours, 10 parts of ε-caprolactone and stannous octoate were added, and the mixture was heated to 120°C and reacted for 14 hours to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone grafted product;

[0035] Wherein, the amount of stannous octoate added is 2wt% of trimethylsilyl carboxymethyl hydroxyethyl cellulose;

[0036] 5 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone grafted product were added to a mixed solution of 25 parts of isopropanol and 25 parts of 2% mass concentration of hydrochloric acid, stirred evenly, heated to 75°C and reacted for 30 minutes, filtered and dried to obtain modified carboxymethyl hydroxyethyl cellulose.

[0037] As a preferred embodiment of the preparation method of the present invention, the composition comprises, by weight, 15-40% of a reinforcing component, 10-25% of a dispersing component, 5-15% of a cationic polymer, 1-5% of a modified carboxymethyl hydroxyethyl cellulose and the remainder of water.

[0038] Another object of the present invention is to overcome the deficiencies in the prior art and provide an application of a gel reducer in preparing concrete.

[0039] Beneficial effects of the present invention:

[0040] (1) The present invention provides a gel reducer and a preparation method thereof. When added to concrete, compared with blank concrete, the initial expansion of the concrete is basically not reduced, the slump loss is less affected, the workability of the concrete can be significantly improved, and the early and late strengths of the concrete are improved.

[0041] (2) The concrete glue reducer provided by the present invention can significantly improve the mixing performance of concrete by compounding N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a specific ratio as the reinforcing component in the glue reducer, and the mixed components with the dispersed components compounded in a specific ratio can significantly improve the concrete mixture performance. Even if only 0.03% of the mass of the cementitious material is added, the concrete strength can be significantly improved while reducing the cement dosage by 20%. At the same time, the cost can be reduced, energy saving and environmental protection can be achieved, and huge economic and social benefits can be achieved. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0045] Maleic anhydride in the present invention, CAS No. 108-31-6, is a common commercial product;

[0046] Acrylic acid, CAS: 79-10-7, content: 99.5%, common commercial product; the others are common commercial products.

[0047] (1) The specific preparation of modified triisopropanolamine in the embodiment of the present invention is as follows:

[0048] The triisopropanolamine and maleic anhydride in a molar ratio of 1:1 are mixed, and 3 wt% of p-toluenesulfonic acid is added as a catalyst. The temperature is raised to 120°C and kept for reaction for 6 hours. After cooling, the modified triisopropanolamine is obtained.

[0049] (2) The specific preparation of modified N,N-dimethylisopropanolamine in the embodiment of the present invention is as follows:

[0050] Slowly add acrylic acid to N,N-dimethylisopropanolamine under stirring, continue stirring and reacting for 35 minutes after the addition is completed, and dilute to a solution with a mass concentration of 50% after cooling;

[0051] Wherein, the mass ratio of acrylic acid to N, N-dimethylisopropanol is 1:1.2.

[0052] (3) The specific preparation of dispersant A in the embodiment of the present invention is as follows:

[0053] Add raw materials of sodium α-olefin sulfonate, 2-acrylamido-2-methylpropane sulfonic acid and deionized water into a reactor, pass nitrogen to deoxygenate for 10-20 minutes, raise the temperature to 60-90° C., dropwise add the ammonium persulfate aqueous solution and methacrylic acid which are placed separately within 3-6 hours, continue the reaction for 1-2 hours, and then cool to room temperature to obtain the dispersant A;

[0054] The molar ratio of methacrylic acid to sodium α-olefin sulfonate is 2:1; the mass of 2-acrylamido-2-methylpropane sulfonic acid is 2% of the total mass of methacrylic acid and sodium α-olefin sulfonate; the mass of ammonium persulfate is 3% of the total mass of methacrylic acid and sodium α-olefin sulfonate; and the mass of deionized water in the reaction is 3 times the total mass of the reactants.

[0055] (4) The specific preparation of the cationic polymer in the embodiment of the present invention is as follows:

[0056] 12% methacrylamide, 3% bis(trimethylsilyl) vinyl phosphate, 2% crotonic anhydride, 7% sodium hypophosphite monohydrate and 22% water were added to a reaction kettle and stirred to dissolve;

[0057] Measure the temperature in the kettle and control it at 12°C. After the temperature stabilizes, add 2.8% ammonium persulfate at one time.

[0058] 5 minutes after adding ammonium persulfate, 8% solution A and 10% solution B were added dropwise in sequence. After solution A was added, solution B was added dropwise within 10 minutes. The addition time of solution B was 1.7 hours and the addition time of solution A was 2.2 hours.

[0059] Wherein, solution A is composed of thioglycolic acid and water in a mass ratio of 1:14, and solution B is composed of methacryloyloxyethyl trimethylammonium chloride, hydroxyethyl dimethacrylate of phthalic anhydride and water in a mass ratio of 7:4:14;

[0060] After the addition is completed, 1.4% sodium metabisulfite is added at one time, and the mixture is aged for 1 hour. After aging, the mixture is cooled. When the temperature of the reaction solution is lower than 30°C, 10% of a 30% sodium hydroxide solution is slowly added. The mixture is filled with water to 100% by mass and stirred evenly to obtain a cationic polymer.

[0061] (5) The modified carboxymethyl hydroxyethyl cellulose in the embodiment of the present invention is specifically prepared as follows:

[0062] Depolymerization: carboxymethyl hydroxyethyl cellulose (number average molecular weight of 100000, carboxymethyl substitution degree of 0.7, hydroxyethyl substitution degree of 1.2) was dissolved in ethanol, 37% mass concentration of hydrochloric acid was added under stirring, and the temperature was raised to 75°C. After reacting for 4 hours, hexane was added until no solid was precipitated, and small molecule carboxymethyl hydroxyethyl cellulose (number average molecular weight of 12000) was obtained after filtration and drying; wherein, the mass ratio of carboxymethyl hydroxyethyl cellulose, ethanol and 37% mass concentration of hydrochloric acid aqueous solution was 1:5:0.5;

[0063] Protection: By weight, 8 parts of small molecule carboxymethyl hydroxyethyl cellulose were dissolved in 60 parts of N, N-dimethylformamide, stirred evenly, heated to 110°C, and then 10 parts of hexamethyldisilazane, 10 parts of water and 0.2 parts of phosphoric acid were added dropwise, reacted for 8 hours, and filtered to obtain a crude product;

[0064] Purification: Disperse the crude product in acetone, filter, add distilled water, filter and dry to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose;

[0065] Grafting: by weight, 8 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose and 80 parts of xylene were mixed, heated to 80°C, stirred for reaction for 1.5 hours, 10 parts of ε-caprolactone and stannous octoate were added, heated to 120°C and reacted for 14 hours to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone graft; wherein the amount of stannous octoate added was 2wt% of the trimethylsilyl carboxymethyl hydroxyethyl cellulose;

[0066] Deprotection: Add 5 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone grafted product to a mixed solution of 25 parts of isopropanol and 25 parts of 2% mass concentration hydrochloric acid, stir evenly, heat to 75°C and react for 30 minutes, filter and dry to obtain hydrophobically modified carboxymethyl hydroxyethyl cellulose.

[0067] (6) The novel high-efficiency and environmentally friendly adhesive reducer for concrete of the present invention is specifically prepared as follows: according to the formula, the reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are stirred at 25° C. for 2 hours to uniformly disperse the adhesive reducer for concrete.

[0068] Embodiment 1:

[0069] This embodiment provides a method for preparing a glue reducing agent, the main steps of which are:

[0070] (1) Based on 100% by mass, the gelling agent comprises: 15% of reinforcing component, 25% of dispersing component, 10% of cationic polymer, 5% of modified carboxymethyl hydroxyethyl cellulose and the balance of water;

[0071] Wherein, the reinforcing component is N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:1:2:1;

[0072] The dispersing component is ethylenediaminetetramethylenephosphoric acid and dispersant A in a mass ratio of 1:3;

[0073] (2) According to the formula, the reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are stirred at 25°C for 2 hours and uniformly dispersed to obtain a gel reducer for concrete.

[0074] Embodiment 2:

[0075] This embodiment provides a method for preparing a glue reducing agent, the main steps of which are:

[0076] (1) Based on 100% by mass, the gelling agent comprises: 25% of a reinforcing component, 10% of a dispersing component, 5% of a cationic polymer, 3% of a modified carboxymethyl hydroxyethyl cellulose and the balance water;

[0077] Wherein, the reinforcing component is N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:3:2:1;

[0078] The dispersing component includes ethylenediaminetetramethylenephosphonic acid and dispersant A in a ratio of 1:5.

[0079] (2) According to the formula, the reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are stirred at 25°C for 2 hours and uniformly dispersed to obtain a gel reducer for concrete.

[0080] Embodiment 3:

[0081] This embodiment provides a method for preparing a glue reducing agent, the main steps of which are:

[0082] (1) Based on 100% by mass, the gelling agent comprises: 35% of a reinforcing component, 15% of a dispersing component, 15% of a cationic polymer, 1% of a modified carboxymethyl hydroxyethyl cellulose and the balance water;

[0083] Wherein, the reinforcing component is N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:2:2:1;

[0084] The dispersing component is ethylenediaminetetramethylenephosphoric acid and dispersant A in a mass ratio of 1:8.

[0085] (2) According to the formula, the reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are stirred at 25°C for 2 hours and uniformly dispersed to obtain a gel reducer for concrete.

[0086] Embodiment 4:

[0087] This embodiment provides a method for preparing a glue reducing agent, the main steps of which are:

[0088] (1) Based on 100% by mass, the gelling agent comprises: 40% of a reinforcing component, 20% of a dispersing component, 13% of a cationic polymer, 2% of a modified carboxymethyl hydroxyethyl cellulose and the balance water;

[0089] Wherein, the reinforcing component is N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:3:5:1;

[0090] The dispersing component is ethylenediaminetetramethylenephosphoric acid and dispersant A in a mass ratio of 1:6.

[0091] (2) According to the formula, the reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are stirred at 25°C for 2 hours and uniformly dispersed to obtain a gel reducer for concrete.

[0092] Comparative Example 1:

[0093] The difference between this comparative example and Example 1 is:

[0094] The reinforcing components are N-hydroxyethylpiperazine, methyl vinyl ketone and modified triisopropanolamine in a mass ratio of 1:1:2, and do not contain modified N, N-dimethylisopropanolamine.

[0095] Comparative Example 2:

[0096] The difference between this comparative example and Example 1 is:

[0097] The reinforcing components are N-hydroxyethylpiperazine, methyl vinyl ketone and modified N, N-dimethylisopropanolamine in a mass ratio of 1:1:1, and do not contain modified triisopropanolamine.

[0098] Comparative Example 3:

[0099] The difference between this comparative example and Example 1 is:

[0100] The reinforcing components are N-hydroxyethylpiperazine, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:2:1, and do not contain methyl vinyl ketone.

[0101] Comparative Example 4:

[0102] The difference between this comparative example and Example 1 is:

[0103] The reinforcing components are methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine in a mass ratio of 1:2:1, and do not contain N-hydroxyethylpiperazine.

[0104] Comparative Example 5:

[0105] The difference between this comparative example and Example 1 is:

[0106] The dispersing component is ethylenediaminetetramethylenephosphonic acid, and does not contain dispersant A.

[0107] Comparative Example 6:

[0108] The difference between this comparative example and Example 1 is:

[0109] The dispersing component is dispersant A, which does not contain ethylenediaminetetramethylenephosphonic acid.

[0110] Performance Testing:

[0111] Taking C30 concrete as an example, the raw materials include Conch P032.5 cement, river sand (fineness modulus is 2.5), crushed stone is 5-20μm continuous graded crushed stone, and the water reducer is FS-2080 polycarboxylic acid water reducer provided by Shenzhen Tongzhouda Technology Development Co., Ltd. (the water reducer dosage is 1.8% of the total mass of the cementitious material).

[0112] The gel reducer prepared in Examples 1 to 4 and Comparative Examples 1 to 6 was diluted with water at a mass ratio of 1:10 to obtain a gel reducer solution, which was used to prepare C30 concrete (the amount of the gel reducer was 0.3% of the total mass of the cementitious material), and compared with a blank group without the gel reducer. The workability of the concrete was tested according to the experimental method specified in the Standard for Test Methods for Performance of Ordinary Concrete Mixtures (GB / T 50080-2016); the strength of the concrete at 7d, 28d, and 60d was tested according to the test method specified in the Standard for Test Methods for Mechanical Properties of Ordinary Concrete (GB / T 50081-2002).

[0113] It should be noted that the cementitious materials are cement, fly ash and mineral powder; in all embodiments and comparative examples, the reduced amount of cement and water is added to the amount of river sand and gravel accordingly to avoid different performance test results due to inconsistent overall concrete quality.

[0114] The concrete mix ratios are shown in Table 1. The blank concrete is a concrete mix ratio without adding a gel reducer, and the test concrete is a concrete mix ratio with adding the gel reducers of Examples 1 to 4 and Comparative Examples 1 to 6.

[0115] The performance results are shown in Table 2.

[0116] Table 1: Concrete mix ratio (kg / m 3 )

[0117]

[0118] Table 2: Performance results

[0119]

[0120] Note: The unit of slump and expansion is mm; the unit of compressive strength is MPa.

[0121] It can be seen from Table 2 that when the dosage of the new high-efficiency and environmentally friendly gel reducer for concrete of the present invention is 0.3% of the gel material, the amount of cement in the concrete can be reduced by 20%, and the early and late strengths of the concrete are significantly enhanced, and the workability is excellent.

[0122] Comparative Example 7:

[0123] The difference between this comparative example and Example 1 is:

[0124] The reinforcing component is N-hydroxyethylpiperazine and methyl vinyl ketone in a mass ratio of 1:1.

[0125] Comparative Example 8:

[0126] The difference between this comparative example and Example 1 is:

[0127] The reinforcing component is methyl vinyl ketone and modified triisopropanolamine in a mass ratio of 1:2.

[0128] Comparative Example 9:

[0129] The difference between this comparative example and Example 1 is:

[0130] The reinforcing component is methyl vinyl ketone and modified N, N-dimethyl isopropanolamine in a mass ratio of 1:1.

[0131] Concrete was prepared according to the method of Comparative Example 6, and the performance results were measured, see Table 3.

[0132] Table 3

[0133]

[0134] It can be seen from comparative examples 1, 2, 4, 7 to 9 that in the reinforcing component system, N-hydroxyethylpiperazine, modified triisopropanolamine and modified N,N-dimethylisopropanolamine have a synergistic effect of enhancing mechanical properties.

[0135] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing an environmentally friendly adhesive reducer for concrete, characterized in that: include, The triisopropanolamine and maleic anhydride are mixed, and p-toluenesulfonic acid accounting for 2-4 wt% of the mixture is added, and the mixture is heated to 110-120° C. and kept for reaction for 4-6 hours, and then cooled to obtain modified triisopropanolamine; Slowly drop acrylic acid into N, N-dimethylisopropanolamine under stirring, continue stirring and reacting for 30 to 40 minutes after the dropwise addition is completed, and dilute to a solution with a mass concentration of 50% after cooling to obtain modified N, N-dimethylisopropanolamine; Sodium α-olefin sulfonate, 2-acrylamido-2-methylpropane sulfonic acid and deionized water are added to the reactor, and nitrogen is passed to deoxygenate for 10 to 20 minutes, and then the temperature is raised to 60 to 90° C., and an aqueous ammonium persulfate solution and methacrylic acid are added. After the reaction is continued for 1 to 2 hours, the temperature is cooled to room temperature to obtain dispersant A; N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine are mixed to obtain a reinforcing component, wherein the mass ratio of N-hydroxyethylpiperazine, methyl vinyl ketone, modified triisopropanolamine and modified N,N-dimethylisopropanolamine is 1:1 to 3:2 to 5:1; Mixing ethylenediaminetetramethylenephosphonic acid and dispersant A uniformly to obtain a dispersed component; The reinforcing component, the dispersing component, the cationic polymer, the modified carboxymethyl hydroxyethyl cellulose and water are mixed and stirred uniformly to obtain a gelling agent; The preparation method of the cationic polymer comprises the following steps: adding 12% methacrylamide, 3% bistrimethylsilyl vinyl phosphate, 2% crotonic anhydride, 7% sodium hypophosphite monohydrate and 22% water into a reaction kettle, stirring to dissolve them; measuring the temperature in the kettle, controlling the temperature at 12°C, and adding 2.8% ammonium persulfate at one time after the temperature stabilizes; 5 minutes after the addition of ammonium persulfate, dripping 8% solution A and 10% solution B in sequence, and dripping solution B within 10 minutes after the addition of solution A, and dripping solution B for 1 minute. .7h, the solution A was added dropwise for 2.2h; wherein, solution A was composed of thioglycolic acid and water in a mass ratio of 1:14, and solution B was composed of methacryloyloxyethyl trimethylammonium chloride, hydroxyethyl dimethacrylate of phthalic anhydride and water in a mass ratio of 7:4:14; after the addition was completed, 1.4% sodium metabisulfite was added at one time, aged for 1 hour, cooled after aging, and when the temperature of the reaction solution was lower than 30°C, 10% of a 30% sodium hydroxide solution was slowly added, water was added to 100% by mass, and the cationic polymer was obtained after uniform stirring; The modified carboxymethyl hydroxyethyl cellulose has a preparation method comprising: dissolving carboxymethyl hydroxyethyl cellulose in ethanol, adding hydrochloric acid with a mass concentration of 37% under stirring, heating to 75°C, reacting for 4 hours, adding hexane until no solid is precipitated, filtering and drying to obtain a small molecule carboxymethyl hydroxyethyl cellulose with a number average molecular weight of 12,000; wherein the mass ratio of carboxymethyl hydroxyethyl cellulose, ethanol and a hydrochloric acid aqueous solution with a mass concentration of 37% is 1:5:0.5, the number average molecular weight of the carboxymethyl hydroxyethyl cellulose is 100,000, the degree of substitution of the carboxymethyl group is 0.7, and the degree of substitution of the hydroxyethyl group is 1.2; by weight, dissolving 8 parts of the small molecule carboxymethyl hydroxyethyl cellulose in 60 parts of N,N-dihydrogen ether; methylformamide, stir evenly, heat to 110°C, then drop 10 parts of hexamethyldisilazane, 10 parts of water and 0.2 parts of phosphoric acid, react for 8 hours, filter to obtain a crude product; disperse the crude product in acetone, filter, add distilled water, filter and dry to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose; by weight, mix 8 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose and 80 parts of xylene, heat to 80°C, stir to react for 1.5 hours, then add 10 parts of ε-caprolactone and stannous octoate, heat to 120°C and react for 14 hours to obtain trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone graft; wherein the amount of stannous octoate added is 2wt% of trimethylsilyl carboxymethyl hydroxyethyl cellulose; 5 parts of trimethylsilyl carboxymethyl hydroxyethyl cellulose polycaprolactone grafted product were added to a mixed solution of 25 parts of isopropanol and 25 parts of 2% mass concentration hydrochloric acid, stirred evenly, heated to 75°C for reaction for 30 minutes, filtered and dried to obtain modified carboxymethyl hydroxyethyl cellulose.

2. The preparation method according to claim 1, characterized in that: The triisopropanolamine and maleic anhydride are mixed, wherein the molar ratio of the triisopropanolamine to the maleic anhydride is 0.8-1:

1.

3. The preparation method according to claim 1 or 2, characterized in that: The method comprises slowly dropping acrylic acid into N,N-dimethylisopropanolamine under stirring, wherein the mass ratio of acrylic acid to N,N-dimethylisopropanolamine is 0.8-1:1-1.

2.

4. The preparation method according to claim 1, characterized in that: The molar ratio of methacrylic acid to sodium α-olefin sulfonate is 2:0.8-1; 2-Acrylamido-2-methylpropanesulfonic acid accounts for 1-2% of the total mass of methacrylic acid and sodium α-olefin sulfonate; Ammonium persulfate accounts for 2-3% of the total mass of methacrylic acid and sodium α-olefin sulfonate; Deionized water accounts for 2 to 3 times the total mass of the reactants.

5. The preparation method according to claim 1, characterized in that: In the dispersed component, the mass ratio of ethylenediaminetetramethylenephosphonic acid to dispersant A is 1:3-8.

6. The preparation method according to any one of claims 1, 2, 4 or 5, characterized in that: Based on 100% by mass, the invention comprises 15-40% of reinforcing components, 10-25% of dispersing components, 5-15% of cationic polymers, 1-5% of modified carboxymethyl hydroxyethyl cellulose and the balance of water.

7. Use of the gel reducing agent prepared by the preparation method according to any one of claims 1 to 6 in the preparation of concrete.

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