A cycloaromatic amide-containing concrete water-retaining agent, a preparation method and application thereof

Abstract

The application provides a concrete water-retaining agent containing cycloaromatic amide and a preparation method and application thereof, raw materials are as follows: 70-80 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG), 4-6 parts of cycloaromatic amide, 400-500 parts of water, 50-60 parts of acrylic acid, 9-10 parts of acrylamide, 2-2.5 parts of oxidizing agent, 0.3-0.5 parts of chain transfer agent, 0.4-0.6 parts of reducing agent and 0.3-0.6 parts of catalyst. Compared with the prior art, the application synthesizes a polycarboxylic acid type concrete water-retaining agent containing cycloaromatic amide through an aqueous phase free radical polymerization reaction at normal temperature, the synthesis process is simple and easy to operate, the concrete segregation and bleeding problems can be solved, the workability of concrete can be improved, and the concrete slump and spread degree over time and early and late strength can be improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of concrete admixture preparation, and particularly relates to a concrete water-retaining agent containing cyclophane amide as well as a preparation method and application thereof. BACKGROUND

[0002] In recent years, with the development of a large number of domestic infrastructure projects and the real estate industry, China's river sand, pebble and other sand and gravel materials are facing the severe challenge of resource depletion, and their prices are also rising. This situation has led to the current use of machine-made sand or most of the use of machine-made sand combined with a small amount of river sand in commercial concrete stations becoming the mainstream. However, due to the problems of poor gradation and high stone powder content of machine-made sand, and the high sensitivity of polycarboxylate superplasticizer to the quality fluctuations of sand and gravel materials used in concrete in actual application, the problems of concrete segregation and bleeding have not been effectively solved.

[0003] The main method to improve the problem of concrete segregation and bleeding is to add a water-retaining agent. At present, most of the water-retaining agent products in China are polyacrylamide water-retaining agents and some modified cellulose traditional water-retaining agents. These products have a great impact on the fluidity of concrete, and at the same time, the stability of these products is poor, which cannot effectively improve the workability of concrete for a long time, and also has an impact on the mechanical properties of concrete.

[0004] The patent with publication number CN 112851860 A, published on May 28, 2021, discloses a degradable cellulose-polyacrylamide composite water-retaining agent and a preparation method. Brominated nanocellulose is used as an ATRP macromolecular initiator, and a bromo-isobutyl group is used as an initiation site. Through ATRP atom transfer radical polymerization, acrylamide is in-situ polymerized on the cellulose molecular chain. Polyacrylamide and nanocellulose are crosslinked through chemical bonds to form a complex three-dimensional network, which has a stronger stable structure and is beneficial to enhancing the structural stability and water retention of the water-retaining agent matrix. At the same time, the composite water-retaining agent contains abundant hydrophilic hydroxyl, carboxyl and amino groups, as well as a complex pore structure, showing excellent water absorption. When the composite water-retaining agent is discarded outdoors and the nanocellulose component is biodegraded, the chemical crosslinking network of cellulose-polyacrylamide will be damaged and the molecular chain will be broken, realizing the special function of biodegradation. However, it has an impact on the mechanical properties of concrete. SUMMARY

[0005] The purpose of the present application is to provide a concrete water-retaining agent containing cyclophane amide and a preparation method thereof. By introducing a cyclophane amide structure, the number of amide groups in the water-retaining agent is greatly increased, which can effectively regulate the hydration reaction of cement. At the same time, the cavity structure formed by the force of intramolecular hydrogen bond of cyclophane amide is stable, which can fill part of the micropores in cement stone, improve the microstructure of cement stone, and thus improve the strength and toughness of cement stone.

[0006] The application further aims to provide an application of the concrete water-retaining agent containing cycloaromatic amide to concrete.

[0007] The specific technical scheme of the application is as follows:

[0008] The concrete water-retaining agent containing cycloaromatic amide comprises the following raw materials in mass parts:

[0009] 70-80 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG), 4-6 parts of cycloaromatic amide, 400-500 parts of water, 50-60 parts of acrylic acid, 9-10 parts of acrylamide, 2-2.5 parts of oxidant, 0.3-0.5 parts of chain transfer agent, 0.4-0.6 parts of reducing agent, and 0.3-0.6 parts of catalyst.

[0010] The number average molecular weight of the ethylene glycol monovinyl polyoxyethylene ether is 2400-3200 g / mol.

[0011] The cycloaromatic amide is cyclo[6]aromatic amide.

[0012] The oxidant is 30% mass concentration hydrogen peroxide;

[0013] The chain transfer agent is one or more of mercaptoacetic acid, mercaptopropionic acid and mercaptoethanol.

[0014] The reducing agent is one or more of L-ascorbic acid, reducing agent E51 and N-ethylaniline.

[0015] The catalyst is 1% concentration ferrous sulfate aqueous solution.

[0016] The application provides a preparation method of the concrete water-retaining agent containing cycloaromatic amide, comprising the following steps:

[0017] 1) mixing, stirring and dissolving water, cycloaromatic amide and ethylene glycol monovinyl polyoxyethylene ether, adding an oxidant as a bottom liquid after dissolution;

[0018] 2) mixing acrylic acid, acrylamide and chain transfer agent with water to form a solution as A liquid, mixing reducing agent and catalyst with water to form a solution as B liquid, and simultaneously starting dropping A liquid and B liquid into the bottom liquid;

[0019] 3) after dropping, keeping warm, and then cooling to room temperature.

[0020] The mass ratio of water in the bottom liquid, water in A liquid and water in B liquid is 4.0-5.0:1:1.0-2.0.

[0021] In step 1), the stirring and dissolving is performed at 20-30°C.

[0022] In step 2), the time for dropping A is 40-60 min; the time for dropping B is 60-80 min.

[0023] In step 3), the time for the heat preservation is 50-60 min.

[0024] The application of the concrete water-retaining agent containing cyclophane amide provided by the application is used for concrete.

[0025] Compared with the prior art, the polycarboxylic acid type concrete water-retaining agent is synthesized at normal temperature through a water phase free radical polymerization reaction, the amide groups in the water-retaining agent can be adsorbed on the surface of cement particles, a hydration film is formed around the cement particles, the free water is uniformly bound in the concrete system, the concrete in a segregation state is converted into concrete with normal working performance, and the role of water retention and thickening is played. Moreover, the cyclophane amide structure is introduced, the number of amide groups in the water-retaining agent is greatly increased, the hydration reaction of cement can be effectively regulated, the cavity structure formed by the force of intramolecular hydrogen bond of the cyclophane amide is stable, part of micropores in the cement stone can be filled, the microstructure of the cement stone is improved, and the strength and toughness of the cement stone are improved. The preparation method is simple and easy to operate, the problem of segregation and bleeding of concrete can be solved, the workability of concrete can be improved, and the slump loss and the expansion degree of concrete and the early and late strength are improved. DETAILED DESCRIPTION

[0026] To make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely in combination with the embodiments of the application. Obviously, the described embodiments are some embodiments of the application but not all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0027] In the following examples, the test materials and reagents used in the examples can be obtained from commercial channels unless otherwise specified.

[0028] Unless otherwise specified, the specific techniques or conditions in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0029] Embodiment 1

[0030] A preparation method of a concrete water-retaining agent containing cyclophane amide comprises the following steps:

[0031] 1.1 Raw materials (by weight):

[0032] Ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 2400 g / mol) 70 parts, cyclo[6]formamide 4 parts, water 490 parts, acrylic acid 50 parts, acrylamide 9 parts, oxidizing agent 30% concentration hydrogen peroxide 2 parts, chain transfer agent mercaptopropionic acid 0.3 parts, reducing agent L ascorbic acid 0.4 parts, catalyst 1% concentration aqueous ferrous sulfate 0.3 parts.

[0033] The preparation method of cyclo[6]formamide is as follows:

[0034] S1: 2.2 g (3.7 mmol) of 2,4-bis(tetraethylene glycol monomethyl ether)-5- (methoxycarbonyl)benzoic acid was dissolved in 40 mL of dry CH2Cl2, 0.66 g (5.2 mmol) of oxalyl chloride and 10 μL of dry DMF were added, and a large amount of bubbles was observed. Reaction at room temperature for 40 min, then reflux at 45°C for 30 min. After the reaction was completed, it was cooled to room temperature, and CH2Cl2 and oxalyl chloride were removed by cold trap method, paying attention to connect the drying tower, then the remaining oxalyl chloride was removed by oil pump pumping. 2.2 g of 2,4-bis(tetraethylene glycol monomethyl ether)-5-(chlorocarbonyl)benzoic acid methyl ester was obtained.

[0035] S2: 2.2 g (3.7 mmol) of 2,4-bis(tetraethylene glycol monomethyl ether)-5- (chlorocarbonyl)benzoic acid methyl ester obtained by the above reaction was dissolved in 40 mL of dry CH2Cl2, and 0.73 g (3.7 mmol) of 2,4-dimethoxy-5-nitroaniline and 0.52 g (5.2 mmol) of Et3N were slowly added dropwise into 30 mL of dry CH2Cl2 solution with a constant pressure dropping funnel. After the dropwise addition was completed, the reaction was carried out at room temperature for 3 h. After the reaction was completed, the solution was acidified by dropwise adding dilute hydrochloric acid, and the pH value of the solution was checked to be acidic. The triethylamine hydrochloride was washed with water, and then extracted with CH2Cl2 for 2-3 times. The organic layers were combined, dried over anhydrous Na2SO4, filtered, and rotary evaporated. Purification was performed by column chromatography (silica gel) using CH2Cl2:CH3OH = 20:1 (V / V) as the eluent to obtain 2.5 g of yellow solid with a yield of 86%.

[0036] S3: 1.8 g (2.3 mmol) of 2,4-bis(tetraethylene glycol monomethyl ether)-5-((2,4- dimethoxy-5-nitrophenyl)carbamoyl)benzoic acid methyl ester was added into a 100 mL round-bottom flask, and then 12 mL of aqueous solution containing 0.66 g (11.5 mmol) of KOH and 50 mL of THF were added. The reaction was carried out by heating to 70°C and refluxing. After the reaction was completed, the THF was removed (caution: due to the presence of water, it is easy to boil, so rotary evaporation should be careful), CH2Cl2 was added, and the solution was acidified with dilute hydrochloric acid. The organic layer was extracted with CH2Cl2 for 2-3 times, combined, dried over anhydrous Na2SO4, and filtered to obtain 1.7 g of yellow solid with a yield of 97%.

[0037] S4: 1.08 g (1.42 mmol) of 2,4-bis(tetraethyleneglycol monomethyl ether)-5-((2,4-dimethoxy-5-nitrophenyl)carbamoyl)benzoic acid, 0.12 g (0.71 mmol) of 4,6-dimethoxy-l,3-benzenediamine 8, 0.43 g (4.26 mmol) of Et3N and 0.54 g (2.13 mmol) of bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl) were dissolved in 50 mL of dry CH2Cl2. Stirring was carried out at room temperature for 5 h. After completion of the reaction, dilute hydrochloric acid was added, washed with water, extracted with CH2Cl2, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The product was isolated and purified by column chromatography (silica gel) using CHCl3:CH3OH = 15:1 (V / V) as the eluent to obtain 0.91 g of a yellow solid with a yield of 78%.

[0038] S5: 160 mg (0.097 mmol) of the pentamer dinitro compound and 64 mg of Pd / C (10% Pd) were dissolved in 27 mL of a CHCl3 / CH3OH (V / V = 2 / 1) mixed solvent. After completion of the reaction by hydrogenation reduction at 45°C for about 10 h, Pd / C was removed by filtration under N2and in the dark. The obtained filtrate was rotary evaporated to obtain a gray solid pentamer diamine. The obtained product was directly used in the next step of the double-molecule ring formation reaction.

[0039] S6: 160 mg (0.097 mmol) of the pentamer dinitro compound and 64 mg of Pd / C were dissolved in 27 mL of a CHCl3 / CH3OH (V / V = 2 / 1) mixed solvent. After completion of the reaction by hydrogenation reduction at 45°C for about 10 h, Pd / C was removed by filtration under N2and in the dark. The obtained filtrate was rotary evaporated to remove the solvent to obtain a gray solid pentamer diamine. 4,6-bis(l-butene)phthaloyl dichloride was dissolved in 10 mL of dry CH2Cl2, and was slowly added dropwise into a 50 mL dry CH2Cl2solution containing the pentamer diamine and 59 mg (0.58 mmol) of Et3N at 0°C. After 2 h, the reaction was continued at room temperature. After completion of the reaction, 10% dilute hydrochloric acid was washed three times, dried over anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure to obtain a crude product. The crude product was dissolved in 2 mL of CH2Cl2, and 6 mL of EA was added to precipitate, centrifuged, and the supernatant was poured out to obtain a gray-white solid cyclo[6]arenamide. The structural formula of the cyclo[6]arenamide is:

[0040]

[0041] 1a: R 1 = -(CH2CH2O)4CH3, R 2 = -CH2CH2CHCH2.

[0042] 1.2 Preparation method:

[0043] The method comprises the following steps:

[0044] 1) Add 280 parts by weight of water, ethylene glycol monovinyl polyoxyethylene ether, and cyclo[6]aromatic amide into a reaction container, stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then maintain a constant temperature of 20°C;

[0045] 2) After constant temperature, add an oxidizing agent of 30% hydrogen peroxide into the reaction container;

[0046] 3) Uniformly drop a solution A mixed by 70 parts by weight of acrylic acid, acrylamide, chain transfer agent, and water into the reaction container, and drop for 40 min;

[0047] 4) At the same time as step 3), uniformly drop a solution B mixed by a reducing agent, a catalyst (1% FeSO4 solution), and 140 parts by weight of water into the reaction container, and drop for 60 min;

[0048] 5) After all the materials are dropped, maintain the existing temperature for 50 min, and then cool to room temperature, to obtain a cycloaromatic amide-containing concrete water-retaining agent product.

[0049] Example 2

[0050] A preparation method of a cycloaromatic amide-containing concrete water-retaining agent, comprising the following steps:

[0051] 1.1 Raw materials (by weight):

[0052] 75 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 2800 g / mol), 4.5 parts of cyclo[6]aromatic amide, 450 parts of water, 55 parts of acrylic acid, 9.5 parts of acrylamide, 2.2 parts of an oxidizing agent, 0.4 parts of a chain transfer agent, 0.5 parts of a reducing agent, and 0.4 parts of a catalyst (1% ferrous sulfate aqueous solution).

[0053] The chain transfer agent is mercaptoacetic acid;

[0054] The reducing agent is E51.

[0055] 1.2 Preparation method:

[0056] The method comprises the following steps:

[0057] 1) Add 300 parts by weight of water, ethylene glycol monovinyl polyoxyethylene ether, and cyclo[6]aromatic amide into a reaction container, stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then maintain a constant temperature of 25°C;

[0058] 2) After constant temperature, add 30% concentration hydrogen peroxide oxidant to the reaction container;

[0059] 3) Uniformly drop solution A, which is made by mixing 65 parts (by weight) of acrylic acid, acrylamide, chain transfer agent and water, into the reaction container, drop for 50 min;

[0060] 4) At the same time as step 3), uniformly drop solution B, which is made by mixing 85 parts (by weight) of reducing agent, catalyst (1% concentration FeSO4 solution) and water, into the reaction container, drop for 70 min;

[0061] 5) After all materials are dropped, maintain the existing temperature for 50 min, then cool to room temperature, to obtain the finished product of the concrete water-retaining agent containing cyclic aryl amide.

[0062] Example 3

[0063] A method for preparing a concrete water-retaining agent containing cyclic aryl amide, comprising the following steps:

[0064] 1.1 Raw materials (by weight):

[0065] 80 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 3000 g / mol), 5 parts of cyclic [6] aryl amide, 480 parts of water, 60 parts of acrylic acid, 10 parts of acrylamide, 2.5 parts of oxidant, 0.5 parts of chain transfer agent, 0.6 parts of reducing agent, and 0.5 parts of 1% concentration FeSO4 solution.

[0066] Chain transfer agent: mercaptoethanol is used;

[0067] Reducing agent: N-ethyl aniline is used.

[0068] 1.2 Preparation method:

[0069] Comprising the following steps:

[0070] 1) Add 300 parts (by weight) of water, ethylene glycol monovinyl polyoxyethylene ether, and cyclic [6] aryl amide into the reaction container, stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then constant temperature to 30°C;

[0071] 2) After constant temperature, add 30% concentration hydrogen peroxide oxidant to the reaction container;

[0072] 3) Uniformly drop solution A, which is made by mixing 60 parts (by weight) of acrylic acid, acrylamide, chain transfer agent and water, into the reaction container, drop for 60 min;

[0073] 4) At the same time as step 3), solution B, which is a mixture of a reducing agent, a catalyst (1% FeSO4 solution) and water 120 parts, is added to the reaction container uniformly dropwise, and the dropping is completed in 80 min;

[0074] 5) After all the materials are added dropwise, the existing temperature is maintained for 60 min, and then the temperature is lowered to room temperature, thereby obtaining the finished product of the concrete water-retaining agent containing cycloaromatic amide.

[0075] Example 4

[0076] A method for preparing a concrete water-retaining agent containing cycloaromatic amide, comprising the following steps:

[0077] 1.1 Raw materials (by weight parts):

[0078] Ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 3200 g / mol) 80 parts, cyclo[6]aromatic amide 6 parts, water 500 parts, acrylic acid 60 parts, acrylamide 10 parts, oxidizing agent 2.5 parts, chain transfer agent 0.5 parts, reducing agent 0.6 parts, and catalyst 1% FeSO4 solution 0.6 parts.

[0079] Chain transfer agent: thioethanol and mercaptopropionic acid are used in a mass ratio of 1:1;

[0080] Reducing agent: E51 and L ascorbic acid are used in a mass ratio of 1:1.

[0081] 1.2 Preparation method:

[0082] Comprising the following steps:

[0083] 1) Add water 312.5 parts (by weight), ethylene glycol monovinyl polyoxyethylene ether, and cyclo[6]aromatic amide to the reaction container, and stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then maintain the temperature at 30°C;

[0084] 2) After constant temperature, add the oxidizing agent of 30% hydrogen peroxide to the reaction container;

[0085] 3) Add solution A, which is a mixture of acrylic acid, acrylamide, chain transfer agent and water 62.5 parts (by weight), to the reaction container uniformly dropwise, and the dropping is completed in 60 min;

[0086] 4) At the same time as step 3), solution B, which is a mixture of a reducing agent, a catalyst (1% FeSO4 solution) and water 125 parts (by weight), is added to the reaction container uniformly dropwise, and the dropping is completed in 80 min;

[0087] 5) After all the materials are added dropwise, the existing temperature is maintained for 60 min, and then the temperature is lowered to room temperature, thereby obtaining the finished product of the concrete water-retaining agent containing cycloaromatic amide.

[0088] Example 5

[0089] A method for preparing a concrete water-retaining agent containing a cyclic arylamide, comprising the following steps:

[0090] 1.1 Raw materials (by weight parts):

[0091] 75 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 2800 g / mol), 4.5 parts of cyclic [6] arylamide, 400 parts of water, 55 parts of acrylic acid, 9.5 parts of acrylamide, 2.2 parts of oxidizing agent, 0.4 parts of chain transfer agent, 0.5 parts of reducing agent, 0.4 parts of 1% concentration of ferrous sulfate aqueous solution as catalyst.

[0092] Chain transfer agent: thiolacetic acid is used in combination with mercaptopropionic acid, mass ratio 1:1;

[0093] Reducing agent: E51 is used in combination with N-ethylaniline, mass ratio 1:1.

[0094] 1.2 Preparation method:

[0095] Comprising the following steps:

[0096] 1) Add 250 parts (by weight) of water, ethylene glycol monovinyl polyoxyethylene ether, and cyclic [6] arylamide to the reaction container, stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then constant temperature to 25°C;

[0097] 2) After constant temperature, add 30% concentration of hydrogen peroxide oxidizing agent to the reaction container;

[0098] 3) Uniformly drop solution A mixed by acrylic acid, acrylamide, chain transfer agent and 50 parts (by weight) of water into the reaction container, drop for 60 min;

[0099] 4) At the same time as step 3), uniformly drop solution B mixed by reducing agent, catalyst (1% concentration of FeSO4 solution) and 100 parts (by weight) of water into the reaction container, drop for 70 min;

[0100] 5) After all the materials are added, maintain the existing temperature for 60 min, then cool to room temperature, to obtain the finished product of the concrete water-retaining agent containing a cyclic arylamide.

[0101] Comparative Example 1

[0102] A method for preparing a concrete water-retaining agent, comprising the following steps:

[0103] 1.1 Raw materials (by weight parts):

[0104] Ethylene glycol monovinyl polyoxyethylene ether (EPEG, number average molecular weight 2800 g / mol) 75 parts, water 450 parts, acrylic acid 55 parts, acrylamide 9.5 parts, oxidizing agent 2.2 parts, chain transfer agent 0.4 parts, reducing agent 0.5 parts, catalyst 0.4 parts of 1% concentration of ferrous sulfate aqueous solution.

[0105] Chain transfer agent: mercaptoacetic acid is used;

[0106] Reducing agent: E51 is used.

[0107] 1.2 Preparation method:

[0108] Comprising the following steps:

[0109] 1) Add water 300 parts (parts by weight) to the reaction vessel, stir until the ethylene glycol monovinyl polyoxyethylene ether is completely dissolved, and then constant temperature to 25℃;

[0110] 2) After constant temperature, add 30% concentration of hydrogen peroxide oxidizing agent to the reaction vessel;

[0111] 3) Uniformly drop solution A made by mixing acrylic acid, acrylamide, chain transfer agent and water 65 parts (parts by weight) into the reaction vessel, drop for 50 min;

[0112] 4) At the same time as step 3), uniformly drop solution B made by mixing reducing agent, catalyst (1% concentration of FeSO4 solution) and water 85 parts (parts by weight) into the reaction vessel, drop for 70 min;

[0113] 5) After all the materials are added, maintain the existing temperature for 50 min, then cool to room temperature, to obtain the finished product of the concrete water retaining agent containing ring aromatic amide.

[0114] Comparative example 2

[0115] Meishan Huiluo on sale water retaining agent: HLP-FWR.

[0116] Comparative example 3

[0117] No water retaining agent is added.

[0118] The determination of the application of the concrete water retaining agent containing ring aromatic amide to concrete, the water retaining agent content is folded solid according to the mass percentage of the mixture, and the concrete mix proportion and materials are as follows: the test mix proportion is concrete unit weight 2400 kg / m 3 ; sand ratio 50% (machine-made sand); Faguang cement 250 kg / m 3 ; Hoban fly ash 60 kg / m 3The concrete admixture is PC100H provided by Meishan Conch New Material Science and Technology Co., Ltd., and the mixing amount is 1.8% of the amount of the glue material.

[0119] Table 1: Evaluation results of concrete test

[0120]

[0121]

[0122] As shown in Table 1, the concrete of the five sample concrete water retaining agents containing cycloaromatic amide has higher expansion degree than the concrete of the admixture used in the comparative experiment, and the concrete of the five sample concrete water retaining agents containing cycloaromatic amide does not have the phenomena of slurry running and bottom grabbing, and does not have the phenomenon of bleeding after being placed for 10 minutes, and the water retention performance is much better than that of the comparative water retaining agent.

[0123] The concrete of the above samples is formed and subjected to strength test, and the strength test results are shown in Table 2.

[0124] Table 2: Evaluation results of concrete test

[0125] Sample No. 3d strength / MPa 7d strength / MPa 28d strength / MPa Example 1 16.2 30.9 36.1 Example 2 16.5 30.6 36.3 Example 3 15.7 30.1 35.8 Example 4 15.9 30.3 36.0 Example 5 16.3 30.8 36.2 Comparative Example 1 14.7 28.7 33.0 Comparative Example 2 14.5 28.9 33.4 Comparative Example 3 13.8 27.4 30.3

[0126] As shown in Table 2, the 3d, 7d and 28d strength of the concrete of the five sample concrete water retaining agents containing cycloaromatic amide is higher than that of the admixture used in the comparative experiment.

[0127] The concrete water retaining agent containing cycloaromatic amide provided by the present application can not only solve the problems of concrete segregation and bleeding, and improve the workability of concrete, but also improve the slump flow and expansion degree of concrete, and improve the compressive strength of concrete.

[0128] The above embodiments are described to facilitate the understanding and use of the present application by those skilled in the art. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A concrete water-retaining agent containing cyclic aromatic amides, characterized in that, The concrete water-retaining agent containing cycloaromatic amide comprises the following raw materials in mass parts: 70-80 parts of ethylene glycol monovinyl polyoxyethylene ether (EPEG), 4-6 parts of cycloaromatic amide, 400-500 parts of water, 50-60 parts of acrylic acid, 9-10 parts of acrylamide, 2-2.5 parts of oxidant, 0.3-0.5 parts of chain transfer agent, 0.4-0.6 parts of reducing agent, and 0.3-0.6 parts of catalyst. The structural formula of the cyclic arylamide is: ​ 2. The cyclophane amide-containing concrete water retaining agent according to claim 1, characterized by, The chain transfer agent is one or more of mercaptoacetic acid, mercaptopropionic acid and mercaptoethanol.

3. The cyclophane amide-containing concrete water retaining agent according to claim 1, characterized by, The reducing agent is one or more of L-ascorbic acid, reducing agent E51 and N-ethylaniline.

4. The cyclophane amide-containing concrete water retaining agent according to claim 1, characterized by, The catalyst is a 1% concentration of ferrous sulfate aqueous solution.

5. A process for the preparation of the cyclophane carboxamide-containing concrete water retaining agent according to any one of claims 1 to 4, characterized in that, The preparation method comprises the following steps: 1) mixing, stirring and dissolving water, cycloaromatic amide and ethylene glycol monovinyl polyoxyethylene ether, after dissolution, adding an oxidant as a bottom liquid; 2) mixing acrylic acid, acrylamide and chain transfer agent with water to form a solution as A liquid, mixing reducing agent and catalyst with water to form a solution as B liquid, and simultaneously starting dropping A liquid and B liquid into the bottom liquid; 3) after dropping, keeping warm, and then cooling to room temperature.

6. The preparation method according to claim 5, characterized in that, The mass ratio of water in the bottom liquid, water in A liquid and water in B liquid is 4.0-5.0:1:1.0-2.

0.

7. The preparation method according to claim 5, characterized in that, In step 2), the dropping time of A liquid is 40-60 min, and the dropping time of B liquid is 60-80 min.

8. The preparation method according to claim 5, characterized in that, The keeping warm time in step 3) is 50-60 min.

9. Use of a cyclophane amide-containing concrete water retaining agent according to any one of claims 1 to 4, characterized in that, The concrete water-retaining agent containing cycloaromatic amide is used for concrete.

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