A dispersant-resistant agent for underwater non-dispersible concrete and a method for preparing the same

Abstract

The application discloses an anti-dispersing agent for underwater non-dispersible concrete and a preparation method thereof, and belongs to the technical field of concrete admixtures. The preparation method comprises the following steps: mixing and heating acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid sodium, a crosslinking agent, sodium hydroxide and a modified isopentenyl polyoxyethylene ether solution, then adding ammonium persulfate and ascorbic acid, stirring, adding hydroquinone and continuing to stir, so that the anti-dispersing agent for underwater non-dispersible concrete is obtained. The anti-dispersing agent provided by the application can be used in underwater non-dispersible concrete, so that the concrete has the properties of anti-dispersion and fluidity, good resistance to water scouring, high water-land strength ratio and greatly shortened setting time compared with conventional anti-dispersing agents.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of concrete admixtures, and particularly relates to an anti-dispersion agent for underwater non-dispersive concrete and a preparation method thereof. BACKGROUND

[0002] Underwater concrete is widely used in underwater structure construction such as dams, marine engineering, bridge foundations, and wharfs. Its main feature is the ability to resist water erosion and harden in water, maintaining good strength and durability. By adding anti-dispersion agents and other admixtures, the problem of concrete strength reduction and structural unevenness caused by the dispersion of underwater concrete when it comes into contact with water can be effectively prevented, ensuring construction quality and structural safety. Underwater concrete anti-dispersion agent is an important admixture for improving the performance of underwater concrete. The development of anti-dispersion agents aims to reduce the dispersibility of concrete in water and improve its stability and durability.

[0003] In the prior art, patent CN114316131A proposes a polyacrylamide for underwater non-dispersive concrete and a preparation method and concrete thereof. A ternary polymer is prepared by copolymerization of acrylamide, acrylic acid, and allyl-A-D pyranogalactoside. Wang Ying et al. (CN110054434A) prepared a flocculant for underwater non-dispersive concrete by mixing graft-modified konjac flour, polyethylene glycol bislaurate, dispersant, sodium salt of nitrilotriacetic acid, lithium polystyrene sulfonate, and wollastonite in proportion. The freshly mixed concrete with the flocculant has good viscosity and fluidity, and the concrete has the characteristics of self-leveling and self-compacting after being poured underwater. Lin Xian et al. (CN1191287C) prepared a polyacrylamide-polyvinyl alcohol copolymer by introducing nitrogen into acrylamide monomer and polyvinyl alcohol, adding hydrogen peroxide, ferrous sulfate, or adding cerium nitrate amine for polymerization, or mixing naphthalene sulfonate formaldehyde condensate to prepare a modified polyacrylamide flocculant. Zhao Yan et al. disclosed in patent CN108203256A a flocculant for high-strength underwater non-dispersive concrete. The concrete prepared by mixing the components of the flocculant in proportion has the characteristics of short setting time, no segregation when coming into contact with water, non-dispersion underwater, and high strength compared with the concrete without the flocculant. The anti-dispersion agents / flocculants provided by the above prior art are mainly prepared by modifying acrylamide. The products obtained have reduced fluidity after increasing cohesiveness, and the influence of dynamic water scouring on underwater non-dispersive concrete under actual working conditions has not been studied.

[0004] Therefore, how to provide an anti-dispersion agent for underwater non-dispersive concrete with good comprehensive performance is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0005] To solve the above technical problems, the present application provides an anti-dispersion agent for underwater non-dispersive concrete and a preparation method thereof.

[0006] To achieve the above object, the present application provides the following technical solutions.

[0007] An anti-dispersing agent for underwater non-dispersible concrete, having a structural formula as shown in formula (I):

[0008]

[0009] (I);

[0010] wherein R1 is independently selected from , , , ;

[0011] R2 is independently selected from , ;

[0012] m = 200-500;

[0013] n = 15-70.

[0014] Beneficial effects: The anti-dispersing agent provided by the present application is a polymer with a micro-crosslinking structure (i.e. a polymerization structure containing R2 in formula I), which enhances its coating effect on cement paste. The benzene ring group increases the rigidity of the structure itself, enhances the cohesiveness of the concrete, and improves its resistance to scouring under dynamic water impact. The long side chain isoprenyl polyoxyethylene ether can form hydrogen bonds with water molecules, play a certain water retention and wetting role, reduce the yield stress of concrete, improve the thixotropy of concrete, and enhance the fluidity. Moreover, the sulfonic acid group contained in the 2-acrylamide-2-methylpropane sulfonic acid sodium in the structure has strong polarization ability to water molecules, improves the overall salt tolerance of the structure, and enhances the adaptability of the anti-dispersing agent in different water environments. The underwater non-dispersible concrete doped with the anti-dispersing agent can achieve the effects of having both anti-dispersibility and fluidity, good resistance to dynamic water scouring, high water-land strength ratio, and significantly shortened setting time compared with conventional anti-dispersing agents.

[0015] A preparation method of an anti-dispersing agent for underwater non-dispersible concrete, comprising the following steps:

[0016] Mixing acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid sodium, a crosslinking agent, sodium hydroxide, and a modified isoprenyl polyoxyethylene ether solution and heating to increase the temperature, then adding ammonium persulfate and ascorbic acid, stirring after treatment, and then adding hydroquinone for continuous stirring to obtain the anti-dispersing agent for underwater non-dispersible concrete.

[0017] Preferably, the crosslinking agent is one of dimethyl diallyl ammonium chloride and diallyl malonic acid diethyl ester.

[0018] Preferably, the preparation method of the modified prenyl polyoxyethylene ether solution comprises the following steps:

[0019] After the prenyl polyoxyethylene ether is melted, the monoisocyanate is added, heated and reacted, and then cooled, and water is added and uniformly mixed to obtain the modified prenyl polyoxyethylene ether solution.

[0020] Preferably, the molecular weight of the prenyl polyoxyethylene ether is 800 g / mol, 1200 g / mol, 2400 g / mol or 3000 g / mol.

[0021] More preferably, the molecular weight of the prenyl polyoxyethylene ether is 2400 g / mol.

[0022] Preferably, the monoisocyanate comprises one of phenyl isocyanate, benzyl isocyanate, p-methyl phenyl isocyanate and p-nitro phenyl isocyanate.

[0023] Preferably, the heating temperature is 60 DEG C.

[0024] Preferably, the stirring treatment is that after stirring for 0.5 h, standing for 5 min, and then stirring for 20 min.

[0025] Preferably, the time of the continuous stirring is 5 min.

[0026] The above anti-dispersing agent for underwater non-dispersible concrete is used as an anti-dispersing agent; the amount of the anti-dispersing agent in the concrete raw materials is 1.5-3.5 kg / m 3 .

[0027] Compared with the prior art, the present application has the following advantages and technical effects:

[0028] The anti-dispersing agent provided by the present application has the following advantages: first, the micro-crosslinking structure is introduced in the structure, which enhances the coating effect on the cement slurry; the benzene ring group increases the rigidity of the structure itself, which enhances the cohesiveness of the concrete and improves the anti-scouring effect under dynamic water impact; the long side chain prenyl polyoxyethylene ether can form hydrogen bonds with water molecules, which plays a certain water-retaining and wetting role, reduces the yield stress of the concrete, improves the thixotropy of the concrete, and enhances the fluidity. In addition, the sulfonic acid group contained in the 2-acrylamide-2-methylpropane sulfonic acid sodium in the structure has strong polarization ability to water molecules, which improves the overall salt tolerance of the structure and enhances the adaptability of the anti-dispersing agent in different water environments. Furthermore, the raw materials used in the anti-dispersing agent are simple and easy to obtain, no volatile solvent is used in the preparation process, the main reaction is carried out in an aqueous solution, no waste liquid and waste gas are discharged, and no purification and separation are required, the production process meets the green environmental protection requirements, and compared with the traditional polyacrylamide-cellulose ether and polysaccharide anti-dispersing agent, the product has shorter setting time and higher early strength. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0030] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with specific embodiments.

[0031] Unless otherwise specified, the raw materials in the embodiments of the present application are all commercially available.

[0032] Unless otherwise specified, the room temperature or normal temperature in the embodiments of the present application refers to 25±3℃.

[0033] Embodiment 1

[0034] A preparation method of an anti-dispersing agent for underwater non-dispersible concrete, comprising the following steps:

[0035] (1) 0.1 mol of isopentenyl polyoxyethylene ether with a molecular weight of 1200 g / mol is heated to a molten state at 80℃, then 0.1 mol of phenyl isocyanate is added, and after stirring at 80℃ for 3 h, it is cooled to 25℃, and then 4000 g of deionized water is added to obtain a modified isopentenyl polyoxyethylene ether solution W1. The structural formula of the modified isopentenyl polyoxyethylene ether is as follows:

[0036] ;

[0037] (2) 0.05 mol of acrylic acid, 0.4 mol of 2-acrylamido-2-methylpropane sulfonic acid sodium, 0.1 g of a dimethyl diallyl ammonium chloride solution with a mass fraction of 60%, 0.04 mol of sodium hydroxide are sequentially added to W1 obtained in step (1), and after stirring, it is heated to 60℃, then 0.1 g of ammonium persulfate, 0.02 g of ascorbic acid are sequentially added, and after stirring for 0.5 h, it is left standing for 5 min, then stirred for 20 min, and then 0.01 g of hydroquinone is added, and stirring is continued for 5 min to obtain an anti-dispersing agent, and the structure is as follows:

[0038]

[0039] Embodiment 2

[0040] A preparation method of an anti-dispersing agent for underwater non-dispersible concrete, comprising the following steps:

[0041] (1) Take 0.1 mol of isopentenyl polyoxyethylene ether with a molecular weight of 2400 g / mol, heat to a molten state at 80°C, then add 0.1 mol of benzyl isocyanate, keep stirring at 80°C for 3 h, then cool to 25°C, and add 4000 g of deionized water to obtain a modified isopentenyl polyoxyethylene ether solution W2. The structure of the modified isopentenyl polyoxyethylene ether is as follows:

[0042] ;

[0043] (2) Add 0.05 mol of acrylic acid, 0.4 mol of 2-acrylamido-2-methylpropane sulfonic acid sodium, 0.1 g of a dimethyldiallyl ammonium chloride solution with a mass fraction of 60%, and 0.04 mol of sodium hydroxide to W2 obtained in step (1) in sequence, stir uniformly, then heat to 60°C, then add 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid in sequence, continuously stir for 0.5 h, then stand for 5 min, then stir for another 20 min, then add 0.01 g of hydroquinone, continue stirring for 5 min, and an anti-dispersant is obtained. The structure is as follows:

[0044]

[0045] Example 3

[0046] A preparation method of an anti-dispersant for underwater non-dispersible concrete, comprising the following steps:

[0047] (1) Take 0.1 mol of isopentenyl polyoxyethylene ether with a molecular weight of 2400 g / mol, heat to a molten state at 80°C, then add 0.1 mol of p-methylphenyl isocyanate, keep stirring at 80°C for 3 h, then cool to 25°C, and add 4000 g of deionized water to obtain a modified isopentenyl polyoxyethylene ether solution W3. The structure of the modified isopentenyl polyoxyethylene ether is as follows:

[0048] ;

[0049] (2) Add 0.05 mol of acrylic acid, 0.4 mol of 2-acrylamido-2-methylpropane sulfonic acid sodium, 0.1 g of a dimethyldiallyl ammonium chloride solution with a mass fraction of 60%, and 0.04 mol of sodium hydroxide to W3 obtained in step (1) in sequence, stir uniformly, then heat to 60°C, then add 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid in sequence, continuously stir for 0.5 h, then stand for 5 min, then stir for another 20 min, then add 0.01 g of hydroquinone, continue stirring for 5 min, and an anti-dispersant is obtained. The structure is as follows:

[0050]

[0051] Example 4

[0052] A method for preparing an anti-dispersant for underwater non-dispersible concrete comprises the following steps:

[0053] (1) Take 0.1 mol of isopentyl polyoxyethylene ether with a molecular weight of 2400 g / mol, heat it at 80°C until it is molten, then add 0.1 mol of p-nitrophenyl isocyanate, keep stirring at 80°C for 3 hours, cool it to 25°C, and add 4000 g of deionized water to obtain modified isopentyl polyoxyethylene ether solution W4. The structural formula of the modified isopentyl polyoxyethylene ether is as follows:

[0054] ;

[0055] (2) To the W4 obtained in step (1), 0.05 mol of acrylic acid, 0.4 mol of sodium 2-acrylamido-2-methylpropanesulfonate, 0.1 g of a 60% mass fraction dimethyldiallylammonium chloride solution, and 0.04 mol of sodium hydroxide were added in sequence, stirred evenly, and then heated to 60°C. 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid were then added in sequence. The mixture was stirred for 0.5 h and allowed to stand for 5 min. After stirring for 20 min, 0.01 g of hydroquinone was added and the mixture was stirred for 5 min to obtain an anti-dispersant. The structure is shown below:

[0056]

[0057] Comparative Example 1

[0058] A method for preparing an anti-dispersant comprises the following steps:

[0059] (1) 0.1 mol of isopentyl polyoxyethylene ether having a molecular weight of 1200 g / mol was added to 4000 g of deionized water to obtain isopentyl polyoxyethylene ether solution A1;

[0060] (2) To A1, 0.05 mol of acrylic acid, 0.4 mol of sodium 2-acrylamido-2-methylpropanesulfonate, 0.1 g of 60% dimethyldiallylammonium chloride solution, and 0.04 mol of sodium hydroxide were added in sequence. After stirring evenly, the temperature was raised to 60°C. 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid were then added in sequence. The mixture was stirred for 0.5 h and allowed to stand for 5 min. After stirring for 20 min, 0.01 g of hydroquinone was added. The mixture was stirred for 5 min to obtain an anti-dispersant. The structure is shown below:

[0061]

[0062] Comparative Example 2

[0063] A method for preparing an anti-dispersant for underwater non-dispersible concrete comprises the following steps:

[0064] (1) Take 0.1 mol of isopentyl polyoxyethylene ether with a molecular weight of 2400 g / mol, heat it at 80°C until it is molten, then add 0.1 mol of benzyl isocyanate, keep stirring at 80°C for 3 hours, cool it to 25°C, and add 4000 g of deionized water to obtain modified isopentyl polyoxyethylene ether solution A2. The structural formula of the modified isopentyl polyoxyethylene ether is as follows:

[0065] ;

[0066] (2) To A2 obtained in step (1), 0.05 mol of acrylic acid, 0.1 g of a 60% mass fraction dimethyldiallyl ammonium chloride solution, and 0.04 mol of sodium hydroxide were added in sequence, stirred evenly, and then heated to 60°C. 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid were then added in sequence. The mixture was stirred for 0.5 h and allowed to stand for 5 min. After stirring for 20 min, 0.01 g of hydroquinone was added and the mixture was stirred for 5 min to obtain an anti-dispersant. The structure of the anti-dispersant is shown below:

[0067]

[0068] Comparative Example 3

[0069] A method for preparing an anti-dispersant for underwater non-dispersible concrete comprises the following steps:

[0070] (1) 0.1 mol of isopentyl polyoxyethylene ether with a molecular weight of 2400 g / mol was heated at 80°C until it melted, and then 0.1 mol of p-methylphenyl isocyanate was added. The temperature was maintained at 80°C and stirred for 3 hours, then cooled to 25°C and 4000 g of deionized water was added to obtain a modified isopentyl polyoxyethylene ether solution A3. The structural formula of the modified isopentyl polyoxyethylene ether is shown below:

[0071] ;

[0072] (2) To A3 obtained in step (1), 0.05 mol of acrylic acid, 0.4 mol of acrylamide, 0.1 g of a 60% by mass dimethyldiallyl ammonium chloride solution, and 0.04 mol of sodium hydroxide were added in sequence, stirred evenly, and then heated to 60°C. 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid were then added in sequence. The mixture was stirred for 0.5 h and allowed to stand for 5 min. After stirring for 20 min, 0.01 g of hydroquinone was added and the mixture was stirred for 5 min to obtain an anti-dispersant. The structure of the anti-dispersant is shown below:

[0073]

[0074] Comparative Example 4

[0075] A method for preparing an anti-dispersant for underwater non-dispersible concrete comprises the following steps:

[0076] (1) 0.1 mol of isopentyl polyoxyethylene ether with a molecular weight of 2400 g / mol was heated at 80°C until it melted, and then 0.1 mol of p-nitrophenyl isocyanate was added. The mixture was stirred at 80°C for 3 hours, then cooled to 25°C and 4000 g of deionized water was added to obtain a modified isopentyl polyoxyethylene ether solution A4. The structural formula of the modified isopentyl polyoxyethylene ether is shown below:

[0077] ;

[0078] (2) To A4 obtained in step (1), 0.05 mol of acrylic acid, 0.4 mol of sodium 2-acrylamido-2-methylpropanesulfonate and 0.02 mol of sodium hydroxide were added in sequence, stirred evenly and then heated to 60°C. 0.1 g of ammonium persulfate and 0.02 g of ascorbic acid were then added in sequence. The mixture was stirred for 0.5 h and allowed to stand for 5 min. After stirring for 20 min, 0.01 g of hydroquinone was added and the mixture was stirred for 5 min to obtain an anti-dispersant. The structure of the anti-dispersant is shown below:

[0079]

[0080] Technical effects:

[0081] The underwater non-dispersible concrete anti-dispersant prepared in the examples and comparative examples was added to C40 concrete in a solid content of 0.05% of the cementitious mass. The mix ratio of C40 concrete (kg / m 3 )for:

[0082] Water-cement ratio 0.38, cement 306kg / m 3 、FA97kg / m 3 , sand 802kg / m 3 , G 5-10 631kg / m 3 , G 10-20 431kg / m 3 、Water 153kg / m 3 , polycarboxylate water reducer 1wt%, anti-dispersant 2.6kg / m 3 .

[0083] A blank group (no anti-dispersant added) and a control group (the anti-dispersant was replaced with the mainstream polysaccharide UWB-Π anti-dispersant on the market, with the dosage being 10% of the gelling material) were also set up.

[0084] The test method refers to GBT 37990-2019 “Technical requirements for underwater non-dispersible concrete flocculants”, DL / T5117-2021 “Test procedures for underwater non-dispersible concrete”, and the test indexes are respectively suspended matter content, setting time, and water-land strength ratio. The anti-scouring performance of underwater non-dispersible concrete is tested by referring to the standard test method of CRD-C61-89A (1989). The results are shown in Table 1:

[0085] Table 1 Test data of underwater non-dispersible concrete

[0086]

[0087] Note: The test of a is carried out in 20% sodium chloride solution

[0088] As shown in Table 1, the suspended matter content of the concrete prepared by using the anti-dispersing agent obtained in Examples 1-4 is significantly reduced compared with the blank group, which indicates that the anti-dispersibility in static water state is good. At the same time, the scouring weight loss is less than that of the control group, and the 1h expansion degree is higher than that of the concrete mixed with UWB-II, which indicates that the anti-dispersibility in dynamic water is better, and the cohesiveness is increased while maintaining good workability. Among them, the technical effect of the concrete prepared by using the anti-dispersing agent of Example 3 is the best. Compared with Example 1, Comparative Example 1 does not introduce a benzene ring group, and its rigidity is slightly poor, so the anti-dynamic water performance is poor; in Comparative Example 2, 2-acrylamide-2-methylpropanesulfonic acid sodium is lacking, the overall cohesiveness is reduced, and the anti-dispersibility is weakened; compared with Example 3, in Comparative Example 3, acrylamide is used to replace 2-acrylamide-2-methylpropanesulfonic acid sodium, and there is no obvious change in performance in aqueous solution, but there is a difference in high-salt-concentration water; compared with Example 4, Comparative Example 4 does not add a crosslinking agent, and basically loses the anti-dispersing effect.

[0089] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing an anti-dispersant for underwater non-dispersible concrete, characterized in that: The following steps are involved: Acrylic acid, sodium 2-acrylamido-2-methylpropanesulfonate, a crosslinking agent, sodium hydroxide and a modified isopentenyl polyoxyethylene ether solution are mixed and heated to a high temperature, and then ammonium persulfate and ascorbic acid are added. After stirring, hydroquinone is added and stirring is continued to obtain the anti-dispersant for underwater non-dispersible concrete; The preparation method of the modified isopentenyl polyoxyethylene ether solution comprises the following steps: After melting the isopentenyl polyoxyethylene ether, monoisocyanate is added, heating for reaction, cooling, and then adding water and mixing evenly to obtain the modified isopentenyl polyoxyethylene ether solution; The monoisocyanate is selected from one of phenyl isocyanate, benzyl isocyanate, p-methylphenyl isocyanate and p-nitrophenyl isocyanate.

2. The method for preparing an anti-dispersant for underwater non-dispersible concrete according to claim 1, characterized in that: The cross-linking agent is dimethyldiallylammonium chloride.

3. The method for preparing an anti-dispersant for underwater non-dispersible concrete according to claim 1, characterized in that: The molecular weight of the isopentenyl polyoxyethylene ether is 800 g / mol, 1200 g / mol, 2400 g / mol or 3000 g / mol.

4. The method for preparing an anti-dispersant for underwater non-dispersible concrete according to claim 1, characterized in that: The heating temperature is 60°C.

5. The method for preparing an anti-dispersant for underwater non-dispersible concrete according to claim 1, characterized in that: The stirring treatment is as follows: stirring continuously for 0.5 h, then standing for 5 min, and then stirring for 20 min.

6. The method for preparing an anti-dispersion agent for underwater non-dispersible concrete according to claim 1, characterized in that: The stirring time is continued for 5 minutes.

7. An underwater non-dispersible concrete, characterized in that: The anti-dispersant for underwater non-dispersible concrete prepared by the preparation method according to any one of claims 1 to 6 is used as an anti-dispersant; the amount of the anti-dispersant in the concrete raw material is 1.5 to 3.5 kg / m 3 .

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