Normal-temperature synthetic concrete viscosity reducer and preparation method thereof

Abstract

The application discloses a normal-temperature-synthesized concrete viscosity reducer and a preparation method thereof, and belongs to the technical field of building materials. The concrete viscosity reducer comprises the following components: liquid polyether 60-75% by mass, unsaturated carboxylic acid monomer 3-6%, unsaturated functional monomer 0.05-0.5%, oxidizing agent 0.1-0.5%, reducing agent 0.03-0.2%, chain transfer agent 0.05-0.3%, alkali solution 1-3%, and the rest is deionized water. The viscosity reducer prepared by the application can obviously reduce the viscosity of concrete mixture, can be synthesized at normal temperature, has low production energy consumption and cost, can increase economic benefits, has the characteristics of low mixing amount, and can obviously reduce the inversion slump flow cylinder emptying time of high-strength concrete.

Description

Technical Field

[0001] This invention relates to a concrete viscosity reducer synthesized at room temperature and its preparation method, belonging to the field of building materials technology. Background Technology

[0002] Ultra-high performance concrete (UHPC) has shown great potential for application in high-end building structures due to its excellent mechanical properties and durability. However, UHPC generally suffers from high viscosity during preparation and construction, which not only increases construction difficulty but may also affect the quality of the final building structure. Therefore, solving the high viscosity problem of UHPC is a key challenge to achieve its widespread application. The main reasons for the high viscosity of UHPC include high dosage of cementitious materials, a variety of mineral admixtures, and a low water-cement ratio.

[0003] To address the high viscosity issue of high-performance concrete (UHPC), methods such as increasing the dosage of water-reducing agents, optimizing mix design, and introducing air-entraining agents can be employed. However, researching and developing novel admixtures and polycarboxylate mother liquors to replace traditional materials offers a more effective solution. For instance, due to the designability of its molecular structure, polycarboxylate mother liquors allow for the control of the degree of polymerization of the main chain, the density of the side chains, the molecular weight of the polyether monomers, and the types of functional groups to achieve high performance in polycarboxylate water-reducing agents. Therefore, developing novel polycarboxylate mother liquors and synthesizing viscosity-reducing polycarboxylate mother liquors that combine water-reducing and viscosity-reducing functions can effectively solve the adaptability problems associated with compounding viscosity-reducing components in water-reducing agents, reducing viscosity without sacrificing the performance of UHPC.

[0004] Compared to four-carbon and five-carbon polyethers, six-carbon polyethers have higher polymerization activity and produce polycarboxylate mother liquor with excellent performance. However, they have problems such as lower reaction temperature and higher refrigeration energy consumption. Therefore, developing six-carbon viscosity-reducing mother liquor synthesized at room temperature is the future development direction for polycarboxylate mother liquor synthesis. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a concrete viscosity reducer synthesized at room temperature and its preparation method, which can significantly reduce the viscosity of concrete mixtures and can be synthesized at room temperature with low production energy consumption and cost, thus meeting the needs of industrial production.

[0006] To address the shortcomings of existing technologies, the technical solution provided by this invention is as follows:

[0007] A room-temperature synthesized concrete viscosity reducer comprises the following components by mass: 60-75% liquid polyether, 3-6% unsaturated carboxylic acid monomer, 0.05-0.5% unsaturated functional monomer, 0.1-0.5% oxidant, 0.03-0.2% reducing agent, 0.05-0.3% chain transfer agent, 1-3% alkaline solution, and the remainder being deionized water.

[0008] A method for preparing a concrete viscosity reducer synthesized at room temperature includes the following steps:

[0009] (1) Add deionized water to the reducing agent and chain transfer agent, stir until dissolved, and obtain solution A;

[0010] (2) Mix unsaturated carboxylic acid and unsaturated functional monomer with water to obtain solution B;

[0011] (3) Add deionized water to the liquid polyether, then add oxidant, stir well to obtain mixed solution 1;

[0012] (4) Add the catalyst to mixed solution 1 and stir for 5-10 min to obtain mixed solution 2;

[0013] (5) Add solution A and solution B dropwise to mixed solution 2 at a uniform rate, stir, and then adjust the pH with an alkaline solution to obtain concrete viscosity reducer.

[0014] Furthermore, in step (1), the reducing agent is one or more of ascorbic acid, reducing agent E51, or sodium formaldehyde sulfoxylate; the chain transfer agent is one or more of mercaptopropionic acid, mercaptoethanol, or sodium hypophosphite.

[0015] Furthermore, in step (2), the unsaturated carboxylic acid is one or two of acrylic acid, methacrylic acid, or malonic anhydride; the unsaturated functional monomer is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, or silane coupling agent KH570.

[0016] Furthermore, in step (3), the liquid polyether is one or a mixture of two of liquid hexacarbon polyether, liquid tetracarbon polyether, or liquid pentacarbon polyether; the oxidant is one or more of hydrogen peroxide, ammonium persulfate, or potassium persulfate.

[0017] Furthermore, by mass, liquid hexacarbon polyether accounts for 50-95% of liquid polyether; the concentrations of liquid tetracarbon polyether, liquid pentacarbon polyether, and liquid hexacarbon polyether are all 60 wt.%.

[0018] Furthermore, the four-carbon polyether is methyl allyl polyoxyethylene ether (HPEG), the five-carbon polyether is isopentenyl polyoxyethylene ether (TPEG), and the six-carbon polyether is one or both of ethylene glycol monovinyl polyethylene glycol ether (EPEG) or 4-hydroxybutyl vinyl polyoxyethylene ether (VPEG).

[0019] Furthermore, in step (4), the catalyst is a ferrous sulfate solution. After adding the oxidant and stirring evenly, the catalyst is added to prevent too many free radicals generated by the reaction between the catalyst and the oxidant, which would result in a product with a large molecular weight and poor product performance.

[0020] Furthermore, in step (5), the time for adding liquid A is 1-1.5h, the time for adding liquid B is 0.8-1h, and the stirring time is 0.5-2h.

[0021] Furthermore, in step (5), the pH is adjusted to 5.0-6.0 with an alkaline solution; the alkaline solution is one or both of sodium hydroxide solution and potassium hydroxide solution; the concentration of the alkaline solution is 30 wt.%.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) By adding some tetracarbon polyether or pentacarbon polyether to the six-carbon polyether macromonomer, the activity of the reactants is reduced. While ensuring the reaction rate and shortening the reaction time, the reaction can be carried out at room temperature, which effectively reduces the energy consumption of the reaction process and reduces the production cost.

[0024] (2) The concrete viscosity reducer prepared by the present invention can significantly reduce the viscosity of concrete, and the raw materials for synthesis are simple and easy to obtain, the synthesis process is simple, and it can be mass-produced.

[0025] (3) The viscosity reducer described in this invention has the characteristic of low dosage, which can significantly reduce the slump time of high-strength concrete by more than 30%. Detailed Implementation

[0026] Example 1

[0027] A room-temperature synthesized concrete viscosity reducer comprises the following components by mass: 60% liquid polyether solution, 4.5% unsaturated carboxylic acid monomer, 0.09% unsaturated functional monomer, 0.25% oxidant, 0.05% reducing agent, 0.1% chain transfer agent, 1.3% alkaline solution, and the remainder being deionized water.

[0028] A method for preparing a concrete viscosity reducer synthesized at room temperature includes the following steps:

[0029] (1) Add deionized water to ascorbic acid and mercaptoethanol, stir until dissolved, and obtain solution A;

[0030] (2) Mix acrylic acid, hydroxyethyl methacrylate and silane coupling agent KH570 with water to obtain solution B;

[0031] (3) Add deionized water to liquid HPEG and liquid EPEG with a mass ratio of 1:9, then add hydrogen peroxide, stir well to obtain mixed solution 1;

[0032] (4) Add ferrous sulfate to mixed solution 1 and stir for 10 min to obtain mixed solution 2;

[0033] (5) Add solution A and solution B to mixed solution 2 at a uniform rate. The addition time of solution A is 1.5h and the addition time of solution B is 1h. Then stir for 0.5h and adjust the pH to 6.0 with sodium hydroxide solution to obtain concrete viscosity reducer.

[0034] Example 2

[0035] A room-temperature synthesized concrete viscosity reducer comprises the following components by mass: 60% liquid polyether solution, 4.5% unsaturated carboxylic acid monomer, 0.09% unsaturated functional monomer, 0.25% oxidant, 0.05% reducing agent, 0.1% chain transfer agent, 1.3% alkaline solution, and the remainder being deionized water.

[0036] A method for preparing a concrete viscosity reducer synthesized at room temperature includes the following steps:

[0037] (1) Add deionized water to ascorbic acid and mercaptoethanol, stir until dissolved, and obtain solution A;

[0038] (2) Mix acrylic acid, hydroxyethyl methacrylate and silane coupling agent KH570 with water to obtain solution B;

[0039] (3) Add deionized water to liquid TPEG and liquid EPEG with a mass ratio of 1:9, then add hydrogen peroxide, stir well to obtain mixed solution 1;

[0040] (4) Add ferrous sulfate to mixed solution 1 and stir for 5 minutes to obtain mixed solution 2;

[0041] (5) Add solution A and solution B to mixed solution 2 at a uniform rate. The addition time of solution A is 1.5h and the addition time of solution B is 1h. Then stir for 0.5h and adjust the pH to 5.0 with potassium hydroxide solution to obtain concrete viscosity reducer.

[0042] Example 3

[0043] A room-temperature synthesized concrete viscosity reducer comprises the following components by mass: 60% liquid polyether solution, 4.5% unsaturated carboxylic acid monomer, 0.09% unsaturated functional monomer, 0.25% oxidant, 0.05% reducing agent, 0.1% chain transfer agent, 1.3% alkaline solution, and the remainder being deionized water.

[0044] A method for preparing a concrete viscosity reducer synthesized at room temperature includes the following steps:

[0045] (1) Add deionized water to ascorbic acid and mercaptoethanol, stir until dissolved, and obtain solution A;

[0046] (2) Mix acrylic acid, hydroxyethyl methacrylate and silane coupling agent KH570 with deionized water to obtain solution B;

[0047] (3) Add deionized water to liquid TPEG and liquid EPEG with a mass ratio of 2:8, then add hydrogen peroxide, stir well to obtain mixed solution 1;

[0048] (4) Add ferrous sulfate to mixed solution 1 and stir for 5 minutes to obtain mixed solution 2;

[0049] (5) Add solution A and solution B to mixed solution 2 at a uniform rate. The addition time of solution A is 1.5h and the addition time of solution B is 1h. Then stir for 0.5h and adjust the pH to 5.5 with sodium hydroxide solution to obtain concrete viscosity reducer.

[0050] Example 4

[0051] A room-temperature synthesized concrete viscosity reducer comprises the following components by mass: 60% liquid polyether solution, 4.5% unsaturated carboxylic acid monomer, 0.09% unsaturated functional monomer, 0.25% oxidant, 0.05% reducing agent, 0.1% chain transfer agent, 1.3% alkaline solution, and the remainder being deionized water.

[0052] A method for preparing a concrete viscosity reducer synthesized at room temperature includes the following steps:

[0053] (1) Add deionized water to ascorbic acid and mercaptoethanol, stir until dissolved, and obtain solution A;

[0054] (2) Mix acrylic acid, hydroxyethyl methacrylate and silane coupling agent KH570 with water to obtain solution B;

[0055] (3) Add deionized water to liquid HPEG and liquid VPEG with a mass ratio of 1:9, then add hydrogen peroxide, stir well to obtain mixed solution 1;

[0056] (4) Add ferrous sulfate to mixed solution 1 and stir for 7 minutes to obtain mixed solution 2;

[0057] (5) Add solution A and solution B dropwise to mixed solution 2 at a uniform rate. Solution A is added over 1.5 hours and solution B is added over 1 hour. Then stir for 0.5 hours and adjust the pH to 5.5 with potassium hydroxide solution to obtain concrete viscosity reducer.

[0058] Experimental Example 1

[0059] The performance of the concrete viscosity reducers prepared in Examples 1-4 was compared according to the "Standard for Test Methods of Performance of Ordinary Concrete Mixtures" GB / T 50080-2016. The performance was evaluated based on the slump time of the concrete inverted slump cone; a shorter slump time indicated a better viscosity reduction effect. Similarly, the air content of the concrete was determined according to GB / T 50080-2016, and the compressive strength of the concrete was tested according to GB / T 50081-2019, "Standard for Test Methods of Physical and Mechanical Properties of Concrete". No viscosity reducer was added to the control group. Comparative Examples 1 and 2 used two different commercially available viscosity reducers, and tests were conducted according to the aforementioned standards.

[0060] The concrete mix proportion adopts the engineering C80 concrete mix proportion, as shown in Table 1.

[0061] Table 1. Mix Proportions for C80 Concrete

[0062]

[0063] The effects of different concrete viscosity reducers on concrete performance are listed in Table 2.

[0064] Table 2. Effects of different concrete viscosity reducers on concrete properties

[0065]

[0066] Table 2 shows that the initial drainage time and 2-hour drainage time of the blank group without the added viscosity reducer were 13.1 s and 15.7 s, respectively. In Comparative Examples 1 and 2, after incorporating commercially available viscosity reducers 1 and 2, respectively, the concrete viscosity decreased to some extent, but the initial drainage time and 2-hour drainage time remained above 10.0 s, making pumping difficult. However, after adding the viscosity reducer prepared according to this invention, the initial drainage time and 2-hour drainage time of the concrete were significantly reduced, and the 7-day and 28-day compressive strengths showed no significant decrease. This indicates that the viscosity reducer prepared according to this invention can effectively reduce the concrete viscosity without adversely affecting the strength.

Claims

1. A synthetic concrete viscosity reducer at ambient temperature, characterized by: The composition comprises the following components: 60-75% by mass of liquid polyether, 3-6% of unsaturated carboxylic acid monomer, 0.05-0.5% of unsaturated functional monomer, 0.1-0.5% of oxidizing agent, 0.03-0.2% of reducing agent, 0.05-0.3% of chain transfer agent, 1-3% of alkali solution, and the rest is deionized water; the liquid polyether is a mixture of liquid six-carbon polyether and one or both of liquid four-carbon polyether or liquid five-carbon polyether; the liquid six-carbon polyether accounts for 50-95% by mass of the liquid polyether; the concentrations of the liquid four-carbon polyether, the liquid five-carbon polyether and the liquid six-carbon polyether are all 60 wt.%; the four-carbon polyether is a methyl allyl polyoxyethylene ether, the five-carbon polyether is an isopentenyl alcohol polyoxyethylene ether, and the six-carbon polyether is one or both of ethylene glycol monovinyl polyethylene glycol ether or 4-hydroxybutyl vinyl polyoxyethylene ether; The preparation method of the concrete viscosity reducer synthesized at room temperature comprises the following steps: (1) adding deionized water to the reducing agent and the chain transfer agent, stirring until dissolved to obtain A liquid; (2) mixing the unsaturated carboxylic acid and the unsaturated functional monomer with deionized water uniformly to obtain B liquid; (3) adding deionized water to the liquid polyether, then adding the oxidizing agent and stirring uniformly to obtain a mixed solution 1; (4) adding a catalyst to the mixed solution 1, stirring for 5-10 min to obtain a mixed solution 2; (5) adding A liquid and B liquid to the mixed solution 2 at a constant speed, adjusting the pH with an alkali solution after stirring to obtain the concrete viscosity reducer.

2. The synthetic concrete viscosity reducing agent at room temperature according to claim 1, characterized by: In step (1), the reducing agent is one or more of ascorbic acid, reducing agent E51 or ammonium sulfite; the chain transfer agent is one or more of mercaptopropionic acid, mercaptoethanol or sodium hypophosphite.

3. The synthetic concrete viscosity reducing agent at room temperature according to claim 2, characterized by: In step (2), the unsaturated carboxylic acid is one or both of acrylic acid, methacrylic acid or maleic anhydride; the unsaturated functional monomer is at least one of hydroxyethyl methacrylate, hydroxypropyl methacrylate or silane coupling agent KH570.

4. The synthetic concrete viscosity reducing agent at room temperature according to claim 3, characterized by: In step (3), the oxidizing agent is one or more of hydrogen peroxide, ammonium persulfate or potassium persulfate.

5. The synthetic concrete viscosity reducing agent at room temperature according to claim 4, characterized by: In step (4), the catalyst is a ferrous sulfate solution.

6. The synthetic concrete viscosity reducing agent at room temperature according to claim 5, characterized by: In step (5), the time for adding A liquid is 1-1.5 h, and the time for adding B liquid is 0.8-1 h; the stirring time is 0.5-2 h.

7. The synthetic concrete viscosity reducing agent at room temperature according to claim 6, characterized by: In step (5), the pH is adjusted to 5.0-6.0 with an alkali solution; the alkali solution is one or both of sodium hydroxide solution or potassium hydroxide solution; the concentration of the alkali solution is 30 wt.%.

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