A low-sensitivity concrete water reducer and preparation method thereof

Abstract

The present invention relates to the technical field of building admixtures, and specifically to a low-sensitivity concrete water reducer and a preparation method thereof. The low-sensitivity concrete water reducer comprises, by weight, 300 to 440 parts of a polyether monomer, 650 to 750 parts of water, 1 to 6 parts of a chain transfer agent, 28 to 60 parts of an olefin monomer, 3 to 5.5 parts of a 4A zeolite, 1.8 to 5.6 parts of an initiator, 0.4 to 1.2 parts of a reducing agent, and 12 to 19 parts of caustic soda. In the preparation method of the low-sensitivity concrete water reducer provided by the present invention, the 4A zeolite is ultrasonically dispersed into an olefin monomer solution, and the catalytic effect of the 4A zeolite is utilized to improve the reaction conversion rate during the dropwise addition process. At the same time, the multi-hole characteristics of the 4A zeolite are utilized to stably adsorb the polycarboxylic acid polymer generated by the reaction into the 4A zeolite cavities, thereby reducing the adsorption of other materials and reducing sensitivity. Under the synergistic effect of the 4A zeolite, the dispersibility of the water reducer in the slurry system is improved, thereby enhancing the water-reducing effect in the concrete.

Description

Technical Field

[0001] The present invention relates to the technical field of building admixtures, and in particular to a low-sensitivity concrete water reducing agent and a preparation method thereof. Background Art

[0002] In 1982, Japan published the first patent for a polycarboxylate superplasticizer, marking the beginning of research and development in this field. Nearly 40 years of development have resulted in the continuous improvement and widespread application of polycarboxylate superplasticizers. Research on polycarboxylate superplasticizers began in my country in the late 20th century, initially with ester-based superplasticizers and later with various ether-based superplasticizers. To meet diverse flooring and project requirements, the development of polycarboxylate superplasticizers in my country has rapidly progressed.

[0003] Polycarboxylic acid water reducers have strong adjustability in molecular structure and can produce products with different performances through different monomer compositions and polymerization processes. They have great potential for high performance and have become the most effective, economical and simplest technical approach to achieving high durability and performance improvement of concrete.

[0004] The Southwest region has a wide variety of cement types, resulting in significant variations in water requirements and admixture adsorption. Sand is primarily manufactured from pebble sand, and the mud and stone dust content in manufactured sand is strictly controlled. Wet sand production is typically used. To achieve the required mud and stone dust content, large amounts of flocculants are used in the sand washing water treatment process. This results in widespread residual flocculants in the manufactured sand, with significant fluctuations in flocculant content. Fluctuations in cementitious materials, such as cementitious materials and manufactured sand, significantly impact the application of admixtures, leading to alternating production losses and delays.

[0005] Concrete water reducers are highly sensitive to external fluctuations, which will affect their expansion. Therefore, it is of great significance to develop a low-sensitivity concrete water reducer that is less affected by mud adsorption. Summary of the Invention

[0006] In order to solve the problem of concrete water reducer being affected by mud adsorption mentioned in the above background technology, the present invention provides a low-sensitivity concrete water reducer, which is calculated by weight and comprises 300-440 parts of polyether monomer, 650-750 parts of water, 1-6 parts of chain transfer agent, 28-60 parts of olefin monomer, 3-5.5 parts of 4A zeolite, 1.8-5.6 parts of initiator, 0.4-1.2 parts of reducing agent and 12-19 parts of caustic soda.

[0007] On the basis of the above technical solution, further, the polyether monomer is at least one of methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether or vinyl polyoxyethylene ether.

[0008] On the basis of the above technical solution, further, the average molecular weight of the methyl allyl polyoxyethylene ether is 1964-3592, and its structural formula is: CH2=CH(CH3)CH2O(CH2CH2O)nH, wherein n=43-80.

[0009] On the basis of the above technical solution, further, the average molecular weight of the isopentenyl polyoxyethylene ether is 1980-3608, and its structural formula is: (CH3)2C=CHCH2O(CH2CH2O)nH, wherein n=43-80.

[0010] On the basis of the above technical solution, further, the average molecular weight of the vinyl polyoxyethylene ether is 1893-3653, and its structural formula is: C6H 12 O3(CH2CH2O)nH, wherein n=40~80.

[0011] On the basis of the above technical solution, further, the chain transfer agent is isopropyl alcohol, phosphorous acid and hypophosphorous acid and their salts (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, bisulfite, dithionite and metabisulfite and their salts (sodium sulfite, sodium bisulfite, preferably sodium dithionite, potassium sulfite, sodium metabisulfite, potassium bisulfite, potassium dithionite, potassium metabisulfite, etc.), mercaptoethanol, mercaptoglycerol, thioglycolic acid, mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, 2-mercaptoethanesulfonic acid and their salts. One or more combinations thereof.

[0012] On the basis of the above technical solution, further, the initiator is one or more combinations of hydrogen peroxide, potassium persulfate or sodium persulfate, ammonium persulfate, and azobisisobutylnitrile.

[0013] On the basis of the above technical solution, further, the reducing agent is one or more combinations of vitamin C, oxalic acid, ferrous sulfate, cuprous sulfate, oxalic acid, sodium bisulfite, sodium sulfite, glucose, fructose, ethylenediamine, diphenylamine, sodium monohydrogen phosphate or potassium monohydrogen phosphate.

[0014] On the basis of the above technical solution, further, the vinyl monomer is acrylic acid, crotonic acid, citraconic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, etc., as well as monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts, etc., or at least one of their anhydrides.

[0015] The present invention also provides a method for preparing any of the above-mentioned low-sensitivity concrete water reducers, comprising the following steps:

[0016] 3-5.5 parts by weight of 4A zeolite, 28-60 parts by weight of olefin monomer, and 140-170 parts by weight of water are added to a reaction kettle. A high-power industrial-grade continuous flow concentrated ultrasonic disperser is turned on and ultrasonication is continued for 2-3 hours to obtain a 4A zeolite-olefin monomer dispersion.

[0017] 300-440 parts by weight of a polyether monomer and 300-400 parts by weight of water are added to a reaction kettle, stirred and dissolved at 15-45° C., and 1.8-5.6 parts by weight of an initiator are added to obtain a mixture A;

[0018] To the mixture A obtained above, solution 1 is added dropwise in sequence: 1 to 6 parts by weight of a chain transfer agent, 0.4 to 1.2 parts by weight of a reducing agent, and 160 to 180 parts by weight of water;

[0019] Solution 2: obtained 4A zeolite-olefin monomer dispersion;

[0020] After the dropwise addition for 1 to 3.5 hours, the mixture is kept at a temperature below 55° C. for 1 to 2 hours for aging reaction, and then neutralized with an alkaline solution to a pH of 5.8 to 6.8 to obtain the low-sensitivity concrete water reducer.

[0021] The low-sensitivity concrete water reducer provided by the present invention adds 4A zeolite to the system, which can utilize the catalytic effect of the 4A zeolite to improve the reaction conversion rate. At the same time, the multi-hole characteristics of the 4A zeolite are utilized to stably adsorb the polycarboxylic acid polymer generated by the reaction in the 4A zeolite pores, thereby reducing the adsorption of other materials and reducing sensitivity. Under the synergistic effect of the 4A zeolite, the dispersibility of the water reducer in the slurry system is improved, and the water-reducing effect in the concrete is enhanced.

[0022] In the preparation method of the low-sensitivity concrete water reducer provided by the present invention, 4A zeolite is ultrasonically dispersed into an olefin monomer solution. During the dropwise addition process, the catalytic effect of the 4A zeolite can be utilized to improve the reaction conversion rate. At the same time, the multi-hole characteristics of the 4A zeolite are utilized to stably adsorb the polycarboxylic acid polymer generated by the reaction in the 4A zeolite pores, thereby reducing the adsorption of other materials and reducing sensitivity. Under the synergistic effect of the 4A zeolite, the dispersibility of the water reducer in the slurry system is improved, and the water-reducing effect in concrete is enhanced, thereby obtaining a low-sensitivity concrete water reducer.

[0023] Other features and beneficial effects of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood through practice of the present invention. The objectives and other beneficial effects of the present invention can be achieved and obtained through the structures particularly pointed out in the description and claims. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and should not be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have meanings consistent with the meanings of these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined as such in the present invention.

[0026] The present invention provides the following examples and comparative examples.

[0027] Among them, in the following examples and comparative examples, the average molecular weight of methyl allyl polyoxyethylene ether is 1964-3592, and its structural formula is: CH2=CH(CH3)CH2O(CH2CH2O)nH, wherein n=43-80. The average molecular weight of isopentenyl polyoxyethylene ether is 1980-3608, and its structural formula is: (CH3)2C=CHCH2O(CH2CH2O)nH, wherein n=43-80. The average molecular weight of vinyl polyoxyethylene ether is 1893-3653, and its structural formula is: C6H 12 O3(CH2CH2O)nH, wherein n=40~80.

[0028] Example 1

[0029] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 320 parts by weight of methyl allyl polyoxyethylene ether, 650 parts by weight of water, 3.5 parts by weight of isopropyl alcohol, 33 parts by weight of acrylic acid, 2.8 parts by weight of hydrogen peroxide, 0.8 parts by weight of vitamin C, 3.2 parts by weight of 4A zeolite, and 13 parts by weight of flake caustic soda.

[0030] The specific preparation method comprises the following steps:

[0031] (1) 3.2 parts by weight of 4A zeolite, 33 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0032] (2) 320 parts by weight of methyl allyl polyoxyethylene ether and 330 parts by weight of water were added to a reaction kettle, stirred and mixed at room temperature of 25° C. to dissolve, and 2.8 parts by weight of hydrogen peroxide was added;

[0033] (3) adding solution 1: 3.5 parts by weight of isopropyl alcohol, 0.8 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 2 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0034] Example 2

[0035] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 350 parts by weight of methyl allyl polyoxyethylene ether, 670 parts by weight of water, 2.7 parts by weight of thioglycolic acid, 43 parts by weight of methacrylic acid, 3.0 parts by weight of hydrogen peroxide, 0.8 parts by weight of vitamin C, 3.4 parts by weight of 4A zeolite, and 14 parts by weight of flake caustic soda.

[0036] The specific preparation method comprises the following steps:

[0037] (1) 3.4 parts by weight of 4A zeolite, 43 parts by weight of methacrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-methacrylic acid dispersion;

[0038] (2) 350 parts by weight of methyl allyl polyoxyethylene ether and 350 parts by weight of water were added to a reaction kettle, stirred and dissolved at room temperature of 25° C., and 2.8 parts by weight of hydrogen peroxide was added;

[0039] (3) Solution 1: 2.7 parts by weight of thioglycolic acid, 0.8 parts by weight of vitamin C, and 160 parts by weight of water; Solution 2: the 4A zeolite-methacrylic acid dispersion obtained in (1) are sequentially added dropwise to the material obtained in step (2); after the addition is continued for 2.5 hours, the mixture is kept at a temperature below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to a pH of 6.1, thereby obtaining the low-sensitivity concrete water reducer.

[0040] Example 3

[0041] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 380 parts by weight of isopentenyl polyoxyethylene ether, 690 parts by weight of water, 2.9 parts by weight of thioglycolic acid, 42 parts by weight of acrylic acid, 3.0 parts by weight of hydrogen peroxide, 1.6 parts by weight of ethylenediamine, 3.8 parts by weight of 4A zeolite, and 17 parts by weight of flake caustic soda.

[0042] The specific preparation method comprises the following steps:

[0043] (1) 3.8 parts by weight of 4A zeolite, 42 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0044] (2) adding 380 parts by weight of isopentenyl polyoxyethylene ether and 370 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 3.0 parts by weight of hydrogen peroxide;

[0045] (3) adding solution 1: 2.9 parts by weight of thioglycolic acid, 1.6 parts by weight of ethylenediamine, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0046] Example 4

[0047] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 360 parts by weight of isopentenyl polyoxyethylene ether, 670 parts by weight of water, 2.2 parts by weight of mercaptoethanol, 52 parts by weight of itaconic acid, 2.6 parts by weight of hydrogen peroxide, 0.8 parts by weight of vitamin C, 4.2 parts by weight of 4A zeolite, and 18 parts by weight of flake caustic soda.

[0048] The specific preparation method comprises the following steps:

[0049] (1) 4.2 parts by weight of 4A zeolite, 52 parts by weight of itaconic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-itaconic acid dispersion;

[0050] (2) adding 360 parts by weight of isopentenyl polyoxyethylene ether and 350 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.6 parts by weight of hydrogen peroxide;

[0051] (3) Solution 1: 2.2 parts by weight of mercaptoethanol, 0.8 parts by weight of vitamin C, and 160 parts by weight of water; Solution 2: the 4A zeolite-itaconic acid dispersion obtained in (1) are sequentially added dropwise to the material obtained in step (2); after the addition is continued for 3 hours, the mixture is kept at a temperature below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to a pH of 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0052] Example 5

[0053] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 400 parts by weight of isopentenyl polyoxyethylene ether, 710 parts by weight of water, 2.4 parts by weight of mercaptoethanol, 48 parts by weight of acrylic acid, 2.8 parts by weight of hydrogen peroxide, 0.9 parts by weight of vitamin C, 4.5 parts by weight of 4A zeolite, and 19 parts by weight of flake caustic soda.

[0054] The specific preparation method comprises the following steps:

[0055] (1) 4.5 parts by weight of 4A zeolite, 48 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0056] (2) adding 400 parts by weight of isopentyl polyoxyethylene ether and 390 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.8 parts by weight of hydrogen peroxide;

[0057] (3) adding solution 1: 2.4 parts by weight of mercaptoethanol, 0.9 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0058] Example 6

[0059] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 320 parts by weight of vinyl polyoxyethylene ether, 630 parts by weight of water, 2.8 parts by weight of mercaptoethanol, 44 parts by weight of acrylic acid, 2.2 parts by weight of hydrogen peroxide, 0.7 parts by weight of vitamin C, 4.2 parts by weight of 4A zeolite, and 17 parts by weight of flake caustic soda.

[0060] The specific preparation method comprises the following steps:

[0061] (1) 4.2 parts by weight of 4A zeolite, 44 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0062] (2) adding 320 parts by weight of vinyl polyoxyethylene ether and 310 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.2 parts by weight of hydrogen peroxide;

[0063] (3) adding solution 1: 2.8 parts by weight of mercaptoethanol, 0.7 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0064] Example 7

[0065] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 380 parts by weight of vinyl polyoxyethylene ether, 690 parts by weight of water, 4.8 parts by weight of sodium monohydrogen phosphate, 44 parts by weight of acrylic acid, 2.2 parts by weight of hydrogen peroxide, 0.7 parts by weight of vitamin C, 4.2 parts by weight of 4A zeolite, and 17 parts by weight of flake caustic soda.

[0066] The specific preparation method comprises the following steps:

[0067] (1) 4.2 parts by weight of 4A zeolite, 44 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0068] (2) adding 380 parts by weight of vinyl polyoxyethylene ether and 370 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.2 parts by weight of hydrogen peroxide;

[0069] (3) Solution 1: 4.8 parts by weight of sodium monohydrogen phosphate, 0.7 parts by weight of vitamin C, and 160 parts by weight of water; Solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) are sequentially added dropwise to the material obtained in step (2); after the addition is continued for 3 hours, the mixture is kept at a temperature below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to a pH of 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0070] Comparative Example 1

[0071] The commercially available XTX-B polycarboxylate water reducer was used.

[0072] Comparative Example 2

[0073] The commercially available PC-SM polycarboxylate water reducer was used.

[0074] Comparative Example 3

[0075] A concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 400 parts by weight of isopentenyl polyoxyethylene ether, 710 parts by weight of water, 2.4 parts by weight of mercaptoethanol, 48 parts by weight of acrylic acid, 2.8 parts by weight of hydrogen peroxide, 0.9 parts by weight of vitamin C, 4.5 parts by weight of conventional zeolite, and 19 parts by weight of flake caustic soda.

[0076] The specific preparation method comprises the following steps:

[0077] (1) 4.5 parts by weight of conventional zeolite, 48 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a conventional zeolite-acrylic acid dispersion;

[0078] (2) adding 400 parts by weight of isopentyl polyoxyethylene ether and 390 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.8 parts by weight of hydrogen peroxide;

[0079] (3) adding solution 1: 2.4 parts by weight of mercaptoethanol, 0.9 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the conventional zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0080] Comparative Example 4

[0081] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 400 parts by weight of isopentenyl polyoxyethylene ether, 710 parts by weight of water, 2.4 parts by weight of mercaptoethanol, 48 parts by weight of acrylic acid, 2.8 parts by weight of hydrogen peroxide, 0.9 parts by weight of vitamin C, 2 parts by weight of 4A zeolite, and 19 parts by weight of flake caustic soda.

[0082] The specific preparation method comprises the following steps:

[0083] (1) 2 parts by weight of 4A zeolite, 48 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0084] (2) adding 400 parts by weight of isopentyl polyoxyethylene ether and 390 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.8 parts by weight of hydrogen peroxide;

[0085] (3) adding solution 1: 2.4 parts by weight of mercaptoethanol, 0.9 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0086] Comparative Example 5

[0087] A low-sensitivity concrete water reducer and a preparation method thereof are prepared from the following raw material components in parts by weight: 400 parts by weight of isopentenyl polyoxyethylene ether, 710 parts by weight of water, 2.4 parts by weight of mercaptoethanol, 48 parts by weight of acrylic acid, 2.8 parts by weight of hydrogen peroxide, 0.9 parts by weight of vitamin C, 7 parts by weight of 4A zeolite, and 19 parts by weight of flake caustic soda.

[0088] The specific preparation method comprises the following steps:

[0089] (1) 7 parts by weight of 4A zeolite, 48 parts by weight of acrylic acid, and 160 parts by weight of water were added to a reactor, and a high-power industrial-grade continuous flow energy-concentrating ultrasonic disperser was turned on and ultrasonicated continuously for 2 hours to obtain a 4A zeolite-acrylic acid dispersion;

[0090] (2) adding 400 parts by weight of isopentyl polyoxyethylene ether and 390 parts by weight of water into a reaction kettle, stirring and mixing at 35° C. to dissolve, and adding 2.8 parts by weight of hydrogen peroxide;

[0091] (3) adding solution 1: 2.4 parts by weight of mercaptoethanol, 0.9 parts by weight of vitamin C, and 160 parts by weight of water; and solution 2: the 4A zeolite-acrylic acid dispersion obtained in (1) to the material obtained in step (2) in sequence; after the addition for 3 hours, the mixture was kept at below 55° C. for 1 hour for aging reaction, and then neutralized with alkali to pH = 6.2, thereby obtaining the low-sensitivity concrete water reducer.

[0092] It should be noted that the specific parameters or some commonly used reagents in the above embodiments are specific embodiments or preferred embodiments under the concept of the present invention, and are not intended to limit the present invention; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

[0093] A comparative experiment was conducted on the concrete water reducers synthesized in Examples 1 to 7 and Comparative Examples 3 to 5, as well as commercially available polycarboxylate water reducers of the XTX-B and PC-SM models. Qingpeng P·O42.5R cement, a mud content of 2.3%, machine-made mountain sand with a fineness modulus of 3.2, and continuously graded crushed stone with a mud content of 0.6% and a nominal particle size of 5-10 mm and 10-20 mm were used as materials. The admixture was 0.3% by mass of the cement (converted to solid content). The concrete loss over 2 h was tested according to the test method provided in GB8076-2008 "Concrete Admixtures".

[0094] The concrete mix ratio for the test is shown in Table 1:

[0095] Table 1 Concrete components

[0096] raw material cement Machine-made sand Small stones Big rocks Tap water Single dosage / kg 320 780 300 815 165

[0097] The 3h loss of each water reducer measured by the test is shown in Table 2:

[0098] Table 2 Test results of examples and comparative examples

[0099]

[0100] From the test data in the table above we can see that:

[0101] Under the same dosage conditions, the examples of the present invention are compared with comparative examples 1 and 2. After the water-reducing agent prepared by the present invention is added, the influence of mud adsorption becomes smaller, and the initial water reduction and slump retention performance of concrete are similar to those of the benchmark group, with lower sensitivity. However, the comparative examples are all greatly affected by mud adsorption, with obvious reduction in initial water reduction and slump retention performance, which is not conducive to construction.

[0102] Compared with Example 5, the use of conventional zeolite to replace 4A zeolite in Comparative Example 3 results in a poor loss over time. Conventional zeolite lacks the molecular sieve effect of 4A zeolite, and the water-reducing agent polymer and conventional zeolite cannot work synergistically to delay the hydration reaction and improve the dispersion performance, so the loss over time is relatively large.

[0103] Compared with Example 5 and Comparative Example 4, reducing the weight of 4A zeolite beyond 3.0 to 5.5 parts by weight will result in a difference in loss over time. The amount of 4A zeolite is small, the synergistic effect is weak, and thus the loss is relatively large.

[0104] Compared with Example 5, when the weight of 4A zeolite is increased beyond 3.0 to 5.5 parts by weight, the loss over time will be poor. The excessive amount of 4A zeolite has a strong adsorption effect on the high molecular weight water reducer, which cannot be effectively dispersed, resulting in a large loss.

[0105] From the comparison between the above examples and comparative examples, it can be seen that the present invention reduces the sensitivity of concrete water reducer by adopting 4A zeolite in a specific ratio under a specific system, is suitable for use in southwest my country, and has important significance.

[0106] Finally, 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-sensitivity concrete water reducer, characterized by: The raw materials are calculated by weight as follows: 300-440 parts of polyether monomer, 650-750 parts of water, 1-6 parts of chain transfer agent, 28-60 parts of olefin monomer, 3-5.5 parts of 4A zeolite, 1.8-5.6 parts of initiator, 0.4-1.2 parts of reducing agent and 12-19 parts of caustic soda; the polyether monomer is at least one of methyl allyl polyoxyethylene ether, isopentenyl polyoxyethylene ether or vinyl polyoxyethylene ether; The average molecular weight of the methyl allyl polyoxyethylene ether is 1964-3592, and its structural formula is: CH2=CH(CH3)CH2O(CH2CH2O)nH, wherein n=43-80; The average molecular weight of the isopentenyl polyoxyethylene ether is 1980-3608, and its structural formula is: (CH3)2C=CHCH2O(CH2CH2O)nH, wherein n=43-80; The average molecular weight of the vinyl polyoxyethylene ether is 1893 to 3653; Water reducer pH = 5.8 ~ 6.8; The vinyl monomer is at least one of acrylic acid, crotonic acid, citraconic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts, or anhydrides thereof.

2. The low-sensitivity concrete water reducer according to claim 1, characterized in that: The chain transfer agent is one or more combinations of isopropyl alcohol, mercaptoethanol, mercaptoglycerol, thioglycolic acid, mercaptopropionic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, 2-mercaptoethanesulfonic acid and salts thereof.

3. The low-sensitivity concrete water reducer according to claim 1, characterized in that: The initiator is one or more combinations of hydrogen peroxide, potassium persulfate or sodium persulfate, ammonium persulfate, and azobisisobutyronitrile.

4. The low-sensitivity concrete water reducer according to claim 1, characterized in that: The reducing agent is one or more combinations of vitamin C, oxalic acid, ferrous sulfate, cuprous sulfate, oxalic acid, sodium bisulfite, and sodium sulfite.

5. A method for preparing a low-sensitivity concrete water reducer according to any one of claims 1 to 4, characterized in that: The following steps are involved: 3-5.5 parts by weight of 4A zeolite, 28-60 parts by weight of olefin monomer, and 140-170 parts by weight of water are added to a reaction kettle. A high-power industrial-grade continuous flow concentrated ultrasonic disperser is turned on and ultrasonication is continued for 2-3 hours to obtain a 4A zeolite-olefin monomer dispersion. 300-440 parts by weight of a polyether monomer and 300-400 parts by weight of water are added to a reaction kettle, stirred and dissolved at 15-45° C., and 1.8-5.6 parts by weight of an initiator are added to obtain a mixture A; Solution 1 and solution 2 were added dropwise to the mixture A obtained above: Wherein, solution 1 comprises 1 to 6 parts by weight of chain transfer agent, 0.4 to 1.2 parts by weight of reducing agent, and 160 to 180 parts by weight of water; Solution 2: obtained 4A zeolite-olefin monomer dispersion; After 1 to 3.5 hours of dropwise addition, the mixture is kept at a temperature below 55° C. for 1 to 2 hours for aging reaction, and then neutralized with an alkaline solution to a pH of 5.8 to 6.8 to obtain the low-sensitivity concrete water reducer.

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